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HEADQUARTERS, DEPARTMENT 0 THE ARMY AUGUST 1961
*FM 6-2
FIELD MANUAL'] HEADQUARTERS, L DEPARTMENT OF THE ARMY No. 6-2 J WASHINGTON 25, D.C., 7 August 1961
ARTILLERY SURVEY
Paragraphs Page
PART ONE. GENERAL
CHAPTER 1. INTRODUCTION 1-7 4
2. ARTILLERY SURVEY PURPOSE AND RESPONSIBILITIES 8-14 5
PART TWO. SURVEYING EQUIPMENT AND PROCEDURES
CHAPTER 3. SURVEY EQUIPMENT Section I. General 15-18 8 II. Discussion of survey accessories 19-26 9
CHAPTER 4. TAPES AND TAPING Section I. General 27—29 10 II. Taping procedures and techniques 30-44 10 III. Accuracy and errors 45—49 17
CHAPTER 5. AIMING CIRCLE M2 Section I. General 50—52 18 II. Use of aiming circle 53-64 23 III. Care and maintenance 65-67 28
CHAPTER 6. TRANSIT Section I. General 68—72 30 II. Use of transit 73—87 34
CHAPTER 7. THEODOLITE, WILD T16 Section I. General 88—95 45 II. Use of theodolite 96-98 48 III. Care and maintenance 99-107 51
CHAPTER 8. THEODOLITE, WILD T2, MIL-GRADUATED Section I. General 108-114 54 II. Use of theodolite 115-121 56 III. Care and maintenance 122-131 61 IV. Sexagesimal theodolite Wild T2 132—137 65
CHAPTER 9. TELLUROMETER MRA 1/CW/MV Section I. General 138,139 67 II. Principles of operation 140-144 70 III. Tellurometer operations and computations 145-161 72 IV. Tellurometer maintenance 162-165 84
CHAPTER 10. TARGET SET, SURVEYING Section I. General 166-170 89 II. Use and care of the target 171-174 89
This manual supersedes TM 6-200, 13 June 1958.
1 Paragraphs Page CHAPTER 11. ARTILLERY GYRO AZIMUTH SURVEYING INSTRUMENT Section I. General 175,176 91 II. Use, care, and maintenance of artillery gyro azimuth surveying instrument 177-181 92
CHAPTER 12. ALTIMETER Section I. General 182-186 95 II. Use of the altimeter 187-193 98 III. Procedures and computations 194-196 104
CHAPTER 13. FIELD NOTES 197-206 110
PART THREE. SURVEY METHODS AND COMPUTATIONS
CHAPTER 14. TRAVERSE Section I. Procedures 207-216 127 II. Computations 217-228 131 III. Traverse adjustment 229-233 142 IV. Location of traverse errors 234-236 145
CHAPTER 15. TRIANGULATION Section I. General 237-239 147 II. Single triangle and single chain 240-249 148 III. Quadrilaterals 250-256 153 IV. Central point figures 257, 258 159 V. Resection 259-263 162 VI. Intersection 264-267 165 ' VII. Trilatération 268-270 165
PART FOUR. ARTILLERY SURVEY OPERATIONS AND PLANNING
CHAPTER 16. FIELD ARTILLERY BATTALION AND BATTERY SURVEY OPERATIONS Section I. General 271-282 167 II. Position area survey 283-287 170 III. Connection survey 288, 289 173 IV. Target area survey 290-294 173
CHAPTER 17. DIVISION ARTILLERY SURVEY 295-299 177 18. CORPS ARTILLERY SURVEY 300-315 179
19. OTHER ARTILLERY UNIT SURVEYS Section I. Field artillery group surveys 316, 317 188 II. Field artillery missile command surveys 318, 319 188 III. Air defense artillery surveys 320-326 189 CHAPTER 20. SURVEY PLANNING Section I. General 327-338 192 II. Steps in survey planning 339-343 194 III. The survey plan 344-347 195 IV. Standing operating procedure 348,349 195
PART FIVE DETERMINATION OF AZIMUTH BY ASTRONOMIC OBSERVATIONS
CHAPTER 21. BASIC ASTRONOMY Section I. General 350-361 197 II. Astronomic triangle 362-366 204 III. Star identification 367-371 207
2 Paragraphs Page CHAPTER 22. THE ALTITUDE METHOD Section I. General 372-375 212 II. Determining field data 376-389 213 III. Computations 390-392 217
CHAPTER 23. HOUR-ANGLE METHOD Section I. General 393,394 223 II. Determining field data 395-403 223 III. Computations 404—407 224
CHAPTER 24. AZIMUTH BY SIMULTANEOUS OBSERVATIONS 408-411 230
25. COMPARISON OF METHODS 412-418 234
PART SIX. CONVERTING SURVEY CONTROL, CONVERSION OF COORDINATES, AND TRANSFORMATION
CHAPTER 26. CONVERTING SURVEY CONTROL 419-424 238 27. CONVERSION OF COORDINATES 425-430 243
28. TRANSFORMATION 431-437 248
APPENDIX I. REFERENCES 253 II. SURVEY TECHNIQUES 256 III. DUTIES OF SURVEY PERSONNEL 259
INDEX 261
3 PART ONE GENERAL
CHAPTER 1 INTRODUCTION
1. Purpose 4. Definitions a. This manual is a guide for commanders, Technical terms not included in AR 320-5 survey officers, and personnel engaged in the are defined the first time they are used in this conduct of artillery surveys. It provides a manual. basis for instruction, guidance, and reference 5. Fundamental Operations of Survey in surveying principles and procedures, and in Survey results are obtained from the follow- the care and operation of surveying instru- ing: ments. Procedures covering all situations can- a. Planning. A thorough plan which gives not be prescribed; therefore, the instructions full consideration to the factors affecting survey contained herein should be used as a guide in and conforms to basic essentials contributes developing the application of suitable tech- to a successful accomplishment of the survey. niques. The material presented herein is ap- b. Fieldwork. Survey fieldwork consists of— plicable without modification to both nuclear (1) Measuring distances. and nonnuclear warfare. (2) Measuring horizontal and/or vertical b. Users of this manual are encouraged to angles. submit recommended changes or comments to (3) Recording all pertinent data. improve the manual. Comments should be c. Computations. The computations are per- keyed to the specific page, paragraph, and line formed simultaneously with the fieldwork. The of the text in which the change is recom- known data and the fieldwork data are com- mended. Reasons should be provided for each bined to produce the location and/or height of comment to insure understanding and complete a point and/or the direction of a certain line. evaluation. Comments should be forwarded 6. Accuracy direct to the Commandant, U.S. Army Artillery Three minimum orders of accuracy are pre- and Missile School, Fort Sill, Oklahoma. scribed for artillery surveys: artillery fourth- 2. Scope order survey, 1:3,000; artillery fifth-order survey, 1:1,000; and artillery 1:500; e.g., an This manual expounds the survey personnel accuracy of 1:3,000 means that for each 3,000 and equipment available to artillery units, the units of distance surveyed, the error cannot measurement of angles and distances, and the exceed 1 unit. The order or accuracy required determination of relative locations on a rec- depends on the intended use of the survey data. tangular grid system. 7. Survey Specifications and Techniques 3. References Specifications and techniques required to Publications used as references for the achieve each artillery order of survey accuracy manual and those offering further technical set forth in paragraph 6 are listed in appendix information are listed in appendix I. II.
4 CHAPTER 2
ARTILLERY SURVEY PURPOSE AND RESPONSIBILITIES
8. Purpose of Artillery Survey 10. General Responsibilities of Artillery Artillery survey operations provide a com- Units mon grid which will permit the massing of Each artillery commander is responsible for fires, delivery of surprise observed fires, de- seeing that required survey control is furnished livery of effective unobserved fires, and trans- to subordinate units as soon as possible. mission of target data from one unit to another. 11. Battalion (Separate Battery) Survey The establishment of a common grid is a com- Responsibilities mand responsibility. The battalion (separate battery) survey offi- 9. Responsibilities of the Corps of cer plans, coordinates, and supervises battalion Engineers (battery) survey operations. Battalion (sepa- rate battery) survey personnel perform the a. The survey responsibilities of the Corps survey operations necessary to establish— of Engineers are described in AR 117-5 and a. The grid coordinates and the height of— TM 5-231. In regard to artillery survey, engi- (1) The battery center for each light, neer responsibilities include— medium, and heavy artillery battery. (1) The supply of maps. (2) The position of each weapon for very (2) The supply of trig lists and other sur- heavy artillery. vey control data. (3) The battery center for mortar battery (3) Extension of ground control as de- or mortar platoon in applicable or- scribed in b and c below. ganization. (4) The position of each launcher and, b. When existing survey control is not avail- when required, guidance radar and able, the normal procedure is for the survey orienting station for artillery missile company of the engineer base topographic battalions (separate battery). battalion to extend control to the rear boundary b. An orienting line for each weapon posi- of army areas; the survey platoon of the engi- tion and missile guidance element when re- neer topographic battalion (army) to extend quired and to compute the orienting angle for control to the rear boundaries of subordinate each weapon position. corps; and the survey platoon of the engineer c. The grid coordinates, the height, and a topographic company to extend control as di- line of known direction for radar positions rected by the corps commander. when so directed. c. The survey element organic to the engi- d. The grid coordinates, the height, and a line of known direction for each target area neer combat battalion, missile command base observation post (OP) (always required (medium), has the responsibility of providing for direct support artillery; as directed for survey control point throughout the width of other artillery). the missile command area for use by the survey e. The grid coordinates and the height of platoons of the target acquisition battalion, critical points in the target area ; i.e., registra- missile command (medium). tion points, restitution points (always required
5 for direct support artillery; as directed for a. The grid coordinates, the height, and a other artillery). line of known direction for each— /. The grid coordinates, the height, and a (1) Division artillery survey control line of known direction for additional points as point. directed by the battalion commander. (2) Corps artillery battalion (separate battery) survey control point. 12. Division Artillery Survey Responsibility (3) Flash ranging observation post of the The division artillery survey officer coordi- target acquisition battalion. nates and supervises the survey operations of (4) Counterbattery radar set of the target subordinate echelons. He establishes the divi- acquisition battalion. sion artillery survey information center (ex- (5) Survey control point required for the cept for airborne division artillery). The divi- searchlight battery (platoon) in areas sion artillery survey party performs the survey for which maps are not available. operations necessary to establish— (6) Additional points designated by the a. The grid coordinates, the height, and a corps artillery commander; e.g., Air line of known direction for each— Force radio and radar installations (1) Survey control point (SCP) for each located in the corps area, including organic or attached field artillery target director posts. battalion and separate battery. (7) Meteorological orienting station in (2) Division artillery observation post areas for which large-scale maps are (when required). not available. (3) Attached searchlight platoon survey (8) Drone platoon in areas for which control point in areas for which maps maps are not available. are not available. b. The ground location of each sound rang- (4) Meteorological orienting station in ing microphone of the target acquisition batta- areas for which large-scale maps are lion. not available. c. Declination stations as needed. (5) Additional point designated by the d. A line of known direction for meteorol- division artillery commander; e.g., a ogical orienting stations in areas for which survey control point for a tank unit large-scale maps are available (position can assigned an indirect fire mission. be inspected to required accuracy). b. The grid coordinates and heights of points in the target area as directed by the division 14. Air Defense Artillery Survey artillery commander. The survey operations performed by an air c. Declination stations as needed. defense artillery (ADA) unit are determined d. A line of known direction for meteorol- by the mission assigned to the unit. ogical orienting stations in areas for which a. The purpose of the survey operations of large-scale maps are available (position can air defense artillery units assigned a ground be inspected to required accuracy). support field artillery (FA) mission is to pro- vide survey control that will permit the mass- 13. Field Artillery Target Acquisition ing of fire, delivery of surprise observed fires, Battalion Survey Responsibility and delivery of effective unobserved fires. The The field artillery target acquisition battalion survey operations performed are the same as coordinates the survey operations of lower those performed by a field artillery missile bat- echelons. To facilitate this coordination, the talion. battalion establishes a corps survey informa- b. The purpose of the survey operations of tion center (SIC), where records are main- air defense artillery units assigned an air de- tained of all fourth order and higher survey fense mission is to provide survey control that control points existing in the corps area. The will permit the exchange of target information survey platoons within the battalion perform and that will insure the delivery of air defense the survey operations necessary to establish— fires outside the limits of restricted areas.
6 c. When suitable maps are available and the azimuth to an orienting point for there are no restricted areas, personnel and each weapon. ADA gun battalions and ADA automatic weap- (2) The slant range from each weapon to ons (AW) battalions with electronic fire con- its radar range-calibrating point. trol equipment must perform the survey op- f. When suitable maps are not available, per- erations necessary to establish the slant range sonnel of ADA AW battalions without elec- from the track radar to the radar range- tronic fire control equipment perform no survey calibrating point for each battery. operations except when there are restricted d. When suitable maps are not available and/ areas. When there are restricted areas, they or when there are restricted areas, personnel perform the survey operations necessary to of the ADA gun battalions perform the survey establish the grid coordinates, the height, and operations necessary to establish— the azimuth to an azimuth mark for each fire (1) The grid coordinates, the heights, and unit. the azimuth to an orienting point for g. The grid coordinates and the azimuth to the battalion surveillance radar and an orienting point for the track radars of ADA the track radar of each battery. missile batteries in an air defense role normal- (2) The slant range from each track ly will be determined by engineer survey op- radar to its radar range-calibrating erations. However, personnel of semimobile point. ADA missile batteries may be required to (3) When directed, the distance from determine these data by performing limited each track radar to the orienting survey operations. point. h. Personnel of ADA missile batteries as- e. When suitable maps are not available and/ signed a ground support FA mission perform or when there are restricted areas, personnel of survey operations to determine the grid co- ADA AW battalions (batteries) with electronic ordinates and height of track radars and an fire control equipment and personnel of 75-mm azimuth to an orienting point for each track light ADA battalions (batteries) perform the radar. For further discussion of survey opera- survey operations necessary to establish— tions for air defense artillery unit refer to (1) The grid coordinates, the height, and chapter 19.
7 PART TWO SURVEYING EQUIPMENT AND PROCEDURES
CHAPTER 3 SURVEY EQUIPMENT
Section I. GENERAL 15. General (4) Clamping handles (certain FA units Survey equipment consists of instruments only). and accessories necessary to perform a survey. (5) Hand levels (certain FA units only). Survey instruments include those items of b. Station marking equipment which in- equipment with which measurements are made. cludes— Survey accessories include those items of equip- (1) Ranging poles. ment which assist in making measurements and (2) Ranging pole tripod (certain FA units in recording, computing, and plotting survey only). data. (3) Levels for level rod (FA units only). 16. Survey Instruments (4) Target cloth. a. The instruments employed in artillery (5) Hatchets. surveying are— (6) Wooden and/or steel stakes. (1) Steel tape. c. Recording and computing equipment (2) Aiming circle. which includes— (3) Transit. (1) Notebooks. (2) Department of the Army forms. (4) Theodolite (FA units only). (3) Pencils. (5) Altimeter (FA units only). (4) Logarithmic and mathematical tables (6) Target set, surveying. (TM 6-230 and/or Vega tables). (7) Tellurometer. (5) Army Ephemeris (TM 6-300-61). (8) Surveying Instrument Azimuth Gyro d. Numerous items of miscellaneous equip- Artillery. ment which include— b. The survey instruments in a above are dis- (1) Star identifiers (certain FA units cussed in chapters 4 through 12. only). (2) Computing machines (certain FA 17. Survey Accessories units only). The accessories employed in artillery survey- (3) Military slide rules (FA units only). ing are— a. Taping equipment which includes— 18. Surveying Equipments Sets (1) Plumb bobs. a. Field artillery units are issued angle- (2) Steel arrows (taping pins). measuring instruments as separate items. Field (3) Tension handles (certain FA units artillery units authorized altimeters and/or only). computing machines are issued those items
8 separately. All other items of survey equip- (2) Artillery survey set, third order. ment, with the exception of forms and tech- b. Artillery survey set, fourth order was de- nical manuals, are issued to field artillery units signed for use by units performing survey in two surveying equipment sets. These sets with the aiming circle; artillery survey set, are— third order was designed for use by units using (1) Artillery survey set, fourth order. the theodolite or transit.
Section li. DISCUSSION OF SURVEY ACCESSORIES
19. General ous readings. It must therefore be tested oc- a. Logarithmic tables are discussed in TM casionally with a weight of known value. 6-230. 23. Clamping Handle b. The military slide rule is discussed in TM The clamping handle is used to hold and 6-240. apply tension to the tape when a partial tape c. Survey computation forms are explained length is being measured. in conjunction with the method of survey in which they are employed within this manual. 24. Hand Level d. Other accessories which are used fre- The hand level is used to measure approxi- quently are discussed in paragraphs 20 through mate differences in elevation. It is used in 26. artillery survey to train taping personnel to recognize when the tape is held horizontal. This 20. Plumb Bob instrument consists of a metal sighting tube The plumb bob is used in artillery surveying with plain glass covers at the ends and a level as a taping accessory and as an angle measur- vial mounted on the tube. It is usually hand ing instrument accessory. Most plumb bobs held in front of the eye. The landscape, level used consist of a body and removable cap made bubble, and index line can be seen in the tube. of brass and a replaceable point made of steel. The plumb bob used with the M2 aiming circle 25. Ranging Pole is of one-piece steel construction. The ranging pole is constructed of tubular steel. It consists of two interlocking sections, 21. Taping Pins one of which is pointed. The length of the as- Steel arrows, called taping pins, have a ring sembled pole is 6 feet, 6 inches. The pole is on one end and a sharp point on the other. painted in six 1-foot sections which are alter- These pins are issued in sets of 11. They are nately red and white. For storage, the pole is used to mark, temporarily, the positions of the disassembled and placed in a canvas case. ends of the tape on the ground as tape lengths are measured. 26. Ranging Pole Tripod The ranging pole tripod is used for holding 22. Tension Handle a ranging pole over a survey station. In use, The tension handle is used in training survey the tripod is set up so that the head of the personnel to apply the correct amount of ten- tripod is approximately 3 inches horizontally sion to a steel tape. This handle is a spring from the survey point. The' ranging pole is balance, graduated in pounds from 0 to 30. then placed in the collar of the adjustable arm. With prolonged use the spring of the tension The pole is then made vertical by using the handle will gradually stretch, causing errone- level for the level rod.
9 CHAPTER 4
TAPES AND TAPING
Section I. GENERAL
27. Tapes and Accessories should never be pulled around an object that will put a sharp turn in the tape. Do not jerk a. Field artillery survey personnel are equipped with 30-meter steel tapes for making the tape, step on it, or allow vehicles to run linear measurements (taping). These tapes over it. If there is a loop in the tape, it may are graduated on one side only, in meters, deci- be kinked or broken when tension is applied. meters (0.1 meter), and centimeters (0.01 Before applying tension, the tapemen should meter) throughout, with the first decimeter see that the tape is not looped. graduated in millimeters (0.001 meter). There c. After use, the tape should be wiped clean is a blank space at each end of the tape. A reel and dry and then oiled lightly. The tape is oiled by running it through an oily rag as it is being and two leather thongs are furnished with each tape. reeled in. The tape should be loosely wound on its reel when not in use. In winding the b. In addition to a tape, each taping team tape on the reel, insert the end of the tape with should be equipped with 2 plumb bobs, 1 plumb the 30 meter graduations into the reel and wind bob and arrow holder, 1 clamping handle, 1 set the tape in such a manner as to cause the num- of 11 arrows (taping pins), 1 hand level, 1 bers to be wound facing the axle of the reel. tension handle, 2 leather thongs, 2 notebooks, and 2 pencils (fig. 1). 29. Repair of Broken Tape a. A sheet metal sleeve coated on the inside 28. Care of Steel Tapes with solder and flux is fitted over the broken a. Steel tapes are accurate surveying instru- ends of the tape and hammered down tightly. ments and must be handled with care. Al- By applying heat, even from an ordinary though steel tapes are of durable construction, match, the tape is securely fastened together. they can be easily damaged through improper b. The repaired section of the tape must be care and use. checked with another section of the tape to in- b. In use, the tape should be completely re- sure that the ends of the tape were placed to- moved from its reel and kept straight to pre- gether and that a true measurement can still vent its being kinked or broken. The tape be made.
Section II. TAPING PROCEDURES AND TECHNIQUES
30. Horizontal Taping, Generalmeasured is the forward station. The distance a. The method of taping used in artillery between stations is usually several times great- surveys is known as horizontal taping. In this er than a full tape length. The taping team, method, all measurements are made with the starting at the rear station, determines the tape held horizontally. The point from which distance by measuring successive full tape the distance is to be measured is the rear sta- lengths until the distance remaining is a par- tion. The point to which the distance is to be tial tape length. This length is then measured.
10 &
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Figure 1. Taping equipment.
The distance between stations is determined possession. The pin given to the rear tapeman by adding the product of the number of tape represents the first full tape length. The front lengths and the length of the tape to the partial tapeman moves toward the forward station tape length. Each measurement is made with with the zero end of the tape. the tape held horizontally between the rear and h. As the end of the tape reaches the rear forward stations. station, the front tapeman stops, either on the count of paces or on the command TAPE given h. A taping team consists of two men—a by the rear tapeman. The rear tapeman sights front tapeman and a rear tapeman. The rear along the tape toward the forward station and tapeman commands the taping team. The rear signals the direction that the front tapeman tapeman determines and reports the distance should move to aline the tape, first with the measurement; the front tapeman independent- forward station and then with an estimated ly checks the distance measurement. Additional horizontal plane. The tape must be alined with- personnel are required for taping at night. in .5 meter of the line-of-sight from one sta- tion to the succeeding station and within .5 31. Measuring First Full Tape Length meter of the horizontal plane. To measure the first full tape length— c. Each tapeman places the leather thong on a. The front tapeman gives one taping pin his wrist and the plumb bob cord on the proper to the rear tapeman, keeping 10 pins in his graduation on the end of the tape. The rear
11 tapeman commands PULL and each tapeman the front tapeman sighting back on the rear exerts a pull of 25 pounds on the tape. station, or by the rear tapeman through the use d. After the tapemen have properly alined of intermediate points established in alinement and applied tension to the tape, the rear tape- with the forward station.) man places his plumb bob exactly over the rear b. The rear tapeman should place his plumb station and commands STICK. At this com- bob exactly over the point at which the taping mand, the front tapeman drops his plumb bob pin enters the ground. and then marks the point of impact with a tap- c. The rear tapeman pulls the taping pin ing pin. When the pin has been placed in the from the ground before moving forward to the ground, the front tapeman reports STUCK, next pin position. If a taping pin is lost during which instructs the rear tapeman to move for- the measurement of the distance, the tapemen ward to measure the next tape length. must make the entire measurement again, e. When a team is taping on sloping ground rather than complete the measurement from a void of brush and tall grass, the plumb bob recovered pin hole. need not be used at the uphill end of the tape. The end of the tape may be held immediately 33. Breaking Tape adjacent to the taping pin. To measure tape lengths when the tape can- 32. Measuring Succeeding Full Tape not be alined with a horizontal plane within Lengths one-half meter (IVk ft.) because of the slope of the ground, the tapemen use a special pro- To measure succeeding full tape lengths, the tapemen use the procedure discussed in para- cedure known as breaking tape (fig. 2). In graph 31, except as follows: breaking tape— a. The front tapeman should a.obtain The fronthis ap- tapeman pulls the tape forward proximate horizontal alinement by sighting a full tape length, drops it approximately on along the tape at the rear station, moving right line, and then comes back along the tape until or left until the tape is approximately on line. he reaches a point at which a partial tape (Final alinement is made as directed by the length, when held level, is not held above the rear tapeman. However, if the rear tapeman armpits of the downslope tapeman. At this cannot see the forward station, final alinement point, the front tapeman selects any convenient is made by either the instrument operator or full meter graduation. The tapemen then meas-
30 METERS
,30-METER GRADUATION
25-METER GRADUATION ►5 METERS AT
is A ^ ,^5-METER GRADUATION 10 METERS O-METER GRADUATION 15 METERS
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Figure 2. Breaking tape.
12 ure the partial tape length, applying the full the tape until the plumb bob is exactly over 25 pounds tension to the tape. the pin. b. After he has placed the taping pin, the c. When the zero graduation is exactly over front tapeman waits until the rear tapeman the forward station, the front tapeman com- has come forward. The front tapeman tells mands READ. The rear tapeman reads the the rear tapeman which full meter graduation graduation marked by the plumb bob cord and was used, e.g., “Holding 25,” which is repeated announces the measurement of the partial tape by the rear tapeman. He receives a pin from length to the nearest 0.01 meter. the rear tapeman and moves forward, repeat- d. The front tapeman repeats the reading ing this procedure until the zero mark is aloud, and both tapemen record the meas- reached. urement. c. When holding a point on the tape other than the zero graduation, the front tapeman 36. Determining Taped Distance must receive a pin from the rear tapeman be- To determine and check the distance meas- fore moving forwa/rd. urement (fig. 3) — a. Each tapeman counts the number of pins 34. Measuring Distances in Excess of in his possession. (The pin in the ground at 10 Tape Lengths the last full tape length is not counted.) To measure a distance longer than 10 full b. The rear tapeman determines the dis- tape lengths, the tapemen use the procedures tance measurement by multiplying the length discussed in paragraphs 31 through 33 except of the tape (30 meters) by the number of full as follows: tape lengths measured and adding the partial a. When the front tapeman has set his last length read from the tape. (The number of pin in the ground, he has established a point full tape lengths measured is equal to the num- which is 10 full tape lengths from the rear sta- ber of taping pins in his possession plus 10 for tion. The front tapeman waits at the last pin each exchange of pins.) position until the rear tapeman comes forward. c. The front tapeman independently checks b. Both tapemen count the pins to verify the distance measurement by multiplying the that none have been lost. (One pin is in the number of full tape lengths by the length of ground; 10 pins should be in the possession of the tape and adding the partial tape length. the rear tapeman.) (The number of full tape lengths is equal to c. The rear tapeman gives the front tapeman 10 for each exchange of pins plus the differ- the 10 pins. ence between 10 and the number of pins in his d. Both tapemen record 10 tape lengths, and possession.) then continue taping. d. The rear tapeman reports the distance measurement to the recorder or the chief of 35. Measuring Partial Tape Lengths party. To measure the partial tape length between the forward station and the taping pin repre- 37. Taping at an Occupied Station senting the last full tape length, the tapemen When a taping team is making a measure- use the following procedure : ment at a station occupied by an instrument, a. The front tapeman moves to the forward the tapeman at the station must be careful not station and places the plumb bob cord on the to disturb the instrument. If a plumb bob is zero graduation of the tape. The rear tapeman used with the instrument, the tapeman can moves forward along the tape to the taping pin. make his measurement at the plumb bob cord b. If slack is needed, the front tapeman com- of the instrument. mands SLACK and the rear tapeman allows the tape to move forward. When the front 38. Use of Two Taping Teams tapeman is ready, he commands PULL and the When two taping teams are used to measure rear tapeman exerts a pull of 25 pounds on the distance between two stations, one taping the tape, using the clamping handle to hold the team uses a pin to establish a starting station tape. As he applies tension to the tape, the a half tape length (15 meters) from the rear rear tapeman slides his plumb bob cord along station. In this case, the front tapeman does
13 13.74 METERS BREAKING - TAPE TS1 SCP *éhm
PIN I PIN 2 ^ * PIN 3 4 PIN 4 PIN'S PIN 6 REAR TAPEMAN FRONT TAPEMAN 6 X 30 = 180.00 10-4 =6 + ■ 13.74 6X 30.00= 180.00 193. 74 + 13.74 193.74
Figure 3. Determining taped distance. not give a pin to the rear tapeman. The taping tapeman keeps his eyes on the line to the for- pin marking the half tape length represents one ward station and should not look back. He full tape length plus 15 meters. After the start- should determine the number of paces to the ing station is established a half tape length tape length so that he can stop without being from the rear station, the taping procedures signaled when he has moved forward a tape followed are the same as those discussed in length. paragraphs 31 through 37, except that each b. By moving forward at a point 2 or 3 tapeman adds 15 meters to the distance meas- meters in front of the rear end of the tape, the urement. (This procedure precludes both teams rear tapeman can usually locate the taping pin placing their taping pins in the same hole.) by the time the front tapeman has stopped. c. When there is an instrument used at 39. Taping at Night either the forward or the rear station, the tape- Daytime taping methods may be used at men will remain clear of the line of sight. night with certain modifications. A piece of white cloth should be tied to each end of the 41. Tape Alinement tape to assist the tapemen in following and The tapemen must carefully aline the tape. locating the tape. Three men should be added The maximum allowable error in both horizon- to each taping team. One man accompanies tal and vertical alinement is one-half meter for each tapeman as a light holder; the third man a full 30-meter tape length. The tapemen aline marks the taping pin. When the rear tapeman the tape with the stations which establish the comes to the taping pin, the third man walks line by sighting along the tape toward the sta- the length of the tape, freeing it from any ob- tions at each end of the line (fig. 4). The tape- structions. This procedure is repeated for each men then make the tape horizontal by holding full or partial tape length. Light holders must it parallel to an estimated horizontal plane. If take necessary security measures with their difficulty is encountered in keeping the tape lights. level in rough terrain, then the hand level should be used. To use the hand level to estab- 40. Moving Forward lish a horizontal plane, the downslope tape- a. The front tapeman should selectman— a land- mark (rock, bush, etc.) in line with the for- a. Sights through the level at the upslope ward station. In moving forward, the front tapeman.
14 FORWARD STATION
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=4 Ttïuç ALt »£toc/vr
Figure 4. Tape alinement.
b. Raises or lowers the objective end of the tape by using the leg muscles and the large hand level until- the image of the level bubble muscles of the back. To do this, the tapeman is centered on the center horizontal crossline. faces across the tape with his shoulders parallel c. Determines the point on the upslope tape- to the length of the tape, passes the hand of man which is level with his eye. (The hori- one arm through a loop in the thong, and places zontal plane is established.) the elbow of that arm tight against some part d. Instructs the upslope tapeman how to hold of his body (fig. 5). When the tapeman is his end of the tape so that the tape will be standing, he applies tension by bending the parallel to the established horizontal plane. knee away from the other tapeman, causing the (The downslope tapeman must not hold the weight of the body to push against the arm tape higher than his armpits. Both tape ends holding the tape. When the tapeman is kneel- should be held the same distance below the ing, he applies tension by pushing the knee established horizontal plane.) which is away from the other tapeman against Note. The tapemen should check the accuracy of the bubble of the hand level when it is first used each day. the arm holding the tape. This is accomplished by having the upslope tapeman b. The clamping handle is used to hold the use the hand level to sight back at the downslope tape- tape at any point other than a tape end. In man to verify the established horizontal plane. order to avoid kinking the tape, the tapeman 42. Applying Tension to Tape should hold the clamping handle with the index The tapemen must apply 25 pounds tension and middle fingers. Normally, the handle will (pull) to each full or partial tape length. clamp as tension is applied to the tape. If ad- a. The tapemen should apply tension to the ditional pressure is required, it is applied to the
15 REAR TAPEMAN FRONT TAPEMAN
«
k. . :
Figure 5. Applying tension to a tape.
outside of the finger grips by using the thumb establish the point on the ground to which each and ring finger. length is measured by dropping his plumb bob. c. The tension handle (a scale which meas- After establishing the point with the plumb ures tension in pounds) should be used by the bob, the front tapeman marks that point with front tapeman until both tapemen become ac- a taping pin. (The rear tapeman can locate customed to the “feel” of 25 pounds tension. each pin more readily if the front tapeman has cleared the ground of grass, leaves, etc., by 43. Use of Plumb Bobs kicking a groove in the ground.) The tapemen use plumb bobs to project points on the tape to the ground. Each tape- 44. Use of Taping Pins man holds the plumb bob cord on the proper The tapeman must use the taping pins to tape graduation with the thumb of one hand on mark points on the ground for each full or par- the cord and the forefinger of that hand be- tial tape length. The front tapeman marks the neath the tape (fig. 5). After alining the tape point struck by the plumb bob by sticking the and applying tension to it, each tapeman lowers pin into the ground at exactly the point where the plumb bob by letting the cord slip across the tip of the plumb bob hit. The shaft of the the tape until the tip of the plumb bob is ap- pin should be placed at about a 45° angle with proximately one-fourth inch above the desired the ground and perpendicular to the length of point. Swinging of the plumb bob is eliminated the tape. (When moving forward, the tapemen by gently-lowering the tape until the plumb should not pull the tape through the loop of bob tip touches the ground and then slowly the taping pin.) When taping over a hard sur- raising it. face, it may be necessary to mark the point struck by the plumb bob in an identifiable a. The rear tapeman uses the plumb bob to fashion (point of arrow or pencil) and the establish his end of the tape directly over the point of the arrow should be laid at the point point from which each tape length is measured. struck by the plumb bob, perpendicular to the b. The front tapeman uses the plumb bob to line of direction of the tape.
16 Section III. ACCURACY AND ERRORS
45. Comparative Accuracy for (3) Kinks in the tape. Double-Taped Distances b. Systematic errors can be eliminated or a. When the distance between two stations minimized by strict adherence to proper pro- has been determined by double-taping, the two cedures and techniques. Tapemen should be measurements are compared and the compara- especially attentive to keeping the tape hori- tive accuracy for the two measurements is de- zontal when taping on a slope and should break termined. Comparative accuracy is expressed tape when necessary. They should avoid the as a ratio between the difference in the meas- tendency to hold the tape parallel to the slope. urements and the mean of the measurements. When taping in strong winds, tapemen must be The ratio is expressed with a numerator of especially careful to apply the proper tension one; e.g., 1/1,000 or 1:1000. The denominator to the tape. Tapes should be checked fre- is determined by dividing the mean of the quently for kinks. One of the chief causes for measurements by the difference in the measure- kinked tapes is improper use of the clamping ments. After computing the comparative ac- handle. curacy, the denominator of the fraction is al- c. Systematic errors can be due to improper ways reduced to the next lower hundred. repair of the tape (repaired too long or too b. An example of the computation of a com- short), causing taped distances to be longer or parative accuracy for a distance measurement shorter than their true distances. is as follows : Distance measurement by 48. Accidental Errors taping team no. 1 = 357.84 meters Accidental errors are errors which may ap- Distance measurement by ply in either direction. Accidental errors are taping team no. 2 = 357.76 meters usually small in magnitude when compared with systematic errors. The principal accident- Difference between al error encountered in taping is caused by measurements - 0.08 meters small errors in plumbing. When taping, tape- Mean of the measurements = 357.80 meters men should be careful in plumbing over points. Comparative accuracy = When taping in strong winds, tapemen must be 1 _ 1 _ 1 especially careful to minimize swinging of the 357.80-r-0.08 4472 4400 plumb bob cord. This can be accomplished by c. Certain comparative accuracies for dou- keeping the plumb bob close to the ground. ble-taped distances are prescribed in subse- quent chapters of this manual. 49. Errors Caused by Blunders Blunders are mistakes made by personnel. 46. Errors in Horizontal Taping They result in errors which are usually large Horizontal taping errors are of three cate- in magnitude. gories as follows : a. Systematic errors. a. The principal blunders made by tapemen b. Accidental errors. are— c. Errors caused by blunders. (1) An incorrect exchange in taping pins. (2) An error in reading the tape. 47. Systematic Errors (3) An omission of the half tape length Systematic errors are errors which apply in when double-taping with two teams. the same direction. a. The systematic errors encountered(4) Loss of ain taping hori- pin. zontal taping cause distances to be measured b. Blunders can be detected and eliminated longer or shorter than their true lengths. The by strict adherence to proper procedures and principal causes of systematic errors are— by adoption of a system of checks; e.g., by (1) Failure to aline the tape properly. double-taping, by pacing each taped distance, (2) Failure to apply sufficient tension to and, in some cases, by plotting the grid co- the tape. ordinates of the stations on a large-scale map.
17 CHAPTER 5
AIMING CIRCLE M2
Section I. GENERAL
50. General objective end of the telescope is The aiming circle M2 (fig. 6) is employed to beveled to form a permanent sunshade. obtain angular values in artillery surveys exe- (2) The vertical level vial is positioned cuted to an accuracy of 1:500 (target area on the left side of the telescope. This base only). It is essentially a fixed-focus low- level is used to establish a horizontal power telescope mounted on a composite body plane when reading deviations in (fig. 7) containing a magnetic compass and elevations using the reticle. The lugs leveling screws for establishing a horizontal supporting the telescope level vial plane. The instrument proper is supported by form an open sight with which to a base plate for mounting on a tripod. Angular aline the instrument approximately measurements in azimuth and elevation are in- on a station. dicated on graduated scales and associated (3) The reflector is a plastic signal micrometers. mounted on top of the telescope and 51. Aiming Circle Body at the vertical axis of the instrument. The reflector is used as a target for The aiming circle body is made up of four other instruments sighting on the composite parts—the telescope body assembly, aiming circle. At night, the reflector the body assembly, the worm housing, and the can be illuminated externally by use base plate assembly (fig. 7). of the instrument light. a. The telescope body assembly consists of (4) A neutral filter is provided for view- the optical system, the vertical level vial, the reflector, and a neutral filter. ^ ing the sun directly for astronomic observation. The filter is slipped onto (1) The optical system forms a 4-power, the eyepiece end of the telescope for fixed-focus telescope. The reticle of observing the sun and is attached to the telescope (fig. 8) has a horizontal the side of the telescope body when and a vertical crossline etched on it. not in use. The horizontal and vertical crosslines are graduated every 5 mils from 0 b. The body assembly consists of the azimuth to 85 mils and are numbered every and elevation worm mechanisms, the magnetic 10 mils. These graduations are used compass, the compass reticle, the compass to measure relatively small deviations needle actuating lever, and two horizontal plate in azimuth and elevation from a refer- levels. ence line (e.g., high-burst registra- (1) The azimuth mechanism of the in- tion). The telescope eyepiece (fig. 9) strument has a fast and a slow motion. is inclined upward at an angle of 45° Horizontal angles are read in two from the axis of the telescope to per- parts; the hundreds of mils are read mit the observer to look down into from the azimuth scale, and the tens the telescope while standing erect. The and units of mils are read from the
18 AIMING CIRCLE
TRIPOD
INSTRUMENT LIGHT LAMP HOLDER AND REMOVER COVER FOR AIMING CIRCLE
CANVAS\ COVER]
BACK j PLATE
PLUMB BOB }“1
RA PD 222958
Figure 6. Aiming circle with equipment. azimuth micrometer. The azimuth lotver scale is not used in survey. The scale is graduated every 100 mils from azimuth micrometer scale is located on 0 to 6,400 mils and is numbered every the azimuth knob. It is graduated 200 mils. The 3,200 and 6,400 portion every 1 mil from 0 to 100 mils and is of the azimuth scale has a second scale numbered every 10 mils. (numbered in red from 0 to 3,200) (2) The elevation mechanism of the aim- below the primary azimuth scale. The ing circle is similar to the slow azi- graduations of the primary (upper) muth motion. Stop rings in the azimuth scale are used for survey. The mechanism prevent the telescope from second (lower) scale is used for laying striking the body assembly. Vertical the weapons of the firing battery. This angles from minus 440 mils to plus
19 FOUR MAJOR PARTS OF THE AIMING CIRCLE BODY ELEVATION KNOB RETICLE BODY ASSEMBLY EYE LENS FIELD LENS 0BJECT1 PRISM LENS / DAMPER 'y MAGNETIC! RETICLE NEEDLE aoDiMr*î ASSEMBLY AZIMUTH SCALE
WO*M9L* HOUSiMO^ —LEVELING SCREW SPRING PLATE PLATE ASSEMBLY BASE PLATE
7-
Figure 7. Schematic cutaway drawing of an aiming circle showing composite parts.
805 mils can be measured with the micrometer scale is graduated every aiming circle. Vertical angles are read mil from 0 to 100 mils. The scales are in two parts; the hundreds of mils numbered every 10 mils from left to are read from the elevation scale and right in black numerals and from the tens and units of mils are read right to left in red numerals. The red from the elevation micrometer scale. numerals on the elevation micrometer The elevation scale is graduated and scale are used in conjunction with the numbered every 100 mils from minus red numerals on the elevation scale. 400 mils to plus 800 mils. The plus The black numerals on the micrometer symbol and minus symbol are not scale are used with the black numer- shown, but the minus numerals are als on the elevation scale. shown in red and the plus numerals (3) The magnetic compass is located in are shown in black. The elevation the oblong recess in the top of the
20 small glass magnifier and a reticle with three etched lines on it are at
BO one end of the recess (south end of the magnetic needle) to aid in alining 70 —
60 — the end of the needle. On the opposite
50 — end of the recess is an actuating lever
40 — which locks or unlocks the magnetic 30 — needle. When the lever is in a vertical
20 — position, the needle is locked. When 10 20 30 40 50 60 70 80 10 — I I I the lever is turned to the right or the l| I I I I I I I I I I l| I I I left, the needle is unlocked. — 10 80 70 60 50 4 0 30 20 10 (4) The aiming circle has two plate levels. — 20 30 One is a circular level vial for initial 40 rough leveling, the other is a tubular 50 level vial used to accurately level the 60 instrument. 70 c. The worm housing is that portion of the 80 aiming circle below the azimuth scale and above the base plate. It consists of the worm gear of the orienting (nonrecording) motion, the leveling screws, and the spring plate. The Figure 8. Telescope reticle as viewed in telescope. orienting knob which controls the nonrecording (lower) motion of the aiming circle is similar body assembly. The magnetic needle to the azimuth (recording) motion in that the is provided with copper dampers to orienting motion is permitted fast movement aid in settling the needle quickly. A by lateral movement of the left orienting knob.
ELEVATION KNOB ELEVATION MICROMETER REFLECTOR
EYELENS
SLOT FOR INSTRUMENT LIGWT NEUTRAL FILTER (STORED POSITION) TUBULAR LEVEL m ELEVATION SCALE CIRCULAR LEVEL
OBJECTIVE NEUTRAL FILTER (STORED POSITION)
LOCKING LEVER FOR TUBULAR LEVEL COMPASS NEEDLE ' ORIENTING KNOB COVER MAGNIFIER
AZIMUTH MICROMETER
ORIENTING KNOB AZIMUTH KNOB AZIMUTH SCALE
SPRING PLATE
BASE PLATE
NOTATION RAD
Figure 9. Aiming circle.
21 The two orienting knobs should be used simul- provided to keep the socket clean and clear from taneously for slow movement of the orienting obstruction when the instrument is not attached motion. Caps are provided for the orienting to the tripod. The base plate is fitted with a knobs when they are not in use to preclude use rubber washer, which makes a watertight seal of the orienting motion by mistake. The leveling when the cover is latched to it. screws are attached to a spring plate which is attached to the base plate. 52. Aiming Circle Accessory Equipment d. The base plate assembly is the base of the The accessory equipment (fig. 10) for the instrument when it is mounted on the tripod, aiming circle consists of the tripod, backplate and it is also the base of the carrying case. It with canvas cover, instrument light, plumb bob, is a flat plate to which the instrument is fixed. lamp holder and remover, and carrying case On the underneath side is a socket into which cover. the tripod screw is threaded to attach the in- a. The tripod (fig. 6) has three telescoping strument to the tripod. A latch type cover is legs, an aluminum head and cover, and a carry-
INSTRUMENT LIGHT
LAMP HOLDER AND REMOVER
PLUMB BOB
HAND LIGHT
RETICLE LIGHT BACK PLATE
CANVAS COVER
Figure 10. Accessory kit.
22 ing strap. The legs are adjusted and held in light assembly for general illumination around place by means of leg clamp thumbscrews. The the instrument (leveling and reading the leg hinges at the tripod head are adjusted for scales) and to illuminate the reflector. The de- friction by clamping screws. The ends of the gree of light is regulated by a rheostat located legs of the tripod are fitted with an aluminum on the battery tube. The battery tube is held boot and a bronze spike for ease in embedding to the back by means of a clamp. the legs in the ground. The carrying strap is d. When in use, the plumb bob is suspended provided for carrying the tripod when the legs from a hook in the tripod screw. When the are retracted and strapped together. plumb bob is not in use, it is stored in a loop b. The backplate and cover (fig. 10) are held in the canvas cover of the accessary kit. to one of the tripod legs by two clamps. The e. The lamp holder and remover is a small backplate cover is the case for the instrument rubber tubular accessory, which is used for light, the plumb bob, and the lamp holder and storing spare lamps and for removing burned remover. out bulbs from their sockets. c. The instrument light consists of a battery /. The cover of the carrying case is a light- tube containing two flashlight batteries and weight dome-shaped piece which is clamped to two flexible cords. One of these cords carries the base plate to provide a waterproof case for the current to the telescope through a lamp the instrument. The cover is provided with a bracket assembly that fits into a slot on the carrying strap and two strong clamps for secur- telescope. The other cord is attached to a hand ing the cover to the base plate.
Section II. USE OF AIMING CIRCLE
53. Setting up the Aiming Circle instrument and tripod should be picked up as a The procedure for setting up the aiming cir- unit and moved until the plumb bob hangs with- cle is as follows: in half an inch of the point. a. Unstrap the legs of the tripod. Loosen d. Level the instrument by using the proce- the leg clamp thumbscrews and extend the tri- dure specified in paragraph 54. pod legs to the desired length. Tighten the 54. Leveling the Aiming Circle thumbscrews slightly (enough to hold the legs The procedure for leveling the aiming circle in place). Embed each leg firmly in the ground, is as follows: making sure that the tripod head is approxi- mately level and approximately over the point a. Obtain a rough level by using the circular at which the angles are to be measured. Then vial attached to the magnetic needle housing. firmly tighten the leg clamp thumbscrews, and Place the tubular level vial parallel to two level- remove the tripod head cover. ing screws. Center the bubble by using these two leveling screws. Grasp the leveling screws b. Open the base plate latch cover and thread between the thumb and forefinger of each hand. the tripod screw into the aiming circle until Turn the screws so that the thumbs of both it is firmly seated. Unsnap the aiming circle hands move either toward each other or away cover latches, remove the cover, and hang it from each other at the same time. This move- on one of the tripod legs. ment tightens one screw as it loosens the other. c. Attach the plumb bob and extend it so that The bubble always moves in the same direction it hangs about an inch above the point over as the left thumb. which the instrument is to be set. If the plumb b. Rotate the instrument 1,600 mils and cen- bob is within half an inch (laterally) of the ter the bubble by turning the third leveling point, it can be brought to the point by loosen- screw. ing the tripod screw and shifting the instru- ment on the tripod. If the plumb bob is more c. Return the instrument to the first position than half an inch from the point, the tripod and relevel the bubble if necessary. legs may be adjusted to bring the plumb bob d. Return the instrument to the second posi- to the point. If this is not possible, then the tion and relevel the bubble if necessary.
23 e. Repeat c and d above until the bubble is procedure for measuring horizontal angles is as centered in both positions. follows : f. Rotate the instrument 3,200 mils from the a. Set up and level the aiming circle. first position; if the bubble is not centered, b. Zero the azimuth and micrometer scales. bring the bubble halfway to the center by turn- c. Sight approximately on the rear station by ing the same two leveling screws used to level using the fast lower (nonrecording) motion. the instrument in the first position (a above). d. Place the crossline exactly on the rear sta- g. Rotate the instrument 3,200 mils from the tion by using the slow lower (nonrecording) second position. If the bubble is not centered, motion. The last motion coming onto the sta- bring the bubble halfway to the center by turn- tion should be from left to right to reduce ing the third leveling screw. backlash. Close the orienting knob covers. h. Rotate the instrument through 6,400 mils. e. Disengage the azimuth (recording) con- If the bubble does not move more than one trol knob and rotate the aiming circle to bring graduation, the instrument is considered level. the crosslines near the forward station but If the bubble does move more than one gradu- keeping them to the left of the station. ation, the leveling procedure should be re- /. Release the azimuth control knob, allowing ? peated. If, after repeated attempts, the instru- the mechanism to reengage. Using the slow ment cannot be rotated throughout 6,400 mils motion of the azimuth control knob, bring the without causing the bubble to move more than crosslines exactly to the point from left to one graduation from the position obtained after right. completion of a through g above, the instru- g. Read and record the value of the angle on ment should be turned in for repair. the azimuth and micrometer scales to the near- est 0.5 mil. 55. Taking Down the Aiming Circle h. With this value still on the scales, repeat The procedure for taking down the aiming c through / above. circle is as follows : i. Read and record the accumulated value of a. Tighten leveling screws to their stops. the two measurements of the angle to the near- b. Lock the magnetic needle. est 0.5 mil. c. Place the azimuth knob over the notation j. Divide the accumulated value by 2. If the strip. second value of the angle is smaller than the first, add 6,400 to the second value before divid- d. Unhook the plum bob and replace it in the ing by 2. The mean value should agree with backplate cover. the first reading by 0.5 mil; if not, the angle e. Close the backplate cover. must be remeasured. /. Place the carrying case cover over the aiming circle and latch the cover locks. 57. Measuring Vertical Angles g. Unscrew the tripod screw and remove the Vertical angles are measured in conjunction instrument from the tripod. with horizontal angles. Usually, a vertical angle is measured each time a horizontal angle h. Replace the tripod head cover. is measured. Vertical angles, if possible, are i. Collapse the tripod legs and tighten the measured to height of instrument (HI) at each thumbscrews. forward station. The height of instrument is j. Strap the tripod legs together. measured on a ranging pole. If the instrument ✓ operator constantly sets up the instrument at a 56. Measuring Horizontal Angles certain height, a constant height of instrument In artillery survey, horizontal angles are may be used throughout a traverse. The pro- measured at the occupied station in a clockwise cedure for measuring vertical angles is as fol- direction from the rear station. Horizontal lows: angles are always read to the lowest visible a. Set up and level the aiming circle. point at the forward and rear stations. In b. After the first repetition of the horizontal sighting on a station, the vertical crossline is angle is measured, place the horizontal placed so that it bisects the ranging pole. The crossline at the height of instrument on the
24 forward station by using the elevation control also be called the grid azimuth of magnetic knob while keeping the vertical crossline on the north (fig. 11). station. 59. When to Declínate the Aiming Circle c. Read and record the value of the vertical angle to the nearest 0.5 mil. If the black nu- To determine the declination constant for merals are used, the vertical angle is plus; if each instrument and to keep it current, certain the red numerals are used, the vertical angle is rules prescribe how often and under what cir- minus. cumstances the aiming circle should be decli- nated. These rules are as follows : d. After the second repetition of the hori- zontal angle is measured, measure the vertical a. As a general rule, the aiming circle must angle a second time. be redeclinated when it is moved 25 miles or more from the area in which it was last decli- e. Determine the mean vertical angle by add- nated. Any appreciable move (a few miles) of ing the first and second reading of the vertical the aiming circle may change the relationship angle and dividing by 2. The mean vertical of grid north and magnetic north as measured angle should agree with the first reading by 0.5 by the instrument. In some locations, a move mil. of less than 25 miles may cause the aiming cir- 58. Declination Constant cle to have to be redeclinated. The three types of north referred to in artil- b. The aiming circle must be redeclinated lery survey are: true north, magnetic north, after an electrical storm or after receiving a and grid north. For purposes of this manual severe shock, such as a drop from the bed of the term “true north” is considered to be syn- a truck to the ground. The magnetic needle is onymous with astronomic and geodetic north. a delicately balanced mechanism, and any shock All points for artillery survey purposes are may cause a significant change in the declina- located with respect to grid north. To deter- tion constant for the instrument. mine grid north from a magnetic reading in- c. The aiming circle should be redeclinated strument, determine the angular difference every 30 days because of the annual variation between grid north and magnetic north. The resulting from the gradual movement of the clockwise angle from grid north to magnetic magnetic field. The annual variation may cause north is called the declination constant. It may only a slight change (0.3 mil per year at Fort
GRID NORTH GRID NORTH A
MAGNETIC MAGNETIC NORTH NORTH
DECLINATION DECLINATION CONSTANT / CONSTANT
Figure 11. Schematic diagram illustrating the angular value which represents the declination constant.
25 Sill, Okla.), or it may be vastly significant (for b. Set the known grid direction to the azi- other parts of the earth). muth mark on the scales of the instrument and, d. The aiming circle shouldwith be the declinated lower motion (nonrecording), sight on when it is initially received and redeclinated the azimuth mark. when it is returned from ordnance repair. c. Release the magnetic needle. With the Variations in the declination constant due to upper motion (recording), center the needle the time of day are not significant enough to through the magnetic needle magnifier. warrant a redeclination at any specific time. d. Read the declination constant directly from the scales (to 0.5 mil). 60. Where to Declínate the Aiminge. Relevel Circle the aiming circle; repeat b through A declination station should be established d above. Determine a second declination con- at a place convenient to the using units. It stant by using a second known azimuth mark if may be established by a field artillery battalion, one is available; if not available, use the same division artillery, or target acquisition bat- azimuth mark. talion. The declination station should be a sta- /. Compare the two declination constants tion at which azimuths to two or more azimuth determined. If they vary more than 2 mils, re- marks are known (at least two azimuth marks peat the entire procedure. If they agree within are desired but one will suffice). For best re- 2 mils, determine the mean and record it to the sults azimuth marks should be at least 1,000 nearest 1 mil on the notation strip of the aiming meters from the declination station (if neces- circle. sary the azimuth marks may be as close as 300 meters). 62. Procedure for Decimating the Aiming a. Declination stations are established by Circle When a Declination Station is using a transit or theodolite. The direction to not Available the azimuth marks is determined by applying In rapidly moving situations, time may not an angle measured from a known direction, by permit establishment of a declination station. computing the azimuth (providing the coordi- Under such circumstances, declination is per- nates of the declination station and the azimuth formed as follows: mark(s) are known), or by astronomic obser- a. Select a point on the ground that is iden- vations. tifiable on the map. Place the instrument over b. Declination, stations should be established this point and prepare it for declination by in an area free from magnetic attractions. The leveling it and performing the checks in para- following minimum distances from common graph 66. objects with magnetic attraction are pre- b. Select two distant points which can be scribed : identified on the map and scale the direction Power lines 150 meters to each point from the map. Electronic equipment 150 meters c. Use the direction scaled from the map and Railroad tracks 75 meters declínate the instrument by following the Heavy and medium artillery, tanks 60 meters Light artillery, trucks 40 meters procedure in paragraph 61. Barbed wire or helmets 10 meters d. Compare the declination constants deter- c. Any survey control pointmined may be to used each as of a the two distant points. They declination station providing an azimuth is must agree within 10 mils. known to some distant point. e. If the declination constants agree within ✓ 10 mils, mean the readings and record the decli- 61. Procedure for Decimatingnation the constant.Aiming If they do not agree, repeat Circle at a Declination Station the entire procedure. When a declination station is available, the f. Verify the declination constant determined procedures in decimating the aiming circle are by this method as soon as possible. as follows: a. Set up the aiming circle63. in theDetermining prescribed Vertical Angle Correction manner. Level the instrument and perform the The purpose of a vertical angle correction checks outlined in paragraph 66. (VAC) is to insure that the vertical angle de-
26 termined with the instrument is correct. A + 1.5 mils = difference at azimuth mark 1 vertical angle correction is determined at the + 1.8 mils = difference at azimuth mark 2 same time that the declination constant is de- + 1.6 mils = mean difference or vertical angle correction termined. There are two methods which may b. To determine the vertical angle correction be used to determine the vertical angle correc- by the alternate method, two stations are estab- tion, the comparison method and the alternate lished approximately 100 meters apart. The method. stations should be marked with a hub or some a. To determine the vertical angle correction other convenient marker. It is not necessary to by the comparison method, the vertical angles know the coordinates and height of the sta- from the declination station to the azimuth tions or the distance between them. The aim- marks must be known. These vertical angles ing circle is set up at one of the stations. The may be measured with a transit or theodolite height of instrument is marked on a ranging or they may be computed from height and dis- pole with a pencil. The height of instrument tance. If computed vertical angles are used, the is measured from the height of the station measured vertical angles should be observed to marker (e.g., hub) to the center of the objec- s tive lens of the telescope. The ranging pole is height of instrument at the unoccupied stations. placed vertically over the second station. The The vertical angle correction is determined by vertical angle to the mark on the ranging pole the comparison method as follows: is then measured with the aiming circle. (One (1) After determining the declination con- edge of a card may be held coincident with the stant, verify the level of the instru- pencil mark to assist in sighting. As an arbi- ment. Measure the vertical angle to trary rule, such a card is usually placed so that each azimuth mark to which the ver- the top edge is coincident with the mark.) The tical angle is known. Read and record aiming circle is then moved to the second point the value to the nearest 0.5 mil. and set up. The height of instrument at the (2) Verify the level of the instrument and second station is marked on the ranging pole. measure the vertical angle to each azi- The pole is set up over the first station, and the muth mark a second time. Record the vertical angle from the second station to the value of the second angle. first station is measured. The vertical angles measured at the two stations are compared. If (3) Mean the vertical angles measured to they are numerically equal but of opposite sign each azimuth mark and compare the (e.g., +7.0 and —7.0), the level line checks': if mean of each with the corresponding not, a vertical angle correction must be deter- known vertical angle. Determine the mined. The correction is numerically equal to differences (±). The differences deter- one-half of the algebraic sum of the two angles. mined should be within 1 mil of each The algebraic sign of correction is opposite b other. A mean difference should be the sign of the algebraic sum of the tivo angles, determined. This mean difference to For example, if one angle were +22 mills and\ the tenth of a mil should be written the other were —24 mils, the vertical anglel on the notation strip with the declina- correction would be +1.0 mil. The vertical \ tion constant (i.e., VAC 4.0 mils). angle correction must be applied to all vertical \ angle measurements. \ Example: 64. Measuring Grid Azimuth With the + 23.0 mils = known vertical angle to azimuth mark 1 Aiming Circle + 21,5 mils = mean measured vertical angle to azimuth mark 1 A decimated aiming circle can be used to measure grid azimuths. The procedures in + 1.5 mils == difference measuring a grid azimuth are as follows : — 9.0 .nils = known vertical angle to azimuth mark 2 a. Set up the aiming circle (pars. 53 and — 10.8 mils = mean measured vertical angle to azimuth 54). mark 2 b. Using the upper motion, set the declina- + 1.8 mils = difference tion constant on the scales of the instrument.
27 c. Release the magnetic needle and center the g. Repeat the procedure and determine the needle by using the lower motion. grid azimuth a second time. The two azimuth d. Lock the needle. determinations should agree within 2 mils. If e. Using the upper motion, turn the instru- they do not agree, repeat the entire procedure. ment and sight at the desired point. If the two determinations are within toler- /. Read and record the measured grid azi- ances, mean the two azimuths. muth as indicated on the scales of the aiming h. Record the measured grid azimuth to the circle to the nearest 0.5 mil. nearest 0.1 mil.
Section III. CARE AND MAINTENANCE
65. Care of the Aiming Circle instrument should be checked periodically by an Proper care of an instrument will prolong ordnance maintenance unit. its life and insure better results to the user. i. The instrument should be kept clean and Listed in a through i below are several pre- dry. Metal parts should be cleaned of grease cautions which should be observed while using and oil with mineral spirits paint thinner and the aiming circle. then wiped dry. The polished surfaces should a. To protect the screw threads, do not be given a thin coat of light grade aircraft tighten the adjusting, clamping, or leveling instrument lubricating oil to prevent rust. screws beyond a snug contact. Electrical parts should be cleaned with carbon tetrachloride. Rubber parts, other than elec- b. The lenses should be cleaned only with trical parts, should be cleaned with warm lens tissue or a camel’s-hair brush. Care should soapy water. After the rubber parts are dry, be taken not to scratch the lenses or remove a coating of powdered technical talcum should the bluish coating. The bluish coating reduces be used to preserve the rubber. Canvas should the glare for the observer. be cleaned with a dry brush or by scrubbing c. The tripod legs should not be embedded with brush and water. Saddle soap may be in the ground with leg clamp thumbscrew used to remove oil or grease from canvas firm/y tightened. The thumbscrews should be straps. left'slightly loosened until the legs are em- bedded. 66. Maintenance Checks and Adjustments 1. The tripod head should be wiped clean of If the maintenance checks described in a dijt and moisture and should be examined for through e below (with the exception of check- nicks or burs before the instrument is attached ing the azimuth and elevation scales and associ- t* the tripod. ated micrometer for simultaneous zero read- / e. The magnetic needle should be locked ing) show that an adjustment is necessary, the jvhen not in use. aiming circle should be turned in to the sup- / /. The azimuth knob should be positioned porting ordnance maintenance unit for repair. j over the notation strip before the instrument Checks should be performed each time prior to / is put in its case. using the instrument. The maintenance checks g. Care should be taken to avoid forcing are as follows : movement of the worm gears either in disen- a. Level Vial Check. After the aiming circle gaging or engaging them. In disengaging, be has been leveled, rotate the instrument through sure that the gear is free before rotating the 6,400 mils. If the bubbles (circular and tubular instrument. To reengage the worm gear, move levels) do not remain centered, the instrument the instrument back and forth slightly until should be turned in for repair. the two gears mesh. b. Magnetic Needle Check. Set up and level h. The aiming circle should not be lubricated the aiming circle. Center the south end of the by unit personnel. All parts requiring lubrica- magnetic needle. To test the needle for slug- tion are enclosed and should be lubricated only gishness, move an iron or steel object back and by ordnance instrument repair personnel. The forth in front of the aiming circle. Permit the
23 needle to settle. If the needle does not return (2) The elevation micrometer is checked to center in the reticle, the instrument should and adjusted as follows: be turned in for repair. (a) Set the zero of the elevation scale c. Tilted Reticle Check. After the aiming opposite the index mark. circle has been set up and leveled, place the (b) If the zero of the elevation microm- crosslines on some well-defined point. Elevate eter is opposite the index, no ad- and depress the telescope. If the vertical cross- justment is necessary. If it is not line moves off the point, the instrument should opposite the index, loosen the be turned in for repair. screws on the end of the elevation d. Level Line Check. The purpose of the level knob and slip the elevation microm- line check is to determine if the vertical angles eter scale until the zero is opposite are measured correctly with the instrument. the index. If the vertical angles are not measured cor- (c) Hold both the elevation knob and rectly and there is not adequate time to turn micrometer scale and tighten the the instrument in for repair, a vertical angle knob screws. correction should be determined. The perform- (d) Check to insure that neither the ance of this check and the procedure for deter- knob nor the scale moved while mining a vertical angle correction are discussed tightening the screws. in detail in paragraph 63. f. The telescope level vial is checked as fol- e. Micrometer Adjustment Checks. The only lows: adjustments that may be made by using unit personnel are the adjustments of the microm- ( 1 ) Level the instrument. eters so that they read zero when the main (2) Set the elevation scale and the eleva- scales with which they are associated read zero. tion knob on zero. The micrometer checks and adjustments should (3) Check the position of the telescope be made prior to determining the declination level bubble. It should be centered. constant and the vertical angle correction. (4) If the bubble is not centered, the in- (1) The azimuth micrometerstrument shouldis checked be turned in for re- and adjusted as follows: pair. (a) Setg. theThe zero telescope of the level azimuth vial isscale not used when opposite the index mark. measuring a vertical angle. Therefore, it is not (h) If the zero of the azimuth microm- necessary to turn in the instrument for repair eter is opposite the index, no ad- solely for the adjustment of the telescope level justment is necessary. If it is not vial. opposite the index, loosen the screws on the end of the azimuth knob and 67. Moving the Aiming Circle slip the micrometer scale until the When moving the instrument from station to zero is opposite the index. station, a man on foot may carry the instru- (c) Hold both the azimuth knob and the ment, mounted on its tripod, over his shoulder. micrometer scale and tighten the When he passes through trees or underbrush, knob screws. the instrument should be cradled in both arms {d) Check to insure that neither the with the instrument head forward. When the knob nor the scale moved while instrument is carried in a vehicle, it should be tightening the screws. placed in its case and protected from shock.
29 CHAPTER 6
TRANSIT
Section I. GENERAL ✓
68. General crosshairs. The center horizontal crosshair and a. The transit is an instrument which may the vertical crosshair are used in making point- be used to obtain angular values for artillery ings. The upper and lower horizontal cross- fifth-order survey. This instrument, which is hairs are stadia hairs which are used for being replaced by the Wild T16 theodolite, can measuring distances by stadia (TM 5-232). be used to measure both horizontal and vertical (The stadia hairs are not used in field artillery angles. Two types of transits are issued to surveys.) The telescope is supported by trun- artillery units—the 1-minute transit and the nions resting on bearings in the standards 20-second transit. The main difference between which permit its rotation in a vertical plane. the two transits is the graduations on the hori- The telescope can be rotated through 360°. The zontal scales. The least readings on the hori- telescope can be clamped in the vertical plane zontal scales of a 1-minute transit and a 20- by means of the vertical motion clamping screw second transit are 1 minute and 20 seconds, (fig. 12). When the clamping screw is tight, respectively. Their vertical scales are identical; the telescope can be moved a small amount by the least reading on the vertical scales is 1 means of the vertical motion tangent screw. A minute. vertical circle is fixed on one end of the axle of the telescope and rotates with it. The ver- b. The transit is issued with a tripod and tical circle is graduated and is known as the accessories. The accessories include a hard- main vertical scale. Attached to one of the wood carrying case, waterproof cover, dust cap, standards is a vernier which is used in conjunc- sunshade, wrench, screwdriver, plumb bob, tion with the main vertical scale in reading magnifying glass, adjusting pins, and night- vertical angles. Fastened beneath the telescope illumination equipment. (The night-illumina- is a level vial, which is not used in artillery tion accessories may be mounted on the instru- surveys. ment (fig. 12).) The transit and all accessories fit into the carrying case. e. Attached to the upper plate are the A-shaped standards which support the tele- c. The principal components of the transit scope. Also attached to the upper plate are are the telescope, the standards, the upper verniers which are used in conjunction with (vernier) plate, the lower plate, the leveling the main horizontal scale to read horizontal head, and the footplate. The upper plate and all angles. Two glass windows are provided in the parts of the instrument which rotate with the upper plate. The A vernier is read through upper plate (including the standards and the one of the glass windows. The B vernier is telescope) are referred to as the alidade of the not read in artillery survey. Two mutually transit (fig. 13). perpendicular level vials, known as plate levels, d. The telescope, which may be either the are fastened to the upper plate. One of them external or the internal focusing type, magnifies is parallel to the trunnions of the telescope. an image about 18 to 25 diameters. The tele- These plate levels indicate whether or not the scope contains a crosshair ring which has four plates of the instrument are level. A compass
30 is also mounted on the upper plate. In artillery plate is a horizontal circle which is graduated surveys, the compass is used only to determine both clockwise and counterclockwise from 0° to rough azimuths. 360°. This is known as the main horizontal /. The upper and lower plates are each at- scale. The center of the circle coincides with tached to spindles. The spindle of the upper the axis of rotation of the spindles. plate fits into the hollow spindle of the lower h. The spindle of the lower plate fits into the plate. Thus, the axis of rotation of the upper hollow center of the leveling head. The spindle plate coincides with the axis of rotation of the of the upper plate passes through the spindle lower plate. of the lower plate and the hollow center. The p. Attached to the upper side of the lower bottom of the hollow center is the top half of
FOCUSING VERTICAL MOTION KNOB CLAMPING SCREW SUN SHADE VERTICAL CIRCLE VERTICAL THREE OF FOUR MOTION CROSS HAIR TANGENT RING RETAINING SCREW SCREWS
EYEPIECE NIGHT LIGHTING Sä SWITCH PLATE LEVELS BATTERY READING CASE GLASS m
VERNIER
VERNIEf UPPER PLATE LIGHT TANGENT SCREW SWITCH
LOWER PLATE CLAMPING SCREW UPPER PLATE CLAMPING SCREW
LOWER PLATE TANGENT SCREWS. LEVELING SCREWS
Figure 12. Transit.
31 a ball which pivots in a socket in a sliding the instrument and centering it over a point. plate. This plate, known as the shifting center, The footplate can be fastened to the head of is mounted below the footplate. The socket of the tripod by means of threads in the footplate the shifting center fits through a hole in the and on the head of the tripod. A hook is pro- footplate. The hole in the footplate is larger vided at the bottom center of the leveling head than the socket. This permits the alidade, the to which can be fastened the cord of a plumb lower plate, and the leveling head to pivot bob. The hook is fastened to the spindle of about the ball-and-socket joint and also to slide the upper plate. in any direction relative to the footplate. i. Four leveling screws are fastened to arms These movements provide means of leveling on the leveling head. These screws are used in
TELESCOPE ALIDADE
STANDARDS
UPPER PLATE
LOWER HORIZONTAL PLATE SCALE
HOLLOW CENTER
LEVELING HEAD LEVELING ASSEMBLY
FOOT PLATE TRIPOD
Figure IS. Transit, exploded view.
32 conjunction with the plate levels to level the and screw the footplate onto the tripod head. instrument. They have shoes which bear on Remove the plumb bob from the transit box the footplate. When any two adjacent screws and suspend it from the hook under the instru- are loose, the instrument can be shifted on the ment. footplate. When they are tight, the instrument is clamped to the footplate. Turning dia- 70. Centering Instrument Over Station metrically opposite screws in opposite direc- a. If the transit is not initially set up over tions tilts the alidade in one plane about the the station, then it can be picked up as a unit ball-and-socket joint. with the tripod, with the legs in their same j. The tripod head is mounted on three relative positions, and moved until the plumb wooden legs. Each leg is fastened to a lug on bob hangs within 2 or 3 inches of the station the underside of the tripod head with a bolt mark. Push two of the tripod legs firmly into ánd wingnut. The bottom of each leg is shod the ground so that the plumb bob, the point, with a pointed steel shoe. An aluminum or and the third leg are in line and the station composition cap is provided to protect the point is between the plumb bob and the third threads of the tripod head when the instru- leg. When the third leg is then pushed into the ment is not in use. ground, it will swing the plumb bob close to the station point. Raise or lower the plumb k. The spindle attached to the lower plate bob until it hangs about 1 inch over the station can be clamped to the leveling head by the mark. lower plate clamping screw. The spindle at- tached to the upper plate can be clamped to b. Loosen the wingnuts on the tripod legs the spindle attached to the lower plate by and alter the position of the legs until the means of the upper plate clamping screw. plates are approximately level and the plumb Thus, the two plates may rotate together about bob is over the station. Assure a firm setup the leveling head (lower or nonrecording mo- by pushing the legs will into the ground. When tion), or the upper plate may rotate within the the plumb bob is close enough to the station lower plate (upper or recording motion). Tan- that any further adjustment can be made by gent screws are provided, one for each spindle, using the shifting plate, the tripod legs are which provide a means for rotating either tightened in place. spindle a small amount when the correspond- c. Lower the plumb bob so that it can move ing clamping screw is tight. Rotation of a freely, just above the station mark. Loosen plate with its clamp loose is known as fast two adjacent leveling screws so that the instru- motion. Rotation of a plate by means of its ment head may be shifted on the footplate, tangent screw with the plate clamped is and then move the plumb bob over the station known as slow motion. Thus, there are fast mark. Tighten two adjacent screws to hold the and slow upper (recording) motions and fast transit in this position. and slow lower (nonrecording) motions. 71. Leveling Transit 69. Mounting Transit Beforeon the leveling Tripod the transit, remove the dust The tripod is set up as nearly as possible cap, attach the sunshadé, and loosen the lower directly over the station with the legs spread fast motion and the vertical motion clamping at an angle that will insure stability. The tri- screw. Turn the alidade so that one of the pod head should be placed approximately plate levels is parallel to two diagonally op- horizontal by adjusting the position of one or posite leveling screws (fig. 14). When one more of the legs. Remove the tripod head plate level is longer than the other, the long cover. Remove the transit from the case by plate level is used. Grasp the heads of the grasping the cross members of the standards, leveling screws, one between the thumb and being careful not to grasp the vertical circle. forefinger of each hand. Turn the screws so With one hand, place the transit on the tripod that the thumbs move either toward each other by holding the transit by the standard not con- or away from each other. This tightens one taining the vertical circle and, with the other screw and loosens the other. The bubble always hand, loosen the lower motion clamping screw moves in the same direction as the left thumb.
33 ing procedure until the buble moves less than one graduation when the alidade is rotated through 360°. If it is impossible to level the transit by the above-mentioned procedures, the -vX plate levels should be adjusted (par. 83). 72. Adjusting for Parallax Before a transit (or theodolite) is used for measuring angles, the telescope must be prop- erly focused (adjusted for parallax). The - / telescope is adjusted for parallax by bringing the focus of the eyepiece and the focus of the objective lens to the plane of the crosshairs (crosslines). Improper adjustment for paral- lax causes apparent motion of the target (point sighted on) when the eye is moved across the eyepiece. This parallax (apparent motion) introduces error in measured angles. Figure H. Leveling the transit. When parallax exists, an instrument operator After the bubble has been brought to the center is unable to make consistently accurate point- of its vial, rotate the upper plate so that the ings. Proper adjustment for parallax does not plate level is parallel to the other set of diagon- necessarily produce the clearest and sharpest ally opposite leveling screws and center the image of a distant object. The instrument is bubble. Return the plate level to the first posi- adjusted for parallax as follows : tion and recenter it if necessary. Return the a. Point the telescope toward a bright space plate level to the second position and recenter such as the sky. it if necessary. Repeat this procedure until the b. Focus the eyepiece by rotating it until the bubble is centered in both positions. Rotate crosshairs appear sharp and black. the alidade through 360°. If the bubble does not move more than one graduation through- c. Point the telescope on some distant object out the rotation, the transit is considered level. and focus the objective lens by rotating the If the bubble moves off center more than one focusing knob until the image of the object is graduation, place the plate level parallel to the clear and sharp. leveling screws first used but on the opposite d. Test the adjustment by moving the eye side of the leveling head from the position in slowly across the eyepiece. If the image of the which the bubble was first centered. Move the object sighted on appears to move with respect bubble toward the center one-half of the devia- to the crosshairs, parallax is present. The tion, using the leveling screws. Repeat this focus of each lens should be changed slightly procedure with the plate level parallel to the until the crosshairs are sharp and clear, the other pair of diagonally opposite screws. Again image is clear, and there is no apparent mo- rotate the plate 360°. The bubble should not tion. The focus of each lens may have to be move more than one graduation. If it moves readjusted throughout the day, if the ob- more than one graduation, continue the level- server’s eyes become tired.
Section II. USE OF TRANSIT
73. Scales scale is a complete circle graduated from 0° to a. The horizontal scales of a transit (figs. 15 360°, clockwise and counterclockwise. There and 16) consist of the main scale and two are two series of numbers which label the verniers (A and B). Normally, only the A graduations. The inner series increases from vernier is used in artillery surveys. The main 0° to 360° in a clockwise direction; the outer
34 series increases in a counterclockwise direc- (fig. 15). The least reading on the vernier is tion. The inner series (clockwise) is used in 20 seconds. To read an angle, first determine artillery surveys. The main scale is attached the value on the main scale opposite the index to the lower plate and rotates only with the in the center of the vernier. If the index falls lower motion of the transit. The verniers are between two main scale graduations, the grad- arcs, mounted edge-to-edge with, and inside of, uation having the smaller value (graduation to the main scale. They are attached to the upper the right of the index) must be read. In figure plate and rotate in a horizontal plane with the 15, the value on the main scale is 125° 45'. alidade. Next, determine the value on the vernier. The b. The vertical scales differ from the hori- value on the vernier is always read on that zontal scales in that the main scale is inside portion of the vernier to the left of the index. the vernier and rotates with the telescope, but To determine the value on the vernier, observe the vernier is fixed. Furthermore, the main along the scale in a clockwise direction from vertical scale is divided into quadrants of 90° the index until a graduation on the vernier is each (fig. 17). found that coincides with a graduation on the 74. Reading Horizontal Scales of the main scale. In figure 15, this value is 05' 20". 20-Second Transit ^ Finally, add the value read on the vernier to The least reading on the main horizontal the main scale reading. The value of the angle scale of the 20-second transit is 15 minutes read from the main scale and the vernier in
mm o&k
'o oo*>£>
•ßo \t>
MAIN SCALE 125 45 VERNIER 05 20 ANGLE 125 50 20
5S8 VÄP ¿'S®
Figure 15. Horizontal scale, 20-second transit.
35 figure 15 is 125° 45' plus 05' 20" or 125° reading is 09'. Thus, the reading on the vertical 50' 20". scales is 06° 30' plus 09' or 06° 39'. It is easy to determine the sign of a large vertical angle 75. Reading Vertical Scales of the by observing whether the telescope is pointing 20-Second Transit up or down. However, with vertical angles less The least reading on the main vertical scale than Io, it is difficult to determine which way of the 20-second transit is 30 minutes. The the telescope is pointing. The sign of the verti- least reading on the vernier is 1 minute. In cal angle can be determined by the position of measuring vertical angles, both sides of the the zeros on the vertical scale and vernier. If vernier are used. A simple rule of thumb al- the 0 on the vertical scale is between the ob- ways designates the proper side of the vernier jective end of the telescope and the 0 on the to use. Draw an imaginary line from the 0 on vernier (direct or reverse), the vertical angle the main scale toward the 0 on the vernier. is plus ( + ). If the 0 on the vertical scale is This line will point toward the side of the between the telescope eyepiece and the 0 on the vernier which should be used. For example, in vernier (direct or reverse), the vertical angle figure 18, the imaginary line from the main is minus (—). For example, in figure 18 the 0 scale 0 to the vernier 0 points toward the right on the vertical scale is between the telescope side of the vernier, and the right side of the eyepiece and the 0 on the vernier. Therefore, vernier must be used. In this example, the the vertical angle in figure 18 is minus and is main scale reading is 06° 30' and the vernier recorded as —06° 39'.
002 06/ ni* Off/
J «4
W5
¿50 3WO n Scj 342 MAIN SCALE 342 30 VERNIEER 05 ANGLE 342 35
ISO
Figure 16. Horizontal scales, 1-minute transit.
36 HÖR V£RT. S 100> < <50
1.900,MT
30
Figure 27. Vertical scales.
'O z\0 06 30
VP 20 Main Scale — 06°_3(y Vernier + 09' 09 Angle -06° 39'
Figure 18. Reading on vertical scales of the transit.
37 76. Reading Scales on the 1-Minute reversed (ID and R). One measurement of Transit the angle is made as described in a above; then the telescope is plunged (rotated 180° in a a. The least reading on the main horizontal vertical plane so that the focusing knob is be- scale of the 1-minute transit is 30 minutes low, rather than above, the telescope). The (fig. 16). The least reading on the vernier is 1 minute. The horizontal scales of a 1-minute telescope is again pointed exactly at the rear station, using the lower motions (the upper transit are read in a manner similar to that in which the horizontal scales of a 20-second motion is not disturbed). The telescope is then transit are read. In figure 16, the main scale pointed exactly at the forward station, using reading is 342° 30' and the vernier reading is the upper motions. The accumulated value of 05'. The value of the angle read from both the two measurements of the angle is then read on the horizontal scales and recorded. In scales is 342° 30' plus 05' or 342° 35'. artillery fifth-order surveys, the number of b. The vertical scales of the 1-minute transit separate measurements of an angle that are and the 20-second transit are identical and are taken is two (1 D and R). The same number read in the same manner. of measurements must be made with the tele- 77. Measuring Horizontal Angles scope reversed that are made with the telescope direct. The direct measurement^ are always a. With the transit set up over the station made first; the telescope is plunged, and then at which the angle is to be measured, adjust the reversed measurements are made (each for parallax and set the 0 of the A vernier measurement is accumulated on the scales). exactly opposite the 0 of the main horizontal The values of the first direct and the last re- scale, using the upper motions. Using the fast versed measurement are read and recorded. lower motion, point the telescope approxi- The mean angle is determined by dividing the mately at the rear station by sighting, first accumulated value of the measurements by the over the top of the telescope and then through number of measurements; for example, an it. Clamp the lower plate clamping screw. angle 1 D and R is meaned as follows : With the slow lower motion, place the cross Direct (D) 135° 16' 20" hairs exactly on the station. (The final direc- tion of movement of the cross hair should be Reverse (R) 270° 32' 20" made from right to left by rotating the tangent Mean angle 135° 16' 10" screw in a clockwise direction.) Unclamp the When an angle is measured 1 D and R and the upper plate clamping screw. Rotate the alidade direct reading exceeds 180°, then the angle is until the telescope is pointed approximately at meaned by adding 360° to the reverse reading the forward station by sighting, first over the and dividing the sum by 2. This mean angle top of the telescope and then through it. After is considered to be the measured value of the clamping the upper plate, use the slow upper angle. The value of the first direct measure- motion to place the cross hairs exactly on the ment of an angle should be compared with the forward station. (The final direction of move- value of the mean angle. The primary purpose ment of the crosshairs should be made from of this comparison is to detect errors, such as right to left by rotating the tangent screw in a making an improper number of repetitions clockwise direction.) Unclamp the lower mo- with the telescope in the direct or reversed tion. (The loiver motion should be unclamped positions. at all times except for measuring an angle.) c. When a transit is used to measure the Read the value of one measurement of the angle (s) at a station, the angle closing the angle from the horizontal scale. Record this horizon should be measured. The angle closing value. the horizon is measured from the forward sta- b. The complete measurement of any hori- tion of the last required angle to the rear sta- zontal angle consists of the mean of at least tion of the first required angle. If only one two separate measurements. When two sepa- required angle is measured, the angle closing rate measurements are made, one is made with the horizon is measured from the forward sta- the telescope direct and one with the telescope tion to the rear station of the required angle.
38 The angles about a station should be measured angles measured about a station, including the in a clockwise sequence. The angle closing the angle closing the horizon, should not vary from horizon is usually measured last. Figure 19 360° by more than a value computed as illustrates horizon closure. The sum of the follows : Number of angles measured Least reading of transit Including closure angle Number of measurements per angle For example, if three angles (including the more than the value computed as explained angle closing the horizon), are measured one above, the angles must be remeasured. • D and R, with a 1-minute transit, the sum of d. When the angles measured about a station the angles should not vary from 360° by more have been determined within the tolerance ex- than— plained in c above, their meaned values must 3 x 60 seconds = 90 seconds be adjusted so that their sum equals 360° 00' 2 00". The amount by which each angle must be If the sum of the angles varies from 360° by adjusted is determined by dividing the differ- ence between the sum of the angles and 360° 00' 00" by the number of angles measured about the station. The quotient resulting from this division may not be a whole number. In that case, the remainder is distributed, 1 sec- REQUIRED ond each, among the angles having the greatest ANGLE values. For example, three meaned angles were determined and are adjusted as follows: ANGLE CLOSING Angle 1 165° 49' 20" Angle 2 90° 06' 20" THE HORIZON Angle 3 104° 04' 00" Sum 359° 59' 40" In this case, the sum of the angles differed from 360° by 20". To determine the amount by which each angle is to be adjusted, divide 20" (difference between sum and 360°) by 3 (num- ber of angles). The quotient is 06" with a re- mainder of 02". Distribute the remainder by adding 01" to the corrections for the 2 largest 1st REQUIRED ANGLE angles, thus making the corrections 06", 07", and 07". Apply the corrections to the mean angles in such a way as to make their sum equal to 360° 00' 00", as follows :
Mean Corrections Adjusted 2d REQUIRED Angle 1 165° 49' 20" (+07") 165° 49' 27" ANGLE Angle 2 90° 06' 20" ( + 06") 90° 06' 26" Angle 3 104° 04' 00" (+07") 104° 07' 07" Sum 359° 59' 40" 360° 00' 00" ANGLE V_3d REQUIRED e. The procedures discussed in a through d CLOSING ANGLE above apply to measurements made with both THE HORIZON the 20-second and 1-minute transits. 78. Measuring Vertical Angles With 4th REQUIRED Transit ANGLE a. The vertical angle to a point is measured from the horizontal plane passing through the Figure 19. Horizon closure. axis of the telescope of the transit. To measure
39 a vertical angle to a point with the transit, set the forward station of a horizontal angle. (If the transit over the station at which the angle the vertical angle is required to the rear station is to be read. With the telescope in the direct of the first angle, it is measured in conjunction position, place the crosshairs on the point at with the pointings on the forward station of HI. (The final direction of rotation of the the angle closing the horizon.) After the cross- vertical motion tangent screw should be in a hairs have been placed on the forward station, clockwise direction.) Read the measurement raise (or lower) the telescope until the hori- of the vertical angle on the main vertical scale zontal crosshair is pointed at the HI. Unclamp and the vernier. Plunge the telescope and the lower motion. Rotate the transit so that again place the crosshairs on the point. Read the vertical scale can be read conveniently. the measurement of the vertical angle on the Read the vertical scales. Rotate the transit so vertical scales. Determine the mean vertical that the horizontal scales can be read con- angle by dividing the scale reading by 2. This veniently. Read the horizontal scales. (Read- is the mean angle and is considered to be the ing the vertical scales first permits the measured value of the angle. telescope to be elevated to facilitate reading the b. When measuring a vertical angle in con- horizontal scales.) junction with the measurement of a horizontal c. Figure 20 is a sample record of horizontal angle, read the first value of the measurement and vertical circle readings. of the vertical angle immediately before read- ing the value of the first (direct) measurement 79. Care of Transit of the horizontal angle. Read the value of the The transit is a delicate instrument; care second (reversed) measurement of the vertical must be taken not to drop or bump it against angle immediately before reading the value of any object. In moving the instrument from the last (reversed) measurement of the hori- station to station, a man on foot may carry the zontal angle. The vertical angle is always instrument, mounted on its tripod, over his measured in conjunction with the pointings on shoulder (fig. 21). When he passes through
Ho tiz. onto! 4- Vertical 4 Slalion T R // O / // AZMK /20 15 00 * / /Z 3NSCP ZW 30 ZO 13 TS! MN 4 120 IS 10 ADJ 4- 120 /5 15 H !Z 30
T5! 237 75 Oo 3NSCP 7? 2 //? 27 20
AZMK MN 4 237 77 W AQJ 4 ¿37 77 75
Figure 20. Recording horizontal and vertical circle readings.
40 trees or underbrush, he should carry it under Care must be taken not to scratch the lenses one arm, with the hand of his other arm on and the coating on the lenses. the head of the tripod or the footplate of the d. The vertical circle and vertical circle transit (fig. 22). In either case, the upper vernier should be brushed with a camel’s-hair motion should be clamped and the lower mo- brush or wiped with lens tissue. Lens tissue tion left unclamped. The telescope should be should be wiped across (perpendicular to) the clamped with the telescope pointing upward. graduations to avoid removal of the blacking. When the instrument is carried in a vehicle, it e. The leveling screws should be cleaned one should be placed in its case. Before placing the at a time. Run the screw which is diagonally transit in its case, the transit operator should opposite the screw to be cleaned all the way up. verify that the shifting center is in the center At the same time, run the screw to be cleaned of the footplate and that the leveling screws all the way down. The screw should be are approximately at the same height. The cleaned with a clean cloth. A string may be upper motion should be clamped; the lower pulled through the grooves to aid in removing motion should not. The vertical motion should dust. be clamped. The case should be held on the f. The upper surface of the footplate should lap of the operator or cushioned from shock in be wiped with a clean cloth. This surface must some other ivay. be kept clean at all times. 80. Cleaning Transit 81. Repair of Transit The transit must be kept clean and dry. Adjustment (except as explained in pars. During use, as necessary, and after use, the 82-87) and repair of the transit must be per- instrument should be cleaned as follows: formed by qualified instrument repair person- a. Painted surfaces should be wiped with a nel. Artillery units should turn transits in to clean cloth. the engineer unit which is responsible for pro- b. The exterior of the vernier windows viding maintenance service for necessary ad- should be cleaned with a camel’s-hair brush or justment and repair. wiped with a clean cloth. c. The exterior of the eyepiece and the ob- 82. Adjustment of Transit jective lens should first be brushed with a a. The transit must be kept in good adjust- camel’s-hair brush to remove dust arid then ment to obtain accurate results. There are five wiped with lens tissue to remove moisture. tests and adjustments of the transit that the
IK
Figure 21. Carrying transit on the shoulder. Figure 22. Carrying transit under one arm.
41 artillery surveyor must be capable of perform- in a plane perpendicular to the horizontal axis ing. These tests and adjustments are described of the telescope. in paragraphs 83 through 87. b. Test. b. All tests and adjustments of(1) the Select transit a stable, well-defined point that are made with the instrument mounted on its is at least 100 meters from the tran- tripod and set up in the shade. The five tests sit. Center the vertical crosshair on of the instrument should be made periodically, this selected point. in the sequence in which they are discussed in (2) With the elevation tangent screw, ele- paragraphs 83 through 87. When one of the vate and depress the telescope. If this tests indicates that an adjustment is necessary, adjustment is correct, the point will this adjustment must be made and all previous appear to move up and down on the tests must be repeated before proceeding with vertical crosshair. the next test. c. Adjustment. 83. Adjustment of Plate Levels (1) If the point moves away from the a. Purpose. The purpose of the adjustment vertical crosshair, loosen the screws of the plate level is to make the level vials holding the crosshairs and rotate the parallel to the upper plate. reticle by lightly tapping two opposite b. Test. screws. (1) Using the leveling screws, bring the (2) Sight on the point again and if the bubbles of both plate levels to the vertical crosshair does not follow the centers of their vials. point throughout its entire length, ro- tate the ring again. (2) Turn the transit through 180° of (3) Repeat this process until the condi- azimuth. If these levels are correctly tion is corrected. adjusted, the bubbles will then come to rest centered in their vials. 85. Collimation Adjustment of Vertical c. Adjustment. When the bubble of either Crosshair plate level comes to rest off center in the test, a. Purpose. The purpose of the collimation the bubble should be moved halfway back to adjustment of the vertical crosshair is to make center by turning the leveling screws, and then the line of sight (as defined by the vertical it should be centered by turning the capstan crosshair) perpendicular to the horizontal axis nut at either end of the level tube. of the telescope. d. Frequency of Test and Adjustment. The b. Test. test of the plate levels should be made every (1) Point the telescope at a point about time the instrument is set up for use. When 100 meters distant and set a stake at an error in the adjustment of either plate level that point. Clamp both the upper and is indicated, it is not always necessary to make the lower motions. Mark the stake the adjustment, because the operation of bring- with the letter A exactly on the line ing the bubble halfway back to center by turn- of sight. ing the leveling screws makes the vertical axis (2) Plunge the telescope and set a second of the transit vertical. The adjustment must stake on the line of sight at a distance be made, however, before other tests and ad- from the instrument approximately justments of the instrument. For artillery sur- equal to that of the first stake. Mark vey needs, only the long bubble need be in the second stake with the letter B ex- adjustment; however, in case of damage to actly on the line of sight. Label this the long bubble, the short bubble should also mark B. (The two stakes and the in- be in adjustment. strument should be as nearly in a 84. Verticality Adjustment of Vertical common horizontal plane as possible.) Crosshair (3) Rotate the alidade, using the lower a. Purpose. The purpose of the verticality motions, until the crosshairs are adjustment is to make the vertical crosshair lie again on mark A.
42 (4) Plunge the telescope. If the instru- selected point. If these two vertical ment is in adjustment, the line of angle readings are of the same value, sight will fall on mark B. the collimation adjustment of the c. Adjustment. horizontal crosshair is correct. (1) If the line of sight does not fall on c. Adjustment. mark B, place a mark C exactly on (1) When the two vertical angle readings the line of sight. Normally, mark C differ, adjust the position of the hori- will fall on the stake on which mark zontal crosshair. For this adjust- B was placed. If it does not, a card ment, turn the crosshair retaining may be attached to the stake and ring screws on the top and bottom of mark C is placed on the card. the telescope. Loosen one of these ad- (2) The point midway between marks B justing screws and tighten the other and C is the extension of the straight one. Tightening the uppermost ad- line from mark A through the instru- justing screw will cause the horizon- ment. Place mark D at the point mid- tal crosshair to move down in the .j way between B and C. Place a mark telescope. E at the point midway between C (2) With the telescope in either the direct and D. or reverse position, set the vertical (3) With the telescope pointed at mark C, circle to read the mean of the two adjust the crosshairs until they are vertical angle values read in b (3) exactly on mark E by loosening the above. Then, move the horizontal crosshair ring-retaining screw on one crosshair ((1) above) to where it side of the telescope tube and tighten- bisects the selected point (b above). ing the opposite screw. To move the crosshair to the left, loosen the screw (3) If while adjusting the position of the on the left side; to move it to the horizontal crosshair the crosshair right, loosen the screw on the right moves out of the center of the tele- side. scope, the instrument should be turned in for adjustment of the vertical (4) Rotate the alidade until the vertical vernier. crosshair falls on mark D. (5) Plunge the telescope. The vertical 87. Adjustment of Height of Standards crosshair should fall on mark A. If it a. Purpose. The purpose of the height of does not, the adjustment must be re- standards adjustment is to make the horizontal peated. axis of the telescope perpendicular to the verti- 86. Collimation of Horizontal Crosshair cal axis of the spindle. a. Purpose. The purpose of the collimation b. Test. of the horizontal crosshair is to make the in- (1) With the telescope in the direct posi- strument read the same value for the vertical tion, point at some well-defined, ele- angle to a point, with the transit direct and vated object, such as the point of a with the transit reversed. church steeple. The image of the point b. Test. sighted on must be as narrow as the (1) Select a stable, well-defined point at width of the crosshairs. The vertical least 100 meters from the transit at angle to the point sighted on should any vertical angle that is convenient be at least 30°. Clamp both the upper for observing. and lower motions. (2) For this test, the leveling of the tran- (2) Depress the telescope and set a stake sit is critical, so level the instrument in the ground alined with the line of as accurately as possible. sight. Place a mark on the stake (3) Make the vertical angle readings for exactly where it is in the line of sight, direct and reverse pointings to the and label this mark A.
43 (3) Rotate the alidade 180°, using the zontal crosshair passes through the lower motions; plunge the telescope; elevated point. and again point at the elevated point. (3) Move the crosshairs halfway to the (4) Depress the telescope. If the line of elevated point by using the capstan sight is on mark A, the height of nuts on the movable standard. (An standards adjustment is correct. adjusting pin is used to turn a capstan nut.) . Adjustment. (4) Move the crosshair to the elevated (1) If the line of sight does not fall point by using the lower motions. The exactly on mark A, move the tele- crosshairs should fall on point A when scope until the crosshairs are on point the telescope is depressed. If it does A. not, the test and adjustment must be (2) Elevate the telescope so that the hori- repeated. CHAPTER 7
THEODOLITE, WILD T16
Section I. GENERAL
88. General tical circle level (split bubble) in addition to a. The Wild T16 theodolite (fig. 23) is used the circular level on the tribrach. The plate level is located between the two standards of to obtain angular values for artillery fifth-order survey. Both horizontal and vertical angles the instrument. The vertical circle level is can be measured with the theodolite. The T16 completely built in, adjacent to the vertical theodolite is a compact, lightweight, dustproof, circle. A tangent screw is used to bring the optical-reading, direction-type instrument with ends of this bubble into coincidence. a repeater clamp for measuring horizontal f. An optical plumb system is provided on angles. The scales, graduated in mils, are read- the theodolite for accurate centering over the able directly to 0.2 mil and by estimation to station. The system is located in the revolving the nearest 0.1 mil, and may be illuminated by part (alidade) of the instrument. sunlight or artificial light. g. The horizontal clamp and the horizontal b. The T16 theodolite is issued with the fol- tangent screw for moving the theodolite in azi- lowing accessories : canvas accessory kit, com- muth are located adjacent to each other on the pass, eyepiece prisms, sun filters, sunshade, two lower portion of the alidade. The vertical jewelers’ screwdrivers, two adjusting pins, clamp is located on the standard opposite the camel’s-hair brush, lubricant, plastic instru- vertical circle ; the vertical tangent screw is on ment head cover, two operation and mainte- the lower portion of the same standard. The nance service manuals, battery case with light- horizontal circle clamp, which fastens the hori- ing devices and three spare bulbs, and universal zontal circle to the alidade, is located on the tripod with plumb bob, plug-in sleeve, and front of the horizontal circle casting. tripod key in leather pouch attached to tripod. h. The 28-power telescope of the T16 theodo- c. The carrying case for the T16 theodolite lite is reversible. The crosslines are focused by consists of a base plate and a steel, dome- turning the eyepiece ; the image, by turning the shaped hood. When in the base, the instrument focusing ring. Two horizontal pull-action rests on two supports by means of two bolts screws are provided for correcting the collima- and is fixed to the supports with two locking tion error. Objects viewed through the tele- devices. A desiccant is in the base of the con- scope are inverted. tainer. A wooden padded box is also furnished i. An exterior tilting mirror illuminates for transporting the theodolite in its case. both the horizontal and vertical circles. The 45 sliding connection. In the second socket a plug- l. A circular compass is issued as an acces- in is placed, the other end of which has a lamp sory item for the T16 theodolite. It is mounted to replace the mirror. When the current is in the yoke provided on the right standard. The on, this lamp illuminates both circles, both compass is used only to check azimuth roughly, levels, and the telescope reticle. A rheostat is to orient the sketch in the field notes, or as a provided on the battery case for adjusting the means of assuming direction. To prevent amount of light. Crosslines illumination is breakage of the cover glass, always place the adjusted through the use of the illuminating compass with the dial down in the pocket of mirror for telescope diaphragm. the accessory case. k. Standard equipment includesm. Thediagonal Wild universal tripod is issued with eyepieces for both the telescope and the circle- the theodolite. This model has sliding legs. The reading microscope. Sun filters are provided overall length of the closed tripod is 3 feet; for the telescope eyepiece. the extended length is 5.2 feet. A leather pouch Mirror for collimation, level Illuminating mirror for telescope Compass diaphragm bracket Focusing ring Vertical clamping screw Eyepiece for Eyepiece for telescope circle reading microscope Collimation leve.1 tangent screw Vertical tangent Horizontal plate screw level Horizontal Horizontal circle tangent clamp screw Horizontal * clamping screw Tribrach clamp Leveling screw figure 23. Wild T16 theodolite. 46 attached to the tripod contains a plumb bob tripod until the point of the plumb bob is cen- with a plug-in sleeve and key for the tripod tered exactly over the station. legs. b. Tighten the instrument to the tripod head, making sure that the plumb bob point stays 89. Setting up the Tripod centered over the station. a. Upend the tripod and place the tripod c. Use the optical plumb for final centering head on the toe of the shoe. of the theodolite over the station. b. Loosen the restraining strap and secure d. Do not attempt to use the plumb bob the strap around one tripod leg. when the wind is blowing. Use the optical c. Hold the tripod in the erect position and plumb. test the adjustment of each tripod leg by ele- vating it to about 90° and then releasing it. If 92. Leveling the Theodolite properly adjusted, the leg should fall to about a. Bring the circular level bubble to rough 45° and stop. If not, the tripod leg should be center by turning the three leveling screws. adjusted by tightening or loosening the bolt. b. Loosen the horizontal clamp. Turn the d. With one tripod leg pointed in the direc- instrument until the plate level is parallel to tion of observation, approximately center the any two of the three leveling screws. tripod and embed the tripod legs lightly into c. Center the plate bubble by using these the ground. The head of the tripod should be screws, turning both in toward the center of about shirt pocket height. the instrument or turning both out from the e. Center the fixing screw in the head of the center. The bubble will follow the movement tripod and insert the plumb bob. Center the of the left thumb. tripod over the station. d. Turn the instrument 1,600 mils. Place one /. Check the tripod head for approximate end of the plate level over the third leveling level by sighting against the horizon. screw. Using this leveling screw, bring the g. Firmly embed the tripod legs. bubble to center. h. Remove the tripod head cover and secure e. Return the instrument to the first posi- it to the tripod leg. tion; center the bubble if necessary. /. Turn the instrument 3,200 mils. If the 90. Removing the Theodolite from its Case bubble is in the center of the level vial, turn the a. Loosen the strap on the case and unclamp instrument 6,400 mils. The bubble should re- the latches simultaneously by exerting pressure main centered; if it does the instrument is outward. level. b. Lift the dome-shaped cover directly off the g. Check the optical plumb to insure that instrument and set it to one side. the instrument is still over the station. If not, center over station and repeat the leveling c. Place the fingers under the right and left process. retaining clamps on the base of the case and apply pressure until the instrument releases. h. If the bubble is not centered when turned 3,200 mils from the first position (/ above), d. With the right hand, securely grasp the the level vial is out of adjustment. To adjust, right standard (the one with Wild inscribed move the bubble halfway back to the center of on it) and lift the theodolite off the base. the level vial, using the same leveling screws e. Place left hand under the theodolite and used in the first position. Rotate the instru- fasten the instrument to the tripod, using the ment 1,600 mils. Move the bubble halfway back fixing screw. to the center of the level vial, using the one f. While the theodolite is in use, the dome- remaining leveling screw. The instrument is shaped cover should be replaced on the base now level, and the bubble will come to rest in of the case. its vial at the same offcenter position for any direction in which the instrument is pointed. 91. Plumbing the Theodolite The level vial should be adjusted as soon as a. Carefully movetime the permits. instrument around the 47 93. Illuminating the Circle the eyepiece. If the parallax has been elimi- nated, the crossline will remain fixed on the To illuminate the circle, open the illumina- image. If some parallax still remains, the cross- tion mirror and adjust the light so that both line will appear to jump back and forth hori- the horizontal and vertical circles are uni- zontally across the object. To correct any re- formally illuminated when viewed through the circle-reading microscope. maining parallax, the eyepiece should be changed slightly to bring the crossline to a 94. Focus To Eliminate Parallax sharper focus, and the telescope refocused Parallax is eliminated by pointing the tele- accordingly. This procedure should be repeated scope toward the sky or any other neutral back- until the test shows no remaining parallax. ground and turning the knob on the telescope 95. Taking Down the Theodolite eyepiece until the crosslines are very sharp, fine To take down the theodolite— black lines. In doing this, the observer should a. Place the telescope straight up and tighten be very careful to focus his eye on the cross- the vertical clamping screw. lines and not the sky. Next, point the instru- ment toward a rod or other sharply defined b. Turn each leveling screw to the same object and, still focusing the eye on the cross- height. lines, bring the object into a sharp, clear c. Loosen the central fixing screw and clamp image by turning the focusing ring on the tele- the instrument in its carrying case. scope. Use the horizontal tangent screw to d. Tighten the horizontal clamping screw. exactly center the vertical crossline on the e. Clamp the dome-shaped hood in place. object. To check for elimination of all parallax, f. Replace the tripod head protector and move the eye horizontally back and forth across strap the tripod legs together. Section II. USE OF THEODOLITE 96. Reading Horizontal and Vertical Circles When the circles are viewed through the circle reading microscope (fig. 24), the vertical circle (marked “V”) appears above the hori- zontal circle (marked “Az”). Both circles are graduated from 0 to 6,400 mils with a major graduation each 10 mils. Unit mils and tenths 159 158 are viewed on an auxiliary scale graduated each 0.2 mil from 0 to 10 mils. Circle readings are estimated to the nearest 0.1 mil. The auxil- iary scale is read at the index line which appears superimposed over the auxiliary scale. 97. Setting the Horizontal Circle All measurements with the theodolite should 23 22 be started from an initial reading on the hori- zontal circle of 1.0 mil. For practical purposes this precludes working with a mean of the direct and reverse (D/R) pointings on a start- Az ing station of less than 0 mil. To set this value on the circle, release the repeater clamp (hori- VERTICAL CIRCLE 19896 Ml zontal clamp) and turn the instrument until HORIZONTAL CROE 2264 MILS the major graduation 0 appears on the horizon- Figure 2b. Scale images viewed through the circle- tal circle. Clamp the repeater clamp and set reading microscope. 48 initial circle setting on the starting point (par. ? (INITIAL OR REAR STATION) 97). The size of the horizontal angle is obtained by determining the difference between the (FORWARD STATION)A mean pointing on one station and the mean pointing on another station. The mean point- ing is determined from the direct and reverse circle readings on the same point (fig. 25). a. Set 1.0 mil on the horizontal circle. With the repeater clamp down and the horizontal clamp loose, point the telescope in the direction of station A by sighting first through the peep sight and then through the telescope. When INSTRUMENT approximately alined on the station, clamp the horizontal clamp and refine the pointing with Figure 25. Determining the horizontal angle between the slow motion tangent screw. View the circle stations A and B. again to insure that the reading is still 1.0 mil. This establishes the direction of station A as the index line directly over 1.0 mil on the aux- 1.0 mil with respect to the horizontal circle. iliary scale with the tangent screw. Engage the Record in the field notes (fig. 26) the value of repeater clamp by folding it downward. The the direct reading on station A. Release the horizontal circle is now attached to the turn- repeater clamp (up) ; this causes the circle to ing part of the instrument; the reading of 1.0 detach itself from the moving part of the theo- mil remains on the circle regardless of the dolite. Release the horizontal clamp. Point the direction in which the instrument is pointed. telescope on station B as above, level the ver- tical level bubble, and read and record the 98. Measuring Horizontal and Vertical circle values—horizontal circle reading is 229.3 Angles mils; vertical circle reading is 1598.5 mils In artillery survey, the theodolite is used as (figs. 25 and 26). a direction instrument. The repeater clamp is b. Release the vertical motion clamp and used only to set the horizontal circle with the plunge the telescope. Release the horizontal OAJr^L. y/ñncAL yftiTic/iL fiTATm r MILS MEM mpm 0ÛÛ/.O JZObD ûttoi.ù mr MM (22&.JÙ ~ W J39S. 5 v- /.S 229.*+ ¿âo/.M Figure 26. Field notes for recording measurment of angle between stations A and B. 49 clamp and sight again on station B, with the appropriate column. The mean angle is the telescope in the reverse position. Make point- difference between the mean pointings. In ings as above, level the vertical circle bubble, figure 26, the mean pointing on station A is read the circles and record the values. In figure 0001.0; on station B, 229.4. Therefore, the 26, the values recorded are a horizontal read- mean angle is 228.4 mils. ing of 3429.4 and a vertical reading of 4801.4. d. The vertical circles of the theodolite re- Observe station A with the telescope still re- flect readings of 0 mil at the zenith, 1,600 mils versed and read the horizontal circle and record horizontal direct, 3,200 mils straight down, and the value. The value recorded for the horizon- 4,800 mils horizontal reversed. Hence, the tal circle reading is 3201.1 mils. values read from the vertical circles are not c. The field notes now reflectvertical a direct angles. and Thea circle readings must be reverse pointing at both station A and station converted to vertical angles (fig. 27). B. To determine the size of the angle between e. In the field notes in figure 26, the direct A and B, the mean of the pointings on A must reading on station B resulted in a vertical read- be determined and compared with the mean ing of 1598.5 mils or -f-1.5 mils ; and, with the of the pointings on B. This is done by mentally telescope reversed, the circle reading was subtracting 3,200 mils from the reverse reading 4801.4 mils or +1.4 mils. Hence, the mean (or adding 3,200 mils to it) and meaning the vertical angle from the instrument to station direct reading with the reverse reading. The B is +1.4 mils. results are entered in the field notes under the /. The telescope should be plunged to the Plus Vertical Angles Plus vertical ¿(1)= Plus vertical ¿.(3)= 1600-circle reading circle reading-4800 6400 6400 4800 1600 4800 1600 3200 3200 Telescope Telescope Direct Reverse Minus Vertical Angles Minus verticalZ(2)- Minus vertical¿(4)- circle reading-1600 4800- circle reading Figure 27. Vertical angles from circle readings. SO direct position, after the reverse pointing on angle measurement, the instrument will be the initial station. A direct pointing should be approximately zeroed, and time will be saved made on the initial station with repeater clamp in setting the initial circle setting for the next released (up). Although not a part of this angle measurement. Section III. CARE AND MAINTENANCE 99. Care of Theodolite Operator, Organizational, Field, and Depot The T16 theodolite is a delicate instrument. Maintenance Manual, outlines the echelons of Care must be taken not to drop or bump it maintenance. against any object. If the instrument gets wet, 102. Adjustment of Theodolite remove outside moisture, and as soon as pos- sible place instrument in a warm room or tent. a. The theodolite must be kept in correct In moving the instrument from station to sta- adjustment if accurate results are to be ob- tion, a man on foot may carry the instrument, tained. There are four tests and adjustments mounted on its tripod, under one arm, with the of the theodolite that should be made period- hand of the other arm under the tribrach of ically by the instrument operators. The adjust- the instrument. All motions should be clamped ments are performed in the sequence in which with the telescope pointed upward. When the they are discussed in paragraphs 103 through theodolite is carried over rough terrain, the in- 107. When any test indicates that an adjust- strument should be transported in its carrying ment is necessary, this adjustment should be case. When transported in a vehicle, the theo- made and tested for correctness before proceed- dolite should be in the dome-shaped carrying ing with the next test. case, and the case should be in the padded box. b. The four tests and adjustments of the For short distances, the carrying case may be theodolite are made while the instrument is carried in an upright position on the lap of the mounted on its tripod. For these tests and instrument operator. adjustments, the instrument should be set up in the shade, on firm ground, with the head of 100. Cleaning the Theodolite the tripod as nearly level as possible. The theo- The theodolite must be kept clean and dry. dolite should be protected from the wind. During use, as necessary, and after use, the c. An adjusted instrument will hold an ad- instrument should be cleaned as follows: justment for a long time, if handled properly. a. Painted surfaces should be wiped with a However, excessive movement of the adjusting clean cloth. screws will cause them to become worn, and b. The exterior of the eyepieces and the ob- the instrument will not hold an adjustment. jective lens of the telescope should first be brushed with a camel’s-hair brush to remove 103. Plate Level Adjustment dust and then wiped with lens tissue to remove a. The purpose of the plate level adjustment moisture. Care must be taken not to scratch the is to make the vertical axis of the theodolite lenses or the coating on the lenses. truly vertical when the bubble of the plate level c. The tripod should be kept clean, and mov- is centered. ing parts should be oiled lightly. b. To test the horizontal level, place the horizontal level parallel to two of the three 101. Repair of Theodolite leveling screws and center the bubble. Rotate Adjustment (except as explained in pars. 102 the instrument 1,600 mils and place one end -107) and repair of the theodolite must be per- of the bubble over the third leveling screw. formed by qualified instrument repair person- Level the bubble using only the third leveling nel. Artillery units should turn theodolites in screw. Return the instrument to the starting for necessary adjustment and repair to the position and carefully center the bubble. Rotate engineer unit which is responsible for provid- the instrument 3,200 mils. Any discrepancy ing maintenance service. TM 5-6675-200-15, noted in the position of the bubble is the appar- 51 ent error, or twice the actual error, of the repeat both readings to insure that he has not horizontal level. made an error in reading the instrument. Any c. To adjust the horizontal level, remove one- discrepancy noted between the actual difference half of the apparent error by turning the level- in the two readings and 3,200 mils is the ap- ing screws. The remaining error (actual error) parent error or twice the collimation error. If is removed by turning the capstan adjusting the discrepancy exceeds plus or minus 1 mil, screw in the right support. The capstan screw the crosshairs should be adjusted. is l'Và inches above the horizontal clamping c. Adjustment. The horizontal collimation screw. The adjusting pin is used to move the adjustment is made in the following manner. capstan adjusting screw. Assume that the reading in the direct position is 150.7 mils and the reading in the reverse 104. Optical Plumb Adjustment position is 3352.9 mils. Using the lateral tan- a. The purpose of the optical plumb adjust- gent screw, set the circle to the mean value of ment is to place the center of the rotating axis the direct and reverse pointings (151.8). Ad- of the instrument over the ground point. just the telescope reticle to the target by turn- b. To test the optical plumb, place a plumb ing the adjusting screw. The two adjusting bob on the instrument and level carefully. screws are arranged horizontally and opposite Establish a point on the ground under the each other and are the pull action type. If the plumb bob. Remove the plumb bob. If the reticle must be moved to the right, the left image of the ground point is not under the screw should be loosened slightly and the right crossline (circle on older models), an adjust- screw tightened slightly to hold fast. Repeat ment is required. the test to insure that the proper amount of ad- c. To adjust the optical plumb, move the justment has been made. crossline (circle) over the ground point by turning the optical plumb adjusting screws. 106. Vertical Collimation Adjustments Access to the adjusting screws is obtained by a. The purpose of the vertical collimation removing the screws located 1% inches to the adjustment is to make the line of sight hori- right and left of the eyepiece of the optical zontal when the vertical circle reads 1,600 mils plumb. The adjusting screws are mounted at with the telescope in the direct position and angles of 120°. Each screw acts against a 4,800 mils with the telescope in the reverse counterspring located opposite the eyepiece. By position. very small movements of the screws, the cross- b. To test the vertical collimation, take a line (circle) can be centered over the ground vertical reading on a well-defined point with the point. The last movement must be clockwise to telescope in the direct position and with the compress the counterspring. Check the adjust- collimation level bubble centered. Plunge the ment by rotating the instrument through 6,400 telescope to the reverse position and take a mils. If the crossline (circle) does not remain reverse vertical reading on the same point, with over the ground point, repeat the adjustment. the collimation level bubble centered. The col- After the adjustment has been completed, the limation level bubble must be centered before, cover screws should be replaced. and checked after, each vertical reading. The 105. Horizontal Collimation Adjustment sum of the direct and reverse readings should a. Purpose. The purpose of the horizontal equal 6,400 mils. Any discrepancy between the collimation adjustment is to make the line of sum of the two readings and 6,400 mils is the sight perpendicular to the horizontal axis of apparent error and is twice the collimation level the telescope. error. If the discrepancy exceeds plus or minus b. Test. To test the horizontal collimation, 1 mil, the collimation level should be adjusted. take a horizontal reading on a well-defined point c. To adjust the collimation level, place the with the telescope in the direct position. Plunge telescope in the direct position and sight on the the telescope and, with the instrument in the point. Compute the correct reading by applying reverse position, take another reading on the one-half of the index error of the vertical cir- same point. These two readings should differ cle to the direct reading. If the sum of the two by 3,200 mils. The instrument operator should readings was greater than 6,400 mils, subtract 52 one-half of the apparent error from the direct ing the cover of the vertical circle level. Repeat reading; if the sum was less than 6,400 mils, the test to insure that the proper amount of ad- add one-half of the apparent error to the direct j ustment has been made to the collimation level. reading. Place the correct reading on the in- strument by using the vertical circle tangent 107. Verticality of Vertical Crossline screw. With the correct reading on the instru- Adjustment ment, the collimation level bubble will not be The T16 theodolite is built so that the vertical centered. The bubble must be brought into crossline remains vertical. Therefore, the ver- coincidence by turning its adjusting screw. Ac- ticality adjustment of vertical crossline is not cess to the adjusting screw is gained by remov- performed. 53 CHAPTER 8 THEODOLITE, WILD T2, MIL-GRADUATED Section I. GENERAL 108. General the circular level on the tribrach. The plate a. The Wild T2 theodolite mil-graduated (fig. level is located between the two standards of the 28), is used to obtain angular values for artil- instrument. The vertical circle level is built in, lery fourth-order survey. Both horizontal and adjacent to the vertical circle. A tangent screw vertical angles can be measured with the is used to bring the ends of this bubble into theodolite. The theodolite is a direction type coincidence. instrument. The scales, graduated in mils, are f. An optical plumb system is provided on the readable directly to 0.002 mil and by estima- theodolite for accurate centering over the sta- tion to the nearest 0.001 mil and may be tion. The system is located in the tribrach of illuminated by sunlight or artificial light. the instrument. b. The T2 theodolite is issued with the follow- g. The horizontal clamp (fast motion) and ing accessories: canvas accessory kit, diagonal the horizontal tangent screw (slow motion) eyepieces for the telescope and reading micro- for moving the theodolite in azimuth are located scope, sun filter, dustcap, jeweler’s screwdriver, on opposite sides of the instrument on the lower two adjusting pins, camel’s-hair brush, plastic portion of the alidade. The clamping screw for instrument head cover, instruction pamphlet, the vertical circle (fast motion) and the ver- battery case with lighting devices and three tical circle tangent screw (slow motion) for spare bulbs, universal tripod, with plumb bob, moving the telescope vertically are located one plug-in sleeve, and tripod key in leather pouch above the other on the standard which holds attached to tripod. Some models of the theodo- the vertical circle. These tangent screws and lite have the accessories in the base of the carry- clamps are shown in figure 28. ing case. c. The carrying case for the T2 consists of a h. The 28-power telescope of the T2 theodo- base plate and a steel, dome-shaped hood. When lite can be reversed. The crosslines are focused in the base, the instrument rests on three sup- by turning the eyepiece; the image, by turning ports and is fixed to the supports with locking the focusing ring. An object when viewed devices. A wooden padded bax is also furnished through the telescope is inverted. for transporting the theodolite while in its case. i. An exterior tilting mirror located on the d. The tribrach is that part of the theodolite lower portion of the alidade illuminates the which contains the three leveling screws and horizontal circle. Another exterior tilting mir- thè circular level. The leveling screws are en- ror located on the standard which holds the closed and dustproof. On models manufactured vertical circle illuminates the vertical circle. subsequent to 1956, the tribrach is detachable. The circle selector knob is inscribed with a A locking device holds the instrument and heavy line. When the line is horizontal, the tribrach together. horizontal circle may be viewed through the e. The theodolite has a plate level and a ver- circle-reading eyepiece. When the line is ver- tical circle level (split bubble) in addition to tical, the vertical circle may be viewed. The 54 circle selector knob is located above the in- theodolite has sliding legs. The overall length scription “Wild.” of the closed tripod is 3 feet; the extended j. An electric illumination device is issued length is 5.2 feet. A leather pouch attached to with the T2 theodolite. In the lower housing of the tripod contains a plumb bob with a plug-in the theodolite is a socket to receive a plug from sleeve and wrench for the tripod legs. The head the battery case. The tilting mirrors are re- of the tripod is covered with a screw-on pro- placed with lamps in bulb holders. A rheostat tector cap. is provided on the battery case for adjusting 109. Setting up the Tripod the amount of light. Crossline illumination is adjusted through the use of the illuminating The tripod used with the T2 theodolite is the mirror for telescope diaphragm. same as that used with the T16 theodolite. Therefore, the same procedure may be used for k. Standard equipment includes diagonal eye- setting up the tripod (par. 89). pieces for both the telescope and the circle- reading microscope. A sun filter is provided for 110. Removing the Theodolite from its the telescope eyepiece for viewing the sun. Case l. The Wild universal tripod issued with the The T2 theodolite is removed from its case in ILLUMINATING MIRROR FOR THE DIAPHRAGM VERTICAL CIRCLE COINCIDENCE KNOB .ILLUMINATING MIRROR FOR VERTICAL CIRCLE COLLIMATION-LEVEL CLAMPING SCREW TANGENT SCREW FOR VERTICAL CIRCLE RING FOR FOCUSING CIRCLE-, SELECTOR KNOB „TELESCOPE EYÉPIECE FOR CIRCLE- READING MICROSCOPE PLATE-LEVEL VIAL EYEPIECE OF TELESCOPE HORIZONTAL-CIRCLE ’ VERTICAL-CIRCLE TANGENT SCREW TANGENT SCREW KNOB FOR / COLLI MAtl ON-LEVEL REFLECTOR ONE OF THE 3 LEVEUNG SCREWS CIRCULAR LEVEL CIRCLE-SETTING KNOB & COVER Figure 28. The Wild T2 theodolite. 55 the same manner as the T16 theodolite (par. 113. Adjustment to Eliminate Parallax 90) , except that it is fastened to Thethe telescopebase by of the T2 theodolite is similar three supports with locking devices. to the telescope of the T16 theodolite, and the adjustment to eliminate parallax is accom- 111. Plumbing the Theodolite plished in the same manner (par. 94). The T2 theodolite is plumbed over a station in the same manner as the T16 theodolite (par. 114. Taking Down the Theodolite 91) . The T2 theodolite is taken down and placed in its carrying case in the same manner as the 112. Leveling the Theodolite T16 theodolite (par. 95). All fast motions are The T2 theodolite is leveled in the same man- clamped and the dustcap is returned to the ner as the T16 theodolite (par. 92). objective end of the telescope. Section II. USE OF THEODOLITE 115. Circle Readings tion is numbered. The unit digit is omitted, i.e., a. A system of lenses and prisms permits the 10 mils appear as 1; 250 mils as 25; 3510 mils observer to see small sections of diametrically as 351. opposite sides of either the horizontal circle or d. The micrometer scale (lower window) is the vertical circle (fig. 29). The circles are graduated from 0.000 mil to 1.000 mil. Each viewed through the circle-reading microscope, 0.002 mil is marked with a graduation, and each the eyepiece of which is alongside the telescope fifth graduation is numbered (hundredth of a eyepiece. The circle to be viewed is selected by mil). The scale may be read to 0.001 mil by turning the circle selector knob on the right interpolation. standard. The field of view of the circle-read- 116. Horizontal Circle Readings ing microscope appears to contain two small windows (fig. 30). The upper window con- To determine a reading on the horizontal tains images of two diametrically opposite por- circle— tions of a circle (horizontal or vertical). One a. Rotate the circle selector knob until the of the images, of the circle is inverted and ap- black line on the face of the knob is horizontal. pears above the other image. The lower window b. Adjust the illuminating mirror so that contains an image of the portion of the microm- both windows in the circle-reading microscope eter scale. are uniformly lighted. b. The coincidence knob on the side of the c. Focus the microscope eyepiece. right standard is used to obtain readings for d. Observe the images in the microscope. either of the circles in conjunction with the Bring the circle graduations into coincidence at micrometer scale. Optical coincidence is ob- the center of the upper window, using the tained between diametrically opposite gradua- coincidence knob. tions of the circle by turning the coincidence e. Read the circles. knob. When this knob is turned, the images of the opposite sides of the circle move in opposite 117. Steps in Circle Reading directions across the upper window in the cir- The steps in reading the circles are (fig. 30) : cle-reading microscope. The image of the a. Determine the first erect numbered grad- micrometer scale in the lower window also uation to the left of the vertical line that moves. The graduations on the circle (main marks the center of the upper window. The scale) are brought into coincidence so that they number which labels this line indicates the appear to form continuous lines. The center number of tens of mils. In figure 30, this of the field of view is marked by a vertical line. number is 207. This vertical line is not used in reading the b. Locate the inverted graduations which circle. differs from 207 by 320, this number is 527 c. The main scale (upper window) is gradu- (viewed IZ9)- The inverted number will always ated in two-mil increments. Each fifth gradua- be to the right of the vertical line which marks 56 the center of the field of view. Both values will on the micrometer scale (lower window). In always end in the same number, in this case figure 30, this value is 0.254 mil. number 7. /. Add the angular values determined in d c. Starting from 207, count the number of and e above; 2,076 + 0.254 = 2,076.254 mils, the graduations to the inverted 527. There are six angular value. graduations, representing 6 mils. Each gradu- 118. Vertical Circle Readings ation represents 1 mil. The circle selector knob is rotated until the d. Convert 207, which is tens of mils, to black line on the face of the knob is vertical. 2,070 mils (2,070 + 6 = 2,076 mils, the angular The vertical circle may now be viewed in the value obtained from the main scale). microscope eyepiece. A reading on the vertical e. The vertical line which marks the center circle is determined in the same manner as a of the field of view indicates the value to be read reading on the horizontal circle. MICROMETER DRUM ILLUMINATING MIRROR CIRCLE READING SELECTOR PRISM PRISM VERTICAL CIRCLE READING MICROSCOPE HORIZONTAL CIRCLE READING PRISM ILLUMINATING OPTICAL MIRROR PLUMMET TELESCOPE J ? Figure 29. Circle-reading optical system of the Wild T2, theodolite. 57 direction to the circle reading. The resultant reading represents the read- 6¿S 9cQ ¿cQ 92Q ing for the instrument when it is pointed in the desired direction. (3) Set on the micrometer scale, to the thousandth of a mil, the reading to be 206 207 08 209 set on the circle to place the instru- ment on the desired direction. (4) Turn the instrument with the azimuth clamp and tangent screw and obtain coincidence on the main scale at the wV'"!1 i/////// mil values corresponding to the read- A 25 2 a? "I ing obtained in step (2) above. When coincidence is obtained, the instru- ment is pointing in the desired direc- tion. Figure 30. Scale images viewed through the circle- 120. Measuring Horizontal Angles reading microscope, mil-graduated T2 theodolite. a. The T2 theodolite is a direction instru- ment. The procedures in measuring horizontal 119. Setting the Horizontal Circle angles are (figs. 31 and 32) : There are two cases when it is necessary to (1) With the telescope in the direct posi- set the horizontal circle. tion, point to station A and record the initial circle setting (0.166 mil). a. In the first case, the circle is set to read a given value with the telescope pointed at a (2) With the telescope in the direct posi- target. The initial circle setting 0.150 (±0.100 tion, point to station B and record the mils) is used as an example. circle reading (1215.475 mils). (1) Point the instrument at the target. (3) Reverse the telescope and point to sta- (2) With the coincidence knob, place 0.150 tion B and record the circle reading mil on the micrometer scale. (4415.503 mils). (3) With the circle setting knob, attempt (4) With the telescope in reverse position, to zero the main scale, insuring that point to station A and record the cir- the numbered lines which are 3,200 cle reading (3200.200 mils). mils apart are touching each other. (5) Subtract 3,200 mils from the reverse (4) With the coincidence knob, bring the pointing on station A and mean the main scale graduations into a more perfect coincidence. A A (INITIAL OR REAR STATION) (5) Read the horizontal circle. It should \ (FORWARD read 0.150 (±0.100 mil). With ex- \ STATION)/ treme care, which is time-consuming, \ / a circle may be set to an accuracy of / 0.010 mil. b. In the second case, it is desired to lay the instrument on a line of known direction from a reference direction. (1) Point the instrument on the line for v y which the reference direction is pro- vided and read the circle. INSTRUMENT (2) Add the angular difference between Figure 31. Determining the horizontal angle between the reference direction and the desired stations A and B. 58 MWZOAJT/IL ysfiPUL tfEHr/OfL smm 4- ms Mm mp/A/o JbM/Lf> 0ÛÛÛ' fi>b 3zo¿>t¿¿>¿ mem mr MM TiJSsSoc^ '&B.£>V¿) 8 /Z/S.47S /£?/ 3 Bfy t ZS» R MU/S.So2> /USW JjSZB.tg +ZB' £3/ Figure 32. Field notes for recording measurements of angle, one position with the mil-graduated T2 theodolite. remainder with the direct point on the amount of horizontal spread (twice the station A (0.183 mil). error in horizontal collimation) in the instru- (6) Subtract 3,200 mils from the reverse ment. No value can be specified as the maximum pointing on station B and mean the allowable spread for an instrument; however, remainder with the direct pointing on it should be small (0.150 mil or less) for con- station B (1215.489 mils). venience in meaning the pointings. The amount (7) Subtract the mean pointing on station of spread should be constant; otherwise, there A ( (5) above) from the mean pointing are errors in the pointing. on station B ((6) above) (1215.489— d. In artillery survey, one position is taken 0.183 = 1215.306 mils). The difference in traverse and two positions are taken in is the horizontal angle between sta- triangulation. If the primary requirement of tions A and B (1215.306 mils). the traverse is an accurate direction (FA mis- Note. Procedures (1) through (7) consist sile battalion), then two positions are taken. of one direct and one reverse pointing on e. The initial circle settings should be as each station and are referred to as one position. follows: first position, 0.150 (±0.100) mils; second position, 4800.150 (±0.100) mils. b. When it is necessary to measure the angle to more than one station, a pointing is made on f. When it is necessary, as in triangulation, the initial station with the telescope in the to measure two positions, the second position direct position and then on each station around is measured in the same manner as the first the horizon in a clockwise direction. After a position, except that the second position is reading is obtained on the last clockwise sta- started with the telescope in the reverse posi-. tion with the telescope direct, the telescope is tion, pointing on the initial station. reversed and a pointing is made on each station g. To determine the angle between two ob- in a counterclockwise direction, ending with the served stations, the mean horizontal circle initial station. One set of direct and reverse reading to each station is determined ; and then’ pointings on all of the observed stations consti- the difference between the mean circle readings tutes one position. is determined. When two positions are taken, c. For each position there is a direct and a the value of the angle determined from the first reverse pointing on each observed station. The position is meaned with the value of the angle direct pointing and the reverse pointing on each determined from the second position. Figure station should differ by 3,200 mils plus or minus 33 is an example of the method of recording 59 FLAT A TOP BOX HILL Vf/p/yc/f¿ MM/V *M/¿s &M//VG * Af/¿S TOP ÛOOO.//Z 3ZôG/3 08/4338 /6/0.3/4 -/Û. 3/4 4Ô/4380 08/4.333 4383.873 -/0.387 H/LL *■ (836.663) ¿3/05/ J BOX /7//.0/Û /568.340 +3/060 43//.Ô46 /7//.088 483/042 +3f.û42 M£/tM HOMZ. *■ /QN6L£ fKOM TOB 480Û./P6 [8/4.836 ) F/fsr/vs/r/oA/ /wsce/ffa/H Û /60Û./66 480Û./P/ {8/42023 secoA/g /’as/r/o/v M£/>N AN6U AT H/U MU *- (8/4.202) (8/4.2/9) r/fûM FûP rûnJT F///r 56/4.383 836.669 24/4357 56/4.373 836.627 M£/IN/)N6L (AT HUi H/LL *■ (896.627) (896648) ffiOMHAT TA BOX BOX 0///.Û/6 33/0.984 0///.OOÛ Figure 33. Field notes for recording measurements of two angles, two positions with the mil-graduated T2 theodolite. horizontal circle readings and determining cal angle is equal to the vertical circle reading horizontal angles between three stations, with minus (—) 4,800 mils. The two determinations two positions observed. of the vertical angle then are meaned to obtain h. When two positions are used, if the two the vertical angle to the observed station (fig. observed values for any angle differ by more 33). than 0.050 mil, these observed values should b. For reading the vertical circle in conjunc- be rejected. tion with readings of the horizontal circle, the i. If the observed value (s) are rejected, the first (direct) vertical circle reading is taken angle(s) will be reobserved using approxi- immediately after taking the direct horizontal mately the same initial circle setting which was circle reading. The second (reverse) vertical used to obtain the rejected value (s). circle reading is taken before taking the re- verse horizontal circle reading. After the cross- 121. Measuring Verticallines Angleshave been placed on the station, the tele- a. Vertical angles cannotscope be measuredis elevated direct- (or depressed) until the ly with the theodolite. Instead, the vertical horizontal crossline is exactly on the point to angle to an observed station is computed from which the vertical angle is desired. The vertical a vertical circle reading to the station. When angle generally is read to the height of instru- the collimation level bubble is centered, verti- ment (HI). cal circle readings are measured from a line c. For reading the vertical circle, after sight- which is, in effect, an upward extension of the ing on the observed station, the bubble of the plumb line of the theodolite (fig. 34). One collimation level (split bubble) is brought to determination of the vertical angle is com- the center of its vial. This is accomplished by puted from the vértical circle reading with the rotating the collimation level tangent screw telescope of the instrument pointed at the sta- until the images of the ends of the bubble coin- tion in the direct position. With the telescope cide. The vertical circle reading then is read in direct, the vertical angle is equal to 1,600 mils the circle-reading microscope. The vertical minus ( — ) the vertical circle reading. A sec- scales are read in the same manner that the ond determination of the vertical angle is com- horizontal scales are read. Figure 33 is an puted from the vertical-circle reading with the example of the method of recording vertical telescope pointed at the station in the reverse circle readings and determining the vertical position. With the telescope reversed, the verti- angles. Section III. CARE AND MAINTENANCE 122. Care of Theodoliteshould be in the padded box. For short dis- The T2 theodolite is a delicate instrument. tances, the carrying case may be carried in an Care must be taken not to drop or bump it upright position on the instrument operator’s against any object. If the instrument gets wet, lap. remove all outside moisture and as soon as pos- 123. Cleaning the Theodolite sible place the instrument in a warm, dry room or tent. When the instrument is moved from The theodolite must be kept clean and dry. station to station, a man on foot may carry During use, as necessary, and after use, the the instrument, mounted on its tripod, under instrument should be cleaned as follows : one arm, with the hand of the other arm under a. Painted surfaces should be wiped with a the tribrach of the instrument. All motions clean cloth. should be clamped with the telescope pointed b. The exterior of the eyepieces and the ob- upward. When the theodolite is carried over jective lens of the telescope first should be rough terrain, the instrument should be trans- brushed with a camel’s-hair brush to remove ported in its carrying case. When transported dust and then wiped with lens tissue to remove in a vehicle, the theodolite should be carried in moisture. Care must be taken not to scratch the dome-shaped carrying case, and the case the lenses or the coating on the lenses. 61 VERTICAL CIRCLE EXTENSION ■ READING OF PLUMB LINE HI VERTICAL ANGLE (+) HORIZONTAL PLANE -EXTENSION OF VERTICAL-^ PLUMB LINE CIRCLE READING VERTICAL ANGLE (+) (TELESCOPE REVERSED, 1 ALIDADE ROTATED 180°) y HORIZONTAL PLANE PLUS VERTICAL ANGLES VERTICAL CIRCLE READING EXTENSION OF PLUMB LINE HORIZONTAL PLANE m VERTICAL ANGLE (-) ufó HI VERTICAL-^ / EXTENSION OF CIRCLE PLUMB LINE c— HORIZONTAL PLANE READING (TELESCOPE REVERSED, VERTICAL ANGLEH ALIDADE ROTATED 180°) HI MINUS VERTICAL ANGLES Figure Si. Relation of vertical circle readings and vertical angles. c. The tripod should be kept clean, and 125. Adjustment of Theodolite moving parts should be oiled lightly. a. The theodolite must be kept in correct ad- justment if accurate results are to be obtained. 124. Repair of Théodolite There are five tests and adjustments of the Adjustment (except as explained in pars. theodolite that should be made periodically, in 125-131) and repair of the theodolite must be the sequence in which they are discussed in performed by qualified instrument repair per- paragraphs 126 through 130. When any test sonnel. Artillery units should turn theodolites indicates that an adjustment is necessary, this in for necessary adjustment and repair to the adjustment should be made and tested for engineer unit which is responsible for provid- correctness before proceeding with the next ing maintenance service. test. 62 b. The five tests and theadjustments theodolite of pass the theo-through the station marker dolite are made while the instrument is mount- when the theodolite is properly leveled and ed on its tripod and leveled accurately. For when the station marker is centered in the these tests and adjustments, the instrument reticle circle (crossline) of the optical plummet. should be set up in the shade, on firm ground, b. Test. with the head of the tripod as nearly level as possible. The theodolite should also be pro- (1) Suspend the plumb bob from the tected from the wind. leveled instrument and mark a point on the ground exactly under the point 126. Plate Level Adjustment of the plumb bob. Remove the plumb a. Purpose. The purpose of the plate level bob from the instrument. adjustment is to make the vertical axis of the (2) Check the leveling of the instrument, theodolite truly vertical when the bubble of the and then look into the eyepiece of the plate level is centered in its vial. optical plummet. If this plummet is b. Test. correctly adjusted, the mark on the (1) Turn the instrument until the plate ground ((1) above) will be centered level is parallel to the line through two in the reticle circle of the plummet. leveling screws. With these two level- c. Adjustment. If the station point is not ing screws, center the bubble of the centered in the optical plumbing assembly reti- plate level. cle, bring it to center by means of three ad- (2) Turn the instrument through 1,600 justing screws located near the optical plummet mils and center the plate level bubble eyepiece. With an adjusting pin, loosen the by turning the third leveling screw. retaining nut and raise or lower the reticle by (3) Repeat (1) and (2) above, until the moving the adjusting screw. Adjust either of bubble will come to rest centered in the side adjusting screws. Moving the screw, its vial in both of these positions. with the retaining nut loosened, raises or lowers (4) Turn the instrument through 3,200 the reticle crosslines or circle in the same direc- mils from its position in (1) above. tion the screw travels. The two side adjusting If the plate level is correctly adjusted, screws move the crosslines or circle in the op- the bubble will come to rest at the posite direction from their travel. When the center of its vial with the instrument crossline or circle is centered over the station in this position. point, lock the lower adjusting screw by tighten- c. Adjustment. ing the retaining nut. (1) If the plate level bubble comes to rest off center in b(4) above, move the 128. Verticality of Vertical Crosshair bubble halfway back toward center by Adjustment turning the leveling screws. a. Purpose. The purpose of the verticality (2) With the capstan head adjusting screw adjustment is to make the vertical crosshair below the collimation level illumina- lie in a plane that is perpendicular to the hori- tor, bring the bubble of the plate level zontal axis of the instrument. to the center of its vial. b. Test. (3) Repeat the test (b above) and make (1) Select a well-defined distant point as any additional adjustment of the plate near the same horizontal plane as the level that is required. instrument as possible. d. Frequency of Test and Adjustment. The adjustment of the plate level should be tested (2) Center the vertical crossline of the every time the theodolite is set up for use. telescope on the selected point. With the vertical tangent screw, elevate and 127. Optical Plummet Adjustment depress the telescope. If the vertical a. Purpose. The purpose of the optical plum- crossline continuously bisects the met adjustment is to make the vertical axis of point, the adjustment is correct. 63 c. Adjustment. If the vertical crossline does slant position on the right side of the not continuously bisect the sighted point, rotate telescope the same amount, while at the telescope reticle to a point where the cross- the same time tighten (loosen) the line will bisect the point throughout the eleva- single screw on the left. tion and depression of the telescope. The cross- (5) Repeat the test and adjustment proce- line ring may be rotated by turning the slant dure until the spread between direct screws located between the focusing ring and and reverse pointings is less than eyepiece in opposite directions. 0.050 mil. 129. Horizontal Collimation Adjustment 130. Vertical Collimation Adjustment a. Purpose. The purpose of the horizontal a. Purpose. The purpose of the vertical col- collimation adjustment is to make the line of limation adjustment is to make the line of sight sight perpendicular to the horizontal axis of horizontal when the vertical circle reading is the telescope. 1,600 mils in the direct position or 4,800 mils b. Test. in the reverse position. (1) Select a well-defined distant point. b. Test. Select a well-defined distant point. (2) Center the vertical crossline on the Make a direct and a reverse circle reading. selected point. Determine the sum of the vertical circle read- (3) Read the horizontal circle with the ings. The sum will be 6,400 mils plus or minus telescope in the direct position and (±) the vertical circle spread. This is done as then with the telescope in the reverse follows: position. Determine the difference 1243.400 mils (direct reading) (spread) between the direct pointing 5156.100 mils (reverse reading) and reverse pointing. This is done as 6399.500 follows: 6400.000 0000.200 mil (direct reading) 0000.500 mil (vertical circle spread) 3200.800 mils (reverse reading) Note. The instrument should be adjusted 3200.600 if the spread is more than 0.150 mil. 3200.000 c. Adjustment. 0000.600 mil (spread between direct and reverse pointings) (1) The vertical circle reading (direct Note. The instrument should be adjusted position) is 1243.40 mils. The spread if the spread is more than 0.150 mil. is 0.500 mil and must be applied to c. Adjustment. the direct reading with the appropri- (1) The horizontal circle reading (direct ate sign. Subtract one-half the spread position) was 0.200 mil while pointed from the direct reading (1243.400— on the selected point. The spread is 0.250 = 1243.150). 0.600 mil. Add one-half the spread (2) Place the telescope in direct position to the direct reading (0.200 + 0.300 = on the distant point. With the coin- 0.500). cidence knob, set 0.150 on the microm- (2) With the coincidence knob, set 0.500 eter scale. mil on the micrometer scale. This is (3) With the collimation level (split bub- the mean direct and reverse pointing. ble) tangent screw, bring the main (3) Bring the main scale graduation lines scale graduation lines into coincidence. into coincidence, using the horizontal The telescope is now pointed at the circle tangent screw (slow motion). distant point with the mean direct (4) Place the vertical crossline on the and reverse reading on the vertical selected point by sliding the crossline circle (1243.250). diaphragm. To slide the diaphragm, (4) Aline the images of the ends of the col- loosen (tighten) the two screws in limation level bubble (split bubble), 64 using the two level adjusting screws. dure until the vertical circle spread is These screws are located immediately less than 0.050 mil. under the collimation level. Both 131. Maintenance screws should be rotated the same For maintenance responsibilities, see TM amount in opposite directions. 5-6675-213-12, Operator’s and Organizational (5) Repeat the test and adjustment proce- Maintenance Manual. Section IV. SEXAGESIMAL THEODOLITE WILD T2 132. General is numbered to indicate a degree. The lower a. The T2 theodolite, mil-graduated, is the window is the micrometer scale and is gradu- authorized instrument for obtaining angular ated in minutes and seconds from 0 second to values for artillery fourth-order survey. How- 10 minutes. The scale may be read to 1 second. ever, until the mil-graduated T2 theodolite is 134. Steps in Reading Circles available, the sexagesimal T2 theodolite will be used in artillery fourth-order survey. The steps in reading the circles are as follows (fig. 35): b. The mil-graduated theodolite and the a. Determine the first erect numbered grad- sexagesimal theodolite are identical except for uation to the left of the vertical line that marks the graduations of the horizontal and vertical the center of the upper window. The number circles. This section will deal with the differ- which labels this line indicates the number of ences in the circles. Both instruments are degrees. In figure 35 this number is 285°. operated in the same manner. b. Locate the inverted graduation which dif- 133. Reading Circles fers from 285° by 180°, this number is 105° The circle is viewed through the circle-read- (viewed QOl)- The inverted number will always ing microscope (fig. 35). The upper window is be to the right of the vertical line which marks the main scale, the graduations are spaced at the center of the field of view. Both values will 20-minute intervals, and every third graduation always end in the same number, in this case number 5. c. Starting from 285, count the number of spaces between the graduations determined in a and b above. Each space represents 10 minutes in the reading. In figure 35, there are five spaces, representing 50 minutes. d. The angular value obtained from the main 90 GO scale (upper window) is 285°50' (285° + 50' = 285°50'). e. The vertical line which marks the center of the field of view indicates the value to be read on the micrometer scale (lower window). 85 6 In figure 35, this value is 1'54". f. Add the angular values determined in d and e above (285°50' + 1'54" = 285°51'54", the angular value). Note. The horizontal and vertical circles are read in the same manner. 135. Setting the Horizontal Circle The procedures for setting the horizontal cir- cle of the sexagesimal theodolite are identical Figure 35. Scale images viewed in circle-reading micro- to those for the mil-graduated T2 theodolite. scope of sexagesimal T2 theodolite. However, the initial circle setting when measur- 65 ing angles should be 0°00,30" ± 20". When tion should not differ from the mean angle of measuring two positions, the initial circle set- the second position by more than 10"; if it ting for the second position is 270o00'30" ± does, the angle must be remeasured. (See fig. 20". 36 for sample of recording and measuring 136. Measuring Horizontal and Vertical angles with the sexagesimal T2 theodolite.) Angles 137. Adjusting the Theodolite The procedures for measuring horizontal and The adjustments on the sexagesimal T2 vertical angles are identical to those for the theodolite are performed in the same manner mil-graduated T2 theodolite. When measuring as the adjustments on the mil-graduated T2 two positions, the mean angle of the first posi- theodolite (pars. 102-107). IRON TIN POT ASILVER FIRST POSITION Horn pnfa.1 4 Stntiqr =i Direct and reversed readings Iron on nn on Station Iron. Mean of seconds. Complete -¡Ü.32 14 mean of direction is 00o00l 34“ Vdlue of the angle at POT from ..Tin 32 /S IL IRON to TIN. This angle was ß 2t>Z IS /5 determined by subtracting the !3 Mean direction to IRON Pr>! '34 47 2Ù- (00o00'34") from the mean direction to TIN (82° 15'IS"). ÏLQà . S i Mr Q 03 is circled to indicate that 3 ¡Q3~ OO B 2 x I ry B 352 IV 3Í 47 47 Mean value of angle at POT 172 14 42 45 from IRON to TIN. POT 4 (34 47 Í¿S) 34 41 n Silver 27 02 207 02 31 33 Figure 36. Field notes for recording measurements of two angles, two positions with the sexagesimal T2 theodolite. 66 CHAPTER 9 TELLUROMETER MRA 1/CW/MV Section I. GENERAL 138. General tors have a mirror surface which radiates the The tellurometer is an electronic distance- received signal to the dipole. The dipoles con- measuring device which appears as an item of tain the transmitting and receiving antennas. issue in tables of organization and equipment Both units have identical built-in aerial and of artillery units required to perform fourth- order survey (fig. 37). The tellurometer system consists basically of one master and two remote units. The major components for both the master and remote units are described in para- graph 139. Additional items used to complete a tellurometer measurement include the alti- meter, tellurometer field record and computa- tions form, and logarithmic tables. Distance is determined by measuring the loop transit time of radio microwaves from the master unit to r the remote unit and converting one-half of this loop transit time to distance. Although optical line-of-sight is not required, electrical line-of- sight between the instruments is required. The ir minimum range capability of the equipment is 152 meters and the maximum range capability is 64,000 meters (40 miles) under ideal condi- tions. Approximately forty-five minutes is re- quired to measure and compute a distance re- gardless of the length of the measurement. A distance can be measured during daylight or darkness and through fog, dust, or rain. 139. Description of Components a. The master and remote units are similar in appearance (figs. 38, 39, and 40) but neither master nor remote unit can be operated in a dual role due to its internal characteristics. The units have the same external dimensions (19 x 19 x 17 inches) and weigh 27 pounds. Both have parabolic reflectors which are shown in Figure 37. Tellurometer station with operating the operating position in figure 40. The reflec- equipment and carrying case. 67 communication systems. The luggage-type lid is provided with a sponge rubber seal for handle (fig. 40) permits the instrument to be protection against moisture. A luggage-type carried when it is not in its case. The hinged handle is provided on the top of the lid for door in the lower left hand comer of the con- transporting short distances. Provision is made trol panel (figs. 38 and 39) opens into a com- on the back of the case for securing the carry- partment in which the radiotelephone handset ing straps for backpacking. Compartments are is stored. A cathode ray tube (CRT) visor (fig. provided in the container for spare parts, tube 37) is mounted over the CRT scope to shut out visor, and rain cover. The carrying case meas- light and make scope presentations more clearly ures 23 by 12 by 19 inches and weighs approxi- visible. mately 18 pounds. b. The carrying case (fig. 37) is a light- c. The tripod issued with the tellurometer weight metal alloy, top-opening container. The is the Wild universal tripod, and it is inter- CRT light Pattern Cathode roy selector tube (CRT) graduated Panel light Ö Meter switch © m m Handset compartment & Figure 38. Control panel, master unit. 68 changeable with the tripod used with the T16 tion. An 18-foot cable is provided to permit the and T2 theodolites. built-in power pack to be connected to the bat- d. Three different power sources may be used tery in a vehicle for 24-volt operation. with the tellurometer. A 12-volt, 40-ampere e. The spare parts kit consists of a small hour battery or a 24-volt, 20-ampere hour bat- tery may be cabled directly to a built-in power metal box containing tubes, regulators, lamps, pack (figs. 38 and 39). In addition, a 115-volt, and fuzes. A list of these spare parts is pro- 60-cycle or 230-volt, 50-cycle power supply can vided in the metal container. be utilized through the use of a mains converter /. Additional accessories include a harness (external power pack). A fully charged battery (back straps) and pack, tube visor, plastic rain will permit 4 to 6 hours of continuous opera- cover, metal screwdriver, nonmetallic screw- Cathode ray Pattern selector tube (CRT) Panel light W-'*“ r "' - W;jp Meter switch m « Handset compartment / Figure 39. Control panel, remote unit. 69 driver, two power supply cables, mains con- of difference in height when it is not possible to verter, Handbook—Operation and Mainte- measure the vertical angle between master and nance, and Preliminary Maintenance Support remote units with an optical instrument. The Manual. vertical angle or difference in height is neces- g. A surveying altimeter, issued as a separate TOE line item, should be available with each sary to convert the slope distance measured master or remote unit for the determination with the tellurometer to horizontal distance. Remote Moster Circle omplitude Press pulse Shope I Y amplitude- I Pulse amplitude Remote Master Dipole- r r Y shift- tit X shift- E til Focus Brilliance- Figure UO. Side views of master and remote units. Section II. PRINCIPLES OF OPERATION 140. General wave of 10-centimeter (cm.) wavelength (3000 megacycles) is radiated from the master unit. a. To perform a distance measurement with This radio wave is modulated by what may be the tellurometer system, one master unit and referred to as pattern frequency. The modulated one remote unit must occupy opposite ends of wave is received at the remote unit and, in the line to be measured. A continuous radio effect, reradiated from the transmitted system 70 of the remote unit back to the aerial system of b. All of the frequencies are provided from the master unit. quartz crystals, the A crystal being accurately b. At the master unit, the return wave is set by reference to some standard, such as the compared with the transmitted wave, and the 10 megacycles per second (mes) signal radiated phase comparison or difference in the two by the Bureau of Standards in Washington. The waves is indicated on the circular sweep of the B, C, and D crystal may drift from specific master unit cathode ray tube (CRT) in the frequencies to some degree, but, since they in- form of a small break which marks the phase dicate only coarse increments of a measurement on a circular scale (fig. 41). The CRT graticule as will be shown later, this drift is not critical. is divided into 10 major and 100 minor gradua- tions. The leading edge of the break in the 142. Phase Comparison circular sweep is read clockwise to the smallest a. Phase comparison is the determination of minor graduation. the difference between the phase of one wave c. In effect, the transit time required by the and the phase of another at the same instant. wave to travel from the master unit to the With the tellurometer, it is the difference be- remote unit and back is determined. The transit tween the phase of the transmitted wave and time is determined from a series of readings on the phase of the wave returned to the master the master cathode ray tube. unit. b. With a pattern frequency of 10 mes, a complete rotation of the phase indication on the graduated scale represents a change of 100 millimicroseconds in the transit time of the wave from master unit to remote unit and back. The graticule of the CRT has 100 divi- sions representing 100 millimicroseconds. Each minor division represents 1 millimicro- second and, since radio waves travel at the speed of light (186,310 miles per second), is 25 equivalent to approximately 6 inches. A com- plete rotation of phase is equal to approxi- mately 15 meters. The 10 mes pattern or A pattern phase indicates the final two figures of the transit time in millimicroseconds or the final 15 meters of the entire measure- ment. Since the number of rotations of the A pattern phase cannot be determined, the B, C, and D patterns are introduced to increase the 50 wavelength. The differences between the A 20= Pattern Reading pattern reading and the B, C, and D pattern readings, respectively, give phase readings Figure 41. Cathode ray tube pattern reading. relative to the difference frequency of the modulations, and coarse patterns are derived 141. Carrier Wave Modulating Frequencies to determine relative portions of the distance a. The continuous carrieras follows: wave of approxi- mately 2,800 to 3,200 megacycles is emitted at the antenna. This wave is modulated by a series A minus D—1000 kes pattern—150 meters of pattern frequencies as follows: A minus C—100 kes pattern—1,500 meters Frequencn A minus B—10 kes pattern—15,000 meters Patter master (mes) Remote (mes) A 10,000 9.999 c. Based on the A minus B pattern difference, B 9.990 9.989 the maximum distance which could be measured C 9.900 9.899 D 9.000 8.999 is 15,000 meters. An additional pattern fre- A- None 10.001 quency would furnish an increment (150,000 71 meters) greater than the range of the instru- 144. Fine Readings ment. This is not considered necessary since a. The electronic circular sweep presentation the distance could be determined within 15,000 cannot be centered exactly on the graticule of meters (10 miles) by map inspection and there- the cathode ray tube visually. Any error which by derive the first digit of the transit time. The may be caused by centering errors is corrected table below may be used to determine numerical by the provision of an A-I-, A— presentation. prefixes to the tellurometer transit time: The A+ reading is the display of a positive pulse, and the A— reading represents the nega- Approximate length of Hne Numerical prefix tive pulse. Meters Miles b. A further refinement of centering errors 0-15,000 0-10 0 is provided through a phase reversal of the A 15.000- 10-203 1 0,000 crystal, positive and negative patterns. These 30.000- 20-304 2 5,000 are referred to as A + forward and reverse and 45.000- 30-406 3 0,000 A— forward and reverse. This phase reversal is also displayed on the cathode ray tube, and 143. Coarse Readings the readings are used to determine a mean fine Coarse readings are obtained during the A+ pattern reading. These displays are com- measurement by reading the graticule on the parable to the direct and reverse pointings of master cathode ray tube on the A, B, C, and D the theodolite on an object when measuring pattern frequencies. The resolution of the pat- angles. tern differences to a transit time is discussed c. Meaning of these fine readings is described in paragraph 155. in paragraph 153. Section 111. TELLUROMETER OPERATIONS AND COMPUTATIONS 145. Selection of Stations highly reflective surfaces, i.e., smooth, desert Electrical line-of-sight is required between sands and water. Figure 42 illustrates the the master station and the remote station. In effect of the reflection of microwaves from general, it must be nearly optical line-of-sight water. An error is caused by the tellurometer in that objects, such as hills or mountains, receiving both the direct wave and the reflected should not block the line-of-sight. However, in wave, sometimes referred to as ground swing. some cases a ridge may project as much as 50 Some of the error is removed by the method feet above the line-of-sight, and a measurement of observing. The mean of the four fine read- may be made. In artillery survey, the main ings, each at a different cavity tune setting, use of the tellurometer will be to measure removes a part of the swing error. distance on a traverse, in which case, angles d. The instruments should be set well back will be measured with a theodolite. The theodo- from the edge of the high land so that as much lite will require optical line-of-sight. It would of the reflective area becomes “dead ground” to appear that the best site for a tellurometer the receiving instrument (fig. 42) as possible. station is on top of a high peak; however, the following should be taken into consideration, 146. Operator Training primarily due to effects caused by the reflection a. An instrumentman qualified in the opera- of microwaves. tion of conventional surveying instruments can a. The ground between the two stations acquire, in approximately 40 hours, an adequate should be broken, and preferably covered with knowledge of both the master and remote units trees and vegetation to absorb the ground to perform and supervise all the activities re- waves and prevent them from interfering with quired to complete a field observation and to the direct signal. perform the necessary computations for the b. When possible, the ground should slope determination of a distance. gradually away from each instrument. b. Continued operation of the tellurometer c. If possible, avoid measuring lines over will provide the operator with sufficient knowl- 72 Reflected Microwave^ 1 l[ÎÎÏÏÏÏÏÏt "illllljl}n 777 tfïfiiîimiinjijijT o wrnrn^^^twimm^wnrL Reflected / / Microwave t / / ^ imiwmm* /A Wmmmmnn^mmmn^l¡JI0i r Figure 42. Reflected microwaves. edge to perform a limited amount of mainte- justed at the master unit without nance (par. 163). establishing contact with the remote unit operator (MEASURE-SPEAK 147. Instrument Controls (M/S) key at SPEAK) : The controls for the operation of the master Control Function and remote units are classified in four func- BRILLIANCE and These two controls are ad- tional groups—setting up controls for making FOCUS. justed in conjunction with the master-remote contact, operating controls each other to obtain a for making the measurement, monitoring con- bright, sharp cathode ray trols for checking the circuit adjustments, and tube (CRT) trace which internal controls for preset adjustments of in- appears as a luminous strumental circuits. The physical location of spot at this stage. these controls is shown in figures 38, 39, and X SHIFT and Y SHIFT These two controls are used 40. The functions of the individual controls in to center the image at the intersection of the hori- each functional grouping are as follows: zontal and vertical diam- a. Setting Up Controls. eters of the CRT grati- (1) The following controls may be ad- cule. 73 (2) The following controls are adjusted c. Monitoring Controls. at the master unit after establishing (1) The following controls are used at the contact with the remote unit (M/S key master unit to check the operating cir- at MEASURE): cuits prior to making a measurement: Control Function Control Setting and purpose CIRCLE AMPLITUDE Increases or decreases size SHAPE and Y of circular trace. SWITCHED METER Set to REG position to AMPLITUDE. Adjusts for truest circular check voltage regulators image. in klystron circuit. Set to MOD position with (3) The following controls are adjusted at M/S key at MEASURE the remote unit after contact is estab- to indicate correct crystal lished with the master unit (M/S key pattern modulation. at MEASURE): Set to AVC position, the Control Function meter indicates the signal BRILLIANCE, FOCUS Same function as in (1) strength being received. X SHIFT, and Y SHIFT, above. It should always be tuned b. Operating Controls. to maximum. CHECK PULSE Pressing this button per- (1) The following controls are used at the mits the master unit master unit during a distance meas- operator to view on his urement: CRT the pulse pattern Control Function presented at the remote PATTERN SELECTOR __Sets crystal pattern fre- CRT. quencies required for the CRYSTAL CURRENT measurement. meter. Registers crystal current. OPERATOR M/S key Switches to measuring or voice circuit in each unit. (2) The following controls are used at the Used also as a signaling remote unit to check the operating cir- device during measure- ments. With the M/S key cuits prior to making a measurement: at MEASURE, the opera- Control Setting and purpose tor may hear but cannot SWITCHED METER Same function as in (1) speak to the remote sta- above. tion. CRYSTAL CURRENT CAVITY TUNE dial Tunes frequency of klystron carrier wave radiation. meter. Same function as in (1) above. REFLECTOR TUNE dial -Tunes klystron electrically when kept at peak of crystal current during d. Preset Controls. measurements. (1) The following controls are preset in (2) The following controls are used at the the master unit: remote unit during a distance meas- Control Function urement: ADJUST MODULATION -Under the ADJUST-MOD- Control Function ULATION plate are four PATTERN SELECTOR, Same function as in (1) slotted controls for the M/S key, CAVITY above. adjustment of each crys- TUNE dial, and tal to a specified modula- REFLECTOR TUNE tion level. A nonmag- dial. netic screwdriver should A+ and A— READING be used. key Selects the A+ or A— pat- ADJUST FREQUENCY—Under the ADJUST FRE- tern as required during QUENCY plate are four an observation. controls for the adjust- FORWARD-REVERSE Selects the reverse A+ or ment of crystal fre- READING key A— pattern as required. quencies. Synchronization PULSE AMPLITUDE Sets amplitude of pulse re- turned to the master unit. is done only by a quali- Normally set at 5 unless fied technician. changed by instructions OVEN CYCLE Heats crystals automatic- from the master station. ally. 74 (2) The following controls are preset in e. When a 12-volt battery is used, connect the remote unit: the short (8-ft.) 12-volt power supply cable to Control Function INPUT. Connect the red lead to the positive ADJUST MODULATION-Same function as in (1) post and the black lead to the negative post. above. /. When a 24-volt battery is used, connect OVEN CYCLE Same function as in (1) the long (18-ft.) 24-volt power supply cable to above. INPUT. Connect the red lead to the positive 148. Setting up the Tellurometer post, and the black lead to the negative post. Any attempt to operate a master unit and a Do hot use the short 12-volt power supply remote unit while pointing at each other at a cable with a 24-volt battery, because this will distance of 150 meters (500 feet) or less will damage the unit. result in damage to the units. The instructions g. The system is ready to be turned on after contained in a through k below are applicable the completion of either e or f above. Place the to both the master station and the remote sta- low voltage (LT) switch in the ON (up) posi- tion: tion. This provides a filament current to the а. Unstrap the legs of the tripod, loosen the tubes in the instrument, and it must be turned leg clamp thumbscrews, and extend the tripod on 30 seconds before turning on the high volt- legs to the desired length; tighten the thumb- age (HT) switch. Both the LT and HT switches screws and embed each leg firmly into the must be in the ON position for operation of ground, making sure that the tripod head is ap- the instrument. The HT switch should be in proximately level and approximately over the the OFF position while waiting for the pre- point which identifies one end of the distance arranged time of operation agreed upon by the (line) to be measured. Attach the plumb bob master and remote operators. and extend it so that it hangs about 1 inch h. Turn the METER SWITCH to the REG above the point over which the instrument is (voltage regulator) position and the M/S key to be set up. to MEASURE. The reading on the SWITCHED б. Remove the instrument from the case and METER will vary with the strength of the place it on the tripod head. Thread the tripod battery. To permit a satisfactory measure- screw into the base of the instrument and tight- ment, the reading should be at least 30. A en it to insure that the instrument is fixed to reading of less than 30 indicates that the the tripod. Point the dipole in the approximate charge in the battery is too low for operation. direction of the remote station. The tellurom- i. Adjust the REFLECTOR TUNE dial for eter radiates a conical beam of about 10°. In maximum crystal current. The CRYSTAL windy weather the tellurometer should be tied CURRENT dial should read above 0.2 for best down to prevent the possibility of the instru- operation. The lowest reading on the CAVITY ment being blown over and damaged. TUNE dial will usually give the greatest c. Dismount the parabolic reflector from its CRYSTAL CURRENT reading. closed (travel) position and remount it in the j. Turn the METER SWITCH to MOD (modulate) position and check the modulation open (operating) position, making sure that level of each crystal. The PATTERN SELEC- fasteners fit properly and snugly. Failure to TOR must be turned to each crystal, in turn. do so may result in damage to the unit. The correct readings, as viewed on the d. Remove the power supply cable and the SWITCHED METER should be 40 on A, B, telephone handset from the storage compart- and C and 36 on D. If these readings are not ment under the control panel. Hang the tele- approximated, remove the ADJUST MODULA- phone handset on an improvised hook or TION cover and adjust the modulation trim- bracket on the tripod. Never place the handset mers. The trimmers should be adjusted if the on top of the unit, because inaccuracies are reading varies ± 2 from 40 or 36, depending created if the handset is left there during the on the crystal being checked. A nonmagnetic measurement. Place the low voltage (LT) and screwdriver should be used for this adjustment. the high voltage (HT) switches in the off posi- k. Switch the M/S key to SPEAK and move tion. the METER SWITCH to the AVC position. 75 The SWITCHED METER should read about Meter unit operator Remote unit operator 20 micro-amperes without the two instruments cl. Direction find (DF) c2. When instructed to being tuned and without the other set being the instrument by travers- do so, direction find the turned on. Turn the REFLECTOR TUNE ing it on the tripod until instrument by traversing dial. If the SWITCHED METER needle moves, the SWITCHED METER it on the tripod until the shows a maximum AVC SWITCHED METER the receiver is working. If there is no move- reading. Check plumb shows a maximum AVC ment of the indicator, trouble can be suspected after DF. Instruct the reading. Check plumb in the receiver and a repairman should be con- remote operator to direc- after DF. sulted. tion find his instrument. 1. This step is performed by the master unit dl. Switch to MEAS- d2. Switch to MEAS- only. Switch the M/S key to SPEAK. There URE and turn the ME- URE and turn the ME- should be a spot of light near the center of the TER SWITCH to MOD TER SWITCH to MOD position. Check the modu- position. Check the modu- cathode ray tube. Turn the CIRCLE AMPLI- lation levels by turning lation levels by turning TUDE control (right side panel) to make this the PATTERN SELEC- the PATTERN SELEC- spot as small as possible. Adjust the BRIL- TOR to A, B, C, and D, in TOR to A, B, C, and D, in LIANCE and FOCUS controls (left side panel) turn. Announce each mod- turn. Note the values of for a clear, sharp spot. Center the spot care- ulation reading to the re- the modulation levels. fully in the graticule, using the X SHIFT and corder for entry in block When requested to do Y SHIFT controls (left side panel). VI of the field record and so, report the modulation computations form (fig. readings to the master 43). Request modulation operator. 149. Tuning Procedures readings from the remote Thé instrument tuning procedures follow the operator and announce setting-up procedures and must be completed these to the recorder for prior to making a measurement. These pro- appropriate entry on the field record and computa- cedures start with the M/S key in the SPEAK tions form. Turn the position and require coordination between the METER SWITCH to master unit and the remote unit operators. AVC position. For this reason, the following instructions are el. Announce the fol- e2. Stand by. If re- arranged to insure that the proper sequence is lowing information to the quested to do so, provide followed. In each step, the operation desig- recorder for entry in information to the master nated with the number 1 precedes the opera- block I of the field record operator. tion designated with the number 2. and computations form (fig. 43) : instrument Meter unit operator Remote unit operator numbers, station numbers, a2. Set the CAVITY al. Set the CAVITY weather conditions, and TUNE dial two or three TUNE dial on the pre- operator’s names. numbers below the pre- viously agreed starting /I. With the M/S key /2. Switch the M/S key viously agreed starting number. Verify the maxi- at MEASURE, adjust the to MEASURE and stand number (setting of re- mum CRYSTAL CUR- CRT circle to a convenient by. mote) . Place the METER RENT by using the RE- SWITCH in A VC posi- FLECTOR TUNE dial. reading size by using the CIRCLE AMPLITUDE, tion. Increase the CAV- Place the METER Y AMPLITUDE and ITY TUNE dial setting SWITCH in AVC position SHAPE controls. until a maximum read- and watch the SWITCH- ing is indicated on the ED METER for a maxi- pi. Verify the maxi- p2. If requested to do SWITCHED METER. A mum reading as a signal mum CRYSTAL CUR- so, adjust the PULSE maximum A VC reading at that the master operator RENT reading by turning AMPLITUDE. this point indicates that has tuned his set. the REFLECTOR TUNE the master instrument is dial. With the METER tuned to the remote in- SWITCH in AVC posi- strument. tion, readjust the CAV- 61. Establish communi- 62. Answer the master ITY TUNE for a maxi- cations with remote opera- operator’s call. mum AVC reading on the tor. SWITCHED METER. 76 Meter unit operator Remote unit operator Master unit operator Remote unit operator Inspect the circular pattern is complete and trace on the CRT for a that a reading is desired good clean break. on the next (A—) pat- If a good break cannot tern. be obtained or the pulse When the A— pattern appears too weak or too appears on the CRT, read strong, instruct the re- the value and announce it mote unit operator to ad- to the recorder for entry just the PULSE AMPLI- in block II of the field TUDE. record and computations Note. The tellurometer system is now ready for form. distance measuring. For the A— pattern, continue to read the clock- 150. Measurement Procedure wise edge of the break. A tellurometer measurement consists of one Flick the M/S key set of initial coarse readings, four sets of fine twice to indicate to the readings, and one set of final coarse readings. remote unit operator that the reading of the A— A coarse reading consists of readings on the pattern is complete and A + , A—, B, C, and D patterns, and a fine read- that a reading is desired ing consists of readings on the A+, A—, A— on the next (B) pattern. reverse, and A+ reverse patterns. All read- Turn the PATTERN ings are recorded on the field record and com- SELECTOR to position B putations from (fig. 43) as they are taken. and proceed as with the The completed form constitutes a record of the previous readings. After each reading, flick the distance determined and the system operation switch to indicate readi- during one measurement. The field record and ness to read the "next computations forms for each measurement pattern. should be retained to make up a permanent log When the C and D pat- for the operation of the system. The measur- tern readings have been ing procedures require coordination between completed, return the PATTERN SELECTOR the master unit and remote unit operators. In to position A. This com- each step, the operation designated with the pletes the initial coarse number 1 precedes the operation designated readings. with the number 2. 61. Switch to SPEAK 62. Switch to SPEAK Master unit operator Remote unt¿ operator and advise the remote unit and wait for instructions. a2. When instructed operator that each fine ol. Switch to SPEAK When advised that that the initial coarse reading will be taken in and advise the remote unit fine readings will be operator that the initial readings will start, switch prescribed order (A + , taken, turn the METER coarse readings will be to MEASURE. Each time A —, A— reverse, A+ re- SWITCH to AVC position taken in the prescribed the master unit operator verse) . Normally four sets and set the CAVITY order (A + , A —, B, C, signals by flicking the key, of fine readings are taken. switch to the next pattern TUNE dial to the an- D). Switch to MEAS- The frequency interval be- frequency. nounced setting. URE, turn the PAT- tween sets should be the TERN SELECTOR to The master unit opera- maximum allowable (i.e., The CAVITY TUNE position A, and read the tor’s signal will appear as 3, 5, 7, and 9) over the dial setting should be the value on the CRT to the a flick on the remote unit range of the CAVITY same as that on which nearest division (fig. 41). CRT and as a break in TUNE dial. When mak- the initial coarse readings Announce the value to the the measuring tone on the ing the reverse readings, were taken. recorder for entry in phone. continue to read the block II of the field record and computations form clockwise leading edge of the break. (fig. 43). Flick the M/S key Announce to the remote twice to indicate to the unit operator the remain- remote unit operator that der of the CAVITY the reading of the A+ TUNE dial settings. 77 Master unit operator Remote unit operator Master unit operator Remote unit operator cl. Adjust the CAVITY c2. When instructed to Follow the procedure in TUNE dial, if necessary, do so, increase or decrease al above at the last CAV- for maximum A VC read- the PULSE AMPLI- ITY TUNE dial setting. ings. Check the RE- TUDE. As the readings are made, FLECTOR TUNE dial announce the values to for maximum CRYSTAL, the recorder for entry in CURRENT. Announce block IV of the field “measure” to the remote record and computations unit operator and switch form (fig 43). to MEASURE. /I. Compare the inter- f2. Stand by. Check the circle sweep preted initial and final for focus, brilliance, size, coarse readings for agree- shape, and circle break. If ment (blocks II and IV of the circle break is not the field record and com- apparent, adjust it with putations form). the REFLECTOR TUNE If a significant dis- dial. If the adjustment agreement is evident (par. fails to produce a break, 154), take additional communicate with the re- coarse readings until the mote unit operator and re- error is isolated. quest a high PULSE AMPLITUDE setting. gl. Advise the remote g2. Proceed as instruct- unit operator that the ed. dl. Take the four sets d2. For each of the four measurement is complete of fine readings at the sets of fine readings, use and give further instruc- previously announced the following procedure: tions. CAVITY TUNE dial in- When signaled by the tervals. Flick the M/S Instructions must be ex- key to signal the remote master unit operator that plicit and thoroughly un- unit operator. the A-f reading is com- derstood, since at this plete, switch the PAT- point the instruments will Announce the value TERN SELECTOR to be turned off and com- read for each pattern dur- the A— position. On the munications severed. ing the measurement of second signal from the If at any time in tun- each set to the recorder master unit operator, de- If at any time in tun- ing to a new CAVITY ing to a new CAVITY for entry in block III of press the FORWARD- TUNE dial setting, com- TUNE dial setting com- the field record and com- REVERSE key. When munications cannot be putations form (fig. 43) : the FORWARD-RE- munications cannot be made with the remote made with the master VERSE key is in the After taking the A + unit, return to the last unit, return to the last reverse reading of each REVERSE position, the CAVITY TUNE dial set- master unit operator CAVITY TUNE dial set- set, the master unit op- ting at which contact was ting at which contact was reads the A— reverse pat- erator should pause mo- made and issue instruc- made and await instruc- tern. On the third signal, mentarily before proceed- tions. tions. ing and allow the recorder switch the PATTERN to check the recorded SELECTOR to the A + 151. Computing a Tellurometer Distance values for possible read- position. This presents Measurement ing errors. the A+ reverse pattern to the master unit operator. a. Computations required for a tellurometer On the fourth signal, distance measurement are performed in the fol- raise the FORWARD-RE- lowing order : VERSE key and wait for (1) Interpreting initial coarse readings. instructions. When in- structed to do so, switch (2) Interpreting fine readings. to SPEAK and advance (3) Interpreting final coarse readings. the CAVITY TUNE dial (4) Resolving a transit time in millimicro- to the next setting. seconds from correctly interpreted el. Switch to SPEAK e2. Follow the proced- pattern differences. and advise the remote ure in a2 above at the last unit operator that final CAVITY TUNE dial set- (5) Computing a slope distance in meters coarse readings will be ting. from a transit time in millimicro- taken. seconds. 78 FIELD RECORD AND COMPUTATIONS - TELLUROMETER (TB ENO 23) BLOCK I - STATION DATA HEIGHT STATION INST. NO. OPERATOR METERS WEATHER, MASTER: 1 RECORDER: 3 ¿¿writ's* w?/ A/ea.¿ y A/t 7j- 238 REMOTE: fipncAe 2 BLOCK II ■ INITIAL COARSE READINGS BLOCK IV • FINAL COARSE READINGS A + A + os OS AT os * + OS + 0/A+ 0 7 A + I I LOO CORRECTED TRANSIT TIME (g) y }^7¿ \¿ J yj LOG SLOPE DISTANCE METERSQDI) ' \SS2\2S82 LOG 1/2 V/N METERS 91 ITS.6309 LOG COS VERTICAL ANGLE (XHI ) 9\999\977J 3 LOG SLOPE DISTANCE METERS! IIHZ 3 \s5 2^2882 (l)T(2) LOG HORIZONTAL DISTANCE METERS 3 \SS2\¿áSS ^ 11':;i : : / LOG SEA LEVEL COEFFICIENT (ZI I 9 ! 999\9727 (3> + <4) LOG SEA LEVEL DISTANCE METERS 3 \SS212 38J. BLOCK VIII ■ VERTICAL ANGLE SEA LEVEL DISTANCE METERS 3se,¿.v7 eS2 DIFFERENCE IN HEIGHT VßSS (METERS) VERTICAL ANGLE HORIZONTAL DISTANCE(METERS BLOCK X • FIRST FIGURE (TRANSIT TIME) I DIFFERENCE HEIGHT METERS 3¿\S APPROX DISTANCE MILES (I ) FIRST FIGURE LOG(I) / \S62\2929 NOTEBOOK REFERENCE AREA DATE DA. ISS» 5-139 Figure US. Field record and computations form. 79 BLOCK XI - SEA LEVEL COEFFICIENT GIVEN: The height used to determine log sea level Height of station - METERS. coefficient is height of known station to the near- est 100 meters. Mean height should be used if the FIELD DATA: heights of both stations are known. a. Approximate distance in both miles and meters. HEIGHT LOG SEA LEVEL b. Corrected transit time. c. Height if not available. METERS COEFFICIENT d. Vertical angle (compote if not possible -100 0.0000068 to measure). -50 0.0000034 00 0.0000000 GUIDE: 50 9.9999966 a. BLOCKS II, m & IV - If A+ is less than B, 100 9.9999931 C or A-, add 100 to A+ before determining 200 9.9999863 the difference. 300 9.9999795 b. BLOCKS II, HI fcIV - “Compare with A+” 400 9.9999727 means that this figure must compare t 4 500 9.9999659 MUS with A+ in the final coarse reading. 600 9.9999590 If necessary add 50. 700 9.9999522 c. BLOCK VHU5.) - Measured or computed 800 9.9999453 vertical angle. 900 9.9999386 10Ó0 9.9999317 LIMITATIONS: 1100 9.9999249 This form may be used for obtaining artillery 1200 9.9999181 survey accuracies. 1300 9.9999112 1400 9.9999044 RESULTS: 1500 9.9998976 A sea level distance is determined which 1600 9.9998908 should be treated the same as a taped 1700 9.9998839 distance. 1800 9.9998770 1900 9.9998703 2000 9.9998634 2100 9.9998566 2200 9.9998498 2300 9.9998429 2400 9.9998361 2500 9.9998292 2600 9.9998225 2700 9.9998156 2800 9.9998088 2900 9.9998020 3000 9.9997951 3100 9.9997883 3200 9.9997815 3300 9.9997747 3400 9.9997678 3500 9.9997609 3600 9.9997542 NOTE: The above values were computed for a northing of 3 200 000 and azimuth of 45 degrees and can be used anywhere on the UTM grid with- out causing an error greater than 1:250,000. GPO Figure UU. Back of field record and computations form. (6) Reducing a slope distance to a hori- have been necessary to add 100 to the A+ be- zontal and sea level distance in meters. fore subtracting. b. Tellurometer distancec. measurements The difference are in the forward readings is normally computed at the master station be- added to the difference in the reverse readings, fore party personnel depart for subsequent sur- and the sum is divided by 2 to obtain the mean vey operations. This permits the verification difference (06 + 08 = 14 2 = 07). of the distance determined by map scaling and d. The mean difference is divided by 2 to ob- the resolution of ambiguous pattern differences tain the mean fine reading (07 + 2 = 3.50). if they occur. Figure 43 illustrates recording e. Subparagraphs a through d above correct of readings on a field record and computations for the zeroing error (par. 144). The three form and is used as a reference for the discus- remaining fine readings which were taken at sions on computations. remote dial settings 5, 7, and 9 are meaned the 152. Interpreting the Initial Coarse same as the example above which was taken at Readings (Block II) remote dial setting 3. The mean fine reading for the four sets of fine readings (3.31) is de- a. The phase difference is determined by sub- termined and compared with A+ (03.00) in tracting the coarse readings, B, C, D, and A— block II (3.31 — 3.00 = 0.31). This compari- from the A-(- reading. If necessary, add 100 son is satisfactory because it is within 4 milli- to A+ before subtracting. In figure 43, it is microseconds. necessary to add 100 to A + . /. Four sets of fine readings are made using b. Divide the A-l- A— difference by 2. Com- all parts of the cavity tune dial ; i.e., 3, 5, 7, and pare this value (03.0) with the A-l- reading 9. The use of all parts of the cavity tune dial (05). They compare within 2 millimicrosec- will reduce the reflection error until it is so onds, which is satisfactory. If the readings do small that it will seldom affect artillery survey not compare within 4 millimicroseconds, they accuracies. must be reobserved. After dividing by 2, in some cases, it will be necessary to add 50 when 154. Interpreting the Final Coarse making the A+ comparison. Readings (Block IV) The final set of coarse readings is taken pri- 153. Interpreting the Fine Readings marily as a check on the initial coarse readings. (Block IM) The final coarse readings are interpreted and In the example below, one set of the fine the differences are resolved in the same manner readings in figure 43, block III, are meaned : as the initial coarse readings (par. 152). If the Remote difference between the patterns of the two sets Set dial Forward Reverse 1 3 A+ 05 A+ 59 of coarse readings exceed that shown below, a A- 99 A- j>l third set of coarse readings is taken and the 06 08 differences are resolved. 06 + 08 = 14 -r- 2 = 07 mean difference Pattern Maximum difference 07 2 = 3.50 mean fine reading A 4 A-f- (initial coarse) = 05.00 (block II) B 3 Mean fine reading = 03.50 C 3 Zeroing error = 1.50 millimicroseconds D 2 а. In the forward readings, the A— is sub- 155. Resolving the Transit Time from tracted from the A-K Because the A+ was Pattern Differences (Block V) smaller than the A—, it was necessary to add a. In the spaces provided in block V, transit 100 to 05 before subtracting (100 + 05 = 105, time (fig. 43), enter the final coarse readings 105 — 99 = 06). Add 100 only when necessary. (differences) from block IV, the mean fine б. In the reverse readings, the A— is sub- reading (to the nearest hundredth) from block tracted from the A-l- (59 — 51 = 08). If the III, and the first figure (transit time) from A-t- had been smaller than the A—, it would block X (approximate distance in miles). 81 b. On the line for unresolved transit time, the procedure and eliminates the requirement enter the first digit appearing on each line in for meteorological observations during a meas- block V and the decimal value of the mean fine urement. This index has been corrected mathe- reading (fig. 45). matically by applying the velocity of a radio c. Determine the resolved transit time by wave per millimicrosecond to provide a con- successive comparison and enter the value on stant, the log of which is added to the log of the the line for resolved transit time (fig. 43). The resolved transit time to produce the log of a method used to resolve a corrected transit time is illustrated in figure 45. The resolved transit one-way slope distance in meters. This log time represents the travel time in millimicro- (9.1756509) appears on line 2, block VII (fig. seconds of the electromagnetic wave trans- 43) and is added to the log on line 1 ; the re- mitted from the master unit to the remote unit sulting sum is the log slope distance in meters and return. (line 3, block VII). 156. Computing Slope Distance in Meters c. The log of one-half the corrected refrac- (Block VII) tive index (9.1756509) block VII, line 2 should a. The resolved transit time in millimicro- provide an accuracy greater than 1:10,000 at seconds is a time measurement which must be air temperatures of —40° F. to +120° F. at corrected for the refraction of atmosphere and elevations of —1,000 to + 10,000 feet, and at converted to a one-way slope distance in meters. all conditions of humidity. One-half the cor- The log of the resolved transit time is entered rected refractive index is used because it is in line 2 of block VIL multiplied by the transit time of master to re- b. A mean refractive index is used for the mote to master which is twice the distance refraction correction. This greatly simplifies from master to remote. BLOCK ir-TRANSIT TIMEdE.ET, SX) Obtained from approximate From block X, enter 0 on line for resolved transit time distance in miles (block X OiO (Approx, dis. miles from map scale = 2.3 miles 33803.31 To compare with value closest to 28000; Final A-tB Diff A + B Diff consider enter 2 on line for 13803.31 resolved transit time , 5803.31 / value closest to 4100; To compare with ^ Coarse >- A + CDiff 4803.31 = I enter 3 online for 0.0 A + C Diff consider (3803. 31) \ resolved transit time t 903.31 /value closest to 820; To compare with 803.31 = j enter 8 on line for Readings A + D Diff O 0 A+D Diff consider C703. 3D y resolved transit time (block nr) Î Use this value to Enter the mean fine reading from Mean fine reading (block JH) 3.3 compare with block m. This value will not change A + D Diff Unresolved transit time Unresolved transit time (block HI) 3 .3 Resolved transit time Resolved transit time (block HI) 3 .3 Figure U5. Illustration of resolving a transit time. 82 157. Determination of the Vertical Angle method used in taping is not sufficiently accu- (Block VIII) rate to warrant converting to sea level distance. a. The slope distance has been determined in However, a distance determined with the tel- block VII. The horizontal distance is used in lurometer is of a greater length and of suffi- artillery survey. Consider that the slope dis- cient accuracy for conversion to sea level dis- tance is the hypotenuse of a right triangle. tance rather than horizontal distance at the The horizontal distance may be computed using height at which the measurement was made. the slope distance and the vertical angle or the 159. Survey Party Personnel and Duties slope distance and the difference in height a. One man can operate either the master or (block VIII). remote unit. However, in order to fully utilize b. When the vertical angle is measured, it is the accuracy and speed of a tellurometer sur- entered on line 5 (fig. 43). The vertical angle vey, two men—an instrument operator and a should be measured reciprocally or corrected recorder—are required for each unit. As with for curvature, when measuring over a long all artillery survey operations, two independent distance. The vertical angle may be expressed computations must be made. in either degrees, minutes and seconds, or it b. The theodolite will be used for angle meas- may be expressed in mils, depending on the urement with the tellurometer. Generally, the type of theodolite used to make the meas- tellurometer is used in artillery fourth-order urement. survey in which case fourth-order specifications c. If the vertical angle is not measured, then will be used. If used for artillery fifth-order it must be computed by using the slope dis- survey the tellurometer distances are measured tance and the difference in height. The differ- the same as for artillery fourth-order, and ence in height is obtained from block I, line 3. artillery fifth-order specifications are used for The vertical angle is computed in block VIII. angle measurement. In either case one theodo- d. The heights of the master station and the lite is provided with each master and remote remote station are entered in block I, line 1 and unit. An altimeter is also provided with each 2. The height is obtained from known data or master and remote unit for the determination determined with the altimeter (ch. 12). of height when a vertical angle cannot be measured. 158. Reduction of Slope Distance to Sea Level Distance (Block IX) c. The tripod should be set up over the sta- tion and used for both the tellurometer and a. The slope distance is reduced to sea level the theodolite. The same instrument man and distance by computations, using the slope dis- recorder utilized for distance measurements tance, vertical angle and sea level coefficient. are utilized for angle measurements. The computations are made by following the instruction in block IX (fig. 43). 160. Tellurometer Traverse b. Instructions for the use of the sea level a. The primary use of the tellurometer in coefficient are on the back of the form in block artillery survey is to measure distance for XI (fig. 44). traverse. However, any required distance vary- c. The computations on the field record and ing in length from 150 meters to approximately computations form (fig. 43) end with sea level 40 miles may be measured. The main advan- distance in block IX. To carry the computa- tages of determining distance by tellurometer tions further would be a duplication of effort, over taping are greater accuracy, measurement since most Department of the Army artillery over rough terrain, and the relatively short survey forms provide for the application of time required to measure long distances. the log scale factor to convert to universal b. Short distances can usually be determined transverse mercator (UTM) grid distance. in less time with a tape than with the tel- d. When a tape is used for determining dis- lurometer. The average distance measured in a tance in artillery survey the distance taped is tellurometer traverse will be from 2 to 5 miles, horizontal distance when using a tape. These because of the necessity of distributing survey taped distances are relatively short and the control throughout an area of operation. 83 c. A set of tellurometer equipment consists method of survey for which the tellurometer of one master unit and two remote units. In may be used. traverse, the master station is the mid-station b. Generally, trilatération will not be used and the remote units are located at the forward when a tellurometer traverse could be used to and rear stations. The master unit measures establish survey control, because, in most tac- the distance to the forward and to the rear tical situations and terrain, a tellurometer tra- station each time it is set up. The leapfrog verse is more accurate, is faster, is less method is used for the extension of survey con- complicated, and requires fewer computations trol. Angles are measured at each tellurometer and less reconnaissance. Vertical control can- station. When measurements are complete at not be carried in trilatération, except with the the first three stations, the master station and altimeter. rear remote station are moved to the next suc- c. However, trilatération is a method of sur- cessive points ( fourth and fifth points, respec- vey which may be used when no other method tively). The former forward remote station can be used. If the area is covered with heavy remains in position and on succeeding measure- ground fog, angles cannot be measured with a ments acts as rear remote station. The proce- theodolite; thus, a tellurometer traverse can- dure is continued with the master station being not be used to establish survey control. If a positioned between two remote stations until line of known direction is available, it may be measurements are completed. used as one side of a triangle, and the other sides of the triangle could be measured with 161. Trilatération the tellurometer to establish a point by tri- a. Trilatération (the measurementlatération. ofHeight three to the point could be deter- sides of a triangle to solve for three angles as mined with the altimeter and an azimuth opposed to measuring three angles with a provided with an artillery gyro azimuth sur- known baseline in triangulation) is another veying instrument. Section IV. TELLUROMETER MAINTENANCE 162. General eter generates a 250-volt potential at the a. Discretion must be exercised in assigning Klystron cavity. Power to the unit must be maintenance responsibilities to operating per- turned off before removing the side panels. sonnel. The availability of artillery surveyors Maintenance experimentation by operating per- with a sufficient knowledge of electronics to sonnel must be strictly prohibited. perform all of the tellurometer adjustments 163. Equipment Failures and Remedial and repairs is limited. For this reason, the Actions operator’s maintenance should be confined to a. The following chart has been prepared a level suitable for personnel accustomed to principally as an aid to maintenance instruc- conventional survey equipment. tion and is a guide only. It is not intended to b. The tellurometer is a relatively delicate supplant maintenance directives. For mainte- instrument. Unlike conventional survey equip- nance responsibilities and procedures, refer to ment, the tellurometer is susceptible to many TB ENG 23, Use of The Tellurometer in Mili- effects besides rough handling. The tellurom- tary Surveying. Failure Probable cause Remedy Level Power supply: No power to unit. Power connection broken. Connect Operator. Blown or corroded fuses. Replace or clean. Operator. Battery clips broken or Replace or clean. Operator. corroded. 84 Failure Probable cause Remedy Level Power supply—Continued Vibrator out Report to second-echelon Second echelon. repairman. Battery dead Replace Operator. Sparking at powerpack. Broken cable or cable Report to second-echelon Second echelon. shield. repairman. Switched meter: No REG indication. No power or internal Check power as above; if Operator. failure. power supply is satis- factory, report to sec- Second echelon. ond-echelon repairman. REG too high; needle Defective power cable Report to second-echelon Second echelon. remains above scale. shield. repairman. Crystal current meter: No registration. Defective antenna diode. Tap diode crystal lightly Operator. or replace. Defective current meter. Report to second-echelon Second echelon. repairman. Excessive current on all Antenna reflector still in Place in operating posi- Operator. cavity tune frequen- traveling position. tion. cies. Current below 0.15 ma Low battery Replace Operator. at all frequencies. Maladjusted dipole. Report to second-echelon Second echelon. repairman. Impaired reflector tune Report to second-echelon Second echelon. control (if CRT trace repairman. jumps when control is moved). Current low on one fre- Maladjusted klystron. Report to second-echelon Second echelon. _ quency. repairman. Maladjusted dipole. Report to second-echelon Second echelon. repairman. No change in meter Screws loose on shaft Report to second-echelon Second echelon. when cavity tuner is from knob to tuner. repairman. turned. Cathode ray tube: Brilliance . too dim or Brilliance setting too low. Turn higher Operator. none at all, but signal can be heard on phone. Faulty cathode ray tube. Report to second-echelon Second echelon. repairman. Improperly seated cath- Report to second-echelon Second echelon. ode ray tube. repairman. Burned out filament in Report to second-echelon Second echelon. cathode ray tube. repairman. 85 Failure Probable cause Remedy Level Cathode ray tube — Con- Incorrect pulse amplitude Check pulse at remote Operator. tinued setting. unit. No circle break, but sig- nal tone on phone with normal traces on cath- ode ray tube of each unit. Master unit not properly Flick MEASURE- Operator. tuned to remote unit. SPEAK switch; note (Tuned to a side fre- A VC reading. quency.) If appreciable change oc- curs, improper tuning denoted. Too high brilliance set- Reduce brilliance. Operator. ting. Faulty tubes in IF, limi- Report to second-echelon Second echelon. ter or discriminator. repairman. Faulty diodes in limiter Report to second-echelon Second echelon. output. repairman. Broken lead in discrimi- Report to second-echelon Second echelon. nator. repairman. Unsteady circle. Klystron not securely Report to second-echelon Second echelon. seated. repairman. Moving objects in path of Await cessation. Operator. beam. No circle on master OPERATOR MEASURE- Set switch to MEASURE. Operator. unit cathode ray tube. SPEAK switch on SPEAK at either station. Incorrect cavity tuning. Check at both stations. Operator. Distorted circle on mas- Master unit tuned to har- Check modulation. Operator. ter unit cathode ray monic. tube. Maladjusted shape con- Adjust Operator. trol. Defective X or Y ampli- Report to second-echelon Second echelon. fier tube. repairman. No circle at one crystal Defective crystal on mas- Switch to MEASURE. Second echelon. setting. ter or remote unit. Switch to MOD. If no MOD reading, crystal is defective. Defective oscillator tube Report to second-echelon Second echelon. in circuit. repairman. Different circle sizes at Incorrect crystal fre- Adjust: Operator. different crystal set- quency modulation. A = 40, tings. B = 40, C = 40, D = 36. 86 Failure Probable cause Remedy Level Cathode ray tube — Con- Low battery- Check REG. Operator. tinued Recharge. Small circle not reacting Faulty diode in modula- Report to second-echelon Second echelon. to amplitude control. tion circuit. repairman. Different break presen- Incorrect crystal syn- Paragraph 1636. Operator. tation at different chronization. crystal settings. Radiotelephone : No measuring tone. Faulty connection. Report to second-echelon Second echelon. repairman. OPERATOR MEASURE- Set switch to SPEAK. Operator. SPEAK switch at MEASURE, either unit. Incorrect crystal modu- Adjust: Operator. lation setting. A = 40, B = 40, C = 40, D = 36. No measuring tone. Defective crystal Report to second-echelon Second echelon. repairman. No communication. Units improperly pointed. Direction find. Operator. Faulty telephone connec- Report to second-echelon Second echelon. tion. repairman. OPERATOR MEASURE- SPEAK switch at MEASURE. Large A+ A— spread: Master unit cathode ray Adjust Operator. tube trace incorrectly centered. Defective klystron, when Report to second-echelon Second echelon. condition appears sud- repairman. denly. Defective capacitor in de- Report to second-echelon Second echelon. flection circuit. repairman. b. When adjusting for SHAPE and Y AMP- The following procedure is used to synchronize LITUDE, if it is impossible to obtain a cir- a crystal: cular image on the master cathode ray tube, (1) Master unit. the crystal will have to be synchronized. Each (а) Assume that the A crystal requires synchronization. Switch to SPEAK crystal in the master unit is synchronized with and instruct the remote operator to the corresponding crystal in the remote unit. synchronize the A crystal. When a circular image on the CRT cannot be (б) When the remote operator ac- obtained, switch to other crystals. If a satisfac- knowledges, switch to MEASURE. tory circular image is obtained on the other Set the PATTERN SWITCH to the crystals, it is necessary to synchronize the A crystal. Do not remove the crystal which will not provide a circular image. plastic cover marked ADJUST This must be done by a qualified technician. FREQUENCY on the master unit. • 87 (2) Remote unit. tions—Tellurometer). The computations for (a) Switch to SPEAK, acknowledge the determining sea level distance are also accom- master operator’s instructions, and plished on this form. The completed form with request him to switch to the A field records and computations should be filed crystal. with the survey computation where the distance (b) Remove the plastic cover marked was utilized. ADJUST FREQUENCY and the right side cover to expose the SET 165. Operating Temperature CRYSTAL BUTTON on the remote a. The tellurometer has been designed to op- unit. erate over the range of —40° F. to +104° F. (c) Hold in the spring loaded SET air temperature. The crystals of both the CRYSTAL BUTTON and adjust master and remote units are mounted in an the A+ crystal screw to obtain a oven which automatically maintains operating relatively stationary elliptical trace temperature. The oven begins operation as on the CRT. This trace may have soon as the power source is connected, regard- some motion, but it should not ap- less of whether the low voltage (LT) or the pear as a rapidly moving basket high voltage (HT) is on or off. weave. A nonmagnetic screwdriver b. Readings should not be taken until the should be used. OVEN CYCLE lamp has gone off for the first (d) Repeat synchronization for the A— time. The OVEN CYCLE lamp will then blink crystal. on and off while automatically maintaining op- (e) Repeat synchronization for other erating temperature. crystals B, C, or D as required. c. Approximately 30 minutes is required for (/) Notify the master unit operator the crystals to reach operating temperature at when synchronization is complete. —40° F. air temperature; less than 15 minutes is required, at +40° F. air temperature. If the 164. Notekeeping tellurometer is operated in cold, extremely Field notes of the tellurometer are entered on windy weather, a light windbreak around the DA Form 5-139 (Field Record and Computa- instrument will reduce warmup time. 88 CHAPTER 10 TARGET SET, SURVEYING Section I. GENERAL 166. General the instrument holding screw. The target is a. The target set is used by artillery missile fastened to the tribrach with the instrument firing batteries, which require a very accurate sliding clamp located on the side of the tri- laying azimuth, to mark one end of the orient- brach. ing line. The target set is not used for artillery survey. 169. Leveling and Pointing the Target b. The target is mounted on a tripod. The a. The target tribrach contains three level- tripod is the same type of tripod used with the ing screws, the optical plumb, and a circular T2 or T16 theodolite. The carrying case (12 x level vial. The target contains a longitudinal 10 x 6 inches) is a wooden, top-opening box level vial and is leveled and plumbed over the which contains two targets, two tribrachs, and point in the same manner as the theodolite two night light attachments. Two tripods with (pars. 91 and 92). plumb bob and adjusting wrench and two bat- b. The target is oriented perpendicular to tery cases are issued with the target set. the line-of-sight of the instrument which is pointing on the target. 167. Setting up the Tripod The procedures used for setting up the 170. Illumination of Target tripod for the theodolite are also used for setting up the tripod for the target set. The night light is attached to the back of the target and is plugged into the battery case. 168. Placing the Target on the Tripod The battery case is the same as that used for The tribrach is fastened to the tripod with the theodolite. Section II. USE AND CARE OF THE TARGET 171. Sighting the Targetscope should not be changed during the angle a. A sighting (pointing) is made on the measurement. target by bisecting the extended apex of the large triangle with the vertical crossline and 172. Use of the Target on Short Sightings bisecting the extended vertexes of the two In providing an azimuth for an orienting smaller triangles with the horizontal crossline line in terrain which requires short sightings, (fig. 46). greater accuracy is obtained by using targets b. The distance from the angle measuring instead of range poles to mark stations. A tar- instrument to the target should be approxi- get is placed over the forward and rear sta- mately the same distance as from the angle tions. The tribrachs remain with the tripods. measuring instrument to the object to which The theodolite and targets are moved after the angle is measured. The focus of the tele- each angle is measured. The target on the for- 89 ward station is replaced with the theodolite. a. The longitudinal level is adjusted in the The theodolite is replaced with the rear station same manner as the plate level on the theodo- target. A target is placed over the new forward lite (par. 103). station. This leapfrog procedure provides b. The optical plummet is adjusted in the greater accuracy in centering and leveling on same manner as the optical plummet on the short lines, but little is gained on long lines. theodolite (par. 104). 173. Adjustments of the Target 174. Care and Maintenance of the Target The target requires two adjustments—the The target is a precise instrument and longitudinal level and the optical plummet ad- should receive the same care and maintenance justments. as the theodolite. I Figure U6. Tripod mounted target. 90 CHAPTER 11 ARTILLERY GYRO AZIMUTH SURVEYING INSTRUMENT Section I. GENERAL 175. General source to a usable power to revolve the gyro- scope in the alinement head. The control panel The artillery gyro azimuth surveying instru- includes the controls and indicators necessary ment is a portable gyrocompass used to deter- for the operation and to determine the direc- mine astronomic (true) direction at a fixed tional alinement of the instrument. An integral position. Direction is determined by observing voltmeter circuit is furnished to check various the effect of the rotation of the earth on the operations of the instrument and serves as an gyroscope and applying appropriate corrections aid to troubleshooting. The electronic package to the instrument. Accuracy of a direction ob- contains six removable subassemblies called tained with this instrument is comparable to modules (fig. 49). This type of component that of astronomic observations. packaging facilitates the replacement of faulty components. The complete electronic package 176. Components weighs 52 pounds. The artillery gyro azimuth surveying instru- ment consists of the following items (fig. 47): c. Poiver Source. The artillery gyro azimuth surveying instrument is primarily designed to a. Alinement Head. The alinement head con- operate from a power source of 24 volts direct tains a highly sensitive single axis rate gyro- current (DC). However, a powerpack contained scope (fig. 48). Mounted to the gyroscope as- in the bottom cover of the electronic package sembly is a mirror assembly used to check the can be used to convert 110 volts alternating collimation of the instrument. The mirror may current (AC) to direct current. be seen through the circular window installed in the side of the alinement head. A T2 theodo- d. Interconnection Cables. The instrument is lite (0.002 mil) is mounted on the top of the provided with several cables. One cable is used alinement head in such a manner that the hori- to carry power from the electronic package to zontal circle of the theodolite is locked to the the alinement head. When the instrument is movement of the alinement head. This allows operated on direct current, either a 5 foot the azimuth of any line to be determined with power cable (when the current is provided by reference to true north after orientation of the separate batteries) or a 25 foot power cable instrument has been completed. The base of the (when the current is provided by batteries instrument contains the leveling and alinement installed in a vehicle) is used to carry the power assembly. The instrument is leveled in the from the power source to the electronic pack- same manner as a theodolite. The alinement age. When the instrument is operated on alter- controls consist of an azimuth lock (fast mo- nating current, two powerpack cables are used; tion) and an azimuth vernier knob (slow mo- one connects the power source to the powerpack tion) with an odometer-type scale. The complete and the other connects the powerpack to the alinement head weighs 61 pounds. electronic package. b. Electronic Package. The electronic pack- e. Tripod. The tripod is a heavy duty, age (fig. 47) converts the power from the power specially designed tripod with wooden legs or 91 shorter metal legs. The legs are interchange- a wider scope of situations. The tripod with able to allow operation of the instrument under wooden legs weighs 21 pounds. Section II. USE, CARE, AND MAINTENANCE OF ARTILLERY GYRO AZIMUTH SURVEYING INSTRUMENT 177. Setting up the Equipment consists of calibrating the instrument to insure Setting üp the equipment consists of remov- that the only torque (force) exerted on the ing components from containers, plumbing over gyroscope will be the rotation of the earth. the station to be occupied, assembling the com- Calibration is accomplished by turning the ponents, leveling the instrument, attaching the selector switch to position 1 and the clamp necessary cables, and turning the alinement switch to the READ position and then adjust- head so that the circular window is pointing ing the calibrate knob until the indicator approximately west. needle is zeroed. Bias torques that are com- pensated for by this adjustment are mechanical 178. Coarse Alinement stresses, bearing friction, magnetic fields, fluid Coarse alinement includes the bias adjust- forces, etc. This step is performed before the ment and the head alinement. Bias adjustment gyroscope motor is turned on. Head alinement 0 m 92 Figure U7. The artillery gyro azimuth surveying instrument. consists of obtaining a coarse east-west direc- cator meter. The azimuth lock is then tight- tion with the instrument. This is accomplished ened, and the indicator needle is nulled within by putting the gyroscope into motion and turn- one graduation of zero by using only the azi- ing the alinement head until the indicator muth vernier knob. needle is nulled (zeroed). The gyroscope motor is turned on by turning the selector switch to 179. Fine Alinement position 2. The indicator needle is partially Fine alinement includes the final head aline- nulled in this phase of the operation by turn- ment and the readout of direction. The final ing the alinement head manually until the in- head alinement consists of obtaining a more dicator needle is less than three divisions away sensitive reaction of the gyroscope to the rota- from zero. Care must be taken to insure that tion of the earth. This step is accomplished by the alinement head is not moved unless the turning the selector switch to position 3 and clamp switch is in the ADJUST position and nulling the indicator needle by using only the that sufficient time is given for the indicator azimuth vernier knob. The indicator needle is needle to settle down before reading the indi- nulled within one graduation of zero. Readout £>- I«*î % m Figure U8. Single axis rate gyro. 93 b» m. I - Figure U9. The electronic package disassembled. of direction is accomplished by taking one posi- This process is repeated until the required tion with the theodolite to a desired mark or number of sets of readings are taken. The final reference point. These readings are then re- step is to apply grid convergence to the mean corded and meaned. This gives a direction to true azimuth determined with the instrument. the reference point with the gyroscope rotating This will provide the grid azimuth from the in one direction. The selector switch is then instrument to the reference point. turned to position 4. This causes the gyroscope to reverse its direction of rotation. Again the 180. Taking Down the Equipment indicator needle is nulled within one graduation The equipment is taken down in the reverse of zero by using only the azimuth vernier knob. order from which it was set up. Before remov- By obtaining the relative position of the aline- ing the alinement head from the tripod, care ment head with the gyroscope rotating in a must be taken to insure that the gyroscope is forward and a reverse motion, compensation no longer revolving and that all switches are is made for any further bias torques not turned off. By placing the ear next to the aline- compensated for by the calibration of the in- ment head, one can determine when the gyro- strument. Readout of direction is again ac- scope has stopped by the cessation of the noise complished by taking one position with the of rotation. theodolite and recording and meaning the new 181. Care and Maintenance directions obtained. The directions obtained in Specific maintenance responsibilities and positions 3 and 4 of the selector switch are procedures are covered in appropriate technical meaned. This constitutes one set of readings. bulletins and manuals. 94 CHAPTER 12 ALTIMETER Section I. GENERAL 182. General Variations from this standard set of condi- a. The surveying altimeter is used in artillery tions would be converted to corrections and survey to determine height when stations do applied as required to compensate for their not have optical intervisibility. Though alti- effect. The standard conditions for altimetry metry is not considered a precise method for as it is used by the artillery are as follows : determining heights, during normal weather (1) Instrument temperature—75° F. conditions it is sufficiently accurate for artillery (2) Air temperature—50° F. survey. The altimeter is used to determine the (3) Relative humidity—100 percent. difference in height between two stations. This (4) Latitude—45° N(S). difference in height is then applied to the height (5) Altitude—( + ) 45 meters (m). of the known station to determine the height (6) Gravity acceleration—32.2 feet per of the unknown station. second per second (ft/sec/sec). b. In altimetry, altitude (height) of points (7) Wind—0 miles per hour (mph). is determined from the difference in altimeter readings caused by changes in atmospheric 183. Surveying Altimeter pressure for different altitudes. The basic a. The surveying altimeter is an aneroid principle of altimetry is that the pressure barometer which' measures atmospheric pres- caused by the weight of the column of air sure by mechanical means. The scales are so above the observer decreases as the observer graduated that air pressure is indicated in rises in altitude. An assumption is made that units of height (meters). points of equal pressure are of equal height. If b. The surveying altimeter issued to artillery weather conditions and instrument conditions units (fig. 50) has a range under standard were always standard and never varied, it conditions of 300 meters below to 4,500 meters would be possible to set up a pressure-altitude above mean sea level. The instrument contains ratio that would enable an observer to measure an aneroid element consisting of a single the pressure at any given point and then rapid- vacuum chamber. Expansion and contraction ly compute the altitude (height) of that point. of this chamber are indicated by rotation of In altimetry this is essentially what takes an indicating hand and movement of a revolu- place; however, because weather conditions, in- tion indicator. struments, and geological and geographical c. The altimeter has a circular dial with four conditions vary widely and in certain areas air scales, two outer and two inner, with an an- is compressed and in other areas air is rarefied, nular mirror located between the outer and it is not possible to set up a pressure-altitude inner scales (fig. 51). The indicating hand ratio which by itself will always produce an makes nearly four revolutions in measuring accurate result. It is therefore necessary to throughout the range of the altimeter. A establish a set of standard conditions and use revolution indicator indicates the scale which this as a basis for the pressure-altitude ratio. should be read. Zero on the dial corresponds to 95 a pressure-height of 300 meters below mean which it is to be used. For this reason, the sea level under standard conditions; 4800 on dial, the vacuum chamber, all parts of the the dial corresponds to 4,500 meters above mechanical linkage, and the instrument tem- mean sea level under standard conditions. The perature correction chart are not interchange- least reading on the scales is 2 meters. Each able with corresponding parts of other alti- altimeter dial is custom calibrated for the meters. In the face of the dial is a vacuum chamber and mechanical linkage with desiccant-condition indicator which becomes SPANNER WRENCH FOR TIGHTENING SCREW PLUGS L k. s n LIGHT DIFFUSOR FLASH LIGHT LAMP \ RHEOSTAT AND SWITCH LAMP SCREW PLUG BATTERY SCREW PLUG 96 Figure 50. Surveying altimeter, b,500-meter, 2-meter divisions. pink when moisture within the case is exces- 184. Sling Psychrometer sive. a. A folding sling psychrometer is carried in d. The case is airtight except for a small the lid of the altimeter. The psychrometer con- vent which permits the pressure inside the sists of two identical Fahrenheit* l thermometers case to become equal to that outside. The case mounted side by side with a cloth wick on one can be made completely airtight by shifting a of them (wet bulb). Psychrometer readings movable vent cap to the closed position and are made to the nearest degré# Fahrenheit, as closing the lid. The vent normally is left open. follows : The psychrometer i»; unfolded, the However, it should be closed when the instru- cloth wick is saturated with clean water, and ment is packed for shipping. A built-in night- the psychrometer is revolved at a rate of 2 lighting system utilizes standard flashlight revolutions per second for at least 1 minute. batteries and lamps. Scale lighting is adjusted Temperatures are immediately read and rec- by a switch and rheostat assembly. Batteries orded, first the “wet bulb” and then the “dry should be placed in the case only for actual bulb.” night operations. A silica gel desiccant is in a container in the lower part of the case. b. The thermometers should be checked Carried in the lid of the case are a reading against a standard thermometer or against glass, a folding sling psychrometer, a spanner each other. When this check is made the “wet wrench, calibration charts, correction tables, bulb” readings must be made with the wick and spare parts. dry. A correction factor should be determined ANNULAR VENT MIRROR REVOLUTION DESICCANT INDICATOR INDICATOR ALTITUDE — ■by.i Vt li* Û MSê Bll* i\ mü nrs! *0 -«e 3 I*- ? \ ¿JÁ ¥ ALtACC A W«*** CAOO-JC’S tNC BÍLLCVULC NCWJCBSCV vmr » 1 SC«!. oO* wttr acrt DOir OOfl SCALE ADJUSTING SCREW INDICATING HAND Section II. USE OF THE ALTIMETER Figure 51. Altimeter dial. 97 for any thermometer that does not agree within issued with the instrument should be replaced 2° of the standard or other thermometers. by engineer instrument repair personnel if re- placement is necessary. 185. Weather Conditions The accuracy of heights determined by alti- c. Artillery survey personnel are authorized métrie leveling depends on the stability of pre- to remove and dry or replace the silica gel vailing weather conditions. Valid results cannot desiccant in the instrument when the desiccant- condition indicator turns pink. The silica gel be obtained during periods of strong or gusty can be dried by heating it to 300° F. for at least winds or during thunderstorms or other violent weather. The best results are obtained in winds 10 minutes. of 10 miles per hour or less. Generally, the d. Artillery survey personnel are authorized hours from 1000 to 1400 are the most unstable to replace the lamp for the night-lighting sys- parts of the day and should be avoided if possi- tem when it is necessary and to insert and ble for making altimeter readings. The atmos- remove the batteries for the night-lighting sys- pheric conditions that prevail during fog, mist, tem. The batteries should not be inserted until or light rain are usually suitable for altimétrie the instrument is to be used at night. After leveling. The altimeter should be shaded from its use at night, the batteries should be re- the direct rays of the sun when readings are moved. being taken. e. Artillery survey personnel are authorized 186. Care and Maintenance to replace a broken thermometer in the sling psychrometer. A thermometer can be replaced a. The surveying altimeter is a delicate in- by removing the screw cap from the end of the strument although rugged enough to be used psychrometer head. The cork disc for the cap for field survey if handled with care and pro- must be in place when the cap is replaced. tected from shock. The instrument and its ac- cessories should be kept clean and dry. The /. Altimeters to be used during fieldwork window of the instrument is made of clear should be set so that the scale readings of all plastic, which scratches easily. It should be instruments when located at the same station brushed with a camel’s-hair brush to remove will read nearly the same, preferably within 10 dust and polished with lens tissue or a soft rag. meters. This will simplify construction of the The window should be waxed. The instrument comparison adjustment graph (figs. 53 and should not be oiled. Oil will interfere with the 62). The adjustment of instrument scales operation of the instrument and cause errone- should be performed by engineer instrument ous readings. repair personnel. The amount of the difference b. Artillery personnel are not authorized to in scale reading when two altimeters are read repair the instrument. They should never re- simultaneously at the same station has no ef- move the window. The spare hand which is fect on the accuracy of the scale readings. Section II. USE OF THE ALTIMETER 187. Methods of Altimetrytion (s) . These simultaneous scale readings, ad- justed for instrumental differences, are com- a. Two methods of altimetry are employed pared to determine the indicated difference in in artillery survey. These methods are— height between the base station and the field (1) The single-base method (par. 194). station(s). The wet and dry bulb (fig. 54) (2) The leapfrog method (par. 195). correction is applied to the difference in ad- : b. A base station (point of known height) justed scale readings to obtain the relative and a field station(s) (point(s) for which height(s). height is desired) are used in both methods. d. The field station and base station make c. Both methods of altimetry require that simultaneous observations after coordinating simultaneous readings of altimeter scales be the time by radio communication. When a taken at the base station and at the field sta- radio is not available simultaneous observations 98 may be made by a prearranged observing b. The comparison adjustment should be ap- schedule. The watch of the field station ob- plied to the corrected scale reading of the field server must be synchronized with the watch of station instrument (par. 191). The applica- the base station observer. tion of this adjustment provides the adjusted e. During normal weather conditions, a ma- scale reading. jority of the heights obtained by altimetry will c. The difference between the corrected scale be correct within 3 meters and the maximum reading of the base station and the adjusted error will seldom exceed 5 meters, provided the scale reading of the field station should be cor- following precautions are taken : rected for air temperature and relative humid- (1) Individual instrument temperature ity (par. 192). correction is applied. (2) Comparison adjustment is made. 190. Individual Instrument Temperature (3) Wet and dry bulb correction is made Correction (fig. 54). a. Each artillery surveying altimeter is cali- (4) Difference in height between base sta- brated at an air temperature of 75° F. If the tion and field station is less than 200 instrument temperature differs from 75° F., it meters. will change the value of the scale reading. (5) Distance between base station and When maximum accuracy is required, a correc- field station is less than 20,000 meters. tion must be made for this difference. f. The artillery surveyor need not make cor- b. The corrections for temperature differ- rections for tables II and III which are con- ence are determined from the individual tem- tained in the lid of the altimeter. perature correction chart which is fastened in the lid of each instrument. This chart is differ- 188. Reading the Scales ent for each instrument. Figure 52 is an ex- The altimeter scales are read as follows : ample of the temperature correction chart for a. Place the instrument as nearly level as one instrument. To obtain the correction which possible with the dial in the horizontal posi- should be applied to an instrument reading— tion. The instrument must be protected from (1) Locate the position along the bottom the sun and the wind. of the graph which corresponds to the b. Tap the window of the instrument lightly scale reading, taken to the nearest 100 to overcome any lag due to static electricity. meters. c. Position the eye so that the indicating (2) Project this point upward along a line hand and its reflection in the annular mirror parallel to the vertical lines of the coincide. Care must be taken to select the graph to the curved line of the graph. reflection of the hand and not its shadow. (3) From the point of intersection of the d. Determine the scale which should be read projected line and the curved line, by the revolution indicator. project a second line to the left parallel to the horizontal lines on the e. Read the proper scale under the indicat- graph. ing hand to the nearest 0.5 meter. The reading glass may be used to aid in'reading the scale. (4) At the intersection of the second pro- Note. Extreme care must be taken to insure that the jected line with the left side of the correct scale is read since the scales increase in value graph, determine the meters correc- in a counter-clockwise direction. tion per degree Fahrenheit, noting the sign of the correction. 189. Corrections and Adjustments (5) Multiply this factor by the number of a. The scale reading of eachdegrees instrument by which the instrument tem- should be corrected for the individual instru- perature at which the scale reading ment temperature correction (par. 190). The was taken differs from 75° F. (The application of this correction provides the cor- sign of the product is the sign of the rected scale reading. correction.) 99 TEMP CORRECTION PER DEG F. ABOVE OR BELOW 75° F. .07 ABOVE 75° F ADD CORRECTION ALGEBRAICALLY, BELOW 73° SUBTRACT SERIAL NO. UJCEj-y S STM-3 SK K O Q- -.10 5000 4000 3000 2000 1000 INSTRUMENT SCALE-METERS Figure 52. Individual instrument temperature correction chart. (6) Apply this value to the altimeter scale b. After the field survey is completed, the reading. If the air temperature was final comparison is made at the same station above 75° F, add the value algebrai- and in the same manner as the initial compari- cally. If the air temperature was son (figs. 53 and 62). below 75° F., subtract the value alge- c. The time lapse between the initial and braically. This correction provides the final comparison should be held to a minimum, corrected scale reading, less than 4 hours if possible. c. The following is an example of the appli- d. A comparison adjustment graph is con- cation of an individual instrument temperature structed in the field station record book by in- correction— serting values on the lines in the record book (1) 2431.5 (scale reading). (fig. 53). The procedures in preparing the (2) 50° F (instrument temperature). graph are as follows : (3) 75° — 50° = 25° (number of degrees (1) Use initial watch time and difference to which correction is applied). in corrected scale reading to plot the (4) +0.07 meter (correction per degree) initial comparison point on graph. (fig. 52). (2) Use final watch time and difference in (5) 25° X 0.07 = 1.75 meters (correc- corrected scale reading to plot the tion). final comparison point on graph. (6) 2431.5 — ( + 1.8) = 2429.7 (cor- (3) Join points with a straight line. rected scale reading). (4) Using watch time for each reading in the field record book as argument, 191. Comparison Adjustment read comparison adjustment from left a. The base station instrument is placedside on of graph. a station of known height. The field station 192. Correction for Air Temperature and instrument is placed beside and at the same Relative Humidity height as the base station instrument. The ini- tial comparison is made by recording the time a. A folding sling psychrometer is carried in and the scale reading of each instrument. The the lid of the altimeter case. The psychrometer base station scale reading is recorded in the consists of two thermometers ; the wick of one base station field book (fig. 55). For compari- thermometer is saturated with water to give son purposes, both the base and field corrected the tvet bulb temperature, and the other is left scale readings are recorded in the field station dry to give the dry bulb temperature. These record book (figs. 53 and 62). The base sta- two factors are used to obtain the correction tion instrument remains in the same position to the difference in height for air temperature throughout the altimeter survey. The field sta- and relative humidity. tion instrument is taken to stations of unknown b. To measure these two correction factors— height. (1) Remove psychrometer from case. 100 DESIGNATION DATE. Co##ecreo cefjpecreo fíLTj/)7£TE* ST/iT/OA/ T//y? £ SCJ9J.S 'T//yi£ See 7. e 1?EAOtN6 ZP 0S00 ¿0Z. z 07/0 F/£LD ZF é/2. Z ¿,2¿.Z /0.0 - / 3. 0 uJAiT'ce T./ 07 £ jr/vs£ er ¿s# 0£ 5 OÆ ~r//rt,:r ££c.j/ e//y£ /?£/'A'Ese’/rr/A S / //ots* os oo OO OO OS oo / 3.00 07 FJNfU. ContPEe/soe Dlt-F£PENCE, 62^*0 « 42.00 U- 7^ 4+S0 Co nope P/ sON eoJi/sT 01 ENT FOP CNEPC NEE = - //. £ u 2^ Cû/. 1 pep/SoN 0 Qy/i/sretENT FOP Ú. 09 0S0CE --/ 4. Co/nP.'.llr/SoN PD , tPSTPIENT Cae ¿0. 7S- nflP&E« - /o. e 40.S0 40,2F /#/ '/Pi Conop IP/SOA/ 40,00 D/FFEPE* C£ Figure 53. Comparison adjustment graph (single-base). 101 (2) Slide handle off as far as it will go. (7) Repeat (5) and (6) above until two o (3) Rotate the thermometer 180° and the successive readings agree within I . handle 90° on its link. Record the lowest reading on both the wet and dry bulb thermometers, (4) Saturate the wick of the wet bulb c. By knowing the wet and dry bulb tempera- thermometer with clean water. tures, the correction factor can be determined (5) Revolve thermometers two or more from the chart in figure 54. The chart is en- times a second for at least 1 minute. tered with the wet bulb temperature at the top (6) Immediately read and record the wet and the dry bulb temperature on the left hand bulb and then the dry bulb tempera- side, and the intersection of the two columns tures. is the correction to be multiplied by the differ- TABLE I AIR TEMPERATURE & RELATIVE HUMIDITY CORRECTION FACTOR FOR ALTITUDE Temperature Wet Bulb Temperature Degrees F. Below greeting 34 35 38 40 42 44 46 48 50 32 54 60 Deg. F. Factor _i2_ This chart Is to be used to obtaio the 34 36 0 975 temperature and relative humidity cor- 36 rections required when using the single- 0.792 0.979 base method of altimeter leveling. Use 38 0.983 Q«-984 only with altimeters set and calibrated 40 In meters according to the Smithsonian 0.987 Meteorological Table No. 51. _4Ä_ 0.822 0.990 0.990 0.991 0.992 44 -38 0.992 0.993 0.994 0.995 0.996 46 0.830 0.997 0.998 0.999 48 -34 0.634 50 1.006 1.008 1x009 0.842 54 1.007 1.010 1.011 ■UPU lx£12 1x412 1.013 1.014 1.014 1.016 1.016 1.017 1,917 IxPia, Axfllfl 1x412 l-019i 1x020 1.020 1.021 0.854 1,018 1.023 1.024 luP« IxSlfi. 1x416 1.027 1x421 1.028 1.028 1x422. 1x030 1x421 1.026 1.027 1.032 1.032 1.033 1.034 1x422. 1x462. 1.041 1.043 1x043 68 0.874 1.046 JU046 1x047 0,878 1.042 1.043 1x041 1*046 IxfiML 1x062. 1x450 1x451. 0.882 1.046 1.046 0.886 1.049 1.049 1.050 1.052 0.890 .053 .054 1.055 1.058 1x422 1x069 1x061 1x462. 0.894 1x058. 1x022 1x060 .060 1x061 1.062 1x066. 1x062 1x065 1.063 1.064 0.902 Ji6_ 0.906 1x069 1.074 1x071 A .076 1x476.. 0.910 tOU 1x074 1x075 lxQ75 1.076 1.077 1.078 1x078 1x072 1x080 90 8XAMPLB OF USB OF CHART 1.080 92 0.923 Aooums altimeter "A" reado 900 meters and "B" reads 1100 matero, dry bulb 80*?, wet bulb 60 F. Find 80 In dry bulb temperature column, 1.090 1.090 _26_ follow ocroso to 60 of wet bulb temperature column. 1.093 1.094 1.095 Read correction factor 1.063. Corrected altitude 0.935 1.096 1.097 difference = (1100-900) (1.063) o 212.6 meters. Interpolate the correction factor to the nearest .001 0.943 1.109 Mil 0.951 1x112. Oil ixlU 1x1 A4 1x111 1x111 A.117. 0.955 Alfl Ml 1x111 1.118 1x112 1x112 1x124. 0-959 1x126. U2_ _24_ 0.963 114 114 46 I 48 50 52 58 (continuad on facing pegs) Figure 54. Temperature and humidity correction chart. TABU I (continued) AU T8MF8BATD&B & BLELATIVB H0M1DITY CORRECTXC» FACTOR FOR ALTITUDE Wat Bulb Temperatura Pcgr*»* F. 86 90 92 94 104 1,044 -U 1.052 1.052 _22_ 1.065 80 82 1.076 184 1.074 1.074 1.076 86 1.083 1.084 88 1.084 90 k2*l. 92 . 1.094 , iaoi 2.102 94 1.094 1.095 1.096 1.098 1.103 96 1.103 98 1.103 1.104 1.105 »3100 1.113 1,114 1.118 ü 1.106 1.109 ; 1.113 1,116 1.122 io» : 1.113 : 1.116 1.124 1.126 : 1,132 1.134 104 106 1.117 J 1.120 : 1.124 1,125 1.129 1.132 1.134 1,136 108 1.120 : 1.123 1.124 : 1,129 1.130 : 1.133 ; 1.136 1.139 1.141 1.143 1.144 110 1.123 1.124 ; 1.127 1.128 1.130 : 1.132 1.134 1.140 : 1,143 1.145 m 1.125 1.142 1.144 : 1.147 114 1.129 1.130 1.131 1.132 1.133 1.133 : 1.137 1.140 1.144 1.145 1.151 114 1.134 1.135 1.137 1.138 : 1.141 1.142 1,143 1.145 1.154 1.142 : 1.146 1,147 1.154 1.158 1.163 1.140 1.146 : 1.149 1.151 1.152 1.155 1.164 122 1.145 1.146 1.149 ) 1.154 1.157 1.159 1.164 1,166 1,150 1.158 1.161 1.162 1,169 . 1.174_ 126 1,153 1.157 1.160 1,162 1.164 1,166 1.1731 1.178 74 102 Figure 54' ■Continued. ence in the corrected scale reading of the base c. The altimeter should be cushioned against altimeter and the adjusted scale reading of the road shock, and sudden jarring should be field altimeter. This correction should be in- avoided at all times. terpolated to the thousandth in table I (fig. 54). d. Observations should be avoided during midday. 193. Precautions and Limitations to be e. Observations should be avoided during Observed when Establishing Height thunderstorms, whirlwinds, gusty winds, or with Altimeters squalls. a. The base and field altimeters should be /. Comparison readings should not be taken observed under similar conditions in the field over 4 hours apart. and protected from the sun and strong wind. g. Base and field station watches must be The altimeter should be shaded when it is being synchronized. moved between stations. h. The difference in height between base and b. The altimeter must be in a horizontal posi- field station (s) should be less than 200 meters. tion when observed, preferably on a level and i. The field station(s) should be less than stable surface. 20,000 meters from the base station. 103 Section III. PROCEDURES AND COMPUTATIONS 194. Single-Base Method (1) Station at which observation (s) is a. The single-base method of altimetry re- made. quires one station of known or assumed height (2) Time of observation. (base station). If possible, the base station (3) Instrument temperature. should be centrally located with respect to the (4) Scale reading. points for which the heights are desired (field (5) Instrument temperature correction stations). In order to obtain the required ac- (par. 190). curacy, the field station(s) must be within (6) Corrected scale reading (par. 190). 20,000 meters horizontally and 200 meters ver- tically of the base station. The accuracy of the d. Computations for the single-base method height determination will increase as the hori- are performed on DA Form 6-27 ( Computation zontal and vertical distance between the base —Altimétrie Height) (fig. 57). Instructions and field station (s) decreases. for the use of the form are contained on the reverse side of the form (fig. 58). Figure 58 5. Techniques of observing are the same as contains a note as to the probable results be- those discussed in paragraph 188. cause of the deletion of certain correction fac- c. Recordings are made in DA Form 5-72 tors which may be applied on the form. Also (Level, Transit and General Survey Record contained on the reverse side of the form is a Book). The base station recorder’s notes are height conversion section which is self-explana- shown in figure 55. The field station recorder’s tory. Figure 57 is an example of computations notes are shown in figure 56. The base station for the single-base problem shown in figures 53, will record both wet and dry bulb temperatures. 55, and 56. The field station will determine comparison ad- justment and adjusted scale reading (par. 191). 195. Leapfrog Method Both the base and field stations record the a. In the leapfrog method (fig. 59), two alti- following— meters (A and B) are read simultaneously at a BA5£ 3 : 7~4>P WiATHef: CL £/!R - ùo/iKM c# af per/TT y : A/fi. sar* PF^inMATintj /}ÁTrof*r/tY S/r*GL£- BASF QATF Jie JVt-Y ig to iNSTKoinen/r m/r 77/t osseKyeR: setroepr Bfise tNST SCALS »NST c*K*e<- re» Ter* peftATune T C M P /{EM T/a*t -r/me TSttf* REfiDlN* coXRfcrio* HEAD/H* osoo 90 003. O - .8 OO'S 93 OOO. O - .9 UP*' S9 77 0 0 30 90 CoO. S - .8 90 77 O Ï 'O 9¥ 0/¥ o - .? C,/JZ Column 1 Base station Column 6 Corrected scale reading, algebraic sum, 2 Time of observation column 4 and 5 (par 190) 3 Instrument temperature 7 Base station wet bulb temperature 4 Base station altimeter (par 192, a B b) scale reading 8 Base station dry bulb temperature 5 Instrument temperature correction (par (par 192, a&b) Figure 55. Base station recorder's notes for altimetry (single-base). 104 FIELD 57AT/ON : RAHGE- OSAGE- c#£Xo/e££ LJEATHER: c cH of PA/1TY : nelson nFSifiMATinM ALTtMETRY St#&L£- SMS' OATE JULY IQ 6Û INST/li/M £HT NK: 77/7 OJSfe/rtsÆ/? : BOHSOæ# n/tr APJUSfEO f/etù fNsr SCALE rEMA JCÂif comP»pgrttm ¿CJ9LE REAr, ARKS Sr**'** TEMP RBAOtHG CeAfgc T/*# #£**/#* AOJUSTmtHT REAOIM& 0500 97 fa/2. O fa/2. 2 RA*£E osso 9JL 732.E + . 2 732. 7 - /O.S 72/. 9 Ob 'f 9b 922.0 ■h , 2 722.2 - //.2 in. o c MEE ok EE Ob 30 98 70! F .2 20/. 7 -if.* (.90. S og to 9t faZEO b2 b. 2 Column 1 Field station (for comparison Column 5 Instrument temperature correction (par 190) adjustment the first and last 6 Corrected scale reading, algebraic sum, observations are always made column 4 and 5 (par 190) at the base station) 7 Comparison adjustment (par 191) 2 Time of observation 8 Adjusted scale reading column 6 plus? 3 Instrument temperature (par 191) 4 Field station altimeter scale reading Figure 56. Field station recorder’s notes for altimetry (single-base). base (known) station (Arbuckle). Then altim- figure 60. Altimeter B recorder’s notes are eter A is kept at the base station while altim- shown in figure 61. Both wet and dry bulb eter B is advanced to the first field station temperatures at the time of each altimeter read- (BnSCP 1). The two altimeters are again read ing will be recorded for altimeter A. Compari- simultaneously, and the corrected difference is son adjustment and adjusted scale readings for applied to the base station (Arbuckle) height each observation will be determined for altim- to give the height of the first field station eter B (par. 191). The following is recorded (BnSCP 1). Then altimeter A is taken from for both altimeters A and B— the base station (Arbuckle) to the second field (1) Station at which observation is made. station (BnSCP 2). Altimeter B, which is still (2) Time of observation. at the first field station (BnSCP 1), now be- comes the base station. The altimeters are (3) Instrument temperature. again read simultaneously, and the corrected (4) Scale reading. difference is applied to the base station (BnSCP (5) Instrument temperature correction 1) height to give the height of the second field (par. 190). station (BnSCP 2). Altimeter B is now ad- (6) Corrected scale reading (par. 190). vanced to the third field station (BnSCP 3), d. The recording and computation of the and the same leapfrog procedures used with leapfrog method is the same as for the single- the first and second field stations are repeated. base method except— The altimeters are brought together and read (1) In the single-base method, the base at station Gruber, and a comparison correction station altimeter remains at one base is determined (fig. 62). The comparison correc- station during the survey. In the leap- tion should be made at every third or fourth frog method, altimeter A starts off at station. the base station. Altimeter B advances b. The techniques of observing are the same to the first field station and acts as as those discussed in paragraph 188. the field altimeter. Altimeter A ad- c. Recordings are made in DA Form 5-72. vances to the second field station and Altimeter A recorder’s notes are shown in acts as the field altimeter at which 105 COMPUTATION* ALTIMPTUC HEIGHT ( UNCLE-AASC M LEAFFEOC MITNOO) 5éa.é CASE STATION DET RULE TCMFOUTUtl EC AMMO. e 88 _83_ 3o_ * til FIELD STATION WET RULE TEMPERATURE READINO EASE STATION —T mUL> T WATW »PABinn tc 77 77 i 7-g/i? 7// .O 6 7^.^ BASE STATION 1CALB BBADINC I U 02,5 COS,/ IF (*) n MOA I THAN <10), L°S\7 USB ff) - <10L SION <+ ). <1K L*B MAN oolrN + 4- DOB IIP) —<01 HON I - l.y <±1 (±) /QS\? 64 \S m it» time altimeter B remains at the first whether it is designated base or field field station acting now as the base station. station. Thus altimeters A and B e. In the leapfrog method computations are alternate as the base and field station made on DA Form 6-27 (fig. 63), the same (fig. 59). form which is used for single-base computa- (2) In the single-base method, the wet tions. Data used in figure 63 is taken from and dry bulb temperatures are re- sequence of observations (fig. 59), altimeter A corded at the time of each observation recorder’s notes (fig. 60), altimeter B recorder’s of the base station. In the leapfrog notes (fig. 61), and comparison adjustment method, altimeter A will record the graph (fig. 62). wet and dry bulb temperature at the time of each observation regardless of f. The survey between stations where com- whether it is designated base or field parison observations are made is referred to station. as a “leg”; i.e., FIRST LEG (figs. 59 and 62). (3) In the single-base method, the com- parison adjustment is always made 196. When Used on the corrected scale readings of the a. Altimetry is used in the determination of field station altimeter. In the leapfrog height, when trigonometric height determina- method, the comparison adjustment is tion is not feasible. The situation may exist always made on the corrected scale when, because of heavy fog, optical observation readings of altimeter B regardless of cannot be made. Under these circumstances, GIVEN RESULTS FCR SINGLE*BA3 METHOD: Fee each field tudm, altlnaete teals leading at bate nation FOB SINGLE-BASE METHOD: It cao he expected that height» determined «rill have a maximum and adjiated acalc reading at field oartoa (lakes ai «aaaa tima); *7 bolb tempaatwe and aea bulb «nia of 4 meta» and an average error of 1 meta when otoervattoa wing «uttoard equipment arc tempaam at »tattoo and field (tattoo (trmpsanne at bate (tattoo low po La ted 0 tima of made aa fracrihed. i¿«dlngi at field (Uttoak height oí bass tUdoa. FŒ IZAfFROG METHOD It can be expected that height» detomlncd «rill have a maximum F OH LCAFTOOG METHOD- Fat each leg; altimeter tcale reading at bate »tattoo and adjated orar of 3 meter* and an average error of 1/2 meta when otnerratkmi nrfng «uadard equipment ate teala readío g at fini field tattoo (taken at tama üme); Ay bolb tetaptoaaas aod wet btilb tenpa- made aa prctalbed. auae a: bate »tattoo and fliM field tuttoo (taken at unie tine), height of bate (tattoo Adjiated tcale reading at flnt field »attoo (hate nation for tecond half of leg) and aldmcis icale reading at woond field tuttoo (taken at tame tlme]| dry bulb tenpetatwc sod wet bulb taiupcratve at FOBMULA flra aod teeood field luttooi (taken at tame time). D * G(B • A) • s CorredeJ GUIDE A ■ hue nados adjiated »cale reading B » field tuttoo adjused »cale reading C 9 height corteetton factor FOB LEAPFROG METHOD: Height of bate »tattoo for each field tuttoo except the flnt field D « height of field tuttoo nadoo ii height own pm ad Í01 (xertou» field «attoo. E 9 known height of bate lutlon FOB BOTH METHODS: Uw InowB belgbu to acares ooe-teoA meta. Coavert known height to meta» «rhea gives la feet or yard». UM logarithm» to five place». When knows height of bate tuttoo in sap (16) b below tea level, me nep (19) at a negative vaine aod proceed with compilation. (Ufa 0 TM 6-200 far eddlttoeal Information. HEIGHT CONVERSION- BASE STATION FEET TO METERS TAROS TO METERS BASE STATION HEIOHT IN FEET ¿Vf HEIGHT IM TARDS LOG OF HEIGHT 3,0 9S, 90 LOG OF HEIGHT LOG COMVCRSIOH FACTOR LOG CONVERSION FACTOR NUMBER HA VINO LOO (4) a HEIGHT M METERS HUNIER HAVING LOG (4) = HEIGHT IM METERS GPo aeisea Figure 58. Instructions for use of DA Form 6—27. DESIGNATION . n TF -I9_ ARBOcfLe BM 5CP-/ 8* XP-2 8M 5£f-3 GKuBiK /) 903' Co/UPA P/30/tA 8 903- -} f)8 930 830933 r/83T ifO 88 0930 88 0930 80 /o30 88 A030 80 A/JO 88 //Jo 8 "33 C33rS0f/3eM 8 "33,Fj 8 388. *T/A/6 ST 9T/e" 8 «38 8lr. 0>3r88 8 3T8.’r/MO 3188/0// 8/ri.O 8iT’Of£T88 80 "0' 0 ¡.7/013/ m ¡MM3 A/ , 0013 0, 7/0/3733 08 ~0~ 9i T//M3T 88 ¡MM30 0330 0S 8/83 0 0. •7/0/3730 SB ~8' ¡>¡.7/0*3/ 30 ¡MM3\ 1/380 8033 0 ¡.7/073738 88 0/ 7/0/37. XP ¡0830 0130 0i 8/3 ¡.O 0 ¡7/0/3788 Figure 59. Recorder's notes for sequence of observations, leapfrog method. 107 A f)LTIMBT£R DFSlfiNATlON />LT/M£TRY L£AP£fiOG nine r#3 r C.A9M*9EO T-£/H F>4.HA -Toff 18 ST scpie re*** IC-At-E -r£MP BE/tOMS CQXffgc- r*6* Be A £>/A 6. 0*Y ufer /?£/» /¡RBVCXLE Ft 7/3.. o 7/-2- z /Mai>cf(l£ /■f 3o 8JL 7/3. £ + .2 7/2. 7 79 JO M/L£ Gt/sTY UftHO 8* scf- z. /sso F-ST 1.88.0 * .3 L98. 3 79 7* /¿so 88 887.8 T ■¥ i,f7. 9 82. 79 GRUSB'* 8* 7ŸO.Û 9 .3 790.3 BV 79 G-KUBEX / 788 F* 7 9ao 9.3 7 90.3 Figure 60, Altimeter A recorder’s notes for altimetry (leapfrog). 8 £)¿ T / MfT£ R DESIGNATION /flT/B/STRY l£Af£ROO DATE. xtrsr eotfitciMp CtrnAA**//* AOJusrep X*sr 3CAi.£ JCJ9J-* 3C*i.£ JCJçIX SrRr/eee -remp PCAOtvS PmAOtHt* #e*0/M Bee SCR-/ 82 702. 0 702.á r 14 7*9 2 Bee SOP- / /3SO 82 702.S v- .t 703/ 708.3 Bee ScP-3 /£S0 89 b9/.0 + .7 4,9/ 7 492.8 Bee Sc P-3 / 9 JO 87 Ù90.O + J .0 ¿9A 0 4 9/. 8 08t/8£B / 783 87 790.0 + J .0 7 9/ 0 Figure 61. Altimeter B recorder’s notes for altimetry (leapfrog). the horizontal location of a station may be de- height determination in a small area with the termined by trilatération and the height may be base station centrally located if possible. determined by altimetry. c. The leapfrog method should be used for b. The single-base method should be used for extending height over a large area. 108 fiLTt- ca/ttee r*e torre* rff JCJ9LS sjltrfA ST/JT/0/V T/M£ 5TAT/0A/ rime 9CAL. £ » /le*DlN6 AffBOCXl£ 7SA.A. G*v8£* / 7 SS 79/. 0 AX3t)CXL£ /Sof 7/0. S &£4/8£K /7SS 7*0. 3 + . 7 + . 7 1TC.M 77/ 7 c 90 H ’ St * Ç ^ y- /. 7S ^ N VJ y /.SV /. as hé. 08 Ui 2* F/tfsr i.ea- Figure 62. Comparison adjustment graph (leapfrog). COXTOTATIOW- ALTIMCTRIC HEIGHT A < Tirntt t ** oa LtAFnoe MITHOO) UMl DtSIAMATIOM &S.90 SiaJton tfrèuc/r/e - 8n $CP/ - &/> 5CP2 - &r> $££* 3 • OruS^r T>mm of OéseriMtm /* JO /SSO . /¿So /7J0 MIO ITATIOM MAMÍ 9/9 5CPf &n JCP-Z a)**/ G/*u4er FIELD STATWH MV DULD TCMPEKATUEI RE AM KO (J) BAU ITATIOM A DOT BULB TUMKBATUBE BIAMNO. 79 _Zf. SJ_ 0d ALOIDRAIC SUM M) AMD (1) — (t) E: Y:::T ■ ».» 11 FIELD ETATIOM VET DULD TEMPERATURE READING DUE STATION —T tin » TMMPEEATUEE REAPING 72 7V 7¥ 1+ m 70/\2 <.83x3 i92\3 790 BAU ITATIOM Correct ICAL« BËAOIMO 7/2 ,7 7oVx5 Í87xf if/^8 IF <*) U MORE THAN (10), uum-oov UON(+). 7o4\2 ¿SSj 3 IF (T) IS LEU THAN (10), USE (10) — (W SIGN ( •• ). _L &r & ®T ÄL ÜL CORRECTION FACTOR FROMi TADLE I 7E£4< rur££ JjLÖft IK. mr rm TTT- TAELS II <♦) 1 r i— TABLE III (+) . i L n r~~ LZ1 HEIGHT CORRECTION FACTOR (I ♦ Li. n— LOO (IS 0,02 7,7* Qt 028 i /i Q| Q30\ LO O, 0 3/ ■ 8/ /, 209 , S2 O, 929 \ ‘fi Q.ifO, 20 /, 993.9-9 H 1- o, 937, /* / 1237 , <,8 o, 720,80 202S.2S n r KNOWN HEIGHT OF EASE STATION NUMBER HA VINO LOO (19) 4^ H 1- H 1- tlf——.!■> Mm)) & g> . /Q 109 CHAPTER 13 FIELD NOTES 197. General sketch. The chief of party will initial each a. Field notes are maintained by the recorder. numbered page after checking the data entered They should contain a complete record of all on that page. measurements made during the progress of the d. Figure 64 is an example of the data placed survey. Clarifying sketches and descriptions on the flyleaf of the field notebook. are also made. e. Figure 65 is an example of the index b. All entries are printed neatly and legibly which should be placed on the first two num- with a sharp, hard lead pencil (4H or harder), bered pages of the field notebook. with enough pressure to insure permanency. /. Figure 66 shows the three sections of No erasures are allowed. When data has been which each numbered page consists. Note that entered erroneously,, it is corrected by lining the facing pages of the book comprise one through the incorrect data with a single line numbered page. The heading will include such and placing the correct entry above it. Entire information as type of survey, date, weather, pages that are not to be used are lined out by type and serial number of instrument and diagonal lines between opposite page corners names of the chief of party, instrument oper- and are marked with the word VOID in large ator, tapemen, and recorder as appropriate. letters. c. The recorder accompanies the instrument operator. He records the angles and distances DEPARTMENT OF THE ARMY measured during the survey. He records the CORPS OF ENGINEERS data in the field notebook as it is announced to him and then reads it back to insure the cor- rectness of the data. In surveys performed to LEVEL, TRANSIT ANO GENERAL SURVEY an accuracy of fifth-order or 1:500, the record- er checks the distances measured by the tape- RECORD BOOK man by pacing. In order to readily identify that data to be furnished to the computers, the I* HON MAPTY recorder circles those values in the field note- LOCALITY book. He then gives the required data to the ADVANCED UN/T TffA/M/A/G- computers upon request. In addition to the PROJECT measured data, the recorder makes appropri- ate entries on each numbered page under the BOOK OF remarks section. This includes information 0.7M/L TH£0D0L/r£(776JN/?JJ8o pertinent to the survey and a sketch showing INSTRUMENT the points for which data are recorded on that SfC TA. ßffom/ page. The sketch should be drawn roughly to CHIEF OF PARTY scale and should include an arrow indicating approximate grid north. A straightedge and Figure 64. Example of data placed on protractor should be used in making the flyleaf of field notebook. 110 DESIGNATION. XA/PBX -DATE- .19 .6g PAGE DATE r/rtf p*6£ DPT* T'A r ¿S' Xsn/cx T*éttx C. •* S-/***^ Pos**'*'*' ^ /*•*• St /(, UUL P**, /r JU¿ Po * ft'*'*' Çr**~ Su. > « Cy /f JOC C+r,**<./, ■*■ Su.ru*y /9 0//;/MSC. / f*/À^ Jvù C+*Su.r*/€ J/ JVJ- / r/*-p* f* 0¿- AK*. /Lpp/ JJyU/L 0é* / '»U r PA]/& Pfé/kpéL ¿y Jî/4. 'TA*. *>* p-s /3 a JT ¿VL "TAP* pif**/ -XU- Tr,*~f~ (c.0 ■'/J J /J" J* JVL SMM ¿¿St r*s*Ts** * J? JV£- 3¿+r ¿í. tA*-//* ¿*PtA P*ft . /?f4./A.0¿. /7 jf JUL tSppm»+/¿+ ac**-* ¿¿à /7t* 3 /c /P J/ Jt/L J,PU *~//* \.**m*S ¿¿S P/**.* Figure 65. Example of the index of the field notebook. 198. Traverse Field Notes 202. Quadrilateral Field Notes Figures 67 through 70 are examples of field Quadrilateral field notes are similar to field notes kept by a recorder for traverses. notes for trianguation. 199. Triangulation Field Notes 203. Central Point Field Notes Figures 71 through 74 are examples of field Central point field notes are similar to field notes kept by a recorder for triangulation. notes for triangulation. 200. Intersection Field Notes 204. Trilatération Field Notes Intersection field notes are maintained in the same manner as triangulation field notes (par. Field notes for trilatération operations are 199). maintained on DA Form 5-139, Field Record and Computations-Tellurometer. Distances and 201. Resection Field Notes angles determined through the use of this form , Kesection field notes are similar to field notes and DA Form 6-7A, Computation Plane Tri- for triangulation, except that the height of angle may be entered in field notebook along target (known or estimated) and the height with appropriate remarks and sketches. of instrument (measured to the nearest 0.1 205. Altimetry Field Notes meter) are also recorded in the remarks sec- tion. See paragraphs 194 and 195. Ill DESIGNATION. /?e.ca ret REM IRKS tVUe-. A s «¿ . Oa. +* &€S <.rt/ // e -L Î tr.Se.U. Figure 66. Sections into which a page of the field notebook should be divided. 206. Astronomic Field Notes star by the hour-angle method for a fourth- , a. Figures 75 and 76 are examples of entries order direction. made by the recorder for observations made c. Figure 78 is an example of entries made on the" sun by the altitude method for a fifth- by the recorder at the master station and figure order direction. 79 is an example of entries made by the record- b. Figure 77 is an example of entries made er at a flank station during a simultaneous by the recorder for observations made on a observation. 112 Chtkf *f flrty: *3* 8r»-*~ DtmAkér : £-/emr -//»f 06s**+te: S++-J»m*s ‘T*-?*’. Ftc. 3*++*~* PA*. DFSir.NtTinw Ñrca. Sv-rnay DATF /J~ JU./ J* S+fti mm* y Vr : Af / 7ff •r34r : £*/ Smt+L. H+rtA0m+*J í/«^ ■/»'«»/ C,*r+++nL J>t a /?£M/ AKS 4 <»//« ^ m'< /j l/tr+»**X m*.*-*** A» /Hx t/er' m./ /9A* /e C>*rre. T/+J+ / s -A 3. O 399 t 8n ser 33SO.S ■¥• S.S + r. s 8* Ser /€- /4/ rt A/ s i *e 8/***> &** m* 4 (fe, 7S". : td.. cr Tt */ S éoj C~+rM /ÍX* S* A#*/ 8A ser ¥*r of A * 9 ¿*s**A M7 O i. O A'. 3* ser •*93**0 - 0MÀ A/A, X «*//^X ir x /** SeaC.S’ 7 -í* - ¿s *S‘x Ai $PJ of 4 /A ser /h* 4 (5703 (*7- 4o) A'Co* TS~ / j¿o/.S’ + 7. S’ + /o - * m 6S ~A Cc*X. S’ 7. S . / a • S' A " Ce* /Hn, 4 T3-/ *79/. O r /- .4- * m Os *A 3/fl. O + A-6 -I-SO ZJ^X 7*- X /»A 4 (+4f) C¿7^3S> TS-t Os "A **3S.S- -S-S ~ r.s ¿-o#t*. A** S*k**t TS- X ¿47/ S -1.S -i.S 8* ser /äA 4 fr» t*m Ts- x 3*94 o StfJSlM 0+ Ser 7ftO A* *** /»/< 4 te M* Figure 67. Recorder’s notes for 1:500 (aiming circle) traverse. 113 Ck.et et Par+t, S 9 A* Mk /Í2 28 + o /s Bn SC t& /o Bm SIP 3ZM s*> /¥ fit cf z. o C Pi// *4 SM TS-/ MM /tZ Zg f Pr ++ RJ. i *n SCP •f’OL C.K’ AJi A ¿7 ss +o /¥ ol. <,Z /n CCM + f a. X J t/U Oo ten. Aub hUs trh « ngL . / /HA TS-/ /97 Jl /5 /t*h+fi nm rod n 'Top of- briok. 8n S<.P JS «H Smoke, 5 ■ O.C A *r 1M / &1M 4 /97 3JL /f7 3Z oS A* ** Æ 0tt S C-P Z“3 /¥ ■+J* JÙ TJ- / 4t +S* 34 TS3 Bn SCF <>/ m* 4 ¿03 J£ urn H/LL BO AHj * >¥ ÍV •0 S3 /37 J4 4o *¥ TS T. m» 4- ll 47 Zo ¿ ¥7 S3 (3/3 7t) *±iX- A TS- j. 12. L5 TS- / !7S £7_ 2o SC.P rx». 4 £2 ££. Vo /UjJ^ Î7 Sg JZl w Figure 68. Recorder’s notes for fifth-order (20 second transit) traverse. 114 Chief of *9f UJcA+her : lùinAu - Ce.l Oheevucr : Sei Jmne* T<*m*. : f^cFfc. ßCummkt. nFsicto&TtON Pû3S7"/¿A/ S)Æ£/f SVÆtJSY Q¿jg /7 Ji/Í ¡o 60 JTnsirumtA't Ñrl “T’lk!**S4/S3 0€.<.m*d€*: C.t>l $mt+k Monfmt+t Virtic*/ ver-ti.^/ A mtt-i A ni. U fkm f «rA REM fiR K 5 Az mtc ooo / o a* S c P !S /OC. t +cJ 3. Z m*'*s 3zo/. O COO /. o Uf O f a, 4 193 *« / té Z/ Jt 0« 3C P 3S. 73 0 ê/ t Utes* KJ /St* Sc tm * X Z tttéACOM Á«¿ CS *3 " 3¥3. t /Sft. s r (tAtk w SA rot* J. ti m 00/eo4 ¥'V3. 2. 94s. a Vf J/, s + //■ s" *tt+k 0ht i E#t««s s + Are • S/z / SA m+ZK tS SrAS/sm t\£BJ /sc ¥éJ ** 0* ScP 0 00/. ^ 233 rt f€ 0mA AfKcJ Mtt 39 0/- * CCCJ. û 0**0" m» ^ (7s/y-T) f+ 3¥. i *0Tt00 3mC** /t //■ y - //-4 /SPC / C 47 r¿./ /Sfi. / y 7 ft. y ■£-&- ÛS ’’0" /»" 3- (Tino- s I S+*. /H* jyet.y /st s 9 B Ceo OS 9 act. 7 3¥**< ^ 4//V / + /4./ / «C *Sm0* 00 0 / 0 \ 3*0/0 CCO/. o S+A. /N»c ftlm ^ am uw 3m S < P 3. Z mt/éé /¥** / w TSTKOïïC XI JH 4/033. X /<¥f* Z yyir Figure 69, Recorder's notes for fifth-order (Tl6 theodolite) traverse. 115 Chief' cf Syf &*•**** kJcm.+h*r '■ C/ecr -C*o/ Observer ; S+4 Jmme* 7 K t OUJ CL. 30 5+A^- en Dodge /S /•cn.ttJL Pre.*.. /to OO 33 33. /n A/»r+k Ar ¿ne JC ft. Pod qc. i/71 _£2 09 ~2fJ ÇZ72. /g) f+. SiH f> ‘hh+rf Re r Unften. 0. t **//«« 14J af 8 \fd Ridye, /7> 39 *S SO V-/ 69, J7 ¿ 73.H à,ijhe*h 1S9 /o 33. 3o J7/ 61 3X íra.oT paint of £m»sy MÍ//. Stnt/tn. /« if m .f S£ V 5 RJ. SM Oeds*. Ut Kd . m >rktd ktf 4J_ N»f 2 £■ no / " p*JP6 / * c.*n cre fo. ffnsh (¿37. 9Z) àoith yr««*d a,nd /f mh’tfe TS-/ ' ** G. 03 Miacdem Q t^di BM + H’Cir. T3- i nr J£ ¿7 9/ 63 ¥/ -/ 63 *7 s3 7. s g is Sfnf/Cn. 3j>r 3* Z? ztr sc /C -/ 03 S3!. 77 Mi// ZZ6C Dedjt.. r*-i rs-J Ocd3* /s K*e*P»* Figure 70. Recorder’s notes for fourth-order (T2 theodolite) traverse. » Û*/£F ar AH/irr: S*r. S/9»*M/ l/S/fTMífí: ¿¿¿4#-f/ûr âJ&flÆ*; Mr cAa*** A?Aea*o* *< ■ C&L.. SM/r# DESIGNATION. TRIANGULA TION . DATE /i~ J(/L iQ 59 A/fî. : /789 rtf*. PAZ M/U£/í &£ orre /tBtUZMML MÂUufteo cmutareo asrAtlees STATION R 4- (”/> ttKTA-ty) mrrjwt) Aiere/tt tiZMARS S ÂZ. MF /35B.O mr>VCAl Æ't ¿0, V AML /û09.0 -a/, a */.2 MET za/e.s -0/0 7/2 ST& MM 4 (TïMTZ) Xëïk/ficêà K M6Mi/4y 37 £ASr % mkUTfiv VJA/AT/OJJ !S wr /X H. éJL Figure 71. Recorder’s notes for 1:500 (aiming circle) triangulation 117 CJt,ef ♦/Arty: Sj^Ær*** UU.*.4A€r C/ouéty - IJ+rm Oisertfcr : $++J0met T*mm’• Pf< * fVc.Jtmmmk«. XHS+r* ï***4 Mr : 1~r+msi/t*/f4/f j?*c*rdtr: C^/ Smi+A DFSir.NATirm T/f/fWCi/ÄA/“/M . DATE l9-£2- I "b*. / ^ */ 4 S+A+t** XE/ñ ?**S foBV Jrc //•A «»*. /•CA. y*j s. s //« f /A ♦/ +ù ôÇ C#*tr/ H fc /« i. '/ A/ 77^ 75-*! fHtmj/er <9b SC £ *f 1 t Ht f Amts. ; 9* m S f tahtAs fimrms. Ho I*»« AJ; 4 .9i. SC +0 al A.r#*A I rod S4 + 1* 4» "/ C ««MC AUtM. **- 5L ce ** Momste.r 9/ jy A« MC tt fStooJt - Do do o. Cm*cpm.T < d y/J JTi- 1499. 7 r*. /MM 9/ S7 i HSTëR AJj 4 (9/ S7 (- ù3 io OA m Whifc Hootc. m oc MO y 3./AV 34A.C* 3V3. >2. +ù // //ASM /»g-y m* A / 7/ Q¿ Xê j./« (^7/ ** '3) (++0> /ù S- 75 w >Ar c/i 5 StmTtom Büc. K Mt «/ rm £MiL£ £' T fort >5 k 5 a* fl 7PG£ A, m Jt% Figure 72. Recorder's notes for fifth-order (20 second transit) triangulation. 118 Chief' of P*r + y •' Sg+ J»mes UJeaA-her I Clear - Uicrm. ûhserOtr: Sj-t Hairnet npsiftMATiflN TR/ANGULfíT/úti/ 24 JUL ia it? frif+r«"*,* Nr: T-U.**-7439 KecJer : ¿'«/’/ft. •<*+*/ ✓erf ic«f ✓er+ic*/ S++.+/OH 3| mi/j A ynth KEM R K KS O tc.K ooo /* O torn & /oc*. ft /f S4M t Í Wern1+ A 3 omm 3X0!. O 7o M h ef t AJ 5 kj. Dtck is /««/ 3. ' Af Sc 4k. mJ /S c. + +€á To.?** somme.*. tom* ■4-e D ick /s 9*0. X * to ooo/. O l/tr ftcmf mmo/ts re. +o // 33.0/0 Pick Mo TV» #•« tefz.S /¿If- s -/I. S’ X X——A HA*&V 4292.S /otz.r 4‘}//- S' -H.S- To /»• ooo f. O 3X4/0 e»o /. » 3 tf+rrtf p/c P/ik I3 7S.S /S9Í/ + 37 itsysf /3 7S.S 4/0 3- 9 + 3? Tom M/R&i-mTD Figure 73. Recorder's notes for fifth-order (T16 theodolite) triangulation. 119 lÜeA+h+r ■ C-fe*.*" - Co»/ Obirrucr • Sg/ J*»tS DESIGNATION 7~ÆfAN&UL/jT16N rtATF JUL IQ ho Xnsïrumc*-I‘ Nr.* TZ^fSit Recorder ' Cp! Smtik t/Cr+ te*. 7 Peni A KKS Dodge 3g o7 SO » ¥ Po 3t + Ifû Zjl 2Z 27! SO SS so SS Tto i P»st4/t AS Cckjdo H’) so c : C*.JJo OoJj*. Í9/ <+L dù- SV19.V/ M (BT1) Po+o/tc •Il 37 90 »3 /v 03 '¥ Dooae 27! 12 Ve 33 3i9 Si 39 03 3! 2.9 P! A6cv£ STA Co.d Rr buckle 223 S“} 07 S7 n 20 J¿* ¥0 43 si 09 ûg 372 ¥2 3b V2 3b POTATO C*>ddo H. '°) GL ¥2 ÆL X.lfM * Bovl STA K i O IA»«- 32 V /S 9/' 'X /X -/ /2 flasc*y¿*> HI AT »RBUCKL IV¥ /* OS 3tg ¥7 SX -/ og H- 3.3 M , IftOWf STA OWA ■ V.gM HE/OHT »90vt 5/6 VAL. qr 3.8 tA > STATION en ODO 2.ÍM J- H! - / 4M ~J£F~ Figure 74-. Recorder's notes for fourth-order (T2 theodolite) triangulation. 120 DESIGNATION TRI A NGULATiON (c*m4\r*KTï 3.S JUL ia ÍO wT" ffFM.IRKS SÆCÙA/0 1* V-f ¥¥ 9/ / 7 s-/*. +■/**% ClL.W* SS /t C -/-/re. C+.JJ0 vr (v n)—. SÁ /Irí***/*. /fres, oí ) Ae. í-i*. />f, '//S+r Á* s*r i ä +/** /. 0 3**'A. äV« y*a £2- /3Í ■Vi 3o &+/*/ A'/Jfç. J C C*t<-+ *■*./ O* t'rfÁ**/- /*/ /3 »3 *33 -Vi / ó f <£rm. * * Y Afsto // tci of A ny**. C <&*./?, 's / " /, Ir *3* -T« ?• *32. 4L if2 ÍL'3l -Vi isX '.re. fe 0/ec.Ar ¿/**s à /trbucKtc. *33 sy 3o \/eo /i jr*u * */ 3/3 S9 33. 3/ #/h */ /s */+ +~rje/ f C+.J4o jC0 /i o/) C yo¡ /i *JL y 's Asi le /* ■/■roe. ' *3 es -?1 /»'>« **■ ft*y J>6 OG£ /?«• 23V /S 3/ \ 34ÍSO /*» yr»e*A *■ t Sÿ /5" 3jf 32 MJ s/Ae , >A -/r+t/ K/OWA Pan ra ¿ZOOM vso > CAOffO ?m*s *2 AtO i CKL& V G/OOA* ti Hm* f Figure 7U—Continued. 121 Chief of + $3+ AMa.+her : C fea.*- - UJtLrm QÍseroe*: S^i* Jones S¿/A/ OB3FRV/9T/0/Ÿ DFSifíN ATiotj /fiTSTt/QÆ AñET#00 r>arc 'JUL |Q ±0 ZThs-frumemi tfr-:~7r*.#srt *¿9 rfecovtJc*: C-ff Sms-tk T/>»l ./ A Ve*+ C-/ -4 S+0.+'*** A /*? /?EM t)RKS fio toe *f ft Û 0f /ZO 3b Ve Z»// '- Be*.*. -fK 09 07 33 2V0 4t 37 Cooy ■f-iJe. 9t '3^' /r* W S t*.t\ Mñ ^ \P9 O* 5/. ■ht* /9e•_ i /* /*c*,e3 art Jh. GL es n. s;// m •//f+ry fie terva.+ta fio toe // St Ù 09 fZ ■*¥ *2/ 39 3 sUpe. £è*r ry Hi//, rt» W rf Be. c.A. 09 /3 ¥¥ 2 ¥3 )o 39 vy af- 8U 3077. 200 m UJ Su * Mn A (o9 /JU 3jr ~ö7) D- <¿L o o) >f í F-f s. // s/ü< : S+A+¡O» Poto*.// is foc* fei 30fM P».rK s // st D 09 /7 3o 31 RW B< ck fe** • V *f Rief* Be c ÂC X 09 /í 3g XV* 03 31 ¥/ 3VM W / Tattk Tl \tf. ffé fh SféL+'O** S*>» At# ^ (Til. 3/ 30^) (¿7_ ore -4t "/ /»>/»«e. tn cee:■fer eP m b rb ‘ ** Crete t feet's pr*/ect/rry TÏÏ b* out Oê Temp S 9aP 7^ -p &-s'— We+cM / b S sfouj ^— V \ Aus+**f /R/ 1307*1 Figure 75. Recorder’s notes for fifth-order (20-second transit) observations on the sun, altitude method. 122 » Ci/cf ‘f : &r**l*- ÍÜc.a. + Uer : CUar - U>Mrm. ¿¿**rüer ; £'++ SOft OBS ERlW T/oAj JTWÿ4yg mfOr : ß?*c*rdir .' nFcir.MurmM Bl T/TUDE M£Tf/oO ntTF /f JUÍ- _ I9_¿g- \f4rl.n+*.l lfer+i¿*.l fr :M* R*- ~A vi,ii Nie-.* faé-átA* X ru.Is u/r 3M° 39 i/f /V 320/- O 060 /• O ft* A? //" W Te* 8y SP ¿¿0 Mn ^ *8 30 sô) '3Í2 3. g) S+m.+ 0P% SOI io .s /o C.A.+C.J tom s of B/Jj •S”** »i or 2? 3o 33*1-/ /os 3. X ■r^Vt.g a. 3o o8 Sx 3e i2f¥ 3/21/. 3 S3 si -2. + SSÍ-3- 3077. S-.-4+/0». /S Co./ c*r1 CO. sef ' 'trtam tu/or Ci rc4«. 08 oeei. o Mgr 4: 32ee.9 eee/. 0 b/ock . / a/wia^Ai 's sh*(4 3urr.rt "3 /'?** tñn 08 36 oo\ 33 fi ÿ '±StT?} o* /of f ôCS W*4*r -¿outer. of JV arts. 7 /o2 o. f lis 79-/ of 38 IV9. 2- 371/7 V S3/3. / *-S7 3./ ut-r 9oef. o 32»l- O /« 30 xi o M* \ oT) 'JJet. a. £ t* n Oí V/ 3379-S 979-S’ + 6 jo.S SO 360 ût tr Æ- Figure 76. Recorder’s notes for fifth-order (T16 theodolite) observations on the sun, altitude method. 123 *f Arty : Sft /?r9m/Jf ¿jJeo.4htr : Ctfor - €o»/ ¿ÓJertcr; -3*4 Jomgo STG* oBs€Rv#-rtùh/ PEStGNATioM HOUR ANGL£ M£T/iûO naiF^gy JÜL S-TAl Dot* (< /*c.m.+ tJ O n At %/•*€. ÇZô /S e* /ni Sor y H,// 3SA £ of Í s,// . ?/*/* é» t* 300 A4 Don Jil '¥ So/ Z* AotsOe /to /V S,// P/fo/ Osts! /Pm y o /o/ Z ^/itu/i ?J~ /V — Coff/t* Sr. 9f ~Z 7¥~ A /ar / s 1Z '3 3SÍ Ax vue »s TS - / /OOO.T r Poe A A/S Po/+.rtS : /f__ St SMMMt OO* Vö ZZ Z.0 /7t -3t /* H-& Vom tOOh O TS-/ /7 Don /tin »») ' yy ■?/ Pot+rtS _3£*___*£_ St yy >7f (¡fa S/ 3.0 i 'Oft lfm Figure 77. Recorder’s notes for fourth-order (T2 theodolite) observations on a star, hour angle method. 124 » ot P-'fy: S*y U/e+JAtr'- C+*/’ C4fsr 0^jgr*>er: *5+¿ J+*€s r^^ir.NÆTlOfj S/WU1TÂIŸÎOUS OBSÍXVAT/CM naTC Jf Jt/i. 19 ¿Q Ins*rumt^ A/r : Tí . c,/ t/4r •/««/ CA/ Sto-Z/o* JiS. P£ M/tAKS *rr 2f S-Zai/** /M+ns ** S+VU/JP*- / s /ocM-Zt */ /fM t (íí M 3T> a/ yJuffC.' ‘VO*r Ou A4 A » i 1 */ XJ. S++- **** /s / P'/>* +. D 34/0 /2 37 Ï7 /9 SA Vo 03 &” x L ” Acre+e ¿ /*c.k £/**.. ¡it V R /¿0 19/ 37 J3 Ai 37 /3 uti-Zh qr, **.* J MX t's //, Jt /m*i a 0/ tu it** %s of A4 Am +.+*+10*, •f A*. St*, tt ■ 4A mt /« UJ7~ jva* /3‘ 3¥‘ ^ WI A4Am S - ‘ M. n 34/ù /<-' VI' S3*? 3o' ¿3 W2 > 4Am 5 7A ■ IUM: HX 30 ‘ ¿13 ’ bvbï 43 AD A V / -ML- Figure 78. Recorder’s notes made at the master station for a simultaneous observation. 125 « cJt.'ef 0* P*r¿y: ¿Je.r■' CQ*/- C/e*r 0&J4rJ€r: 3/m*cJ: W=>\v>un\Ciu5//>titLT/9tf£á¿tí OBjfrfMT/tWnhTF JUL iq é>Q A/r.- Tr+ms** **/*#? facirjer: C/>/ Ja PPM 9PK3 St*. ¿/ ft Û 3^€L+*OF9 2.0 *3 £ /a A? St -a /F*A t /s ■Si-a. -20 t X fSjí /t> 3*M SJ+ / X*aref 0 Ft ¿fu ***_ a Peft 3~Af M ■>/ M* $ *7 ÔÏ /+m.f4 é )r /aca,t*4 S S+o. J ters ty o £ ¿ame 7-*e 8*+t* s-tt-ts+AS a.fÁ'oJ 6$ na.// /té A VJ ¿‘ y í» c *» c re *e ér/ocfs jirajec/t'*] J " *>, grau M J. C orn fu. ■j a.//a Ft 0¿ /f a. Sto- 3 0 -ta St Ax ntxster (Aoía rtfj ta S*< FT 2JA 0 3* '23 333 3! Si. ‘ - Pñf/e s Ja- S»*FI - k7‘ »/■ Sta. . "ÍO - 5ta. 2 SSS- 33‘ Si PUMA» K. 7 4M* ) STäXT" xo x. e r« ’11 s Figure 79. Recorder’s notes made at a flank station for a simultaneous observation. 126 » PART THREE SURVEY METHODS AND COMPUTATIONS CHAPTER 14 TRAVERSE Section I. PROCEDURES 207. General 208. Types of Traverse A traverse is a succession of straight lines, There are basically three types of traverse called traverse legs, connecting a succession of which are used. These are open traverse, established points, called traverse stations closed traverse (two kinds: closure on second (TS) (fig. 80). Distances along the line be- known point and closure on starting point), tween these points are determined by direct and directional traverse. measurement, either with a 30-meter steel tape a. Open Traverse. An open traverse is any or by other distance measuring devices. At traverse which starts at a point of known co- each traverse station, a horizontal angular ordinates, proceeds to its destination, and does measurement is taken and used to determine not close. The open traverse is considered the the azimuth of the next traverse leg. A vertical least desirable type of traverse because it pro- angle is also measured and used to compute the vides no check on fieldwork. For this reason, height of the next station. In artillery surveys, traverses are never deliberately left open and the angular measurements are made by using are always closed as soon as possible. Open one of four instruments, depending on the ac- traverses are used only when time does not curacy required and the echelon at which the allow a closure on a known point. traverse is conducted. These instruments are b. Closed Traverse on Starting Point. A the aiming circle, the T16 theodolite, the T2 closed traverse on the starting point is a theodolite, and the transit. traverse which begins at a point of known Horizontal angle Vertical angle to / TS2 measured TS1 0/, \0 OV »O' Vertical angle to Ver,icQl an |e t0 oint Figure 80. Schematic diagram showing a traverse. 9 127 Coordinates, moves to its point of destination, of traverse party members are based on the and returns to and terminates at the starting functional requirements of a traverse. See ap- point. This type of traverse is considered the pendix III for detailed description of duties of second best and is used when both time for individuals. survey and limited control are considerations. a. Eight-Man Traverse Party. It will provide checks on fieldwork and com- (1) Chief of party. The chief of party putations and will afford a basis for compari- selects and marks the locations for son to determine the accuracy of the work per- the traverse stations and supervises formed. the work of the other members of the c. Closed Traverse on Second Known Point. party. He also assists the survey offi- A closed traverse on a second known point is cer in the reconnaissance and plan- a traverse which begins from a point of known ning of the survey. coordinates, moves to its destination, and then (2) Instrument operator. The instrument continues to terminate at a second point of operator measures the horizontal and known coordinates. It is desirable that the vertical angles at each traverse sta- point on which the traverse is closed be a point tion. established to an accuracy at least one degree (3) Recorder. The recorder keeps the field higher than the traverse being performed. A notes for the party in a field note- closing point established to same degree of ac- book. He records the angles measured curacy as the traverse being performed is ac- by the instrument operator, the dis- ceptable. (One exception to this is a traverse tance measured by the tapemen, and started from a map inspected point. Little or all other data pertaining to the sur- no value is obtained from using a map in- vey. The recorder is normally the spected point as an additional point for clos- party member designated to check the ure.) A traverse closed on a second known taped distances by pacing between point is the most preferred type of traverse. It traverse stations. will provide checks on fieldwork, computations, (4) Computer. Two computers compute and the starting coordinates as well as afford a basis for comparison to determine the ac- the grid coordinates and height of each traverse station as the traverse curacy of the work performed. progresses. The computers work in- d. Directional Traverse. A directional trav- dependently and check their results erse is a type of traverse which extends direc- with each other. tional control only. This type of traverse can (5) Tapeman. Two tapemen measure the be either open or closed ; if open, the direc- distances from one traverse station to tional traverse should be closed at the earliest the next. Each tapeman keeps a rec- opportunity. It can be closed either on the ord of the distances taped. The tape- starting direction, or another direction of equal men compare their recorded distances or greater accuracy, by astronomic observa- before reporting the measured dis- tion, or by an azimuth gyro surveying instru- tance to the recorder. ment. Since direction is the most critical element of artillery survey control, it is some- (6) Rodman. The rodman assists the chief times necessary at lower echelons to map spot of party in marking the traverse sta- battery locations and extend direction only. tions, removes the range pole from the rear station when signaled by the 209. Organization of Traverse Parties instrument operator and moves it for- The number of personnel authorized to per- ward to the next traverse station. form survey will depend on the unit’s table of b. Fourth-Order Traverse Party. The fourth- organization and equipment (TOE). The or- order traverse party consists of 10 men. There ganization of these persons into a traverse are two types of fourth-order traverse parties : party and the duties assigned to each member (1) Ten-man traverse party. This party will depend on the unit’s standing operating is basically the same as the eight-man procedure (SOP). The organization and duties traverse party with two additional 128 tapemen who form a second taping equipped with a filter of some type to insure team. greater light security and to prevent undue (2) Tellurometer traverse party. This glare in the telescope of the observing instru- party is equipped with three T2 theo- ment when it is pointed at a station. The dolites and one tellurometer set, which observing instrument should be equipped with includes one master and two remote its organic lighting equipment. units. The personnel are organized as b. Personnel. The standard traverse party follows : one chief of party, three must be supplemented with additional person- instrument operators, three recorders, nel to enable it to function properly at night. two computers, and one rodman. Three additional men who are light holders c. Reduced Strength accompanyParty. Often and assistthe the tapemen. When authorized number of men are not available to possible, a fourth man is used to assist the perform the traverse. Under such circum- rodman. stances, other members of the survey party c. Angle Measuring. The same procedure is may be required to perform more than one used in measuring angles at night as in day- function. Shortages in personnel will seldom light except that at night the instrument must affect the jobs of the instrument operator or be equipped with a night lighting device. the tapemen, since these two functions must be The instrument operator should coordinate performed if a traverse is to be conducted. with the rodman to insure that the lights on Shortages will be apparent in the duties of the range poles are placed and pointed properly rodman, computer, and recorder. If the party and are moved to the next station when the is short one rodman, the chief of party will observation is completed. perform the duties of the rodman in addition d. Recording. The recording procedures are to his own duties. If the party is short one the same as those for surveys during daylight computer, the recorder will also compute. If except the recorder must be supplied with a there is no recorder, the instrument operator flashlight so that he can see to record. He will act as his own recorder. If three or more should record in the remarks section of the men are absent from the party, the fieldwork field notes anything which may have an effect is completed, and computations are performed on the survey, such as burned out lights, only later.Jjy designated personnel. Organization one light on the forward station, etc. of a reduced strength party is not bound by e. Taping. For information on taping at strict rules; however, for a party to function night see paragraph 39. when personnel shortages exist, the party mem- /. Communications. Communications during bers must be trained to operate interchange- a night traverse should be conducted by radio. oKltr However, radio is not always convenient or 210. Night Traverse available and at times the survey party must resort to light signals. These light signals Many times the artillery surveyor will be should be prearranged and simple. For ex- forced to survey at night to accomplish his ample, the instrument operator may have to mission. This can be done by a modification of signal the rodman to raise or lower the bottom daylight techniques and organization. However, light on a range pole or inform him to move night traverses require more work, more train- to the next station, etc. In arranging signals, ing, more personnel, and more coordination. the survey party should avoid waving the a. Equipment Requiredlights, for Night since Traverse.a waving light may easily attract The same equipment used in a daytime traverse the enemy’s attention. Every precaution should is also used in a night traverse with the addi- be taken in sending light signals to avoid detec- tion of the necessary lighting equipment. In- tion by the enemy. cluded in this lighting equipment are flash- lights for all personnel and two aiming post 211. Accuracies, Techniques, and lights for each range pole. If aiming post lights Specifications are not available, two flashlights for each range In artillery survey, there are three minimum pole will suffice. All lighting devices should be accuracies which serve as standards for survey 129 personnel to meet in both fieldwork and com- direction may be determined by using a dec- putations. These accuracies are fourth-order linated aiming circle or by estimating from (1:3,000), fifth-order (1:1,000), and 1:500. The north. term “order” includes not only position accuracy but also directional accuracy. Position 213. Fieldwork accuracies are expressed as a fraction and In a traverse, three traverse stations are mean that for the unit. For example, in a considered of significance. These are referred 1:1,000 survey, for every 1,000 meters sur- to as the rear station, the occupied station, and veyed, the allowable error is 1 meter. Fifth- the forward station. The rear station is that order accuracy is normally performed by field station from which the persons performing the artillery battalions. Fourth-order surveys are traverse have just moved or a point, the azi- normally performed by personnel of the muth to which is known. The occupied station division artillery headquarters battery and the is the station at which the party is located and target acquisition battalion at corps. Since over which the surveying instrument is set. minimum accuracies have been established, cer- The forward station is the next station in suc- tain specifications and techniques must be cession and constitutes the immediate destina- employed to assure the surveyor that the work tion of the party. Field measurements for the he performs will produce results within the traverse are as follows: accuracy required. These specifications and a. Horizontal Angles. Horizontal angles are techniques for traverse are as shown in always measured at the occupied station by appendix II. pointing with the instrument toward the rear station and turning the angle clockwise to the 212. Traverse Requirementsforward station. In measuring horizontal Three basic requirements for a traverse are angles, the instrument is sighted always at the distance between traverse stations, the azi- the lowest visible point of the range pole which muth of a line between successive stations, and marks the rear and forward stations. a vertical angle. Since the purpose of traverse b. Vertical Angles. Vertical angles are is to locate points relative to each other and measured at the occupied station to the height relative to a common grid, two other elements of instrument (HI) on the range pole at the constituting starting data are needed. The forward station. When the distance between coordinates of a starting point and an azimuth two successive stations in a traverse exceeds to an azimuth mark are required. They can 1,000 meters (m), then the vertical angle must be obtained through several means as indicated be measured reciprocally ; i.e., the vertical angle in a through c below. is measured in both directions for that partic- a. Available Control. Starting control may ular traverse leg. The purpose of this is to be available in an existing trig list, or higher eliminate errors caused by curvature and headquarters may provide data for a survey refraction. control point. An azimuth to an azimuth mark c. Distance. The distance is horizontally (starting direction) may be obtained by refer- taped in a straight line between the occupied ence to a trig list, by computation from known station and the forward station or determined coordinates, by astronomic observation, or by using other distance measuring devices. use of an azimuth gyro surveying instrument. b. Maps. If there is no control available, 214. Use of the Range Pole map inspection may be used to determine start- a. When the range pole is used, the point of ing coordinates and height. Starting direction the shoe at the bottom of the pole is placed on may be determined by astronomic observation, the point marking the survey station. The pole by using an azimuth gyro surveying instru- must be vertical. It must be supported, through- ment, by scaling from a map or by using a out observation on the point, by a man holding decimated aiming circle. it or by use of a range pole tripod. A level is c. Assumed. When neither maps nor con- issued to field artillery units for insuring that trol are available, the coordinates and height the range pole is vertical. In use, the level is of the starting point may be assumed. Starting placed with the angular portion against the 130 pole with the circular level vial up. The range designate the exact location of the station. At pole then is made vertical by centering the critical points, i.e., points where survey control bubble in the level vial. The level should be is required or which may be used in subsequent checked by verifying that the bubble is centered survey operations, a reference stake is driven at several points around the range pole. If into the ground so that it slopes toward the the range pole is held by hand, the level should hub (fig. 81). The name of the station is writ- be held against the pole throughout the time ten with a grease pencil either on the reference that the pole is on the station. The range pole stake or on a tag attached to it. To further should never be placed in a vertical position provide ease in identification, a strip of red during surveying except when the pole is in target cloth may be tied to the reference stake. use over a survey station. This will prevent an instrument operator from measuring an incorrect angle by sighting on the pole when it is not over the station being used. b. At night, the range poles are used in the same manner as in daylight except for the lighting devices required at the rear and for- ward stations. Two aiming post lights should be placed on each range pole. One of these lights should be placed on the pole at the height of instrument and the other at the lowest point visible from the instrument. Both lights should be pointed directly at the instrument. If aim- ing post lights are not available, flashlights may be taped or strapped to the range pole in the same manner. To insure that the lights are properly placed, the rodman should not leave the range pole until the instrument operator has indicated that the lights are visible. 215. Marking Stations The number of stations in a traverse should Figure 81. A survey station marked with a be kept to a minimum. Each station must be reference stake. visible from the preceding station. At each station, a stake (hub) is driven flush with tbe 216. Traverse Field Notes ground. The center of the top of the hub is For examples of field notes on traverse, see marked by a stake tack or by marking an X to figures 67 through 70. Section II. COMPUTATIONS 217. Azimuth and Bearing Angle acute angle formed by the intersection of that Relationship line with a north-south line. Figure 82 illus- a. The primary reason that azimuth is a trates the relationship between the azimuth of requirement of a traverse is to enable the a line and its bearing. determination of a bearing angle. The bearing b. The manner in which bearing angles are angle of a traverse leg, not the azimuth, is the computed from a given azimuth depends on the element used in traverse computations. The quadrant in which that azimuth lies (fig. 83). azimuth of a line may be defined as the hori- When the azimuth is in the first quadrant, 0°- zontal clockwise angle from a base direction. 90° (0 mils-1,600 mils), the bearing is equal The base direction used in artillery survey is to the azimuth. When the azimuth is in the grid north. The bearing angle of a line is the second quadrant, 90o-180° (1,600 mils-3,200 131 218. Coordinate Computations North a. If the coordinates of a point are known and the azimuth and distance from that point Azimuth of lins A B* to a second point are known, the coordinates of 2400.0 mils the second point can be determined. In figure 84, the coordinates of station A are known and the coordinates of TS 1 are to be determined. The azimuth and distance from station A to TS West East 1 have been determined by measuring the hori- zontal angle Az Mk-A-TS 1 and by taping the Bearing of line A B 1 distance from station A to TS 1. The grid 800.0 mils easting and grid northing lines through both of the points are shown. To determine the coordinates of TS 1, it is necessary to add the difference in easting (dE) to the easting coor- dinates of station A, and the difference in South northing (dN) to the northing coordinates of station A. Figure 82. Sketch showing azimuth-bearing relationship. b. In figure 84, the traverse leg appears in the first quadrant. It is for this reason that dE mils), the bearing is equal to 180° (3,200 mils) and dN must be added to the easting and north- minus the azimuth. When the azimuth is in the o ing coordinates of station A. If the traverse third quadrant, 180 -270° (3,200 mils-4,800 mils), the bearing is equal to the azimuth leg were to appear in one of the other quad- minus 180° (3,200 mils). When the azimuth rants, the signs of dE and dN would change. is in the fourth quadrant, 270o-360° (4,800 The sign of dE and dN is determined by the mils-6,400 mils), the bearing is equal to 360° quadrant in which the traverse leg lies (fig. (6,400 mils) minus the azimuth. 85). North Bearing = 360°(6,400 mils)—azimuth Bearing = azimuth J3T I West East HI H Bearings azimuth-180° (3,200 mils) Bearing = 180° (3,200 mils)-azimuth South Figure 88. Sketch showing bearing angle determination. 132 Az mk dE TS1 \ dN < A Bearing angle TS2 Figure 84. Schematic diagram showing dE and dN requirements. 219. Determination of dE and dN vertical angle at the occupied station and the The determination of the values of dE and distance from the occupied station to the for- dN between two points when the azimuth and ward station, the difference in height between distance between those points are known re- the two can be determined by solution of a quires the solution of a right triangle. In fig- right triangle. In figure 86, the distance is the ure 84, side A-TS 1 is known because it is a horizontal taped distance from station A to taped distance. The bearing angle at station A TS 1. The vertical angle at station A is the is also known, since it can readily be deter- vertical angle measured to HI at station TS 1. mined from the azimuth of station A to TS 1. The difference in height (dH) between the two Since the intersection of the north-south line stations is that side of the right triangle which » through station A and the east-west line requires solving. through station TS 1 forms a right angle To determine dH: (90° or 1,600 mils), a right triangle is created Tangent of vertical angle = with the hypotenuse (side A-TS 1) known. opposite side _ dH To determine dE: adjacent side ~ distance Sine of bearing angle = or’ opposite side _ dE dH=tangent of vertical angle x distance hypotenuse — distance or, dE- dE + TS1 dE = sine of bearing angle x distance TS1 To determine dN : N+ Cosine of bearing angle = Adjacent side _ dN hypotenuse — distance or, m n dN = cosine of bearing angle x distance 220. Determination of dH In conducting a traverse, the surveyor is re- quired to determine the height of each traverse TS1 TS1 station. This is accomplished by determining dE — dE+ the difference in height (dH) between the oc- cupied and the forward station. By using the Figure 85. Quadrant-sign relationship for dE and dN. » 133 TS1 (Forward eta) Vertical angle >dH Distance (occupied station) Figure 86. Schematic diagram showing right triangle for determination of dH. 221. Scale Factor can be compensated for by reciprocal measure- The log of the scale factor is applied to the ments of the vertical angle from each end of dE and dN computations of all surveys exe- such a leg. In measuring vertical angles cuted to an accuracy of fourth-order. The pur- reciprocally, the vertical angle at each end of pose of the log scale factor is to convert the leg should be measured to the same height ground distance to map distance when the uni- above the station (normally HI). If this can- versal traverse mercator (UTM) grid is used. not be done, DA Form 6-2b (Computation— This factor is not used in surveys to accuracies Trignometric Heights) (fig. 90), must be used less than fourth-order because of the low ac- in computing the height of the forward station. curacies of these surveys. The scale factor value varies with the distance of the occupied 224. DA Form 6—2b station from the central meridian of the UTM a. DA Form 6-2b (figs. 90 and 91) is used grid zone. The scale factors are given for to determine heights of forward stations when every 10,000 meters east and west of central the angles are measured reciprocally or non- meridian and are shown in tabulated form on reciprocally to different heights above the sta- the back of DA Form 6-2. The values of the tion. scale factor are extracted by entering the table b. Entries required are the vertical angles on the back of the form (fig. 88) with the ap- measured, height of station, heights of instru- proximate easting value of the occupied sta- ment, and heights of target. tion to the nearest 10,000 meters. c. The formula to be used is shown on the back of DA Form 6-2b. 222. DA Form 6-2 a. DA Form 6-2 (figs. 87 and 88) is used 225. Azimuth and Distance from to determine coordinates and height from azi- Coordinates muth, distance, and vertical angle. In survey operations, it is often necessary b. Entries on the form are as shown in fig- to determine the azimuth and distance between ure 87. two stations of known coordinates. Some ex- c. Formulas to be used are shown on the amples of a requirement of this nature are back of DA Form 6-2. computation of a starting azimuth for a survey when the coordinates of two intervisible 223. Reciprocal Measurement of Vertical points are known, computation of azimuth and Angles length of a target area base or the base of a The effects of curvature and refraction of triangulation scheme, and computation of azi- lines of sight must be considered for traverse muth and distance between critical surveyed legs in excess of 1,000 meters. These effects points when swinging and sliding the grid is 134 N 135 8 / 32 /34 \/32 \ 7 */34 è> O 3,836 3*836 3,836 3 ! 335* 72¿. 4 T T V 23- 3 27 7 //7 6 /9z o 309- 6 2/S ■ 3 334 SS+ 334* /87. 6 ‘S3 4* ‘Ô Y¡¿* • (FM 6-120) 469*12 1 833*698 , ^ 1— 1—^ 1— ¿070*6 2 9 >é> V¡¿* 6 < & * Q\ 3 8.322,8<9 8^.212 1147 8.249* 72S 2.0SS*4l1 At 1 1 ■ \¿.282*7 76 Pe¿ rSj TfZ rS/ 3of 97S*S34 833* i 98 i 9.4 8 4|0 I 5 8 9.4 8 410 15 8 9.4 6 4.0 I 5 6 9.4 6 4t0 I 5 8 8\SS0\7*i ¿.070*629 9\ TABLE-UTM GRID SCALE FACTORS FOR ARTILLERY Add log scale factor to log ground distance to obtain log UTM grid distance. GIVEN: The easting value used to determine log UTM scale factor is easting of the Coordinates and Height of occupied station. known station to nearest 10,000 meters. Azimuth STATION to REAR STATION. EASTING OF STARTING STATION LOG SCALE FACTOR FIELD DATA: Observe horizontal angles and venical angles. 500.000 500.000 9.9998300 Tape horizontal ground distance between occupied station and forward station. 490.000 510.000 9.9998300 GUIDE: 480.000 520.000 9.9998300 g j Enter field data in blocks marked. 470.000 530.000 9.9998300 C 9 Sign of dH; (♦) when elevation angle, (-) when depression angle. 460.000 9.9998300 LIMITATIONS: I 550.000 9Í9998400 I— t ► ¿oft Sc+fe F&céor This form should not be used for vertical conuol when horizontal distance 440.000 560.000 9.9998400 exceeds 1,000 meters unless reciprocal vertical angles are observed and 430.000 570.000 9.9998500 meaned. 420.000 580.000 9.9998600 This computation requires that HI at occupied station and height of target 410.000 590.000 9.9998700 at forward station be equal. 400.000 600.000 9.9998800 When distance exceeds 1,000 meters or when HI and height of target are 390.000 610,000 9.9998900 unequal use DA Form 6-2b for more accurate vertical control. 380.000 620,000 9.9999000 RESULTS: 370.000 630.000 9.9999200 Coordinates and height of forward station. 360.000 640.000 9.9999300 FORMULA: 350.000 650.000 9.9999500 dE = dist. x Sin Bearing dN “ dist. x Cos Bearing dH = dist. x tan vertical angle. 340.000 660.000 9.9999700 330.000 670.000 9.9999800 320.000 680.000 0.0000000 310.000 690.000 0.0000200 300.000 700.000 0.0000400 290.000 710.000 0.0000600 280.000 720.000 0.0000900 270.000 730.000 0.0001100 260.000 740.000 0.0001300 250.000 750.000 0.0001600 240.000 760.000 0.0001900 230.000 770.000 0.0002200 220.000 780.000 0.0002500 210,000 790.000 0.0002800 200,000 800.000 0.0003100 190.000 810,000 0.0003400 180.000 820,000 0.0003700 170.000 830.000 0.0004100 160.000 840.000 0.0004500 150.000 850.000 0.0004800 140)000 860.000 0.0005200 130.000 870.000 0.0005600 120.000 880.000 0.0006000 110,000 890.000 0.0006400 100,000 900.000 0.0006900 £ U. S GOVEflNMCHT PRINTINC OFFICE. I0S3 O— 355629 Figure 88. Back of DA Form 6-2. COMPUTATION • COORDINATES AND HEIGHT FROM AZIMUTH, DISTANCE AND VERTICAL ANGLE n ran*» mrot (PM 6.120) ? 2 78s/9,¥3 Aft Me T 1 T T“ $ f2/ù y 7 3d ài r« M*«UI« Joe SSOx 4¥8 /3 3 \ 837x02535 x¥/8 3 [ .uncu. n—1 1 XtJ~ /lŸxSŸ'ÏO M to atltii S7¿ Sá 57897 'Ö // .8 ¥1S\o7\/3 9.4 8 4|0 I 5 8 9.4 8 4i0 I 5 B & o'x+Ase* 1 /3Si0 7\ /3 T T 3&0\ 9* 9 99x8+00 9.999x8+00 US \07\ (3 44\52\5O 9\848X5777 r.850\3883 8 /S8x3U3 w r. /80\ i> \8I1'.39§ ruz x4293 Í.HZ\4293 VZ \4Z93 3/S i 2 \2H \03 H\3(. \0Q 480x5385 9^.979 \/798 7 ./bZx¿9¿4 (t)Z. I8Q\ ) \ i43'jr. 974x774! 2.914^1741 ü}.974x 774/ 34Z\Z4\03 I. 455J52Í 2.953x7939\ \o\f37\47oS T 52 'SS! 309.89 3X83(. 145.3/ 405./ , 451x¥7x (3 /79 xSf .io 9,4 8 4|0 I 5 8 9.4 8 4,015 8 & o\)u\3oyÿ / 04tP/5 'è /4Z-23 U .2- '233x4-3x4* 41 n U44IIM 80 SCP SS2 350.04 3,836 003 08 4/L 3 /77 \S9\bö i r 999.2 7 SU x 32x38 9.4 8 4>0 I 5 8 9.4 8 4|0 I 5 8 ^o'xQ^xQoi^ 54/43 ■â> 23 iS! x 32 x58 —;— 3UOx 9\ 999x84oo 9.999 x6400 28\zi\oo 151 32\S8 9\(.71x9(.42 9.994x 1041 7! 308 x8248 (í)r. !8o i P 394$ 2\oSs\l37(. 3 .OSSx 131(. pQSS \ 73 7(. 33l\3Z\58 Z\133x54(8 z\999\<»8n P.3Í4\5&24 rS3 552x89/47 3\83$, 003.8/ 4/8.6 « + fitt roam*« MIT I« TUM «mm MIT «na» ta i4iM er, ¿. 0. 27/Zen, /. O. FORM COITION OF 1 OCT Bl IB OBSOLETC. DA AUO SB 6-2 Figure 89. Sample computation of fourth-order traverse. COMPUTATION—TRIGONOMETERIC HEIGHTS OCCUPIED STATION SCP 3 FORWARD STATION SCP 3 5CP ¥ HORIZONTAL DISTANCE GROUND □ BETWEEN STATIONS UTM GRID □ HEIGHT OF INSTRUMENT AT OCCUPIED STATION 1 + / .(e /. ¿ HEIGHT OF TARGET AT FORWARD STATION / • 6» V ■ / .C t- I+ I ALGEBRAIC SUM (1) AND (2) o\ o I- o\ O i HEIGHT OF INSTRUMENT AT FORWARD STATION / :¿ t- t- ALGEBRAIC SUM (3) AND (4) iÉ2- HEIGHT OF TARGET AT OCCUPIED STATION i-F / ■ ¿ /! ALGEBRAIC SUM (5) AND (4) O 0 o\o t 1/2 OF (7) o\ O o\o VERTICAL ANGLE OCCUPIED STATION + T—r TO FORWARD STATION ^ /\03\¥L \s> o VÍ'- (È VERTICAL ANGLE FORWARD STATION TO OCCMPIED STATION WITH SIGN REVERSED - / 'O o \34\53 ALGEBRAIC SUM (9) AND (10) ? ^ 07 3â h i\o9x38 H h 12 1/2 OF (11) /\o3\V9 1,1,1 1. NON-REOPROCAL ANCLES ONLY VERTICAL ANGLE OCCUPIED STATION “i—r 12 TO FORWARD STATION T I I J I LOG OF HORIZONTAL DISTANCE ii BETWEEN STATIONS 3.939,2/03 3.S3V,83L3 14 LOG TAN (12) 8\ ¿¿3)7/0/ 8.O0S 3232 15 (1J)+(14) 2 \ 207,9209 /; SYO,3¿í-S IF HORIZONTAL DISTANCE IS, GRID, USE LOG SCALE FACTOR FROM 16 REVERSE; GROUND, LEAVE BLANK 999\ 8Ÿ0O yf 999 \S¥oo (15) —(16) 2 ! 208,0809 NUMBER HAVING LOG (17) USE SIGN OF (12) P ! /¿As*} ! JV! 7 IF BLOCK II IS BLANK REPEAT (3) 19 IF BLOCK II IS FILLED REPEAT (I) O : O o\ O 20 ALGEBRAIC SUM (18) AND (19) P /¿/! ¿~ £) 3*\ 7 NON • RECIPROCAL ANGLES ONLY, CURVATURE AND REFRACTION 21 CORRECTION FROM REVERSE 5" + ALGEBRAIC SUM (20) AND (21) JV! 7 /(*/. S 2_ E P STATI0H 23 HEIGHT OF g gopwAR D 3 7/' (p 333. / IF (23) IS KEICHT OF OCCUPIED STATION REPEAT (22); IF (23) IS HEIGHT OF FORWARD STATION t) REPEAT (22) WITH OPPOSITE SIGN /(,/. S |> , 7 ALGEBRAIC SUM (23) AND (24)= HEIGHT OF □ OCCUPIED □ FORWARD STATION SS3\ / 99ä. V COMPUTER CHECKER C/o¿ Sones 5/ni/A SHEET 2 Of 2 SHEETS NOTEBOOK AREA DATE REFERENCE/—~S8 3bx/no‘3 so FORM IS OBSOLETE. DA 1 MAT $6 6-2 b REPLACES DA FORM 6-2b, 1 OCT 52, WHICH Figure 90. Computation of heights, fourth-order survey. 138 TABLE - CORRECTION FOR CURVATURE ANDREFRACTION TABLEHJTM GRID SCALE FACTORS FOR ARTILLERY (No interpolation necessary for Artillery Survey) EASTING OF STARTING STATION LOG SCALE FACTOR Ute only when dH Is computed using non -reciprocal vertical angles. SIGN ALWAYS PLUS 500.000 500.000 9.9998300 Enter In (2l) 490.000 510.000 9.9998300 480.000 520.000 9.9998300 Log Pitt (M) Con (M) 470.000 530.000 9.9998300 460.000 540.000 9.9998300 3.079 .1 450.000 550.000 9.9998400 440.000 560.000 .2 9.9998400 3.230 430.000 570.000 9.9998500 3.322 .3 420.000 580.000 9.9998600 3.386 .4 410.000 590.000 9.9998700 3.435 .5 400.000 600.000 9.9998800 3.473 390.000 610,000 9.9998900 380.000 620,000 .7 3.508 370. 000 630.000 9.9999200 3.537 .6 360.000 640.000 9.9999300 3.562 .9 360.000 650.000 9.9999500 3.584 1.0 340.000 660.000 9.9099700 3.625 1.2 330.000 670.000 9. 9999800 320.000 680.000 0.0000000 3.658 1.4 310.000 690.000 0.0000200 3.687 1.6 300.000 700.000 0.0000400 3.712 1.8 290.000 710.000 0.0000800 3.736 2.0 280.000 720.000 0.0000900 3.784 2.5 270.000 730.000 0.0001100 260.000 740.000 0.0001300 3.824 3.0 250.000 750.000 0.0001600 3.857 3.5 240.000 760.000 0.0001900 3.886 4.0 230.000 770.000 0.0002200 3.912 4.5 220.000 780.000 0.0002500 3.934 5.0 210,000 790.000 0.0002800 200.000 800.000 0.0003100 3.955 5.5 190.000 810,000 0.0003400 3.974 6.0 160, 000 820,000 0.0003700 3.992 6.5 170, 000 830.000 0.0004100 4.007 7.0 160.000 840.000 0.0004500 150.000 850.000 0.0004800 140.000 860.000 0.0005200 130.000 870.000 0.0005600 120.000 880.000 0.0006000 110,000 890.000 0.0006400 100,000 900.000 0.0006900 » Given: UTM grid distance or horizontal ground distance in meters between stations. Height of one station in meters. Field data.* Observe vertical angle between instrument at one station and target at other station. Height of instrument. Height of target. Guide: Enter field data in blocks marked I When vertical angles arc observed in two directions, either station may be designated as the occupied station. Use Blocks U 11, and IV. When vertical angle is observed in one direction, use Blocks U 111, and IV. Use curvature and refraction correction from tabic above. Elevation of occupied station need not he known. In (10), obtain approximate easting coordinate of occupied station from other computations or from map. Use this value to obtain scale factor from table above. If height of either station in (*JM) is below sea level (-), add 1,000 meters algebraically to (23); proceed with computa- tion as* indicated. Subtract 1,0()0 meters algebraically from (25) to obtain height of station. If height of occupied station is used in (2M), then height of forward station is obtained in (25). All angular units used in computation must.be the same (mils or degrees). Limitation: Tliis computation docs not provide for reduction of ground distance to sea level distance. Results: Height:of the unknown station in meters. GOVERNMENT PRINTING OFFICE 1996 0—38953) Figure 91. Back of DA Form 6~2b. 139 û UÄVOWWKT rwfrmœ omet : 1955 o—355492 COMPUTATION - AZIMUTH AND DISTANCE FROM COORDINATES (PM 6-120) E COORDINATE N COORDINATE îI + « + SSV, /&7, (./ 3\S3S\ 940.*/ •Po? SS3 ■ 8i,¥. 2/ 3 ! 83C ! 080 ! 39 IF * IS CtSS THAN ». REPEAT A i T I IF AA IS BLANK. USE A.B. SIGN ( —) ©i IF AA IS FILLED, USE B-AA. SIGN (4) 5> ! 3231 Vb /s/ 93 ANGLE HAVING LOG TAN BEARING A TO B 009] 790 // 32 \ S DETERMINE AZIMUTH FROM BEARING BY PLOTTING oo\o 2 . /3/ \ 7 SL 4£ AND AN ON SKETCH AND USING SKETCH AS GUIDE // 32 S LOG iC - LOG M s LOG TAN REARING A TO R o\32 7 ?S* AZIMUTH A TO B 32 *7\ 3- IF dE IS MORE THAN dM IF dE IS LESS THAN dN REPEAT LOG 4E REPEAT LOG AN N?1 SO? I 7*0 LOG SIN BEARING LOG COS BEARING r 9sá\ CLlo LOG 4E- LOG SIN BEARING B LOG AH- LOG COS BEARING = LOG GRID DISTANCE A TO B IN METERS LOG GRID DISTANCE A TO B I 2 SS3, 0 7* LOG CONVERSION FACTOR T LOG CONVERSION FACTOR I I METERS TO TAROS 0.0 3 8,6029 METERS TO YARDS 0 0 3 8,86 29 LOG CRIO OIST IN M. + LOG CONV FACTOR : LOG GRID DIST IN M. 4 LOG CONV FACTORS LOG GRID DISTANCE A TO B IN YARDS LOG GRID DISTANCE A TO B IN YARDS E COORDINATE N COORDINATE 4400 rf AE — dE + 1 r i r dM + m 4 1 1 r IF A IS LESS THAN B. REPEAT A 1 1 r dt + IF AA IS BLANK. USE A • B. SIGN (—) 1 r IF AA IS FILLED. USE O-AA, SIGN (4) AZ.- +»••<•« AZ. = ANGLE HAVING LOG TAN BEARING A TO 6 DETERMINE AZIMUTH FROM BEARING BY PLOTTING AE AND AN ON SKETCH AMD USING SKETCH AS GUIDE LOG AE - LOG dN S LOG TAN BEARING A IO B AZIMUTH A TO B IF dE IS MORE THAN dN IF dE IS LESS THAN dN REPEAT LOG AN REPEAT LOG AE LOG SIN BEARING LOG COS BEARING LOG AE —LOG SIN BEARING B LOG AN- LOG COS BEARING = LOG GRID DISTANCE A TO B IN METERS LOG GRID DISTANCE A TO B IN METERS LOG CONVERSION FACTOR LOG CONVERSION FACTOR n ^ METERS TO YARDS 0.0 3 8,8629 METERS TO YARDS 0 0 3 8,8629 LOG GRID DIST IN M. 4 LOG CONV FACTOR : ~r LOG GRID OIST IN M. 4 LOG CONV FACTORS LOG GRID DISTANCE A TO B IN YARDS LOG GRID DUTANCE A TO B IN YARDS J£2J JUU GRID DISTANCE s !M c&riftBwe DA .*2"“.. 6-1 nePCACES EDITION OP I NOV 8». WHICH WILU BE USED UNTIL EXHAUSTED. Figure 92. Computation of azimuth and distance, fifth-order survey. necessary. The standardized form for this After computation of the accuracy ratio, the computation is DA Form 6-1 (fig. 92). denominator of the fraction is always reduced to the next lower hundred (e.g., 1:1,099 226. DA Form 6-1 becomes 1:1,000). To determine the radial a. DA Form 6-1 (fig. 92) is used to deter- error of closure, the correct coordinates of the mine the azimuth and distance between two closing point are compared with the traverse points of known coordinates. coordinates of that point and the difference is b. Entries on the form are the coordinates determined, of the two known points. Correct coordinates e. Formulas to be used are shown on the of closing point: 560068.0-3838037.0 front of DA Form 6-1. Traverse coordinates of closing point: 560064.0-3838040.0 227. Accuracy Ratio eE = 4.0 eN = 3.0 a. To determine whether the minimum ac- curacy requirements for a closed traverse have The difference between the two eastings of the been met, an accuracy ratio is computed. If closing point, error in easting (eE), forms one computation of the accuracy ratio reveals that side of the right triangle in figure 93 ; the dif- the minimum prescribed accuracy for the ference between the two northings, error in traverse has not been met and the errors can- northing (eN), forms a second side. The not be determined, the traverse must be rerun. hypotenuse of the right triangle is the radial An accuracy ratio is determined as a ratio error of closure. between the radical error of closure and the b. The radial error may be determined by total length of the traverse. This ratio is ex- computation on DA Form 61, by the Pytha- pressed as a fraction with a numerator of 1 gorean theorem, or by plotting eE and eN to (e.g., 1:1,000 (1/1000), 1:3,000 (1/3000)). scale and measuring the hypotenuse. The most The radial error of closure is the linear dis- common of these systems used is the Pytha- tance between the correct coordinates of the gorean theorem, which, by using data in figure closing station and the coordinates of that sta- 93, would be computed as follows : tion as determined from the traverse. The Radial error: V(eE)2+(eN)2 equation for the determination of accuracy 2 2 : V4.0 +3.0 ratio is as follows: Accuracy ratio = : V16-0 + 9.0 1 : VSKÖ total length of traverse H- radial error : 5.0 meters .Traverse coordinates plot here Radial error of closure eN= 3.0- Correct coordinates plot here eE=4.0 Figure 93. Schematic diagram showing radial error of closure. 141 When the radial error of closure has been . 1 determined, one other factor is required to com- 1111 or, rounded down plete the computation of the accuracy ratio. 1 This factor is the total length of the traverse which is determined by adding the distances of 1100 all traverse legs (excluding distances to offset 228. Closing Azimuth Error stations) in the traverse. Assuming that for The closing azimuth error is determined by the radial error computed above the total comparing the known closing azimuth with the length of the traverse is 5,555 meters, the ac- closing azimuth determined by the traverse. curacy would be determined as follows: The difference between the two is the closing Accuracy ratio: azimuth error. The error is considered within 1 tolerances if it does not exceed 0.5 mil per sta- total length of traverse -=- radial error tion angle for a 1:500 traverse, 0.1 mil per station angle for a fifth-order traverse, and 5 . 1 seconds per station angle for a fourth-order 5555 - 5.0 traverse. Section III. TRAVERSE ADJUSTMENT 229. General constant and equal in their effect upon each traverse leg. Blunders, such as dropped tape Establishing a common grid throughout an lengths or misreading of angles, cannot be entire corps or division artillery sector is not compensated for in traverse adjustment. Addi- as simple as it may at first appear. When ex- tionally, traverses which do not meet the tending survey control over long distances by prescribed standard of accuracy are not ad- traverse, a traverse party may well be within justed but are checked for error. If the error the prescribed accuracy and still be consider- cannot be found, the traverse must be per- ably in error. This problem is magnified when formed again from the start. several traverse parties are employed to extend control and attempt to tie their work together. 230. Sources of Errors Seldom, if ever, will these parties coincide on The sources of errors that are compensated their linkage, but, by adjusting the traverse for by traverse adjustment are not those errors throughout, some compensation will be made commonly known as mistakes or blunders but for those errors which have accumulated. Tra- are errors that fall into one of the following verses executed to a prescribed accuracy of classes : fourth-order must always be closed and ad- justed. An adjusted traverse is one in which a. Instrumental errors—Errors that arise the errors have been distributed systematic- from imperfections in, or faulty adjustment of, ally so that the closing data as determined by the instruments with which the measurements the traverse coincides with the correct closing are taken. For example, a tape may be too data. There is, of course, no possible means of long or too short or a plate level may be out of determining the true magnitude of the errors adjustment. in angle and distance measuring which occur b. Personnel errors—Errors that arise from throughout a traverse. Traverse adjustment the limitations of the human senses of sight is based on the assumption that the errors have and touch. For example, an error may be made gradually accumulated, and the corrections are in estimating the tension applied to a steel tape. made accordingly. There are three adjustments c. Natural errors—Errors that arise from that must be made in adjusting a traverse— variations in the phenomena of nature, such as azimuth, coordinates, and height. These ad- temperature, humidity, wind, gravity, refrac- justments eliminate the effects of systematic tion, and magnetic declination. For example, errors on the assumption that they have been the length of tape will vary directly with the 142 temperature; i.e., it will become longer as the To distribute the azimuth correction through- temperature increases and shorter as the tem- out the traverse, divide it by the total number perature decreases. of angles. In this case, +,19"-H4=+4" per » angle with a remainder of 3". Each of the four 231. Azimuth Adjustment angles will be adjusted by 4" with the three a. Determining Azimuthlargest Correction. angles receiving Since an additional 1 second the computation of position is in part depend- each to compensate for the remaining 3 sec- ent on azimuth, the first step in adjusting a onds. traverse is to determine the azimuth error and correct it. The azimuth error is obtained by Station Measured angle Azimuth correction Adjusted angle determining the difference between the azimuth SCP 135° 36' 10" +05" 135° 36' 15" established by traverse (computed) and the TS 1 155° 13' 45" +05" 155° 13' 50" correct azimuth. The azimuth correction is the TS 2 211° 49' 50" +05" 211° 49' 55" azimuth error with a sign affixed which will SCP 37° 19' 56" +04" 37° 20' 00" cause the computed azimuth, with the correc- c. Action After Adjustment. After the tion applied, to equal the correct azimuth. For angles have been adjusted, the adjusted azi- example, the correct azimuth from a point to muth for each leg of the traverse should be an azimuth mark is known to be 137° 47' 11". computed by using the starting azimuth and The closing azimuth of a traverse to the same azimuth mark is determined to be 137° 46' 52". the adjusted angles at each traverse station. To determine the azimuth correction, the fol- These computations should be performed on lowing computations are performed : fresh sheets of DA Form 6-2, not on the sheets Azimuth error : = correct azimuth — azi- used in the original computations. The ad- muth established by traverse. justed azimuth should be computed throughout = 137° 47' 11" — 137° 46' 52" the entire traverse and checked against the cor- = 19" rect azimuth to the closing azimuth mark be- Azimuth correction = +19" fore any of the coordinate adjustments are begun. b. Application of Azimuth Correction. Since traverse adjustment is based on the assump- 232. Coordinate Adjustment tion that errors present have accumulated gradually and systematically throughout the After the azimuth of each traverse leg has traverse, the azimuth correction is applied ac- been adjusted, the coordinates of the stations cordingly. The correction is distributed equally in the traverse must be adjusted. The first step among the angles of the traverse with any re- in adjusting the coordinates is to recompute mainder distributed to the larger angles. For the coordinates of all stations in the traverse, example, assume that the traverse, for which using the adjusted azimuths to obtain new the azimuth correction was determined, con- bearing angles. sisted of three traverse legs and four angles a. Determining Easting and Northing Cor- as follows:. rections. The easting and northing correction Traverse leg Measured angle for the traverse is determined by subtracting SCP-TS 1 135° 36' 10" (Az Mk-SCP-TS 1) the coordinates of the closing station (as re- TS 1-TS 2 155° 13’ 45" (SCP-TS 1-TS 2) computed with the adjusted azimuth) from the TS 2-SCP 211° 49' 50" (TS 1-TS 2-SCP) SCP (Closing) 37° 19' 56" (TS 2-SCP-Az Mk) correct coordinates of the closing station. Example: Correction = correct coordinates — coordinates established by traverse = 550554.50 — 3835829.35 (correct coordinates) — 550550.50 — 3835835.35 (traverse coordinates) + 4.00 - 6.00 143 b. Application of Easting and Northing Cor- (easting or northing) by the total length of rections. The corrections determined in a all the traverse legs up to that station and above are for the entire traverse. The assump- dividing it by the total length of all of the legs tion is made that these corrections are based in the traverse. For example, using the total on errors proportionately accumulated through- easting and northing corrections previously de- out the traverse. To apply the correction, it must be distributed proportionately. The termined, assume that the total length of the amount of easting or northing correction to be traverse was 22,216.89 meters and that the applied to the coordinates of each station is total length of the traverse legs up to TS 4 computed by multiplying the total correction was 3,846.35 meters. Easting correction at— TS 4 — Total easting correction X traverse length to TS 4 total traverse length -- + 4.00 X 3,846.35 22.216.89 = + 15,385.40 22,216.89 = + 0.69 meter Northing Correction at— TS ,4 = Total northing correction X traverse length to TS 4 total traverse length = - 6.00 X 3,846.35 22.216.89 = — 22,478.10 22,216.89 = — 1.04 meters 233. Height Adjustment height correction is determined by comparing Like azimuth adjustment, the height adjust- the height of the closing point as established ment is based on the assumption that the by the traverse with the known correct height error of closure is accumulated throughout the of the closing point and applying a sign which traverse in equal amounts at each traverse will cause the established height, with the cor- station. rection applied algebraically, to equal the cor- a. Determining Height Correction. The rect height. Example: Height correction: = correct height — height established by traverse = 478.3 meters — 477.5 meters — + 0.8 meter b. Application of Height Correction. The of each station but is applied to the difference height correction is distributed evenly through- in height (dH) between each traverse station. Traverse Adjusted out all stations of the traverse with any re- Station height dH Correction height mainder distributed to those stations for which SCP 478.3 478.3 the greatest dH was determined. The height TS 1 486.7 + 8.4 +0.2 486.9 TS 2 495.9 + 9.2 +0.3 496.4 correction is not applied to the traverse height SCP 477.5 -18.4 +0.3 478.3 144 Section IV. LOCATION OF TRAVERSE ERRORS 234. Analysis of Traverse for Errors the error in northing. Compute the distance A good survey plan when executed by a well- (radial error) and azimuth from the known trained party provides for numerous checks in coordinates to the computed coordinates. If a both computations and fieldwork. However, distance error had been made, the traverse these checks do not always eliminate errors. leg containing the distance error will have the On the contrary, errors are made both in the same azimuth (or back-azimuth) as the radial fieldwork and in computations and are often error (fig. 94), and the distance error will be not discovered until the survey has been com- approximately the same length as the radial pleted. The surveyor should be able to isolate error. The suspected traverse leg is then re- these errors and determine their causes. Often measured to verify the isolation of the error. an analysis of the fieldwork and the computa- Under some circumstances, several legs with tions of a survey in error will save hours of azimuths approximating the azimuth of the repetitious labor and computations. To assist radial error may be suspected as containing in this analysis, the chief of survey party the error. In this case, check the computations should maintain in the field a sketch, to scale, for each suspected leg. If there is no error in of each survey as it is being performed. If the computations, then each suspected leg must available, a reliable map can also be used to be remeasured until that leg containing the advantage. Upon completion of the survey, if error is found. an error is apparent, the following considera- 236. Isolation of Azimuth Error tions will be made. To isolate an error in a traverse, an assumption must be made that a. Indication of Azimuth Error. The azi- only one error exists. If more than one error muth closure and the coordinate closure will be exists, then it will not be possible to isolate the in error beyond the limits allowed for the pre- errors. scribed accuracy. b. Isolation of Azimuth Error. Compare the 235. Isolation of Distance Error computed azimuth to the known azimuth of the a. Indication of Distance Error. The azi- closing point, and determine the azimuth error. muth for the traverse will close within the Determine the azimuth and distance of the allowable tolerance; however, the coordinate radial error. Construct a scaled sketch of the closure will be in error beyond the limits traverse. Draw in the radial error, and then allowed for the prescribed accuracy. construct a line perpendicular to and at the b. Isolation of Distance Error. Compare the midpoint of the radial error. Extend this line known coordinates of the dosing point to the through the area in the sketch showing the computed coordinates of that point. From this fieldwork. The station at which the angular comparison, determine the error in easting and error was made will be on or very near this TS2 TSL Radial error of closure 30 meters Bn SCR TS4 30-meter error Figure 9A. Distance error. 145 extended line. Check the computations and By using this procedure, one or more suspect the field notes for that station. If no error stations may be determined; and then by trial can be found, remeasure the angle. If the re- and error procedure and systematic elimination measured angle compares favorably with the the suspected station in error may be located. original angle, then a multiple error exists and This is done by using the known coordinates of the survey must be rerun. the closing station and the coordinates of the c. Alternate Solution. Another procedure suspected station and computing the azimuth which can be used when a graphical plot can- and distance between the two. The computed not be made is to determine the approximate coordinates of the closing station and the distance of the station in error from the clos- coordinates of the suspected station are used to ing station. This is determined by using the compute the azimuth and distance between the mil relation formula (m = w-r-r), the distance two. If the error is at that station, the azi- of the radial error, and the azimuth error of muths should vary by the amount of the error closure. The radial error is substituted for the of the azimuth closure of the traverse, and the width, and the azimuth error of closure is sub- distances will be approximately the same. If stituted for the mills in the formula. the error is not at that station, the azimuths will disagree but not by an amount equivalent Example : to the azimuth closure error (fig. 95). This Range (in thousands) to suspected station = procedure is repeated for each of the suspected radial error azimuth errors of closure. stations. When the suspected station has been isolated, check the computations and field notes r = w -i- m for that station. If no error can be found, = 100 meters -7- 10 mils remeasure the angle at the station. If the = 10 (range in thousands) remeasured angle compares favorably to the = 10,000 meters original angle, rerun the entire survey. TS1 Correct btry SCP Closure error Azimuth error Computed btry SCP L B* TS2 Actual route of traverse party Computed route of traverse party IS 2' Figure 95. Azimuth error. 146 i CHAPTER 15 TRIANGULATION Section I. GENERAL 237. General angles between two or three unoccupied points a. Triangulation is a method of survey which of known coordinates. employs triangular figures to obtain survey b. Triangulation involves single triangles data. If the values of certain elements of a (fig. 96) as well as chains or schemes of tri- triangle are known, the values of other ele- angles (fig. 97). In a chain of triangles, the ments of the triangle can be computed; e.g., if unknown elements are progressively solved by the length of one side and two angles of a using data determined by computation from triangle are known, the size of the third angle the preceding triangle. and the other two sides can be computed. In 238. Specifications and Techniques the artillery the term “triangulation” is re- In triangulation, certain specifications and stricted to mean operations which involve the techniques are adhered to in both fieldwork and measurement of all three of the angles of a computations to produce an end product of the triangle. If only two angles and a side are desired accuracy. These specifications and tech- measured, the method is known as intersection. niques are shown in appendix II. If only the three sides are measured, the method is known as trilatération. Another 239. Triangulation Field Notes method is resection, in which the coordinates Examples of triangulation field notes are of a point are determined by measuring the shown in .figures 71 through 74. GENERAL BASE BASE BASE CHAIN OF SINGLE TRIANGLES CHAIN OF QUADRILATERALS Figure 96. Single triangle. Figure 97. Triangulation schemes. 147 Section II. SINGLE TRIANGLE AND SINGLE CHAIN 240. Description and Solution of the muth, and a distance. These items become the Single Triangle objectives of any work in the field regardless A triangle is defined as a three-sided figure, of the method of survey employed. To asso- the sum of whose interior angles equals 180° ciate the basic triangle in figure 99 with these (3,200 mils). If the length of one side and the objectives, assume that point A on this triangle value of all three interior angles are known, is a point on the ground the coordinates and the length of either unknown side may be found height of which are to be determined by trian- by the law of sines, or a is to sin A as b is to gulation. In order to accomplish this, the fol- sin B as c is to sin C (fig. 98). This then be- lowing steps must be taken: comes a proportion-type problem. a. Select two other points, B and C, inter- a. To determine the length of side b— visible to each other and point A. The coor- dinates and height of at least one of these two b : sin B : : a : sin A points must be known. b = a b. Measure the interior angles and vertical sin B sin A angles at all three points with an instrument. At the same time, establish the azimuth of one b = a X sin B of the sides. sin A c. The last item needed is the length of one of the sides of the triangle. If the coordinates b. To determine the length of side c— and height of both B and C are known, the c : sin C : : a : sin A distance between them can be computed on a DA Form 6-1 ; if not known the distance must c - a be measured. sin C sin A d. The triangle can now be solved for either c = a X sin C the length AB (side c) or length AC (side b). sin A In solving for one of these sides, the coordi- nates and height of point A can then be deter- 241. Survey Application of Basic Triangle mined. The decision as to which side to compute will be based on distance angles. To determine the coordinates of a point from a point of known coordinates, three items of in- 242. Distance Angles of a Single Triangle formation are needed—a vertical angle, an azi- Distance angles are defined as those angles in a triangle opposite the known side and the required side (side common to an adjacent triangle). Since in a single triangle there is no required side, the distance angles in a single triangle are the angles opposite the known side and the stronger (closest to 90° or 1,600 mils) o b c of the remaining two angles. In a single Sin A" Sin B Sin C triangle, the side which is computed is the side opposite the strongest angle at the base. For example, in figure 99, it is apparent that all of the elements needed are present to determine the length of either side AC or AB. In this triangle, the distance angles are at A (angle opposite the known side) and at C (angle closest to 90° of the remaining two angles). The side the length of which should be deter- Figure 98. Schematic drawing showing law of sines. mined is side AB. If the coordinates and height 148 of point B were known, the coordinates and Then the angles at point D would be measured. height of point A would be determined, as in All the information necessary to compute both traverse by using the azimuth and distance of triangles would then be available. Note that side BA and the vertical angle measured at B side AB is common to both triangles. In solv- to A. If the coordinates of point B were not ing for triangle ABC, side AB would be the known and the coordinates of point C were required side and angle C would be its dis- known, the coordinates and height of point A tance angle, regardless of its value. would be determined, again as in traverse, but by going from C to B and then to A. 245. Distance Angles of a Single Chain of Triangles As stated in paragraph 242, a distance angle ■33“00'00" A- is an angle in a triangle opposite the known side or opposite the required side (side com- mon to an adjacent triangle). The required side is also known as the forward line or for- ward base, in that it will become the base for Distance angles the next triangle in the scheme. In a chain of single triangles, the last triangle in the scheme / ■43o00'Q0r will be handled as a single triangle, and its distance angles will be determined as dis- cussed in paragraph 242. For example, in Figure 99. Schematic drawing showing distance figure 100 the distance angles in triangle ABC angles of a single triangle. are at points A (angle opposite known side CB) and C (angle opposite required side AB), 243. Description andwhereas Solution in triangleof a Single ABD, the distance angles Chain of Triangles are at points D (side opposite known side AB which had been solved in triangle ABC) and B A single chain of triangles is a scheme of (the stronger of angles A and B). single triangles connected by common sides. In figure 100 side AB is common to triangles ABC 246. Strength of Angles and ABD. Each of these triangles may be in- The results obtained by triangulation in the dividually solved by using the law of sines, if field will depend in part on the strength of the one side and the interior angles are known. triangular figures established. In reconnoiter- ing for a triangulation scheme, one of the points which the surveyor must keep in mind is the strength of angles in the triangles which he established. A strong angle is one which approaches-a right angle, or 90° (1,600 mils). As the law of sines will be used to solve the triangulation problem, a small error in the value of an angle near 0° will cause a relatively =“B large error in the sine of that angle and a cor- Figure 100. Schematic drawing showing responding error in the computed length of the a single chain of triangles. side opposite that angle. For this reason, dis- 1 0 tance angles must be between 22 /2 and 1571/2° 244. Survey Application(400 milsof the and Single 2,667 mils). It is for this rea- Chain of triangles son that, in a single triangle, the side opposite the stronger angle is the side computed. In figure 100, assume that it is' required to locate an additional point, D, outside the single 247. Triangle Closure triangle ABC. While the interior and vertical Triangle closure is another term for adjust- angles at A and B were being measured, the ment of the angles within a triangle. For a angles for the new triangle would also be taken. figure to be a triangle, it must have three sides 149 TO COMPUTE SIDE CORRECTED HIM LOG BtSE PC S1 AT I ON OBSERVED CORRECT IO* TAPED BASE 0C ANGLES ANGLES (It BC it ttptd. »or* bloc 3 1075 729 190 LOG SIN * LOG CONVERJAQJ) FEET TO KETERS STOP >13 ,33,01+. I 13 9 '984,917 (Vtt only •htn^^jt in fttl) 4.0 I 5 8 £ ri)-m LOG SCALE FACTOR LOOK >9 ,78,9 1+ 0 9 ,78 3 !090,812 ro COHPUTE SIDE LOG TAgfri^ASE -BC LISTEN 88 8 .88,0 699 SUM SIWOF.-GIES 31 j99l 9 1»0«0» )!00 m 32 IOOI 0 3 1004 511 fenl.r nn lint I) TO FINO STATION ANGLE AT C sm.o. LISTEN 552 820' 9 3 834 OIS' 6 387 4 r~ 1S9° S9* 60 VERT ¿L ST A—AFWO ST 0 0 LOOK OR ANOO it 64,00 25 ,7 742 5 $8514 28 AZIMUTH *). (•) AND I*) VlQl FMD STA —♦ STA-ÄEAP STA 17 28.8 CORRECTED^!. C 8 88 ■ITH SIGN REVERSED 28 412 :a ARE USED ONLT STATION STATION ANCLE AT C ALGEBRAIC SUM CO+fT) ANGLE 55 12 0 55 12 FOR RECIPROCAL 51 . RECIPROCAL VERT ^L » SUM S3 125| 6 72 ,40 AZ TO BEARING ANCLE STA—*F*0 STA I I J60 LOG TAN VERT-st JRECI PROCAL (*) 6SOO m 64 00 mm STA—»FMD STA g ^NON- RECIP (*) 8140(3 332 AZIMUTH LOG S LOG SLOE LOG SIDE. REPCATÍS} REPEATÏ5) STA-»fMO STA 8 40 8 »Eire 3 .004,511 3 1004 511* 3 004,511 LOG SIN LOG CQ5 01- LOG OH 1200 m 32 ,0010 8 4 O', 8 BEARING 9 866.202 BEARING 9 '831* I >404 843 AZIMUTH SUM = FORWARD LOG OE LOG ON STATION 3 ,834 704' 0 412 8 FMD STA 40 ,40,8 2.870,713 2 835, 930 STOP 553 563 4 TO COMPUTE SIDE UTM LOG BASE RC OBSERVED CORRECTION CORRECTED TAPED BASE BC STATION ANGLES ANGLES (It BC It ttptd, v»rft b/»<* (• rlfht) LOG CONVERSION FEET TO METERS LOG SIN A 9 4 8 H. O I 5 8 LOG SCALE FACTOR rn rnMPiiTf B ! 1 SUM A*R*C (>)*(*) s LOG SIDE SUM OF ANGLES 100° OR 1200 lit (Bnttr •« lint I) STATION TO FINO STATION ANGLE AT C }59° S9‘ 60 REAR VERT^J. STA—»FMD STA AZIMUTH VERT FMD STA--»STA CORRECTED »a C If). (•> ANOW NITH SIGN REVERSED STA-M2EAR ST ARE USED ONLT I 1 STATION STATION ANGLE AT C ALGEBRAIC SUM (é)*(TI ANGLE FOR RECIPROCAL A AZIMUTH LOGXL SIDESI I LOG SI LOG SIDE. STA>-»fNO STA REPEAT REPEAT REPEATTS) LOG SIR LOG COS SUM = LOG OH 1200 m BEARIHG BEARING AZIMUTH SUM = FORMARO LOG ON FMD STA-kSTA LOG OC STATION COMPUTER CHECKER IP tfH i» eempatad s*ii| tb« ioo-r*clproe*l »ertical aa|U (ram STA to PVD STA; tu corracttoa (or carvatara SHEET SHEETS ud ralaetioa wbaa loi aida is mora this 1.000 Klink Broadruck .6-8 REPLACES OA FORM 6-6, 1 NOV S3, MHtCH HILL BE USED UNTIL EXHAUSTED. COMPUTATION - PLANE TRIANGLE COORDINATES AND HEIGHT FROM ONE SIDE, THREE ANGLES AND VERTICAL ANGLES Figure 101. Solution of a single triangle, fifth-order survey. 151 £ U. S GOVERNMENT HUNTING OFFKZ. 1953 O—364204 I **■ U»—. I 1 Sin A 1 1" E TOCOMMTI KM ■ VK **U K Sin A ba>eBbaBC nt0 lreeartas ; Q. Azimuth from FORWARD STATION (A) to STATION (B or x Sin C Side CA = -IL x Sin B; • Side BA = jS- a height ot target other than HI use DA Form 6-2b When reciprocal or non-reciprocal angles are measured to Coordinates and height of FORWARD STATION. '^ P* *PP^y CORRECTION to the Divide the difference between SUM OF ANGLES and the compuied tide) should be greater than ^ DISTANCE ANGLES (angles opposite the known base and to compute height. next triangle. Compute the side (CA or BA) which forms the base of the or accuracy may fall below standard. from each end of a side. RECIPROCAL ANGLE is the mean of the vertical angles observed OBSERVED ANGLES to obtain CORRECTED ANGLES. Azimuth STATION to REAR STATION. angles arc measured at a point other than HL Measure height of target (to the nearest 0.1 meter) if vertical Tape base (BC) unless known from other computations. Enter field data in blocks marked. BC is always the know base. known. REAR STATION is station in triangle to which azimuth is STATION is the station for which survey control is known. measured from station to forward station omy. NON*-RECIPROCAL ANGLE is a vertical angle which has been used to compute height. Best results are obtained when RECIPROCAL ANGLES are Coordinates and Height of STATDN. is desired. FORWARD STATION is the station for which survey control Observe horizontal angles A. B, and C. Observe vertical angles to all stations of triangle. RESULTS: FORMULAS: o. LIMITATIONS L GUIDE: f22 1/2 GIVEN: FIELD DATA: i r -I L j I Figure 102. Back of DA Form 6~8. 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 1.8 2.0 2.5 3.0 H—h H—h 3.974 3.992 4.007 3.886 3.912 3.634 3.955 3.857 3.736 3.784 3.824 3.712 AUXILIARY COMPUTATION .7 .8 .9 .6 .1 .2 .3 .4 .5 1.2 1.0 1.4 1.6 3.658 3.562 3.584 3.625 3.687 3.473 3.508 3.537 3.322 3.386 3.435 3.079 3.230 vertical angles (Sign always plus). LOG SIDE (M) CORK (M) LOG SIDE (M) 00RR (M) Uie only when dH ii computed using non-Reciprocal Artillery Survey) (No inteipoUiion neceuary for AND REFRACTION TABLE - GORRECTDN FOR CURVATURE V and the sum of the interior angles must be table of curvature and refraction corrections 180°. However, as actually measured in the on the reverse side of DA Form 6-8 must be field, the sum of the angles will usually vary used. To enter the table, use the log length from 180° by a few seconds. If this amount is of the side along which the height is being ex- within tolerance (app II), the angles are ad- tended. justed to equal 180°. This is done by distribut- 6. When the vertical angle is measured to a ing the closure correction (the closure error target erected over the station or to any point with the sign reversed) equally among the other than height of instrument, the height of three angles. The remainder is applied to the the unknown station is computed on DA Form larger angle (s). The following example illus- 6-2b (fig. 90). Complete instructions for the trates the procedure for adjusting the angles of use of DA Form 6-2b are contained on the a triangle: reverse side of the form (fig. 91). At each Measured angle* Correction Corrected angUs station, the height of instrument and the A = 54° 07' 29" -1" 54° 07' 28" heights of any points which could conceivably B = 78° 30' 27" -2" 78° 30' 25" be used as a target by other parties will be C = 47° 22' 08" -1" 47° 22' 07" recorded. Prior to performing the computa- Sum = 180° 00' 04" Sum = 180° 00' 00" tions, the parties compare notes and determine 248. DA Form 6—8 the heights of targets and heights of instru- ments to be used. a. DA Form 6-8 (figs. 101 and 102) is used for the computation of triangulation schemes. c. In any triangulation scheme, the coordi- In computing single triangles or chains of nates and height of at least one station must be single triangles, only the front side of the form known. This station is used as the starting is used. In computing quadrilaterals, both the point to obtain the height of the next station. front and back sides of the form are used (par. The height control is extended along the for- 253). It is of prime importance to insure that ward line of each triangle in the scheme. In proper orientation is made of the triangle to figure 103, using the height of point C as a be computed in the triangular sketch on the starting point, the height of point B is first front of the form. The known base of the determined since the height of point A must triangle to be computed must always be repre- be computed along the forward line, BA. Once sented on the sketch as in line CB. A sample the height of B is determined, the height of A computation is shown in figure 101. can be determined. Using the height of A, the b. Entries required are as shown in figure height of D is computed and from D, the 101 and appendix II. height of E is determined. c. Formulas to be used are shown on the E back of the form (fig. 102). 249. Height Determination in Triangulation a. Vertical angles at each end of a side D should be measured reciprocally to the height of instrument (HI). Frequently, due to dis- Height of point C tances involved, the instrument operator must is known, //in- measure the vertical angle to a target erected dicates forward line. over the forward station. When the vertical angles are measured reciprocally at HI, the heights of triangulation stations are computed on the DA Form 6-8. If the length of the side is greater than 1,000 meters and/or if the Figure 103. Schematic drawing showing route vertical angle is not measured reciprocally, the of trigonometric height computations. 152 Section III. QUADRILATERALS 250. General as shown in figure 105. Triangles ABC and A quadrilateral is a triangulation scheme. ACD form one chain, and triangles ABD and The difference between a quadrilateral scheme BCD form the other. It is apparent that if and a single chain of triangles scheme is that side DC were of known length and side AB in a quadrilateral two interior angles are meas- were the desired side (forward line), the ured at each point, resulting in two diagonals length of side AB could be computed through as shown in figure 104. In effect, the result is two separate schemes, thus introducing a check two single chains of two triangles each, one feature into the fieldwork and computations. superimposed on the other; if separated, they For this reason, the quadrilateral scheme is would appear as two single chains of triangles preferred over the single chain of triangles. Forward line Direction of control extension Base Figure 10i. Schematic drawing of a quadrilateral. FORWARD LINE FORWARD LINE —-a / /V" BASE BASE \.c \'C FORWARD LINE FORWARD LINE _FORWARD_LINE BASE BASE BASE * * — —À ONE CHAIN OF TRIANGLES OTHER CHAIN OF TRIANGLES IN THE QUADRILATERAL IN THE QUADRILATERAL Figure 105. Schematic drawing of a quadrilateral separated into two single chains of two triangles each. 153 251. Fieldwork for Quadrilaterals provides another route (R2) by which only Since any quadrilateral is basically a net- the length of the forward line is determined. work of triangles and the computations will If the two log lengths in DA Form 6-8 agrce follow the same general form as those for within five digits in the fifth decimal place single triangles, the requirements for field- (0.0000500) of the mantissa, then the field- work are similar to those previously men- work and the computations are assumed to be tioned. The distance angles must be greater correct. If they do not agree within the toler- than 22^2° (400 mils) and less than IST1/^0 ance, then an excessive error has been made, (2,800 mils) and preferably between 30° and and the work must be rechecked. 150° (533 mils and 2,667 mils). The specifica- 254. Distance Angles tions for desired accuracy are identical to those The strength of the distance angles in the tabulated for triangulation (app. II). chain will determine which chain is to be Rl 252. Determining the Forward Line and which is to be R2. The chain containing the stronger combination of distance angles When a quadrilateral is computed, it is re- will produce the more accurate answer and will duced to single triangles, and each triangle is be the Rl chain. The weaker chain will be the computed separately. First, the azimuth and R2 chain. To determine the stronger chain, a length of the base must be determined ; second, table may be used (figs. 106 and 107). The coordinates and height of one station in the two distance angles of each triangle, rounded scheme must be known ; third, the values of the off to the nearest degree or mil indicated in interior angles and vertical angles at each sta- the figures, are used to enter the appropriate tion must be measured; and fourth, the for- chart. The factors obtained for each triangle ward line must be determined in order that of a given chain are then added, and the chain its length may be computed. In a single quad- containing the smaller total value is the rilateral, the forward line is always the side stronger, or Rl, chain. Figure 108 illustrates opposite the known side, or the side in the di- the determination of the Rl and R2 chains. rection in which control is being extended (fig. When the distance angles are used to enter the 104). If the scheme contains a chain of quadri- strength of figure table, the relative strength laterals, the forward line is that side which is of the chain on the left is found to be 5 and common to adjacent quadrilaterals. the relative strength of the chain on the right 253. Strength of Figures is found to be 6. The chain on the left is the Rl chain. Assume that the quadrilateral in figure 104 is to be computed. The coordinates of points 255. Computation of Quadrilaterals C and D are known, so the azimuth and length DA Form 6-8 is used to compute quadri- of the base can be computed on a DA Form laterals (figs. 109 and 110). One form is used 6-1. Each point is then occupied, and the in- to compute each quadrilateral. The Rl chain terior and vertical angles are measured. Since is computed on the front of the form and the side CD is the known side, the opposite side R2 chain is computed on the back. Only the (AB) will be the forward line. The basic log distance of the forward line is sought from quadrilateral (fig. 104) is really two single the R2 chain. In solving quadrilaterals, first chains of triangle (fig. 105). It would be pos- compute the log length of the forward line sible to compute through both chains and ar- through both chains. If the log lengths agree rive at the coordinates and height of points A within 5 in the fifth place of the mantissa, the and B and the distance between them, aver- fieldwork and computations up to that point aging the results to obtain a final answer. are correct. Computation may then be con- However, this method would not only be time- tinued to solve for the desired coordinates. consuming but could produce highly inaccurate This procedure will save time, in that if the results. By use of strength of figures, one log lengths do not agree, the previous work chain is chosen as the principal route (Rl) must be rechecked, and the solution for the co- through which the coordinates and length of ordinates would not have to be redone, which the forward line is computed. The other chain would be the case if the entire front of the 154 e 10° 12° 14° 16° 18° 20° 25° 30 33° 40° 43® 30° 53° 60° 63° 70° 75° 80° 85° 90° 10 428 339 12 339 259 233 14 315 253 214 187 16 284 225 187 162 143 18 262 204 168 143 126 113 20 245 180 153 130 113 100 22 232 177 142 119 103 91 24 221 167 134 III 95 83 64 26 213 160 126 104 89 77 58 28 206 133 120 99 83 72 34 43 30 199 148 IIS 94 79 68 SO 40 33 35 188 137 106 85 71 60 33 27 23 40 179 129 99 79 65 54 38 29 23 19 16 45 172 124 93 74 60 50 34 25 20 16 13 50 167 119 89 70 57 47 32 23 18 14 55 162 115 86 67 54 44 30 21 16 12 10 60 159 112 83 64 51 42 28 19 14 I I 9 65 153 109 80 62 49 40 26 18 13 10 7 5 70 152 106 78 60 48 38 25 17 12 9 7 4 75 ISO 104 76 58 46 37 23 16 11 8 6 3 80 147 102 74 57 45 36 22 15 10 7 5 3 O o 85 145 100 73 55 43 34 21 14 10 7 3 2 0 o 0 90 143 98 71 54 42 33 20 13 9 6 4 2 o 0 0 95 140 96 70 53 41 32 20 13 9 6 4 2 o o 100 138 95 68 31 40 31 19 12 8 6 4 2 o 105 136 93 67 50 39 30 18 12 8 5 4 110 134 91 65 49 38 30 18 II 7 5 3 115 132 89 64 48 37 29 17 7 5 3 120 129 88 62 46 36 28 16 10 7 5 3 125 127 86 61 45 35 27 »6 10 7 5 4 130 125 84 59 44 34 26 16 10 7 5 4 135 122 82 58 43 33 26 16 10 7 » 140 119 80 56 42 32 25 16 10 8 145 116 77 55 41 32 25 16 II 9 ISO 112 75 54 40 32 26 17 13 152 III 75 53 40 32 26 18 154 110 74 53 41 33 27 20 156 108 74 54 42 34 28 158 107 74 54 43 35 30 160 !07 74 36 45 38 33 162 107 76 59 48 42 164 109 79 63 54 166 113 86 71 168 122 98 170 143 Figure 106. Table for determining strength of figure factors (degrees) form had been completed before proceeding of the check obtained through the comparison to the back of the form. of the Rl and the R2 chains, the accuracy of a. Coordinate ¡. Computations. In a single the coordinates obtained is assured. chain of triangles, the forward line in the last b. Height Computations. Height computa- triangle of the chain is always opposite the tions in quadrilateral schemes usually involve stronger angle. In a chain of quadrilaterals, distances in excess of 1,000 meters, which re- the last forward line is in the R1 chain, and quire determination of heights by use of DA it may or may not be opposite the stronger Form 6-2b. For additional information see angle in the last triangle. However, because paragraph 249. » 155 Milt <50 200 250 300 350 400 450 500 550 600 700 600 900 <000 «00 1200 1300 1400 1500 1600 150 605 200 465 334 250 391 272 212 300 347 233 176 143 350 320 210 155 123 104 400 300 192 139 109 91 78 450 283 178 127 97 80 68 56 500 272 <69 119 90 73 61 52 46 550 264 162 112 84 68 56 47 41 37 600 257 157 108 80 64 53 44 38 34 31 700 245 147 99 72 57 46 38 32 28 25 20 600 236 139 93 67 52 41 33 28 24 21 17 13 900 229 133 88 62 48 38 30 25 21 19 14 II 1000 223 129 84 59 45 35 27 23 19 17 12 9 1100 218 125 81 56 43 33 25 21 17 15 II 8 1200 215 123 79 55 41 31 24 20 16 14 10 7 <300 211 119 76 52 39 29 22 18 15 13 3 2 <400 207 117 74 51 37 28 21 17 14 12 3 2 0 <500 205 115 72 49 36 27 20 16 13 II 2 0 1600 202 112 71 48 35 26 19 15 12 10 2 O 1700 199 MO 69 46 34 25 19 14 12 10 O 1800 196 108 67 45 33 24 18 14 Il 9 O 1900 193 106 66 32 23 17 13 Il 9 0 2000 190 104 64 42 30 22 16 13 10 8 2100 187 102 63 41 30 22 16 12 10 8 2200 184 99 61 40 29 21 15 12 9 8 2300 180 97 59 39 28 20 15 II 9 8 2400 176 95 57 38 27 20 15 II 9 8 2500 171 92 55 36 26 20 15 12 10 9 2600 166 89 54 36 26 20 16 13 11 10 2650 164 88 53 36 26 20 16 14 12 2700 161 86 53 36 27 21 17 15 2750 159 85 53 37 28 23 19 2800 155 84 54 38 31 26 2850 153 85 56 42 35 2900 151 87 60 48 2950 153 94 71 3000 163 112 3050 202 Figure 107. Table for determining strength of figure factors (mils). 35° 40° 95° 95 60° 55° 50 45* 85° 85* 35 40° Distonce ongles* 85°-60° * 2 Distance ongles 8 85° - 55° 8 2 Distance ongles *95°- 50° * 3 Distance angles 8 95°-45° *4 8 Total strength of figures 5 Total strength of figures 8 6 RI R2 Figure 108. Schematic drawing showing the determination of R1 and R2 chains. 156 157 SHEETS 9 8 4.0 I 56 , j I OF 2 87 88 42 SHEET 419 in /••(> 3 |95l ASE BC ET TO METERS BASE (in* I) g3?i948:87 8401799 '3 ,836,848 LOG SCALE FACTOR LOG SCALE FACTOR *PED P»5E BC TAPED BASE BC TT TO METERS ' « G CONVEÍJiflí FEET I 5 8 in foot) ¿0^*? 8 * | Q «» only •htn'BQ^l^ 34 91 LOG CONVERS 08 218 447 744 3792 546,702 0E 554 546 ,702! 91 546,484! 57 3 ,840,268129 - 7 534 ,8363 595 6237 790 CpI Smith 3 [939 I2I08 91851 ,0208 3 1939,3584 9 '999 9982 3 :939 ,2126 9 >999,8524 3 !939 ,2108 CHECKER 4P SCP USE LOG SIN e TO CONFITE SIDE TO COMPUTE SIDE 3« = LOG SIDE a LOG SID 'C fO-CJ) fl)-(R) sT.Tio. SC P 4 LOG SIDE. LOG dH REPEAT!*) SUM n STATION SCP 2 LOG SIDE. REPEATTS) SUM = LOG dH LOG SIN A STATION FORWARD MAM aa UTM LOG B*SE PC UTM LOG BASE BC NON-RECIP (*) FROM ONE SIDE, THREE ANGLES AND VERTICAL ANGLES COMMÎT,OK - PUNE TRIANQLE COORDINATES ANO HEIGHT TO COMPUTE SIDE TO COMPUTE SID 5TA-*FwD STA Cpl Jonas nrk .bletk to t¡tht) (It BC it téfêj, (tf BC Ik topod, work block to r Section IV. CENTRAL POINT FIGURES 257. General determined. In figures 111 and 112, each When it is impossible to observe the diago- scheme contains two chains of triangles, one nals of a quadrilateral, the central point is going clockwise around the central point and used. Two central point figures commonly used the other going counterclockwise. In figure 112 are shown in figures 111 and 112. Central point if AB were the base and DC the forward line, figures of six or more sides are not generally the chain of triangles going clockwise would used because of the excessive time and the contain four triangles and the other chain of number of personnel required to accomplish triangles going counterclockwise would contain the fieldwork. only three triangles. However, the relative strength of the chain of four triangles may 258. Computation of Central Point Figures make it the R1 chain when it is compared to The solution of the central point scheme is the relative strength of the chain of only three similar to the solution of the basic quadri- triangles. lateral. The R1 and the R2 chains must be z 4 Figure 111. Central point quadrilateral. Figure lia. Central point pentagon. AI P2 Figure 113. Schematic drawing of a three-point resection. 159 160 48: i 329 '4 377 :5 377 5 373 '5 - 4 Z 0 OF I SHEETS & 14 ,28 ,51 65 .31 .09 71 .02.10 * * 9 4 Í28 59 179 .59 ,60 165 ,31 ,09 3:885 6483 3 756 .8157 91871 .1682 3 885 ,6475 0:000,00I7 01000.0008 3 885 ,6475 3:861 .4134 3:839 ,6619 3 885.6475 3 862 .744 3:885 .6492 9:917 .1538 31885,6492 9 998 .6693 9:975 .764 2 87 48 SHEET 848 895 t*u S GOVERNMENT PAINTING OFFia IB96 O—17911) 3'836 -3'835 :953 ;39 (44) ANO (47, 37 +<») 1/3 OF (41 67 LOC SIN (10) 143)-f (43) LOC CRIO DISTANCE A TO P REPEAT (14) (44) —(43) REPEAT (4D DIFFERENCE BETWEEN [MUST BE LESS THAN CLOOOl] REPEAT (44) OR (47) WHICHEVER IS SMAU.ER (49)+ ($0)3 94 BlPf AT (30) REPEAT (T) (11 + 13) 1W OR noon REPEAT (111 REPEAT (13 REPEAT (11) (IV)-p (40) REPEAT 111) LOC SIN (3* (M) - (13) « ANCLE A. .73 '632 E '554 335 546 702 CHECEER £2 8185 er« + (2B) -(21) 30 IS (39, IS (37, -t-(2B) (27) — (3B) i:68 © 0,21 30' 3:885 6483 7 796 .170 2 IF (14) 13 LES3 THAN (17) MO* 1 (37) — PAC (31) \l400Mf (37) + LOC dH REPEAT LOC TAN VERT .4 VINC 01 HAN IFV27) is, IF (37) IS. PEAT (14) ANCLE LOC TAN (M> ANCLE HAVl 43* OR BOON (31) - (33) LOC TAN (71, LOC TAN 11) REPEAT (ID LOC TAN [U MOREVTHAN LES MORE THAN LESS THAN REPEAT (17, (18) -Ml») (24, *4 (25) WITH SICH REVERSED VERT ** P TO A COHPUTER p| STATION P STATION A CWebb 59 47 48 35 9:066 ,4059 21952 :0542 1556 22 5 ,20 ,45 SUM> LOC dN LOC CDS BEARINC 815 ,4261 94 '28 50:20:45 14 53 45 .00 .00 124 16 109 MANB 3:733 9123 8:971 0:45 3,7562 91424 19 OIOS! ,5 38 M IS 139) IV (37, + (3B ) (37)— (3B, (27) — (3B) (37) + (3B) 4/ 'P2 Û1ÎR1 s 3:882 6799 9:997 ,0316 31885:6483 "'""Is!885 :6483 >TMPP ✓ (A) PAC IMI4) 13 MORE THAN (17) S pi* N ■ SUM > LOC dE LOC SIN BEARINC IF (37) IS IF (37) IV LESS THAN 49* OR BOOM REPEAT (ID MORE THAN LESS THAN MORE THAN REPEAT (14) REPEAT (17) (13) - (IT) ANCLE HAVING LOC TAN (30) LOC TAN (33) LOG TAN (ID 124) 4- (25) ANCLE HAVING LOC TAN (34) (3D - (32) fourth-order survey. Figure llí. Solution of three-point resection, UREY BEARINC 60 26 96,41 ,29 83 18 31 AZ TO BEARINC 179 59 60 71 .02 48 .00 70 37 22 .11 82 ,12 109 22 .47 141 4 179 .59 104 24 104 .24 3 733 ,9123 3:839 ,6619 31815 ,4261 91975 .7642 9 871 1682 3 :862 ,7441 ON REVERSE * DIFFERENCE IN HEIGHTS OP TARGET ANO INSTRUMENT PROM GUIDE REVERSE MM CORRECTION POR CURVATURE AMO REFRACTION PROM TABLE OM RESECTION HEIGHT FROM THREE-POINT AND OOMPUTATION-COORDIHATES PMKVIOUS «OITIOHJ OF THIS FORM ARK OBSOLETE 41- 4N* dE- 51 29 29 6-19 96 .41 14 28 96 .41 (S) + <4)+(7) 9) . (10) (13, + (13, LOG CRIO DISTANCE A TO B (PROM AUI COMP ON REV) LOC SIN (4) OET.ZEH , ) ANO { Ef* } 1/3 OF (B) LOC SIN (7) OBSERVED ANCLE P DO NOT ATTEMPT TO SOLVE PROBLEM «HEN THIS VALUE IS AZIMUTH A TO C MO* OR AAOOM AZIMUTH A TO • <1S) + (14) LEU THAN (A) 10-4(1) IPSO« AUI COMP ON REV) (9) - (4) s ANCLE Ai OeSERVEO ANCLE P OM REV) (PROM AUI COMP MORE THAN'Bl «flWnr, 3 1W* OR )300*1 LOC CRIO DISTANCE A TO C (PROM AUI COMP OH REV, A TO P P TO A AZIMUTH AZIMUTH ♦ i IBO* -I »00H REAR STATION B «A”.» 82 .12 ,38 ITA ANCLE IEPEAT (341 ft A FORM UM 1 Fl» B» 161 1.8 3.0 2.0 2.5 3.5 4.0 4.5 5.0 6.0 7.0 5.5 6.5 AC sin Pj 3.736 3.784 3.712 3.824 3.857 3.912 3.934 3.955 3.974 3.992 3.886 4.007 ? ( l/J (6.Q b more ■l»o|«JJ: Il/2(B.Obta..h.o{«g}: Tan 1/2 (C-B) « TAD (2 - 45°) Tan 1/2 (B*Q Tan 1/2 (B-Q - Tan (2 • 45°) Tan 1/2 (B*Q Tan 2 * 1 1rf; 11Ä 3. sin P, AC tin C .1 .3 .4 .5 .2 .6 .7 .8 .9 1.0 1.2 1.4 1.6 (SIGN ALWAYS MINUS) FOR CURVATURE AND REFRACTION TABLE - CORRECTION SURVEY) NECESSARY FOR ARTILLERY (NO INTERPOLATION AC sin Pg AB tin Pj 3.079 3.322 Known or Estimated Height of Target Meastsed Height Algebraic Sum a and b 3.230 3.386 3.435 3.473 3.508 3.537 3.562 3.584 3.625 3.658 3.687 of fctttxument [Biter, with sign, in block marked Ik ) Side (M) Con (M) Gon(M) Log LOR Side (M) Height of tut ion A. 0.1 meto). Measure height of Instrument (to nearest A, tí not known. Estimate height of target at Ration Enter observed field data in blocks marked d Oner correction fo curvature and refraction in block marked *« may fall below nandard. Angfci P|, Pj, B. and C should be greater than 22 1/2° (400i¿) & accuracy ï 1/a (fcq h more h*,{!5£}: t 1/2 (fcC) h less than Coordinates of stathxu A, 6, and C. Observe horizontal angles P¡ and Pç. Observe vertical angle to station A. Tan 1/2 (B-Q « Tan (E - 45°) Tan 1/2 (B»C) (3555dS), a new nation P When value tn (8) of computation is between 160° (2845ri) and 200° or new stations A,B and/or C must be selected. Find difference between heights of instrument and target as follows. Tan 1/2 (C-B) « Tan (£ - 45°) Tan 1/2 (B»C) Azimuth from sution P to tutkm A. Tan 2 Coced ina tes and height of su lion P. ( t11rt 45 and 90 deuces). 2 « an auxiliary angle readied only In the compuution (always between FIELD DATA- GUIDE: GIVEN. RESULTS: LIMITATIONS: FORMULAS dE+ dN-f 135 ¡56 ,12 ,38 £L°i 82 75 75~!35 :56 82 112 38 179 .59 ,60 104 tfN-f dE- dE- dN4> Figure 115. Back of DA Form 6—19. i988 IPS IF IE IS LESS THAN IF dt: IS LESS THAN COORDINATE COOltDMATE .06 COS HEARING DISTANCE A TO C I ,719 129 ZOO COS BEARING« DISTANCE A TO B 3,837 ,636 :95 3,835 ,129 Is8 3 ,836 ,848 187 ¡87 3 ¡836 |s48 * 3!836!S48 ¡87 REPEAT LOG BEARING BY PLOTTING dE DETERMINE AZIMUTH PROM AND dN ON SKETOI AS GUIDE AZIMUTH A TO C [ENTER IN(1) ON PRONTJ DETERMINE AZIMUTH FROM BEARING BY PUTTING « AND 4N ON SKETCH AS GUIDE REPEAT LO LOG COS BEARING AZIMUTH A TO B [ENTER IN (4) ON FRONT] 4 , COORDINATE COORDINATE 546 ,902 :94 194 5461702 COMPUTATION AUXILIARY 553 ,398 165 dW I I 546 ,702 .94 553 ,925 .95 - 7 ,223 !0I - 9.9861347 I bOG COS BEARING 3 1235 ,3492 0 590 ,4474 318257966 3.858 ,7182 3 .825 ,7966 2 994,7921 3 :858 ,7182 9 .995 ,9741 0 .863 ,9261 * 546 ,902 .94 [ENTER LOG GRID DISTANCE A TO C M (IZ) ON FRONT ] [ENTER LOG GRID DISTANCE A TO B M <1S) ON FFONT ] TO B AND A TO C DISTANCE FROM A AZIMUTH AND RAC REY RAC MAN IF dE IS MORE THAN dN IF JE IS MORE THAN dN LOGAM^CSG LOG dt -LOG SOI BEARINGS 'o'XAfCia 0IS1 LOO GRID DISTANCE A TO C [3 . 05900l3 [>OOXRID LOG dE - LOG dN> LOG TAN BEARING A TO C REPEAT LOG dE PROM STATION A TO STATION C REPEAT LOG dE IOC dtf^-rtc LOG dE-LOG SIN BEARING« «■ ^PBXRID 0IS1 LOG GRID DISTANCE A TO B Û .00¿ ,r44l REPEAT A LOG SIN BEARING A TO C IP AA IS BLANK. USE A-C. SIGN - «5"* 'eacU. IP AA IS PILLED. USE C - AA. SIGH+J **1= ^ IDJD .71 TO STATION B IF A IS LCSS THAN B IF AA IS FILLED, USE B-AA, SIGN* LOG SIN BEARING A TO B IF AA IS BLANK, USE A-B. SION- FROH STATKM A Section V. RESECTION 259. Three-Point Resection points which are inaccessible. In figure 116 Three-point resection is a method of obtain- points A and B are the inaccessible points of ing control from three known points which are known survey control. Points R and Q are inaccessible. The fieldwork required for the points from which the other three points are solution is relatively simple. However, before visible. This scheme resembles a quadrilateral, going into the field, several factors must be except that the angles at points A and B are considered. In figure 113, points A, B, and C not measured. As with three-point resection, are the known points and point P is the occu- certain preliminary operations must be per- pied station for which coordinates are to be formed. Map reconnaissance is required to insure that all interior angles will be greater determined. A map reconnaissance is of prime 0 importance. All points should be selected so than 22Vk° (400 mils) and less than 157V2 that angles PI, P2, C, and B are at least 22%° (2,800 mils) and preferably between 30° and (400 mils) and preferably over 30° (533 mils). 150° (533 mils and 2,667 mils). Also points A In addition, if the sum of the angles PI, P2, and B must be visible from R and Q as well as and Al is between 160° and 200° (2,845 mils R and Q must be intervisible. Fieldwork will and 3,555 mils), no valid solution is possible. consist of measuring angles Rl, R2, Ql, and Q2 Fieldwork consists of measuring angles PI and vertical angles to A from R and Q. and P2 and the vertical angle from P to which- 262. DA Form 6-18 ever known point for which the height is also a. DA Form 6-18 (figs. 117 and 118) is used known, preferably point A. for the computation of a two-point resection 260. DA Form 6-19 problem. If only the coordinates of point R are a. DA Form 6-19 is used for the computa- desired, the section labeled TO LOCATE STA- tion of a three-point resection problem (figs. TION Q, lines 36 to 40, are not used. Similarly, 114 and 115). if only the location of point Q is desired, the b. Entries required are the coordinates of section labeled TO LOCATE STATION R, lines points A, B, and C and the horizontal angles 41 to 45, are not used. and vertical angle measured at point P. b. Entries required are the coordinates of c. The formulas to be used are shown on the the points A and B and the horizontal and back of the form. vertical angles at points R and Q. c. The formulas to be used are shown on 261. Two-Point Resection the back of the form. Two-point resection is a method of survey 263. Limitations and Use of Resection similar to three-point resection. In two-point Unless a resection (two- or three-point) has resection, control is obtained from two known been checked by some other means, the general rule is that it cannot be used as a point from Al which to extend survey control. However, a A2 B battery center and the 01-02 target area base of a field artillery battalion could be located by using a two-point or three-point resection. If known points are available, resection probably would allow these points to be located more rapidly than traversing and would allow the unit to conduct unobserved fire much sooner. If necessary, corrections could be made later Rl Q2 by traversing to a known point. Also, resection R2 Ql could be used to locate any single point, to check a location determined by some other Figure 116. Schematic drawing showing means of survey, or to verify points of sus- two-point resection. pected known control. 162 Ot SERVIO ANO CI Ol 28 ,59,50 COMPUTATION • COORDINATES AND HEIGHT FROM TWO-POINT RESECTION OSSIRVIO ANCLE R, 52 31 10 cm 6-200) 81 31 ,00 21 ANCLE HAVING LOG TAN (20) 50 ¡32 ¡51 3) REPEAT (10) 39 ,30 ,20 00SERVED ANCLE R, £Z_ 45 jOO 00 REPEAT (20) OR (2$), ANGLE 35 58 23 IZSL 59 ,60 5 ,32,51 33 (33)4- (34) 75 28,43 («♦(O [ENTER ON THIS LINE) TO LOCATE STATION 0 149 19 ,20 l S 8:987 ,3238 {!»<} -<»!= AM6L» At 30 40 40 9 1935 4612 31479 ¡567a OBSERVED ANCLE 5fl_ 58,40 8.922 ,7850 9 !985 ,8996- REPEAT (J) 81 31 00 REPEAT (ID 40,45,30 3 465 4668 179 ,59 ,60 ANCLE HAVING LOG TAN (25) 4 47 07 91932 .9643 (7)4(1) [INTER ON THIS LINE] 140 29 40 U LOO UN (10) 9¡803 ¡5616 35 58 .23 31532 5025 tirt {iSU 39 30 .20 9~685 15332 45 132 37 TO LOCATE STATION R 3 LOG GRID DISTANCE A TO B (JO) IS. AND (34) IV 40 45 30 9:966 15675 (PROM AUX COMP ON RE V) 31479 ,5672 MORE THAN (13) (28) (20) 9 707.7484 (H)+(17)+(IS) 3CEŒ33 LESS THAN (IS) (20) (28) 91768 .9374 9'932 .9643 91540 ,2924 REPEAT (28) OR (20). ANGLE A. 45 32 31248 ,5046 (20) IS. 9 899 '5797 MORI THAN (IS) 9~!455 16623 30 ,40,40 91966 '5675 -h LESS THAN (IS) (1S)-(I*) (43)-(44): 1$ (12)4(13)4(14) 01084^6301 LOG GRID DISTANCE A TO I 9:540 2924 76 113 ÎÏ7 ?'28i am REAR STATION I CARLTON AZ A TO B (PROM REV) 46,42,25 TO LOCATE STATION 0 GRUBER '541,835170 3'835'349 loo ,48810 STA ANCLE [VERT ^ 0 TO A 2IPEAT (301 45,32,37 AZ TO BEARING I VITH SIGN REVERSED .47;00( «î 3 405139 133183 46 16 LOC TAN 92, 15,02 179.59,60 VERT ^ s! 13518510 ,441 14 FOXTROT 12 SEP 60 R^EAT|._ *__|R|P«AT I I I REPEAT I I 92.15.02 «oí 31532 ,50251 i.w 13 532,5025 (40) 31532 15025 2l4 AZIMUTH LOC SIN LOG COS A TO 0 92.15 ,02 BEARING 91999 ,6648 BEARING 81594 ftS54 II668i3535 ,44318 4\ 110« 87,44,58 SUM* SUM- r) ^ 180 00 00 LOG dl 31532 ,1673 LOG dN 2:i26 ,5579 ola 272 ,15 .02 JIM 545 241 109 3¡835 215 117 144310 REAR STATION 6 CARLTON TO LOCATE STATION R CRUDER '541 835 l70 3 835 349100 48810 AZ A TO B . -, - _ * _ 1 (PROM REV) 46 .42,25 dl- AZ TO BEARING -Qi I3200 «- I 606 ISO S I 040142 51 ¡2 dM + LOC TAN 76 .13 17 179 ,59,60 VERT 4X 8 1427 ,6176 436 Is REPEAT REPEAT REPEAT I 122 ,55 42 122 ,55,42 (41) 3l28ll937l (4S) 31281 19371 (4S) 31281 19371 - 214 3M* LOC COS «400 «t 91923 9437 BEARING 5 I 1709,5547 ,439 12 AZIMUTH 57 ,04 ,18 SUHs 9 7? |37M A TO R 122^55^42 S^OS 18808 LOC dN 31:017,12082 13 N W -h + 8Í 180 00 00 DIPPERENCE IN HEIGHTS OP TARGET AND INSTRUMENT PROM GUIDE ON REVERSE BILL ' 543;442l20 "3' 834:308l58 438 19 302 55,42 CORRECTION POR CURVATURE AMD REPRACKON PROM TABLE OH REVERSE Col Jona» Col Smith I SHEET I or I .MEET. PREVIOUS COITIONS OF THIS FORM ARC OBSOLETE. THIS FORM TOGETHER BITH DA ^,*6-18 DA FORMS 6-2, 6-8 AND 6-l() REPLACES OA FORM 6-2l, 1 OCT }2, WHICH IS OBSOLETE. Figure 117. Solution of two^point resection, fourth-order survey. AUXILIARY COMPUTATION AZIMUTH AND DISTANCE FROM A TO B E COORDINATE N COORDINATE OP GIVEN: FROM STATON A A A 541 1835 ITO 3 1835 I349 loo Coordinates of stations A and B. Height of station A. TO STATION • 544.031 160 3,837 .417 Î80 z FIELD DATA: IF A IS LESS THAN • Observe horizontal anglesQj, Oj. R}. And Rg. REPEAT A 541 ,835 70 3,835^349 lOO Observe vertical angle(s) from station(i) Q or (and) R to station A. Measure height(s) of instruments) at statlon(i) Q or (and) R to nearest 0.1 meter. IF AA IS tLAMK, USE A- B, SIGN- EE4 IF AA IS FILUaUSE B*AA. SKN4- 2 .195 19 2 .068 18 dH— Estimate height of target at station A, if not known. T 1 GUIDE: 1 ' ANGLE HAVING LOG TAN 3.341 ,6126 BEARING A TO B 46 42 ,25 Enter observed field’data in blocks marked E 3. -P DETERMINE AZIMUTH FROM Find difference(s) between heights erf instruments) and target as follows: BEARING BY PLOTTING dE H h STATION 0 STATION R 31315 .7185 AND dN ON SKETCH AS GUIDE LOG 4C-LOG«ls AZIMUTH A TO B H 1 Known or Estimated LOG TAN GEARING A TO G 01025 .8941 RENTER ON FRONT] 46 Height of Target + 40 Measured Height(s) IF dE IS MORE THAN dN IF «B IS LESS THAN of Instrument - I - I '6 REPEAT LOG dE 3 ¡341 16126 REPEAT L Algebraic Sum a and b I© I © I (fenter, with sign, in block(s) marked *] -2.4 -2.4 LOG SIN BEARING A TO B LOG COS BEARING 9 •479 .5672 LMXR» DISTANCE A TO B LIMITATIONS: Angles A}. A^, B^; Bn, Oj, C^. Rj. and Rg should be greater than 22 1/2° (400tfi) or [ENTER LOG GRID DISTANCE A TO B IN (M) AND/OR (41) ON FRONT] accuracy may fall below specifications RESULTS: Coordinates and heights) of station(s) Q or (and) R. TABLE • CORRECTION FOR CURVATURE AND REFRACTION Azimuth(s) from statlon(i) Q or (and) R to station A. FORMULAS: (NO INTERPOLATION NECESSARY FOR ARTILLERY SURVEY) Aj ♦ Bj = Oj ♦ Rj (SIGN ALWAYS MINUS) Sin A2 Sin Q2 Sin R2 Sin Sin Qj Sin Log Side (M) Caff (M) Con (M) Tan Z = Tan Z = Sin Bj Sin Qj Sin R^ Sin Sin Q2 Sin ^ 3.079 .1 3.712 1.8 3.230 .2 3.736 2.0 Tan S(Aj - 83) = Tan + Bj) Tan(Z - 45°) Tan '¿(Bg - AJ = Tan %(A! + Tan(Z - 45°) 3.322 .3 3.784 2.5 3.396 .4 3.824 3.0 3.435 .5 3.857 3.5 _ AB Sin (Bi ♦ Bg) 3.473 .6 3.886 4.0 y 3 Sin Og 3.508 .7 3.912 4.5 3.537 .8 3.934 5.0 3.562 .9 3.955 5.5 AB Sin Bo AR - 4 3.594 1.0 3,974 6.0 Sin Ri 5.625 1.2 3.992 6.5 3.658 1.4 4.007 7.0 3.697 Z - an auxiliary angle required only in the computations (always between 45 and 90 degrees). 0. a oorumuT raonno arm : im 0 • Man Figure 118. Back of DA Form 6-18. Section VI. INTERSECTION 264. General vey and then the apex angle should not be less Intersection is the method of triangulation than 150 mils and preferably should be at least in which only two angles in a triangle are 300 mils. measured. The third angle is determined by b. The accuracy of location of a point estab- subtracting the sum of the two measured angles lished by intersection is considered to be the from 180° (3,200 mils). same as the accuracy with which the points that established the base are located. However, 265. Specifications survey can be extended from a point located See appendix II for specifications and tech- by intersection only if that survey is of a niques in triangulation. lower accuracy than that of the intersected point. 266. Limitations a. As in triangulation, no267. distance angle in Intersection Computations the triangle should be less than 22^° (400 Intersection computations are the same as mils) or greater than 157%° (2,800 mils); an those for triangulation except that, on the DA angle between 30° (533 mils) and 150° (2,667 Form 6-8, the unmeasured angle must be com- mils) is preferred. The only exception to this puted and the angles in the triangle are not is when intersection is used in target area sur- adjusted. Section VII. TRILATERATION 268. General d. After the angles have been computed, When optical intervisibility between points they can be used in conjunction with the side lengths to extend coordinate control, provided and the need to extend control rapidly over a known direction is available. If sea level dis- relatively long distances precludes the use of some other method of survey, trilatération may tances were used on DA Form 6-7a, they must be used. Trilatération is a method of survey be converted to UTM grid distance when the through which control is extended by measur- coordinates are computed on DA Form 6-2. ing the lengths of the sides of a triangle and The log scale factor is used for this conversion. computing the interior angles of the triangle 270. Limitations of Trilatération from these lengths. The measurements are a. Due to increased lengths of the sides and made using the tellurometer. This provides an lack of optical intervisibility in some cases, di- accurate and rapid means of determining the lengths of the sides, thereby insuring deter- rection must be provided at points within the mination of angles which will permit the ex- scheme by some means other than trilatération. tension of control to fourth- and fifth-order This direction is carried through the computa- tions but some means must be used to place accuracies. the direction on the ground where it can be 269. DA Form 6—7a used. a. DA Form 6-7a is used for the computa- b. For best results, trilatération schemes should be planned so that distance angles, tion of the trilatération problem (fig. 119). 1 when computed, exceed 22 /^° (400 mils) and, b. Entries required for the form are the preferably, exceed 30° (533 mils). UTM grid or sea level distances for the sides c. Extensive map and ground reconnaissance of the triangle. The longest side is always are required to insure sites with electrical placed in block 1 of the form. line-of-sight capabilities and to insure that c. The formulas to be used as shown on the minimum distance angle requirements can be back of the form. met from selected positions. 165 COMPUTATION - PUNE TRIANGLE (Vmini Thrum Sidmrn) RBODIRKD DATA’ ÖTM (rid Hies a, b, aid c. OPTIONAL DATA Flue ÖTH (rid aiimotb liie a, b, or c. KNOWN AZIMUTH _TO_ ■+- -+- Plaie UTN (rid coordiiates statioi A, B, or C. KNOWN COORDINATBS g. Sta. + I -U _1_ KNOWN LENGTH • 91 127!O7 M>JB* Âiwmym amm a •• iongmmt known »id*. T T KNOWN LENGTH b 61 107,25 19 (ir> 3 ,785 ,8457 KNOWN LENGTH e 89.73 .53 20 LOG SIN 1181 9 ,977 ,3186 ID + (21 + 131 242 .07,85 (191 (201 3 ,763 ,1643 PH* OF (HI 1-21 .03 .92 22 LOG ID 3 .960 (3314 (D 91,27 ,07 23 (ZD - (221 9 ,802 ,8329 P—t- <51 - (61 29 76 ,85 ANGLE HAVING LOG SIN (23> = <’| 39°T25' ,35" LOG (7) 3 ¡473 7570 29 (131 3~Í952 ,9633 LOG (91 4 ,082 9260 26 9 ,977 ,3186 (8) 191 7 556 6830 27 (291 + (261 3 ,930 ,2819 LOG 121 3 ,785 8457 3 ,960 ^314 12 (10) - (ID 3^70 8373 (27) - (28) ,969 ,9505 1 13 LOG (3) 3 ,952 9633 30 ANGLE HAVING LOG SIN 1291=5, = es^'ss Isi" (121 - (13) 9 ,817 8740 PARTIAL PROOF 19 10.000 0000 + (19) 9,817 ,8740 31 (181 71° ,38' ,36" 16 -§-0F (19) 9 ,908 ,9370 32 39°,25' ,35" (30) ANGLE HAVING LOG COS (16) = 35°49* MS' 33 68° ,55' ,51" 131)9(32)9(33)^^ 18 2 X (17) =q 71° ,38',36* 3'* 180° ,00',02" REMARKS Sea level distance lines a,b, and c. COMPUTER CHECKER DA 1 ET,* 6-7a Figure 119. Solution of trilatération problem, fourth-order survey. 166 PART FOUR ARTILLERY SURVEY OPERATIONS AND PLANNING CHAPTER 16 FIELD ARTILLERY BATTALION AND BATTERY SURVEY OPERATIONS Section I. GENERAL 271. General next higher echelon may be available in the a. Paragraphs 272 through 282 cover survey form of— operations for all field artillery battalions and (1) One or more trig points in the vicin- batteries which have survey requirements, ex- ity of the battalion installations. cept field artillery target acquisition battalions When available, trig points should be and batteries. Survey operations for field artil- used as the basis for battalion survey lery target acquisition units are discussed in operations if survey control points chapter 18. have not been established for the b. Survey operations are performed by sur- battalion by the next higher echelon. vey personnel in the field artillery battalions (2) One or more survey control points for the purpose of obtaining the horizontal and which have been established by the vertical locations of points to be used in de- next higher echelon in the vicinity of termining firing data and for providing a the battalion installations. These sur- means of orienting pieces, instruments, radars, vey control points should be used as and searchlights. Survey operations of sepa- the basis for battalion survey opera- rate or detached batteries are performed for tions. the same purpose. b. After he has verified that the battalion survey data contains no error, the battalion 272. Battalion Survey Control survey officer should report to his commander a. Battalion installations must be located and the survey officer of the next higher with respect to a common grid to permit echelon any differences which may exist be- massing of the fires of two or more battalions. tween the battalion survey data and the data This grid should be the grid of the next higher provided by the next higher echelon. echelon whenever survey control points on that 274. Use of Assumed Data grid are available or when it is desired to mass When neither survey control points nor trig the fires of more than one battalion. points exist in the vicinity of the battalion b. A battalion survey control point (BnSCP) (battery) installations, the battalion (battery) is a point provided by a higher survey echelon survey officer must establish a point and as- for the purpose of furnishing survey control to sume data for that point. This point (and its the battalion. More than one such point may assumed data) establishes the battalion (bat- • be provided for a battalion. tery) grid and is used as the basis for the bat- talion (battery) survey operations. When the 273. Survey Control Points on Grid of next higher echelon establishes control in the Next Higher Echelon battalion (battery) area, the assumed data a. Survey control points on the grid of the must be converted to that control. 167 275. Converting to Grid of Next Higher c. Intersection. Locating the position of a Echelon point by using the intersection method is rela- a. When data for the point used as a basis tively simple and speedy. However, the method for the battalion (battery) survey operations depends on intervisibility between the ends of differ from the data for that point furnished the base line and the unknown point. Inter- later by the next higher echelon, survey data section must be used to locate points beyond determined by the battalion (battery) will nor- friendly front lines. When practicable, these mally be converted to the grid of the next locations should be checked by intersection higher echelon. The methods of converting from more than one base. survey data are described in chapter 26. Un- d. Resection. The resection method of locat- less the tactical situation causes the commander ing a point requires very little fieldwork. Re- to decide otherwise, battalion (battery) data section normally is used in artillery battalion are converted when data differ by— survey to establish a survey control point or (1) Two mils or more in azimuth. observation post(s) in areas where the only existing control is on points which are inac- (2) Ten meters or more in radial error. cessible. It is used for improvement over map- (3) Two meters or more in height. spotted or assumed data. However, any b. If the next higher echelon should convert location determined by resection must be its survey control to a different grid, the bat- checked by a separate determination (prefer- talion must also convert to that grid. ably traverse or triangulation) at the first op- portunity. 276. Use of Survey Methods Field artillery battalion survey operations 277. Use of Astronomic Observation may be performed by using any or all of the The problem of converting data to a common artillery survey methods, provided the limita- grid is greatly simplified if survey personnel tions of the selected survey methods are not ex- use correct grid azimuth to initiate survey op- ceeded. A comparison of the different methods erations. Correct grid azimuth can be obtained is shown below. by astronomic observation. Battalion survey a. Traverse. For most artillery survey oper- personnel should be trained in the determina- ations, traverse is the best method to use be- tion of grid azimuth by observation of the sun cause of its simplicity, speed, flexibility, and and stars using the altitude method and obser- accuracy when' performed over open terrain vation of Polaris using the hour-angle method. for comparatively short distances. In heavily They should also be trained in the transmission wooded or rough terrain, the expenditure of of direction by simultaneous observations. time in performing a traverse is extensive. b. Triangulation. Triangulation should be 278. Division of Battalion and Battery used in mountainous terrain where taping is Survey Operations difficult or impossible and in rough terrain that a. The survey operations of a field artillery would require an extensive expenditure of time battalion (separate or detached battery) con- to traverse. In gentle rolling or flat, treeless sist of one or more of the following : terrain, triangulation should be used when a (1) Position area survey. large area is to be surveyed. In such terrain, traverse is faster unless distances between sta- (2) Connection survey. tions exceed 1,500 to 2,000 meters. Where dis- (3) Target area survey. tances are large, triangulation will save time b. The survey operations performed by a and personnel. However, more extensive re- field artillery battalion or a separate or de- connaissance is required for triangulation than tached field artillery battery depend mainly on for traverse. Distance and angle measure- ments to achieve any given accuracy when tri- three factors, as follows : angulation is used must be more accurate than (1) The type of unit (including assign- for traverse. ment and mission). 168 (2) The availability of survey control. lished and furnished to searchlight battery (3) The amount of time available in personnel. which to perform initial survey oper- ations. 281. Survey of Alternate Positions Survey operations for alternate positions 279. Sequence of Battalion (Battery) should be performed as soon as survey opera- Survey Operations tions are completed for primary positions. The Battalion (battery) survey operations are survey requirements for alternate positions are performed in the sequence listed below. identical to the requirements for primary posi- tions. a. Planning (Which Includes Reconnais- sance). A general discussion of survey plan- 282. Limited Time Survey ning is contained in chapter 20. In order to Battalion (battery) survey personnel must insure maximum effectiveness, battalion (bat- provide the best firing chart and the best tery) survey operations should be planned and means of orienting weapons in the time avail- initiated prior to the occupation of position, able. When time is a consideration, the survey whenever possible. officer must plan and accomplish the survey b. Fieldwork. Fieldwork consists of estab- operations necessary to furnish the fire direc- lishing survey stations and measuring angles tion officer with an improved firing chart. The and distances necessary to determine required extent of the survey conducted and the meth- survey data. The assignment of personnel to ods employed will depend primarily on the accomplish the required fieldwork is deter- time available. The procedures used for ac- mined by the number of surveying parties complishing the division of operations may be available and the unit SOP. any combination of the following: c. Computations. Each survey computation a. Position Area. must be performed by two computers working (1) Map-spot battery centers (lay by independently and, when possible, checked with compass). a slide rule by the chief of party. Whenever (2) Map-spot battery centers and estab- possible, survey computations should be per- lish orienting lines by directional formed concurrently with the determination of traverse or simultaneous observation. '■ field data. This will insure that errors are de- (3) Map-spot battalion SCP, locate bat- tected and corrected at the earliest possible tery centers, and establish orienting time and will facilitate the early use of a sur- lines by open traverse from desig- veyed firing chart. nated battalion SCP. d. Plotting. After the survey data have been b. Connection Survey. determined, battalion survey personnel may be required to prepare the firing chart (FM (1) Use map for connection survey. 6—40). (2) Establish survey by firing. (3) Employ simultaneous observation or 280. Survey Operations of Searchlight directional traverse from battalion Batteries SCP to 01 or target area survey con- When suitable maps are not available, sur- trol point (TASCP). vey operations are performed by personnel of c. Target Area Survey. searchlight batteries for the purpose of deter- (1) Map-spot both 01 and 02. mining survey data from which light direction personnel can determine orienting data for the (2) Map-spot TASCP and short traverse searchlights. The survey operations which to locate 01 and 02. must be performed are those necessary to es- (3) Map-spot TASCP and locate 01 and tablish the grid coordinates and height of each 02 by intersection from an auxiliary searchlight. If desired, a grid azimuth for base. orientation of the searchlights may be estab- (4) Map-spot critical points. 169 SeeîioirD DD. POS!TI©M ÂiEA SUiVEY 283. ©eraeral vey officer may select the location of the a. Survey control is required in the position orienting station if the battalion (battery) area of each firing battery of the field artillery SOP so states.) battalion (both cannon and missile) and in the d. Registration point. A point in the target position area of the mortar platoon of the com- area the location of which is known on the bat support company of the battle group. Posi- ground and on the firing chart (FM 6-40). tion area survey is performed by battalion e. Orienting angle. The horizontal, clock- (separate or detached battery) survey per- wise angle from the line of fire to the orienting sonnel for the purpose of— line or the orienting line extended : it is never (1) Locating weapons positions and greater than 3,200 mils (FM 6-40). (The radars. orienting angle determined by survey person- (2) Providing means for orienting nel is computed by subtracting the azimuth of weapons and radars. the desired line of fire from the azimuth of (3) Determining orienting angles for the orienting line, adding 6,400 mils if neces- each firing battery. sary. For very heavy artillery, a similar angle is determined for each piece. b. The position area surveys for field artil- lery cannon and missile units are performed to /. Radar orienting point. A point which is a minimum prescribed accuracy of fifth order used to orient the radar. The radar orienting (1:1,000). When the TOE of the unit au- point for field artillery radar sets is established in a direction as nearly in the center of sector thorizes the aiming circle M2 as the instru- of search of the radar as possible. (The radar ment for position survey (separate batteries, mortar platoons), the survey is performed to officer furnishes to the survey officer the ap- a minimum prescribed accuracy of 1:500. proximate azimuth on which the radar orient- ing point should be established.) 284. Terms Used im Conjunction With Position Are®) Survey 285. Meîlhod of Peirîoirmîinig Posifioira Area Survey The following terms are used in conjunction with position area survey : a. Except when time is limited, a closed traverse is used to perform the position area a. Battery Center. A point materialized on survey. The position area survey is initiated the ground at the approximate geometric cen- at a survey control point, the point that estab- ter of the weapons position. The battery cen- lishes the unit grid, or a station established by ter is the chart location of the battery (FM the connection survey. The survey is closed 6-40). (The location of the battery center is on the starting point or on a station established designated by the battery commander or bat- to an accuracy equal to or higher than that of tery executive. The survey officer may select a the survey being performed. tentative battery center if the battalion (bat- tery) SOP so states.) &. If a terrain obstacle, such as a wide stream, prevents the use of a closed traverse b. Orienting Line (OL). A line of known throughout the entire position area, triangula- direction materialized on the ground near the tion must be used to cross the obstacle. How- firing battery, which serves as a basis for lay- ever, the number of triangles used should be ing for direction (FM 6-40). (The azimuth of kept to the minimum. the orienting line is included in the data re- ported to the fire direction center.) 286. Survey for Wessums P@sîffD©mis c. Orienting Station. A point on the orient- a. In surveying a weapons position, an ing line, established on the ground, at which orienting station is established near the bat- the battery executive sets up an aiming circle tery center. Normally, this point is used as one to lay the pieces (FM 6-40). (The location of end of the orienting line, and the traverse leg the orienting station is designated by the bat- used to establish the station is used as the tery commander or battery executive. The sur- orienting line; this keeps the orienting line in 1170 the closed traverse and reduces the chance of determined azimuth to obtain the azimuth from an error in the azimuth of the orienting line. the radar to the orienting point stake. If a traverse leg cannot be used as the orient- b. The vertical angle for the radar can be ing line, a prominent terrain object at least determined in one of two ways—by measuring, 300 meters away should be used. The azimuth at the radar position stake, the vertical angle to of this line is determined by measuring the the orienting point stake (1, fig. 120) or by angle from the last traverse station to the measuring, at the orienting point stake, the selected point at the orienting station. In all vertical angle to the radar position stake (2, cases for night operations, the orienting line fig. 120) or the radar telescope (3 and 4, 120). must be prepared for orientation of the wea- (If the vertical angle is measured at the ori- pons at night; this is accomplished by placing enting point stake, the vertical angle at the a stake equipped with a night lighting device radar will be opposite in sign to the measured on the orienting line approximately 100 meters angle.) If the vertical angle is measured to a from the orienting station. (When an inter- stake, it must be corrected for the height of mediate point cannot be established on the ori- the radar telescope about the ground. (This enting line, an alternate orienting line is correction can be determined by the mil form- established on which the night orienting point ula ; i.e., by dividing the height above the can be set up. ) ground of the radar telescope (in meters) by b. The coordinates andthe height taped ofor the paced battery distance between the radar center are determined by establishing a tra- position stake and the radar orienting point verse station or an offset (an open traverse stake (in thousands of meters).) If the vertical leg) from the orienting station to the battery angle is measured to the radar telescope, it is center. (For very heavy artillery and missile not necessary to determine a correction for the units, the coordinates and height of each piece vertical angle. The telescope on the radar or launcher are determined by an offset from antenna and the survey instrument are pointed the orienting station.) at each other. The vertical angle measured by the survey instrument (with the sign changed) 287. Survey for Radar is set on the vertical angle scale of the radar. If the radar is not in position at the time The vertical angle to the orienting stake is the survey is performed, either the stake mark- then measured with the radar. ing the radar position or the stake marking c. The coordinates and the ground height of the radar orienting point is used as a traverse the radar are determined from the traverse station (1 and 2, fig. 120). If the radar is in data (1, fig. 120) or by establishing an offset position at the time of the survey, the stake (2, 3, and 4, fig. 120). The vertical angle used marking the radar orienting point is used as to determine the ground height of the radar is a traverse station (3, fig. 120) or as a direc- measured to the height of instrument regard- tional traverse station (4, fig. 120). (If the less of the manner by which the vertical angle radar is in position, horizontal and vertical for the radar is determined. (If the vertical angles for the radar are measured to the tele- angle for the radar is determined by measur- scope on the radar parabola. ) ing to the radar telescope and the radar location is determined by an offset from the radar ori- a. The orienting azimuth for the radar can enting point (3, fig. 120), a vertical angle to the be determined in one of two ways—by measur- height of instrument must also be measured.) ing, at the radar position stake, the horizontal The vertical angle to the height of instrument angle for the rear traverse station to the ori- is used to compute the ground height of the enting point stake (1, fig. 120) or by measur- radar. The height of the radar parabola is then ing, at the orienting point stake, the horizontal determined by adding to the computed ground angle from the rear traverse station to the height of the radar the vertical distance in radar position stake (2, fig. 120) or to the radar meters (measured with a tape to the nearest telescope (3 and 4, fig. 120). If the azimuth is 0.1 of a meter) from the ground to the center of determined at the orienting point stake, 3,200 the radar parabola. mils must be added to, or subtracted from, the d. If the theodolite is used to perform the 171 RADAR ORIENTING POINT 0 S' RADAR ORIENTING POINT (Measure vertical angle) TS 5 (Pace to determine correction to (Measure vertical , vertical angle) angle) TS 5 IS RADAR NOT IN POSITION RADAR ORIENTING RADAR ORIENTING POINT X POINT 0 ( Measure vertical angle) h ((Measure one vertical angle to telescope) '(Measure a second vertical angle to HI) TS 5 TS 4 RADAR IN POSITION SOLID LINES INDICATE DISTANCES DETERMINED BY TAPING ARCS WJTH ARROWS INDICATE MEASURED ANGLES Figure 120. Locating and orienting a radar. position area survey, the radar (or radar posi- The next traverse station is used as the other tion stake) can be located by intersection (or end of the base. The base is double-taped to a triangulation). In this case, the radar orient- comparative accuracy of 1:3,000 either by two ing point is established and is used as a traverse taping teams or by one taping team taping the station. The orienting point is also used as one base twice. The radar is located and oriented end of an intersection (triangulation) base. as discussed in a through c above. 172 Section III. CONNECTION SURVEY 288. General any other survey control point established to an accuracy of 1:1,000 on the same grid as the » a. Connection survey is that part of the battalion SCP. When the connection survey is survey operations performed by battalion initiated at the point that establishes the bat- (separate battery) survey personnel for the talion grid (i.e., when data for the starting purpose of locating the target area survey and point is assumed), it must close on the starting the position area survey on a common grid. point. (This point does not become the bat- b. Connection surveys are performed to a talion SCP unless survey control for the point prescribed accuracy of fifth order. is established by the next higher echelon of survey. ) 289. Methods of Performing Connection b. The survey party performing the connec- Survey tion survey must locate at least one observation a. A closed traversepost normally (designated is used 01) to ofper- the target area base or form the connection survey although triangula- a target area survey control point (TASCP). tion or intersection can be used when the ter- The coordinates, the height, and an azimuth rain is unsuitable for traverse. The connection from which the azimuth of the bases may be survey locates one or more of the target area determined for the target area observation base observation posts or it may establish a post(s) are furnished to the survey party per- target area survey control point from which forming the target area survey. target area base survey operations are initiated c. In many cases, heavy or very heavy by another survey party. The connection sur- artillery units need no connection survey. If vey is initiated at a battalion SCP or the point target area survey operations are to be per- that establishes the battalion grid. When the formed, the control is obtained from that con- connection survey is initiated at a battalion trol which is based on the same grid established SCP, it may close on the battalion SCP or on by a light or medium unit. » Section IV. TARGET AREA SURVEY 290. General registrations. (When there are more than two a. Target area survey is that part of the observation posts, any two of them form an survey operations performed by battalion (de- intersection base. The controlling observation tached battery) survey personnel for the pur- post is designated 01, whether it is on the right pose of establishing the target area base and or left end of the target area base ; the auxiliary locating critical points in the target area; i.e., observation posts are designated 02, 03, etc. registration point (s) and restitution points. (FM 6-^0).) b. Critical points are surveyed to minimum b. Azimuth Mark for Target Area Observa- prescribed accuracies of 1:500. tion Post. An azimuth mark which is used to c. The target area base when established by orient the instrument is established at the the target area survey party is surveyed to a target area base for each observation post. The minimum accuracy of fifth order. azimuth to the azimuth mark may be deter- mined by using the back-azimuth of a traverse 291. Terms Used in Conjunction With or intersection leg used to locate the observa- Target Area Survey tion post, by computing the direction to some a. Target Area Base. A target area base con- well-defined known point, or by using the ad- sists of two or more observation posts which jacent observation post (where OP’s are are used to locate the critical points in the intervisible). An auxiliary or intermediate ori- target area and/or targets of opportunity and enting point should be established for night to conduct center-of-impact and high-burst operations. 173 292. Selection of Observation Posts target area. (The consistent accuracy that can a. Initially, two or more observation posts be obtained from the location of points with are selected at points from which the critical angles of this minimum size is approximately points in the target area are visible. If pos- 1:200.) « sible, the distance between any two observation b. The location of each critical point should posts should be sufficient to insure a minimum be checked from at least two intersection bases. angle of intersection at any of the critical As soon as possible, additional observation points of 300 mils (aiming circle). These mini- posts should be selected to provide this check. mum angles at the critical points in the target In addition to providing the check, observation area are necessary to insure results that ap- posts should provide observation in the unit’s proach the accuracies prescribed for target zone of action, especially of those areas which area survey. If the observation posts of the are not visible from the observation posts orig- target area base cannot be located sufficiently inally selected. far apart to provide a minimum angle or inter- 293. Methods of Performing Target Area section of 300 mils, they should be located as Base Survey far apart as possible. In any case, the distance a. The method of survey normally used by between observation posts that are used as the the survey party in the field artillery battalion ends of an intersection base must be sufficient to to perform the target area base survey is a provide a minimum angle of intersection of 150 closed traverse, or when the terrain allows and mils (aiming circle) at any critical point in the the enemy situation is such that traversing to COMPUTED AZIMUTH AND DISTANCE (TASCP) OZ TARGET AREA PARTY O « á Ol ESTABLISHED BY BASE DOUBLE TAPED CONNECTION SURVEY PARTY (1/3000) CONNECTION SURVEY 1/1000 (OP'S NON INTERVISIBLE) COMPUTED LENGTH 02 (TASCP TARGET AREA PART © OP'S ESTABLISHED BY TARGET AREA PARTY l/IOOO (OP'S INTERVISIBLE) CONNECTION SURVEY*^^- Figure 121. Target area base survey. 174 « an OP would disclose its position, triangulation is used. On some occasions it may be necessary to locate the OP by intersection or offset from Registration Restitution Point Point(s) » a traverse station in the vicinity of the OP. /\ si The OP’s are located to an accuracy of fifth I \ order. o b. In issuing the survey order, the survey officer will designate which of the survey parties is to perform the target area base survey. The specific location of both OP’s may also be designated or an approximate location given and specific location left to the discretion Ends of Base Intervisible of the chief surveyor or chief of party. The location of a target area survey control point will be given; or, if one OP is located as part of the connection survey, it may be designated as the target area survey control point. Any Critical Point c. The observation posts are designated 01 and 02. 01 is considered the control OP and / \ is plotted on the firing chart. 01 may be the © Angle ° Azimuth OP on the right or left. 01 is always that OP to Critical Point > requiring the least amount of fieldwork to Angle s Azimuth Azimuth of Base of Base- establish its location. Less directional accuracy Azimuth to will be lost through angular measurements Critical Point when the fieldwork and the number of main & scheme angles are held to a minimum. Ex- amples of target area base surveys are shown in figure 121. STATIONS IN CONNECTION SURVEY » 294. Method of Performing Target Area Ends of Base Not Intervisible Survey Figure 122. Target area survey. a. Intersection must be used to perform the target area survey. The length of each inter- section base of the target area base is obtained mined by comparing the azimuth of the base by computation from the coordinates of the two with the azimuth from each observation post observation posts that establish the base. If the to the point being located (2, fig. 122). The observation posts are intervisible, the azimuth azimuth of the line from each observation post of the base is determined by measuring the is determined by measuring the horizontal horizontal angle at an observation post from angle at the observation post from the estab- the rear station to the observation post at the lished azimuth mark (orienting station for other end of the base. If the observation posts .night operations) to the point in the target are not intervisible, the azimuth of the base is area. When the critical point does not present determined by computation by using the co- a clearly defined vertical line and cannot be ordinates of the ends of the base. (The length accurately bisected, the horizontal angles are of the base may be determined by double-taping measured by using a special technique of point- to a comparative accuracy of 1:3,000 when the ing. Pointings are made by placing the vertical base is located in an area not under direct ob- line in the reticle on the right (left) edge of servation of the enemy.) the object in measuring the first value of the b. If the observation posts are intervisible, angle and by placing the vertical line on the the interior horizontal angles are measured (1, left (right) edge in measuring the second value fig. 122). If they are not intervisible, the of the angle. The mean angle obtained with angles at the ends of the base must be deter- this method must be verified by determining » 175 at least one more mean angle by using the same measurement (1, fig. 122) or by comparison technique. (When this technique is used to of azimuths (2, fig. 122). The coordinates and measure horizontal angles with an aiming cir- height of each point are determined in the same cle, two sets of pointings are made. The ac- manner in which they are determined by tri- cumulated value of one set (one pointing to angulation. each edge of the object) should agree with the e. The party performing the target area sur- accumulated value from the other set within 1 vey furnishes the location of the registration mil. The accumulated values of both sets are point(s) to the party performing the position added together and divided by 4 to determine area survey for computation of the orienting the mean angle to the nearest 0.1 mil.) angle (s). c. Vertical angles are measured to the lowest /. The locations of critical points determined visible point on the object. from the target area base should be checked d. The distance from either end of the in- by establishing a second intersection base. (A tersection base to each critical point is com- second intersection base can be established by puted by using the base length determined in using a third observation post and either of the a above and the angles determined by direct two observation posts used originally.) 176 CHAPTER 17 DIVISION ARTILLERY SURVEY 295. General control point established by division artillery a. Survey operations are performed by sur- are recorded on DA Form 6-5 (Record—Sur- vey personnel of division artillery headquarters vey Control Point) (figs. 123 and 124). battery for the purpose of placing the field c. The division artillery survey officer should artillery units organic, assigned, or attached to maintain close liaison with the corps artillery the division on a common grid. survey officer. By so doing, he can obtain data b. Division artillery surveys are executed for survey control points which have been to a prescribed accuracy of fourth order established by the target acquisition battalion (1:3,000). Specifications and techniques for in the division area. Use of these points can fourth-order survey are found in appendix II. save time and can eliminate unnecessary dupli- cation of survey operations. He can also obtain 296. Division Artillery Survey Personnel data for points established in the vicinity of the A survey officer is assigned to the division target area which can be used by the battalion artillery staff. The division artillery survey survey parties in performing the target area officer plans and supervises the division artil- surveys and the target area base surveys. lery survey operations. He advises the com- mander and appropriate staff officers on mat- 298. Division Artillery Survey Control ters pertaining to survey. He coordinates the a. Division artillery battalions, batteries, and survey operations of the field artillery bat- other division installations that require survey talions (separate batteries) within the division. control should be located with respect to a com- mon grid. This grid should be the corps grid 297. Division Artillery Survey Information whenever control points on that grid are avail- Center able. Control points on the corps grid are nor- a. A file of survey information and a survey mally available in the form of trig points and information map are maintained in the survey survey control points for which data are known information center (SIC) at the division artil- with respect to the UTM (or universal polar lery headquarters. The survey information sterographic (UPS) ) grid for the area of oper- center file and map are located at the division ations. artillery command post and may be located in b. When neither survey control points nor the division artillery operations section. trig points are available in the division area, b. The survey information map shows the the division artillery survey officer establishes locations of survey control points and trig a point and assumes data for that point. This points and the schemes of all surveys per- point (and its assumed data) establishes the formed by the division artillery survey section. division grid which is used as the basis for the The file of survey information consists of the division artillery survey operations. When the trig lists prepared and issued by the Corps of data for the point differ from the data for that Engineers, the trig lists prepared by the field point as established by the field artillery target artillery target acquisition battalion, and data acquisition battalion of corps artillery, survey for each control point established by division data determined by the division artillery are artillery survey operations. The data for each converted to the corps grid. In the initial stages 177 of an operation, it is not necessary for division of the surveys being performed by the bat- artillery to convert azimuth to the corps grid talions. if it differs from azimuth provided by the tar- get acquisition battalion by 1 minute (0.3 mil) c. Normally, division artillery survey opera- or less. However, it should be converted as tions are performed by the division artillery soon as it is practicable. In any case, coordi- survey section. nates and height should be converted to the d. When the time available to perform divi- corps grid if they differ from the data provided sion artillery survey is limited, the division by the target acquisition battalion. artillery commander may direct battalions of the artillery with the division to assist the 299. Division Artillery Survey Operations division artillery survey section in performing a. Division artillery survey operations should the surveys necessary to establish the division provide the best determination of data at the artillery grid after the survey operations of the earliest possible time. Any of the artillery sur- battalion have been completed. When this is vey methods may be used to perform the sur- necessary, the division artillery survey section veys. In areas where survey control points are should, at the first opportunity, reperform the not available in the vicinity of the battalion, portions of the survey performed by battalion common direction can be transmitted by simul- survey sections. taneous observations. (Division artillery sur- vey personnel should be trained in the determi- e. When a target acquisition battery is at- nation of grid azimuth by astronomic and tached to a division artillery, the survey parties simultaneous observations.) of the target acquisition battery may perform b. In addition to providing survey control part of the division artillery survey operations. points for battalions and/or batteries, the divi- The division artillery survey officer, in conjunc- sion artillery survey officer may designate tion with the target acquisition battery com- points for which battalion surveys should deter- mander, plans and supervises the coordinated mine survey data in order to check the accuracy survey operations. 178 CHAPTER 18 CORPS ARTILLERY SURVEY 300. General all survey information is disseminated only a. Corps artillery survey operations are per- through the survey information center. formed by the field artillery target acquisition b. Files of all survey control (fourth-order battalion assigned to each corps artillery head- or greater) existing in the corps area and files quarters. The battalion commander of the field of tie-in points established in adjacent corps artillery target acquisition battalion is the areas by the target acquisition battalions or corps artillery survey officer. The target acqui- division artilleries in those areas are main- sition battalion survey officer is responsible to tained in the survey information center. These the battalion commander for planning and files consist of trig lists published by higher supervising the battalion survey operations. headquarters (including trig lists prepared by b. Survey operations are performed by sur- the Corps of Engineers), trig lists published vey personnel in the field artillery target acqui- by field artillery target acquisition battalions sition battalion for the purposes of placing the operating in the adjacent corps areas, and data field artillery with the corps (and other units for each survey control point established by requiring survey control) on a common grid the target acquisition battalion survey parties and of locating the target acquisition battalion and by the parties of the division artillery head- installations (which include flash, sound, and quarters with the corps. The data for each radar installations). Also included in survey survey control point established by the target operations are the collection, evaluation, and acquisition battalion and by division artillery dissemination of survey information for all headquarters are recorded on DA Form 6-5 surveys executed in the corps area to a pre- (figs. 123 and 124). scribed accuracy of fourth-order or greater. c. An operations map is maintained in the Surveys performed by the target acquisition survey information center. The operations map battalion are executed to a prescribed accuracy shows the locations of all existing trig points of fourth-order. and survey control points and the schemes of completed surveys. Overlays to the map show 301. Survey Information Center the survey operations that are currently being a. A corps survey information center is performed by the survey personnel of the target established and maintaned by the survey infor- acquisition battalion (and division artilleries mation center (SIC) personnel of headquarters with the corps). The overlays also show the battery of the target acquisition battalion. It tactical situation, the location of each installa- is usually located in the vicinity of the corps tion of the target acquisition battalion, present artillery fire direction center. The SIC is an and proposed artillery positions, and proposed agency for collecting, evaluating, and dissemi- survey plans. nating survey data. The dissemination is ac- d. In addition to performing the functions of complished by preparing and distributing trig the survey information center discussed in a lists and by furnishing survey information to through c above, survey information center personnel of other units upon request. Unless personnel assist the survey operations of the directed otherwise by the battalion commander, target acquisition battalion by computing and 179 ssy 1 3 i rsr i Vo* i ijrf 6 FT i i i i o NAME OR DESIGNATION (sc» BECK LOCATED BY J8T*Y ß, Ur F AT AB DESCRIPTION fO«n«r«J and «p«cifi« focctJoa«, *fp* of aork, ote.) NOTEBOOK REFERENCE B»OM //it 4 STATION /S /-INCH ¿/OJUOK/ t* FO*T S/í¿ CENTSO. or 7-INCH SOUAXC e. o*estere /nt _ / Oec /9&>o i ÙSC /1¿>o áíQAX } S METEOS CU EST ONO /•£ NETS SS RECORDS FILED AT /ST- /Nr D/y J*rr. S/c Sou TN 0F SovTHiNSST COf/YEA. O* HOW LOCATED A/>¿- T30 77 ; AN FT Stet. MlUTAAV. 20 - ORDER fisse év/rr/óN. TRIAK6ULATI ON TRI60MÛMETRIC NAME OR DESIGNATION (4#- MK) I/ATZX Towel DISTANCE FROM SCPfPt. ». •ie.> DESCRIPTION CSpocific location, typo of mark, ate.) í I MEASURED cas ESTIMATED /¿lOO OfeTEJH AiIMUTH FROM SCP MATE* Tows A /» LA*6£ ST€€L. M0» CUTRIG LIST (ZD ANGLE TURNED I l M*P OETERMINED CID TRAVERSE QÛ ASTRONOMIC r~~l OTWftt OUATE A Toutes. //V 1900 AßEN M OTHER Ai MKS VISIBLE FROM SCP fir Sux. /IU/TANT ficseo ÿAT/QN . A/orre fitAñY STATION ts HEP Lttftr Sv^S ON TbP OP T-QAtEfi. (Station and AaiovtA »art DoaerIptlona Continuad on Sowaraa Sida) REPLACES DA FORM«6-91 1 OCT 92, RECORD - SURVEY CONTROL POINT DAi^e-S «HIGH «ILL BE USED UNTIL EXHAUSTED. Figure 123. Entries made on front of DA Form 6-5 checking data. Computations and checks per- mander and assisted by the battalion survey formed by the survey information center per- officer, he— sonnel include the following : (1) Plans the corps artillery survey. (1) Checks of field records and computa- (2) Coordinates the survey of the target tions of field parties. acquisition battalion with all other (2) Adjustment of traverses. artillery units in the corps area. (3) Conversion of survey data to the (3) Maintains liaison with, and obtains corps grid when survey operations control data from, the topographic have been performed with assumed engineer unit operating with the data. corps. (4) Transformation of coordinates and (4) Establishes the survey information grid azimuths. center. (5) Conversion of coordinates (geograph- b. The battalion survey officer is assigned to ic to grid and/or grid to geographic). the battalion staff. The battalion survey officer plans and supervises the battalion survey 302. Field Artillery Target Acquisition operations, advises the battalion commander Battalion Survey Personnel and the staff on matters pertaining to survey, a. The target acquisition battalion com- and performs the coordination of the survey mander is the corps artillery survey officer. operations of all field artillery units operating Under the direction of the corps artillery com- in the corps area. An assistant battalion sur- 180 « SCP DESCRIPTION (Cont inu9d) J1 I ü 1 Ausr/u /?o N □□□□Il Ijorri isora t i'íi A ߣCK Fi A* MK DESCRIPTION (Continued) PO/HT TO ßE SIGHTED ON DESCRIPTION PREPARED BY DESCRIPTION CHECKED BY JÔNÊS Leo / Ote. /f£o Figure 124. Entries made on back of DA Form 6—5. vey officer, the survey platoon commander in survey officers normally receive the survey in- headquarters battery, performs duties as di- structions for their batteries from the battalion rected by the battalion survey officer. survey officer. (The relations between the bat- c. A warrant officer, assigned to headquar- talion survey officer and the battery survey ters battery, supervises the operations of the officers in issuing and receiving instructions survey information center. are similar to the relations between the fire direction officer in a howitzer or gun battalion d. A survey platoon commanded by an of- and the battery executive officers.) The battery ficer is assigned to headquarters battery and survey officers must keep their battery com- to each target acquisition battery of the target manders informed of the survey operations that acquisition battalion. The officer is the survey they have been instructed to perform. They officer of the battery. He plans and supervises must also keep their battery commanders in- the survey operations of the survey platoon. formed of the areas in which the battery sur- He advises the battery commander on matters vey platoon will be operating and the progress pertaining to survey. of the survey operations. 303. Coordination and Supervision of Battalion Surveys by the Battalion 304. Field Artillery Target Acquisition Survey Officer Battalion Survey Operations The battalion survey officer normally is au- a. Target acquisition battalion survey opera- thorized by the battalion commander to issue tions are conducted in two phases—an initial instructions on matters concerning survey phase and an expansion phase. operations directly to the batteries. The battery h. The survey operations conducted during 181 the initial phase consist of those necessary to lished with the assumed point and the azimuth establish a survey control point for each divi- established at the assumed point. sion artillery and each corps artillery battalion (and other points as directed by the battalion 3Û6. Azimyfîlhis commander) and those necessary to establish Azimuths at all points of the battalion sur- survey control for the installations that are vey should be correct grid azimuths. Correct organic to the target acquisition battalion that grid azimuth can normally be established by require survey control. astronomic observation or by use of the gyro c. The survey operations conducted during azimuth surveying instrument. When two in- the expansion phase consist of the surveys tervisible survey control points (based on cor- necessary to place survey control points within rect grid data) or trig points exist, correct grid 1,500 to 2,000 meters of any possible artillery azimuth can be obtained from these points. If position in the corps area. the correct grid azimuth between the points d. The battalion survey officer designates to is not known, it can be computed by using the each platoon commander locations where sur- grid coordinates of the points. vey parties are to establish survey control points. These survey control points are estab- 307. Survey Comfrol Poomitfs lished for later extension of control and for Survey parties of the battalion establish sur- checking surveys. vey control points approximately every 1,500 e. Survey operations of the target acquisi- to 2,000 meters along the routes of the surveys. tion battalion are continuous. The amount of A station of this type is established at each survey performed by the target acquisition bat- point for division artillery, for corps artillery talion in any area of operations depends on the battalions, and for those points from which length of time that the corps remains in the target acquisition battery installations are area. When the corps is moving rapidly, the located. The same type of station is also estab- target acquisition battalion may be able to per- lished at each point designated for later exten- form only the initial phase survey operations. sion of control and for checking surveys. Each When the corps remains in one area for an of these survey control points is marked by a extended period of time, the target acquisition hub and a reference stake. An azimuth for battalion conducts extensive survey operations. each survey control point is established either to an azimuth mark or to an adjacent survey 3@5. Use oí Assumed) Oeata control point. A description of each survey Whenever possible, survey platoons initiate control point is prepared on DA Form 6-5 and survey operations at survey control points (or forwarded to the survey information center for trig points). When adequate survey control file. points do not exist in the area of operations, one or more of the survey platoons must initiate 3@S. POssniniBinig Taurgefî Acquisittoem) isaîüery > survey operations, using assumed coordinates Survey OpemMom and height. When at least one survey control The points for which survey control must be point exists in the area of operations, the sur- established by the survey platoon of each tar- veys of the battalion are based on the grid get acquisition battery fall into two general established by the coordinates and height (s) categories—those for installations of the target of the survey control point (s). The surveys of acquisition battalion and those for installations the platoons that used assumed initial data are of other units. The commander of the target converted to the grid established by the survey acquisition battery survey platoon plans the control point (s). When no survey control initial phase operations of the platoon by first points exist in the area, the battalion survey considering the operations necessary to locate officer designates a point and furnishes as- the target acquisition battalion installations. sumed data for the point. (The assumed data He then modifies this plan, as necessary, to should approximate the correct grid data as provide survey control for the installations of closely as possible.) The surveys of all of the other units. If priorities have been established platoons are then converted to the grid estab- by the battalion survey officer, the platoon 20,000 METERS » FEBA OP & OP £ OP M6 OP A MS N/ M4® R2 BN SCP \ M2 / Ö40 11 • ko BN SCP Á ' SCP BN SCP ö (TIE-IN) [~»~lB2 Ö TA BTRY SCP BN SCP BN SCP DIV ARTY SCP ä« (ALSO BN SCP) BN SCP 2 • 71 LEGEND PARTY I tTFl I \ » Figure 125. Target acquisition battery survey during the initial phase. commander must incorporate them in his sur- sound base) is frequently performed by two vey plan. parties starting at a point near the center of the sound base with assumed data. A third 309. Target Acquisition Battery Survey party extends survey control to the starting Platoon Operations During the point. Initial Phase c. An example of the survey operations con- a. The survey operations performed by a target acquisition battery survey platoon dur- ducted by a target acquisition battery survey ing the initial phase consist of the survey platoon during the initial phase is shown in fig- operations necessary to locate the target acqui- ure Í25. The survey operations were accom- sition battery installations that require survey plished by the two traverse parties and one control and to provide a survey control point tellurometer traverse party. for the division artillery and for each corps d. Party number 1 (tellurometer party) has artillery battalion in the platoon’s area of been assigned the task of extending control responsibility. from the target acquisition battery survey con- b. All or part of the target acquisition bat- trol point to several corps field artillery bat- tery survey operations are frequently started talion survey control points, the division artil- with assumed coordinates and height. For lery survey control points, and a survey control example, if survey control points do not exist point tie-in with the adjacent zone. Since this in the vicinity of the selected sound base micro- party is equipped with the tellurometer, its phones, the sound base survey (and location of area of operations is more extensive than that any survey control points along the line of the of either of the two standard traverse parties. » 183 An astronomic observation is used to check complish the required survey operations. The direction at the tie-in survey control point. survey platoon of each battery should be as- e. Party number 2 initiates its survey at the signed tasks in areas as near as possible to its tie-in survey control point and locates two flash battery area to facilitate future operations of ranging observation posts (OP 1 and OP 2), a the corps and to reduce the problems of move- counterbattery radar (Rl), and a battalion ment from the battery area and messing. survey control point and closes on a previously c. Figure 126 is an example of the survey agreed upon survey control point near the cen- operation conducted by a target acquisition ter of the sector. battalion during the initial phase (the critical /. Party number 3 initiates its survey at a traverse stations shown in black are those at previously established battalion survey control which a traverse is initiated or closed). Figure point and locates radar 2, OP 3, OP 4, and the 127 shows an example of the survey opera- six microphones of the sound base. This party tions of a target acquisition battalion during closes its survey on the same survey control the expansion phase. point used by party number 2 as a closing point. 312. Extension of Survey Control from 310. Target Acquisition Battery Survey Rear Areas Platoon Operations Required to When the only existing survey control is a Complete the Initial Phase considerable distance to the rear of the corps The initial phase survey operations per- area, control should, if possible, be extended to the corps area by engineer topographic units. formed by the survey platoon of a target acqui- When this is not possible, the target acquisition sition battery include the operations necessary battalion may be required to extend control to to close all traverses and to check all inter- sected and resected points. It also includes the the corps area; this normally is accomplished by the use of tellurometer traverse schemes. operations necessary to establish a declination This extension of control may be initiated dur- station in the division area and to determine ing either the initial phase or during the the locations of survey control points that are expansion phase, depending on the situation. also located by the target acquisition battery When it is initiated during the initial phase, survey platoons operating in the adjacent divi- it is usually accomplished by the headquarters sion areas. The initial phase survey operations battery survey platoon. (The battery survey of the battalion are considered to end when platoons may be required to furnish one or these operations have been performed by the more tellurometer traverse parties to assist in survey platoons of each of the target acquisi- these operations.) tion batteries. 313. Survey Control for Counterbattery 311. Survey Operations During the Radar Expansion Phase Target acquisition battalion personnel must a. Survey operations of the target acquisi- be familiar with the procedures used to estab- tion battalion during the expansion phase, con- lish survey control for counterbattery radar. sist of establishing a basic net throughout the These procedures are the same as those used corps area, usually by triangulation or tel- to establish survey control for countermortar lurometer traverse. From stations of the basic radar. net, control then is extended, usually by trav- erse, so as to provide survey control throughout 314. Survey Control for Sound Ranging the corps area. The ultimate goal is a survey Microphones control point within 1,500 to 2,000 meters of a. The survey operations necessary to estab- every possible artillery position. This goal is ac- lish survey control for a sound ranging micro- complished to the extent permitted by the time phone depend on the type of sound base selected available. by the sound ranging personnel. When the b. During the expansion phase, the survey microphones are employed in an irregular base, platoons of the battalion are assigned tasks by the microphone positions are marked (either the battalion survey officer as necessary to ac- with a stake or with a microphone) by sound 184 60,000 METERS » “11 I II I III X A 7,x A 4S -44T T' ^ y \ / / V / >- ▲ J^IAL' V ¿ <\*A A 7 ÍJy^l'S1' ^—- V0 O/ \ * — V SCP XXX xxxx A FLASH 0P » • CRITICAL TRAVERSE STATION -«-SOUND BASE O BATTALION POSITION ■»»-HQS BTRY SURVEY LETTER BTRY SURVEY Figure 126. Target acquisition battalion survey operations during the initial phase. ranging personnel. The location of each ir- tion, at a point from which the micro- regular-base microphone is determined in the phone position should be visible. manner used to locate any other survey station. (2) The azimuth and distance from the When the microphones are employed in a regu- traverse station to the microphone lar base, the coordinates of each microphone position are computed by using the are predetermined by computation. The points coordinates of the traverse station on the ground that correspond to the predeter- and the predetermined coordinates of mined coordinates are then established ; this is the microphone computed on DA accomplished as indicated in (1) through (5) Form 6-1. below— (3) The direction of the microphone posi- (1) A traverse is performedtion is establishedroughly par- by setting off on allel to the line of the sound base, fol- the theodolite the horizontal angle at lowing the best traverse route. A the traverse station from the rear traverse station is established within traverse station to the microphone 200 meters of each microphone posi- position. This angle is determined by » 185 60,000 METERS « 'TTrrrn -r TC k TN i / \ '7t x - •r 4- 7 k / -k A + r A: I .A y *> v. ÍP * A A -1' 'Kr 4 > -4 W A \ A -4 J ~r 4 vi. * \ / -N A SCP XXX LEGEND xxxx INITIAL PHASE EXPANSION PHASE Figure 127. Target acauisition battalion survey operations during the expansion phase. « subtracting the azimuth to the rear distance approximately equal to the traverse station from the azimuth to distance to the microphone. (The the microphone position. (The value rodman should pace this distance to that must be set on the horizontal insure that large errors in taping do circle of the theodolite is equal to the not occur.) sum of the initial circle setting (the (5) A taping team then tapes the com- horizontal circle reading when the in- puted distance from the traverse sta- strument is pointed at the rear tion to the microphone position and traverse station) and the (computed) places a hub at the microphone posi- horizontal angle. As an example, as- tion. (To prevent errors, the front sume that the initial circle setting is tapeman should give all taping pins to 0°00'37J" and that the computed hori- the rear tapeman except those actually zontal angle is 173°43'27". The required to make the distance meas- value that must be set on the hori- urement. If it is necessary to break o , / zontal circle is 173°44'04" (0 00 37 ' tape, the normal pin procedure should , + 173°43 27"). To place this setting be followed. When the front tapeman on the horizontal circle of the theodo- has placed his last pin in the ground, lite, set 04'04" on the micrometer he should pull the tape forward a scale, using the coincidence knob; set partial tape length so that the rear 173°40' on the horizontal circle, using tapeman can hold the proper gradua- the horizontal motions.) tion over the last taping pin. The (4) A ranging pole is placed on the line front tapeman should place the hub in of sight through the telescope at a the ground, at the point directly 186 under the zero graduation on the tape. b. The location of the microphone position The tapeman should then check the hub can be checked by using the hub as a B distance by measuring the distance traverse station. It can also be checked by from the hub to the traverse station, measuring the direction to the hub from a using normal taping procedures. As traverse station other than the one used to an example of the method of establish- establish the microphone position and by com- ing the distance, assume that the dis- paring the measured direction with the com- tance from the traverse station to the puted direction to the hub. microphone position is 130.67 meters. c. If sound ranging microphones are estab- This distance consists of four full tape lished from a traverse based on assumed data lengths and a partial tape length of for the starting station, the coordinates of the 10.67 meters. The front tapeman . gives seven taping pins to the rear microphone positions must be converted to the tapeman (retaining four pins) before common grid when the correct grid data for the starting the distance measurement. starting point become available. No change in When the front tapeman has placed the ground location of the microphone is re- his fourth pin in the ground, he pulls quired. the tape forward a partial tape length 315. Survey Control for Flash Ranging so that the rear tapeman can hold the 10.67-meter graduation directly Observation Posts (Long Base) over the last taping pin. The front Flash ranging observation posts are located tapeman places the hub in the ground in the same manner as observation posts for under the zero graduation on the field artillery battalions except they must be tape.) located to an accuracy of fourth-order. » » 187 CHAPTER 19 OTHER ARTILLERY UNIT SURVEYS Section I. FIELD ARTILLERY GROUP SURVEYS 316. Field Artillery Group officer coordinates the survey operations of the a. The field artillery group headquarters bat- battalions of the group. He verifies that survey tery does not perform survey operations. The control points are provided by the next higher battalions of the group are normally furnished survey echelon. He verifies, by frequent inspec- survey control by the artillery headquarters tions, that the survey sections of the group with which the group is working. When survey battalions perform survey operations properly. has not been furnished by the artillery head- Two enlisted survey specialists are assigned to quarters with which the group is working, the group headquarters battery for the purpose of group commander may designate one battalion assisting the group survey officer in carrying to establish a group survey control point. When out his responsibilities. The group headquar- heavy or very heavy battalions of a group are ters battery is not issued survey equipment. required to perform target area surveys, the 317. Field Artillery Battalion Group group commander usually designates one of the In addition to the normal survey responsibili- battalions of the group to perform the target ties, the commander of a battalion group has area surveys for all of the battalions of the survey responsibilities similar to those of a group. group commander. If survey control has not b. The group assistant intelligence officer been furnished to the battalion group by the (assistant S2) is also the group survey officer. artillery headquarters with which it is working, During training, the group survey officer super- the commander of the battalion group directs vises the training of the survey personnel of the the survey officer of his battalion to establish a battalions of the group. The group survey group survey control point. Section II. FIELD ARTILLERY MISSILE COMMAND SURVEYS 318. Field Artillery Missile Command, quired survey control. The survey element of Medium the engineer combat company (or engineer a. The survey requirement of the missile service and support company) has the responsi- command, medium consists of the location and bility for establishing eight third-order survey orientation of the weapons and target locating control points, equally spaced across the width installations of the command, guidance equip- of the missile command. The target acquisition ment in the Corporal missile battalion, tracking battalion survey personnel extend the control and plotting equipment in the drone platoons, from these survey control points to each of the meteorological equipment and ground based battalions of the missile command. The missile navigational aids for Army aviators. battalions are organized under two group head- b. The missile command has organic topo- quarters. Since the artillery group has no graphic engineer surveyors and field artillery survey personnel and equipment, the target target acquisition surveyors to provide the re- acquisition battalion survey parties provide the 188 control to the battalions directly. The target command, air transportable, consists of the acquisition battalion survey parties provide this location and orientation of the weapons and control to a prescribed accuracy of fourth- target locating installations of the command. order. The firing element of the missile command is c. The missile battalions of the command one HONEST JOHN (LITTLE JOHN) bat- have organic survey parties to perform the talion. The survey officer for the missile com- internal survey. The parties are required to mand, air transportable, is the survey officer of determine the location of the launchers to fifth- the HONEST JOHN (LITTLE JOHN) bat- order accuracy. The survey parties must also talion. There are no target acquisition bat- provide orientation data for the launchers and talion or battery survey personnel authorized guidance elements. in the missile command, air transportable. d. The target acquisition battalion com- b. The missile command, air transportable, mander is the missile command survey officer. receives engineer survey support from the topo- He is a special staff member, and he advises the graphic engineer survey section of the organic missile command commander on matters per- engineer combat company. The engineer survey taining to survey in the command. He coordi- personnel establish survey control points as re- nates the survey efforts of the topographic quired by the HONEST JOHN battalion. engineer surveyors and the survey parties of c. The HONEST JOHN (LITTLE JOHN) the target acquisition battalion. battalion has two eight-man survey parties which are used to extend control to each of the 319. Field Artillery Missilefour Command,launchers. They must locate the launchers Air Transportable to fifth-order accuracy and provide direction a. The survey requirementfor oforientation the missile of the launchers and windsets. Section III. AIR DEFENSE ARTILLERY SURVEYS 320. General signed air defense missions and are restricted a. There are three major factors which de- from firing in certain areas, they must be lo- termine the type of survey operations which cated with respect to the grid on which the must be performed by air defense artillery limits of the restricted areas are designated. (ADA) units and the extent of those survey They must be located on the grid by extending operations. These factors are— control to each fire unit from control points 1 ^ « <3 /“\ ^1% SN SV*» 1 sT (1) The type of mission of a unit. uii tue gi. id« (2) The availability of maps. d. When air defense artillery gun and missile units are assigned field artillery type missions, (3) Restrictions placed on air defense fire. their survey requirements are the same as b. When air defense artillery units are as- similar field artillery units. signed air defense missions, they must be capable of transmitting, from one unit to 321. Surveys for Air Defense Artillery another, information concerning the location of Gun Battalions (Batteries) aircraft. To do this, they must be located with a. When suitable maps are available and respect to a common grid. When suitable maps there are no restricted firing areas, survey are available, units can be located with respect control for a gun battalion is established by to a common grid by map inspection for both determining the location of a selected point position and direction. When suitable maps are (battalion SCP) by map inspection and by de- not available, units must be located with re- termining the azimuth from the battalion SCP spect to a common grid by extending control to to an azimuth mark by scaling from a map or each unit from control points located on the by using a decimated aiming circle. grid. b. When suitable maps are available and c. When air defense artillery units are as- there are restricted firing areas, survey control 189 is established by extending control to the bat- curacy of fifth-order. Orientation data that are talion SCP from a control point located on the obtained by survey consist of the following: UTM (or UPS) grid for the zone. Direction is (1) The easting, northing, and height determined by astronomic observation or by components of the parallax from the measurement from a line of known direction. center of the mass of metal (battery Survey operations are executed to a prescribed center or directing point) to the track accuracy of fifth-order (1:1,000). radar antenna. c. When suitable maps are not available, sur- (2) The lateral distance from each gun to vey control for a gun battalion is established by the orienting line (d(4) above). extending control to a battalion SCP as dis- (3) The easting, northing, and height com- cussed in b above. ponents of the parallax from each gun d. Regardless of the method by which con- to the track radar antenna. trol is established for the battalion SCP, con- trol is extended from the battalion SCP to each 322. Surveys for ADA AW Battalions battery, to the battalion surveillance radar, and (Batteries) Equipped With Electronic to a battalion radar range-calibration point by Fire Control and 75-mm Light ADA survey operations executed to a prescribed ac- Battalions (Batteries) curacy of fifth-order. The control which is a. When suitable maps are available and established for these installations is as follows : there are no restricted areas, survey control for each weapon is established by map inspection (1) The horizontal and vertical locations for position and by scaling from a map or by of the antenna of the track radar for using a declinated aiming circle for direction. each battery. b. When suitable maps are available and (2) The horizontal and vertical locations there are restricted areas, survey control is of the antenna of the battalion sur- established by extending control to the battalion veillance radar. (detached battery) SCP from a control point (3) The horizontal and vertical locations located on the UTM (or UPS) grid for the of the battalion radar range-calibra- zone. Direction is obtained by astronomic ob- tion point(s). (The slant range from servation or by measurement from a line of the track radar of each battery to the known direction. Survey operations to extend radar range-calibration point for the control to the battalion SCP are performed to battery must be computed.) a prescribed accuracy of fifth-order. (4) A line of known direction (orienting c. When suitable maps are not available, line) to a distant point from the track survey control is established by extending con- radar antenna of each battery and for trol to the battalion (detached battery) SCP the battalion surveillance radar. as stated in b above. (5) When directed, the range and the d. When there are restricted areas and/or vertical angle to the distant point when suitable maps are not available, the hori- ((4) above) from the track radar an- zontal and vertical locations of each weapon tenna of each battery. If the range are determined, and a line of known direction and the vertical angle are not de- for each weapon is established by extending termined to the distant point, it is control to each weapon from the battalion (de- referred to as the orienting 'point. If tached battery) SCP. Survey operations to the range and the vertical angle are extend the control are performed to a pre- determined to the distant point, it is scribed accuracy of fifth-order. referred to as the known datum point e. Regardless of the method used to de- (KDP). termine the location of a weapon, the slant e. When directed, gun battalion survey per- range from each weapon to the radar range- sonnel assist battery personnel in obtaining calibration point is determined for each weapon orientation data. Orientation data are deter- by survey operations executed to a prescribed mined by survey executed to a prescribed ac- accuracy of fifth-order. 190 323. Surveys for ADA AW Battalions not c. Air defense artillery battalions normally Equipped With Electronic Fire Control are not capable of performing survey. The a. Survey control is not required for ADA control must be extended by an agency having AW battalions not equipped with electronic suitable survey equipment and trained survey fire control when there are no restricted areas. personnel. Arrangements should be made for However, the relative locations of weapons and the nearest engineer or artillery unit capable early warning observation posts must be known of providing the control to perform the neces- so that an early warning system can be estab- sary survey operations. lished. When suitable maps are available, the 325. Air Defense Artillery Missile relative locations of the weapons and observa- Battalions tion posts are determined by map inspection. The target-tracking radar of ADA missile When suitable maps are not available, the rela- battalions must be established on the UTM (or tive locations can be established by limited UPS) grid for the zone. A line of known di- rough survey as explained in FM 21-26. rection from that radar on the grid for the b. When there are restricted areas, survey zone must be established. For permanently control is established to determine the relative emplaced battalions, necessary survey opera- horizontal and vertical locations of each wea- tions are performed by engineer personnel. pon and to provide an orienting line for each For semimobile battalions, the necessary con- weapon. Survey control is extended from sur- trol may be established by scaling from a map, vey control points established within 1,000 when suitable maps are available, or by using meters of the position area of each weapon by a declinated aiming circle for direction. When survey operations performed to a prescribed suitable maps are not available, survey con- accuracy of 1:500. trol is provided by engineer personnel or ex- c. When ADA AW battalions are required tended by the missile battalion personnel from to accomplish the surveys discussed in b above, a survey control point located within 1,000 necessary surveying equipment (two aiming meters of the target-tracking radar. The con- circles per battery and one per battalion head- trol is extended by survey operations executed quarters) must be made available from sources to a prescribed accuracy of fifth-order. outside the battalion. 326. ADA Missile Battalions in FA Role 324. Surveillance Radars The missile-tracking radar of ADA missile a. Each ADA surveillance radar must be es- battalions employed in the field artillery role tablished on the UTM (or UPS) grid for the must be established on the UTM (or UPS) zone. When suitable maps are available, this grid for the zone. A line of known direction is accomplished by map inspection for position from that radar on the grid for the zone must by scaling from a map or by using a declinated be established. When ADA missile battalions aiming circle for direction. are employed in the field artillery role, neces- b. When suitable maps are not available, the sary survey personnel are provided in the horizontal and vertical locations of each sur- TOE. A survey control point must be provided veillance radar are determined, and a line of by engineer personnel or target acquisition known direction is established by extending battalion survey personnel within 2,000 meters control from a control point on the UTM (or of the missile-tracking radar. The missile bat- UPS) grid for the zone by survey operations talion survey personnel extend the control to executed to a prescribed accuracy of fifth- the . radar and launcher positions to a pre- order. scribed accuracy of fifth-order. 191 « CHAPTER 20 SURVEY PLANNING Section I. GENERAL 327. Survey Mission operations. The information which the survey a. The general mission of artillery survey officer should receive includes the following: personnel is to provide accurate and timely a. Situation. During combat, the survey survey information and control to artillery officer should know both the enemy and units and installations. Successful accomplish- friendly situations as they affect the unit mis- ment of this mission requires careful survey sion and especially as they affect survey oper- planning and the formulation of a survey plan ations. which is as complete as possible. b. Mission of the Unit. The survey officer b. The specific mission of artillery survey should know the mission of the unit and plan personnel for any survey operation is contained the survey operations so that they will best in orders and instructions issued by the organ- assist in the accomplishment of the unit mis- ization commander. These orders and instruc- sion. tions are contained in the unit SOP, operations c. Time Available for Survey Operations. orders and training directives. The time available for survey operations may c. After the commander has issued orders be specified by the commander or it may be and/or instructions which require the execu- indicated by the unit mission. The time avail- tion of survey operations, the survey officer able dictates the amount of survey that can be must plan the survey operations and issue accomplished and whether limited time or de- necessary instructions to survey personnel to liberate survey methods are to be used. If thé execute the assigned mission. time available for survey operations is not specified, they should be accomplished as soon d. In some situations the survey officer may as possible consistent with other requirements. be required to prepare plans for proposed sur- vey operations. The survey officer may be re- d. Installations That Require Survey Control quired to submit the proposed plans to the and Their Locations. The installations that re- commander or his representative for consider- quire survey control usually will be specified ation. (During combat, the survey officer usu- in the SOP. For each situation, the com- ally is not required to submit the survey plan mander will indicate only those installations to the commander or his representative when requiring survey control that are not included survey operations are to be initiated immedi- in the SOP. The general location of units that ately.) require survey control usually will be indicated in the commander’s orders or instructions and 328. Information Furnished the Survey may be furnished on a map overlay. The sur- Officer by the Commander vey officer usually will have to determine the In addition to the specific survey instruc- exact location of installations by reconnais- tions, the commander or his representative sance. should furnish the survey officer certain infor- e. Location of the Installation to Which Sur- mation which he must have to plan the survey vey Data Must Be Furnished. The survey offi- 192 c cer must know the location of the installation that the situation places on travel and/or (e.g., FDC for field artillery battalions) to communication. which survey data must be submitted. The lo- 331. Number and Locations of cation of this installation must be known so Installations Requiring Survey Control that the submission of data will not be delayed. The number and locations of installations The location of this installation usually will be that require survey control must be considered indicated by the commander. primarily with respect to time and personnel /. Survey Requirements for Each Installa- available. The survey operations necessary to tion. The survey requirements for each instal- locate a small number of widely scattered in- lation usually will be specified in the SOP by stallations will often require more time and/or the commander. personnel than would be required for a large g. Survey Control Available. Information number of closely grouped installations. In concerning available survey control may be the survey plan, the survey tasks should be so furnished to the survey officer by the com- allocated that the various parties executing the mander or his representative. However, the survey will complete their tasks at approxi- survey officer usually will obtain the informa- mately the same time. This might require, for tion from trig lists issued by higher headquar- example, the use of two parties to establish ters and by personal contact with survey control for one installation which is at a con- personnel of higher headquarters. siderable distance from the starting point h. Personnel Available for Survey Opera- while one party is establishing control for three tions. The commander usually will specify in installations which are relatively close to the the SOP the personnel that are available for starting point. survey operations.' He then usually will specify 332. Survey Requirements for Each for a given operation any differences from the Installation Requiring Survey Control SOP in the personnel available. The survey planner must know the require- i. Restrictions on Survey Operations. Cer- ments of each installation for which control tain restrictions on survey operations may be must be provided. For example, the light, specified by the commander. Most restrictions medium, and the heavy field artillery battalion on survey operations will be dictated by such survey parties must locate each battery center things as the situation, the mission, the avail- whereas the very heavy field artillery battalion ability of personnel, etc. survey parties must locate each piece. 333. Survey Control Available 329. Factors Affecting Survey Planning More extensive survey operations are re- mi-- --.i-'ii -.âCo-.,. — ,i. j nit; minœry 0U1 vey umCex nius>b CUHöIUCX quired in areas where limited survey control many factors in formulating the plan by which exists than are required in areas where survey the survey mission is to be accomplished. The control is dense. factors which affect survey planning cannot be considered independently because each factor 334. Survey Missions is related to other factors. The most import- The field artillery battalion survey opera- ant of these factors are discussed in para- tions must provide the best possible survey graphs 330 through 338. data in the time available. The division artil- lery survey operations must provide timely and 330. Situation as it Affects Survey accurate survey control to subordinate units. Operations Corps artillery must provide timely and ac- The survey planner must consider both the curate survey control to the artillery with the enemy and the friendly situations as they af- corps. fect survey operations. He must consider capa- 335. Number and Status of Training of bilities of the enemy to interfere with or Survey Personnel restrict survey operations. He must consider The survey plan must be based on the use the locations of friendly elements and their of survey methods that are completely familiar missions. He must consider any restrictions to all personnel. Sufficient trained personnel 193 must be made available to perform the re- poor visibility may require the use of the quired survey operations in the allotted time. magnetic needle for determination of a start- ing direction. Icy slopes reduce taping ac- 336. Type of Terrain Over Which the curacy. Poor visibility requires shorter Survey Must Be Performed distances between stations necessitating more a. The visibility, the type of terrain, and the angle turning stations. Trilatération can number and locations of installations requiring often be conducted during periods when poor survey control are the primary factors which visibility precludes the execution of other sur- should be considered in determining the sur- vey operations. vey methods to be used and the amount of time and number of personnel required to accom- 338. Availability of Special Survey plish the survey mission. Equipment b. The survey officer should be so familiar Consideration must be given to the avail- with the effects that various types of terrain ability and operational readiness of such spe- have on survey operations that he can cial survey equipment as the tellurometer and promptly and properly advise his commander artillery gyro azimuth instrument. The pres- on the time and personnel requirements for ence or lack of such equipment can greatly survey operations. affect the time and work required for a survey operation. In addition, proper use of special 337. Weather Conditions techniques, such as simultaneous observation, Bad weather may eliminate or greatly re- can materially affect the accomplishment of duce the capability of survey. For example, the survey mission. Section II. STEPS IN SURVEY PLANNING 339. General the personnel available. (If it cannot, he makes The steps in survey planning are obtaining appropriate recommendations to his com- information (warning order), map reconnais- mander. For example, he can recommend that sance, ground reconnaissance, and formulation additional survey personnel be made available, of the survey plan. They are discussed in para- that the time allotted for survey be increased, graphs 340 through 343. and/or that certain installations be given a low priority.) 340. Obtaining Information c. Makes a tentative survey plan, noting the Obtaining information on mission, terrain, critical areas which will require detailed and situation is a continuing process in survey ground reconnaissance. planning that commences when the commander d. Issues necessary warning order to survey briefs his staff and subordinate commanders. personnel. 341. Map Reconnaissance 342. Ground Reconnaissance A map reconnaissance is performed by using The survey officer makes as complete a re- any suitable map or map substitute. The first connaissance of the ground as time permits. He step in making a map reconnaissance is to plot makes a general reconnaissance of the entire the installations requiring control on the map. area and a detailed reconnaissance of those The survey officer then considers the factors critical areas noted during the map and the affecting survey planning and— general ground reconnaissance. The general a. Makes a tentative choice of survey meth- ground reconnaissance can be performed by ods. (In selecting survey methods, the survey motor vehicle, aircraft, or other means, but the officer should choose between traverse and detailed ground reconnaissance should be per- triangulation when possible.) formed on foot. If no suitable map or map b. Determines whether the survey mission substitute is available, the survey officer must can be accomplished in the allotted time with take the action indicated in paragraph 341 194 after performing the general ground recon- 343. Formulation of the Survey Plan naissance but before performing the detailed On completion of the ground reconnaissance, ground reconnaissance. the survey officer formulates the survey plan. Section III. THE SURVEY PLAN 344. General vey officer closely supervises the work of the The survey plan contains those detailed in- survey parties to insure that the survey plan is structions for each survey party not covered by properly executed and to detect any changes standing operating procedure and general in- in the survey plan which may be necessary. If formation necessary for the efficient accomp- it becomes necessary to change the plan, he lishment of the survey mission. issues appropriate instructions to the party chief(s) concerned. 345. Sequence in Which Survey Plan Is Issued 347. Execution of the Survey Plan The survey plan is issued orally. It should Each chief of survey party plans the detailed be issued in the sequency listed below, which is operations of his party. His planning is similar the five-paragraph sequence in which an opera- to that of the survey officer. The mission of tion order is issued. his survey party is contained in the instructions 1. SITUATION (as it affects the survey issued by the survey officer. The survey plan operations) prepared and issued by the chief of party con- a. Enemy. tains those items from the survey officer’s plan which his personnel should know to accomplish b. Friendly. the survey mission and any additional instruc- c. Attachments and detachments. tions which are necessary. The chief of party 2. MISSION (survey) supervises the operations of his party and is- 3. EXECUTION sues additional instructions as necessary a. Concept of survey operations. throughout the conduct of the survey. When- b. Detailed instructions to each party. ever it becomes impracticable to comply with c. Instructions for more than one the instructions received from the survey of- party. ficer, he reports this fact to the survey officer 4. ADMINISTRATION AND LOGIST- or chief surveyor if either is immediately ICS '(supply) available. If neither is immediately available, 5. COMMAND AND SIGNAL (location the chief of party changes his survey plan as rv/■» r» c» o o »» T ▼ f- #--» c* *1 n/■'»▼v* -rx 11 V\ o 4- /-v -I *~\ 4-lx /-> of survey officer) CVVsVxWXllpllOll U11C41/ uiv^n ux l/l 10 unit’s survey mission for which he is responsi- 346. Changes to the Survey Plan ble. At the first opportunity, he reports to the During the execution of the survey, the sur- survey officer the action which he has taken. Section IV. STANDING OPERATING PROCEDURE 348. General or higher artillery headquarters should contain a section on survey. The SOP for each echelon a. A standing operating procedure is a set must conform to the SOP of the next higher of instructions which gives the procedures that echelon. Therefore, the survey portion of the are to be followed for those phases of operation SOP at each artillery echelon should contain which the commander desires to make routine only those survey procedures which the com- (FM 101-5). The SOP sets down the regular mander desires to make standard throughout procedures that are to be followed in the the command. Survey items which the com- absence of instructions to the contrary. mander desires to make standard only for the b. The SOP of a battalion (separate battery) survey unit or section of his headquarters 195 should be contained in the SOP for that unit procedures for survey operations in a unit in- or section. sures uniform training and minimizes the need for special instruction. 349. Purposes of Survey Section SOP c. To Promote Understanding and Team- The purposes of the survey section SOP work. In those units which have more than are— one survey party, establishment of standard a. To Simplify the Transmission of the Sur- procedures insures uniform performance of vey Plan. Instructions included in a SOP survey operations and minimizes the time and need not be restated in the survey plan. For effort required for coordination. example, if the battalion SOP prescribed the d. To Facilitate and Expedite Survey Opera- size of distance angles for triangulation, this tions and To Minimize Confusion and Errors. information need not be included in the survey When personnel become familiar with, and plan. However, inclusion of this information employ, standard signals, techniques, and pro- in the SOP would not prevent the survey officer cedures, they will accomplish their tasks in a from restating it in the survey plan for em- minimum amount of time. Furthermore, use phasis. of standard procedures reduces confusion and b. To Simplify and Perfect the Training of eliminates many errors, which, in turn, ex- Survey Personnel. Establishment of standard pedites survey operations. 196 » PART FIVE DETERMINATION OF AZIMUTH BY ASTRONOMIC OBSERVATIONS CHAPTER 21 BASIC ASTRONOMY Section I. GENERAL 350. General The line connecting the flattened ends of the The effectiveness of any weapon delivery earth is the earth’s rotating axis, and the points system depends on its position and orientation at which the axis cuts the sphere are called the with respect to the target. The direction or north and south poles, respectively. azimuth required for orientation is determined b. Motion of the Earth. The earth rotates by survey. The preceding chapters have shown on its axis from west to east, making one com- how azimuth can be determined from existing plete rotation each day. As the earth rotates, survey control and extended by traverse or it also revolves about the sun in an elliptical triangulation. This procedure, however, re- orbit (or plane), completing one revolution » quires considerable time and may result in a each year. If the earth’s axis were perpendicu- possible loss of accuracy in extension. By ob- lar to this elliptical plane, the sun’s rays would serving celestial bodies, the surveyor is able to be directed at the Equator throughout the year determine direction, when and where it is and there would be no change in seasons. Be- needed. cause the axis is tilted 23° 30' from the per- 351. Application to Artillery Survey pendicular to this elliptical plane, as the earth revolves about the sun, the rays of the sun are Astronomic observations are made by the directed at different portions of the earth above artillery surveyor to expedite the following or below the Equator (fig. 128). survey operations: a. Determining a starting azimuth for a c. Geographic Coordinate System. Since a survey. rectangular coordinate system cannot be b. Checking the closing azimuth of a survey. c. Providing orienting azimuths for can- nons and rockets and associated fire control equipment. d. Providing orienting azimuths for missiles and associated guidance equipment. SUN'S RAYS SUN SUN S RAYS e. Determining azimuths for the declination of aiming circles. NORTHERN WINTER HEMISPHERE SOUTHERN 352. The Earth HEMISPHERE a. Shape of the Earth. The earth has the FALL shape of an oblate spheroid (flattened sphere). Figure 128. Earth’s orbit showing change in seasons. » 197 adapted to a sphere, a system utilizing angular measurements was adopted. NORTH CELESTIAL POLE (1) Longitude. Planes were passed through the earth so that they inter- « ■s / sected both poles. The lines which rV / O- these planes inscribe on the surface AUTUMNAL N'Ö' OrSF / of the sphere are called meridians of E0UIN0X\ 'V / longitude. A base line for measure- /MERIDIAN ^ * ment was established when the meri- OF LONGITUDE/ NORTH dian that passes through Greenwich, ÎTPOLE England, was given a value of 0°. Longitude is measured in degrees, EQUATOR minutes, and seconds both east and west of the Greenwich meridian. ^SOUTH / Longitude is identified as being east ^^POLE / or west by the initials E (east) or W / VERNAL (west) (i.e., 90° 24' 18" W or 40° / EQUINOX 12' 43" E). (2) Latitude. Other planes were passed b- through the earth all parallel to each other and perpendicular to the earth’s SOUTH CELESTIAL POLE rotating axis. The lines inscribed on Figure 129. The celestial sphere. the earth’s surface by these planes are called parallels of latitude. The parallel of latitude halfway between when extended to the celestial sphere inscribes the poles is called the Equator, which the celestial equator on the celestial sphere. is given a value of 0° and is used as c. The extension of any plane forming a a base for measurement of latitude. meridian of longitude when extended to the Latitude is measured in degrees, min- celestial sphere forms a corresponding line on « utes, and seconds north and south of the celestial sphere which is called a celestial the Equator. Latitude is identified as meridian or hour circle. being north or south by the initials N d. The ecliptic is the great circle cut on the (north) or S (south) (i.e., 34° 48' 12" celestial sphere by the plane of the earth’s Nor 30° 12' 16" S). orbit. Since the earth is assumed to be sta- 353. The Celestial Sphere tionary, the ecliptic is assumed to be the path of the sun. The ecliptic intersects the celestial In practical astronomy, it is assumed that equator at two points at an angle of about the sun and stars are attached to a giant 231/2°. sphere, the center of which is the earth. The stars are so far away from the earth that the e. The point at which the sun crosses the radius of the sphere can be assumed to be celestial equator moving from south to north infinite. It is also assumed that the earth is known as the vernal equinox. The point at stands still and that the sun and stars on this which the sun crosses the celestial equator celestial sphere revolve around the earth. moving from north to south is known as the Some parts of the celestial sphere are related autumnal equinox (fig. 129). The equinoxes to parts of the earth (fig. 129). are imaginary fixed points on the celestial sphere and revolve about the earth with the a. The points at which the extensions of the stars. The sun occupies the same position as earth’s rotating axis intercept the celestial the vernal equinox once each year on or about sphere are called the north and south celestial the 21st of March and the same position as poles, respectively. the autumnal equinox on or about the 21st of h. The plane forming the earth’s equator September. 198 « /. The prime vertical is the vertical circle perpendicular to the observer’s meridian at the *x" zenith, which intersects the horizon at points /PRI directly east and west of the observer (fig. ui 130). 355. Position of a Celestial Body »/ o The positions of celestial bodies are located in the sky by two methods: a. Equator System. The celestial body is lo- Wwp ' cated on the celestial sphere much the same as the observer is located on the earth. The two /NADIR / coordinates in this system are right ascension (RA) and declination (dec) (fig. 131). ^ / y (1) Right ascension is comparable to / longitude and is the distance in hours (h), minutes (m), and seconds (s) measured eastward from the vernal Figure 130. Elemente relative to observer’s position. equinox to the hour circle of a celes- tial body. (2) The declination of a celestial body is 354. Observer’s Position comparable to latitude and is the dis- a. The zenith and nadir for any point on the tance in degrees, minutes, and seconds earth’s surface are the two points on the measured north or south of the celes- celestial sphere where the extended plumb tial equator to a celestial body. If the line of the observer’s instrument intersects the celestial body is north of the celestial sphere. The zenith is the point directly above and the nadir is the point directly below. b. The observer’s geographic locations are as follows: (1) The latitude of the observer’s location is the angular distance of that point north or south of the Equator. (2) The longitude of the observer’s loca- tion is the angular distance of the RIGHT ASCENSION \ point east or west of the prime merid- * ian. c. The line of longitude which passes DECLINATION through the observer’s position is called the observer’s meridian, and the celestial meridian which passes through the zenith is called the 0* observer’s hoar circle (fig. 130). VERNAL " CELESTIAL EQUINOX d. The observer’s horizon is a great circle on the celestial sphere, formed by a plane tan- gent to the earth at the observer’s location and the perpendicular to the plumb line of the ob- server’s instrument (fig. 130). e. A vertical circle is any circle on the celes- tial sphere passing thi’ough the zenith and nadir of a point (fig. 130). Figure 131. Equator system of locating a celestial body 199 equator, the declination is plus ( + ) ; on the stars and solar time based on the sun. if it is south, the declination is minus Both classes of time are based on one rotation (-)• of the earth about its axis, or 1 day. Assuming b. Horizon System. The celestial body may that the earth stands still, the day is based on also be located in the sky with reference to one complete revolution of the celestial sphere the observer’s known geographic location. The (or the sun, for solar time), about the earth. two coordinates of this system are azimuth and a. Sidereal time (ST) is based on a sidereal altitude (fig. 132). These coordinates can be day or the length of time it takes a star to used to locate the celestial body from one point make a complete revolution around the earth. for one time only, because the sun and stars The point from which the sidereal day is change rapidly in location with reference to measured is the vernal equinox. The sidereal the position of an observer on the earth. day for any point begins when the vernal (1) The azimuth to a celestial body from equinox crosses the meridian of that point and the observer can be either determined ends when the vernal equinox again crosses by computation of an astronomic ob- that meridian. Sidereal time for any point at servation of the celestial body or any instant is the number of hours, minutes, measured with an instrument from a and seconds that have elapsed since the vernal known azimuth. equinox last passed the meridian of that (2) The altitude of a celestial body is the point. Sidereal time is not satisfactory for vertical angle measured at the ob- everyday use because the vernal equinox server’s position from the observer’s crosses a meridian at noon on the 21st of horizon- to the celestial body. March, but each day thereafter it crosses about 3 minutes 56 seconds earlier so that on the 21st 356. Time of September it crosses at midnight. Two general classes of time are encountered b. Solar time is based on a solar day. There in astronomy. These are sidereal time based are two types of solar days—one based on the apparent or actual movement of the sun and the other on a fictitious or mean sun. (1) Apparent solar time is based on the NORTH CELESTIAL POLE length of time that it takes the sun to make two successive crossings of the same meridian. Apparent solar days vary in length owing to the sun’s inconsistent rate of movement along the ecliptic. ZENITH (2) In order to have days of equal length, v a mean solar day was devised which * was based on a fictitious sun moving uniformly in its apparent path around OBSERVER S <4% 'j HOUR ■ the earth. This mean solar day is CIRCLE approximately the same length as the average apparent solar day. Mean solar time is based on this mean solar day which is divided into 24 hours, each consisting of 60 minutes. (3) The equation of time is the computed différence in hours, minutes, and sec- onds between apparent solar time and mean solar time. The equation of time varies from plus ( -f ) 16 minutes Figure 132. Horizon system of locating a celestial body to minus (—) 14 minutes. To convert 200 + 1 + ’ +1 m yfj r.r ARC1K OCEAN I \ ft « •SCO« 58 r y SOUNl -H.00 ¥ \ BLOO tuOSON BE A RING ¡EA BAY 4090 900 900 &A.r ALASKA SEA SEA CMMSvST VORTH NOR R CA EUROPE NO Ÿ TH A TL ANTIC A £ PA C ! FI C *<> SIAN SEA OCEAN. ‘ -»* S£V SUL F Of C CEA MEXICO T TOPIC OF C tNCEft ¿50 w TZT> I RABIAN BA CARIB, EAU SEA SE. C> BENSA f. r\a.t W M C EOUi rOR APR w% -790 SO « ». % 6 «Xíb INDIA i 3 ROPIC Of C \PRlCORN 0 asOj- S OUTH O'EAfi 4400 ATL ANT: c / OUT MERCATOR PROJECTION SCALE «/ l : 114,400,000 (opprox) I inch equols 1800 mi les (approx) Z! F OCEAN 0 900 1000 1900 2000 2500 Xyo 0 1000 2000 5000 4000 0 CEA N (Seda* at tnia only alone lha Eqsotar) ♦II ♦ I +■’ ♦ ! +:i . . ■ HI M Figure 133. World time zones based on Greenwich mean time. 202 75°W TIME EASTERN 90°W TIME CENTRAL W 105° Figure ISA. United States standard time zones. Í _ TIME MOUNTAIN W 120° TIME PACIFIC m mean solar time to apparent solar time, the equation of time is added algebraically to mean solar time. leo0 357. Time Arc Relationship Since the sun or stars apparently revolve around the earth once every 24 hours, then it NORTH LOCAL MEAN follows that the apparent rate of movement CELESTIAL POLE TIME on the celestial sphere is 15° of longitude or arc per hour. OBSERVER S MERIDIAN GREENWICH 358. Standard Time and Time Zones MEAN TIME Local mean time (LMT) changes 1 hour for each change of 15° of longitude. Since the sun TIME ZONE moves from east to west, time increases from CORRECTION GREENWICH west to east and decreases from east to west. MERIDIAN For example, with Greenwich as a baseline for time measurement, time changes 1 hour for Figure 135, Greenwich mean time. each change of 15° of longitude (arc) west- ward from Greenwich. Time differs in whole hours from Greenwich mean time (GMT) at 360. Greenwich Sidereal Time 15° W, 30° W, 45° W, etc. (fig. 133). To Greenwich sidereal time (GST) is the length standardize the time within a certain area, of time that has elapsed since the vernal lines of longitude at which time differs from equinox last crossed the Greenwich meridian Greenwich mean time in whole hours are used. (fig. 136). Greenwich sidereal time can be de- termined from Greenwich mean time by adding A time zone area extending 7^2° from each h side of these lines has the same time as that the sidereal time at 0 Greenwich mean time meridian unless otherwise specified by civil au- on the date desired and the correction to side- thorities. For example, the time zone for the real time for Greenwich mean time to the 45° W meridian would extend from 37° 30' W Greenwich mean time. For example, if the to 52° 30' W. In the United States, there are four time zones (fig. 134). These zones are based on the 75° W, 90° W, 105° W, and 120° W meridians and are called eastern, cen- tral, mountain, and pacific standard times, re- spectively. 359. Greenwich Mean Time GREENWICH All computations of astronomic observations in the artillery are based on Greenwich mean time. In order to determine Greenwich mean GREENWICH time for the local mean time of observation, SIDEREAL TIME a correction must be applied for the difference in hours between local mean time (standard VERNAL ^ time) and Greenwich mean time (standard of EQUINOX civil time) (fig. 135). For example, if the longitude of the observer is 92° 13' 42" W and the civil or mean time at that point is based on the standard time of the 90° W meridian, then there is a 6-hour difference or correction to be applied to the local mean time of observa- tion in order to determine the Greenwich mean time of observation. Figure 136. Greenwich sidereal time. 203 Greenwich mean time was 19h 13m 458 on the 21st of July 1961, by adding 19h 13m 45° (Greenwich mean time), 19h 54m 05s (sidereal h m s time at 0 Greenwich mean time), and 3 10 GREENWICH (correction of sidereal time at Greenwich mean ‘MEAN TIME time), the Greenwich sidereal time is 15h 11“ s h m s h 00 (39 ll 00 — 24 ). All computations in NOR TH POL artillery survey dealing with sidereal time are based on Greenwich sidereal time. REAL OR APPARENT GREENWICH APPARENT 361. Greenwich Apparent Time TIME Greenwich apparent time (GAT) is the < length of time that has élapsed since the sun GREENWICH MERIDIAN last crossed the 180th meridian (fig. 137). -FICTICIOUS SUN Greenwich apparent time is determined by 'EQUATION OF TIME algebraically adding the equation of time for Figure 137. Greenwich apparent time. 0h (GMT) and the correction for the partial day (GMT) to Greenwich mean time. Green- astronomic computations for azimuth of the wich apparent time is used in artillery survey sun by the hour-angle method. Section II. ASTRONOMIC TRIANGLE 362. General Determination of azimuth by astronomic ob- servations involves the solution of a spherical Local hour angle triangle visualized on the celestial sphere (fig. 138). The desired result of an astronomic ob- Azimuth angle Parallactic servation, azimuth to the body, is determined angle by solving the triangle for the value of the Co azimuth angle. This value can be computed atitude'i Co Po ar ¡stance when certain other parts of the triangle are alt tude known. The triangle is called the astronomic triangle or the PZS triangle. The letters PZS stand for the three vertexes of the triangle; Decimation namely, the pole, the zenith, and the star (sun). The three sides of the triangle are the Latí ude polar distance, the coaltitude, and the colati- tude. The three angles are the parallactic angle, the azimuth angle, and the local hour angle. 363. Determining the Sides of the Triangle Figure 138. Celestial sphere with three sides and three To determine the sides of the astronomic angles of astronomic (PZS) triangle. triangle, certain basic factors covered in para- graphs 353 through 362 are applied. a value of north or south, it is given a positive a. Polar Distance. The declination of a ( + ) sign if it is north of the celestial equator celestial body is similar to latitude in that it and a negative (—) sign if it is south of the is the angular distance north or south of the celestial equator. The angular distance from celestial equator measured along the hour circle the equator to the pole being 90°, then the of the celestial body, but, instead of giving it angular distance from the celestial body to the 204 pole (polar distance) is determined by alge- 364. Determining the Angles of the braically subtracting the declination of the Triangle celestial body from 90° (fig. 138). For example, The angles of the astronomic triangle are de- if the declination of the celestial body is —13° termined as follows: 06' 45", then the polar distance would be 90°— (-13° 06' 45") or 103° 06' 45". a. Parallactic Angle. The parallactic angle is the interior angle at the celestial body and b. Coaltitude. In order to determine the is used in the formula for determining azi- coaltitude side of the astronomic triangle, the muth by the hour-angle method but cancels out corrected or true altitude must first be de- in the computations. termined from the measured vertical angle to b. Azimuth Angle. The azimuth angle is the the celestial body by applying a correction for interior angle of the astronomical triangle at refraction (and for parallax for the sun only). the zenith and is sometimes referred to as the Since the angular distance from the observer’s zenith angle. This angle is the product of com- horizon to the zenith is always 90°, the true putations and is used to determine the true azi- altitude subtracted from this figure will give muth to the celestial body from the the coaltitude (fig. 138). For example, if the observer. The angle can either be to the east corrected altitude of a celestial body is 28° 30', or west of the observer’s meridian, depending then the coaltitude would be 90° — 28° 30', or on whether the celestial body is east or west of 61° 30'. the observer’s meridian. c. Colatitude. The latitude of the observer is c. Local Hour Angle. The local hour angle the angular distance north or south of the equa- is the interior angle of the astronomic triangle tor along the observer’s meridian. This same at the pole and is used only in hour-angle com- angular distance exists between the celestial putations for azimuth. The local hour angle is equator and the zenith on the celestial sphere. determined in two ways, depending on whether The angular distance from the equator (celes- the observation is made on the sun or on a star. tial equator) to the pole (celestial pole) is 90°. The angular distance from the zenith to the 365. Examples of Determination of the Local Hour Angle pole (colatitude) is found by subtracting the latitude of the observer from 90° if the ob- a. The local hour angle (LHA) for a star (figs. 139 and 140) is determined first by sub- server is in north latitude (fig. 138). For ex- tracting the right ascension of the star from ample, if the observer’s latitude is 34° 13' 3(1" Greenwich sidereal time which determines the N, the colatitude would be 90° — 34° 13' 30" or Greenwich hour angle (GHA) (the time since 50^ 4b ¿5U . in soutiL latitude, the colatitude is me star last crossed the Greenwich meridian). found by adding the latitude of the observer The Greenwich hour angle is then converted to 90°. into degrees, minutes, and seconds of arc, and Hours Minutes Seconds LMT of observation 2 00 00 Correction for time zone + 6 00 00 GMT of observation 8 00 00 Sidereal time at 0h GMT + 12 36 27 Corrections for sidereal time for GMT 1 19 GST of observation 20 37 46 RA of Altair for 1 April 1961 -19 48 53 GHA of Altair at time of observation Ö 48 53~ Degrees Minutes Seconds GHA of Altair in arc 12 13 15 Longitude of observer (W) ( —)94 39 14 LHA of observer -82 25 59 205 the longitude of the observer is algebraically subtracted from the value of the angle, which gives the local hour angle. If the local hour angle is minus or less than 180°, this value is to be used in computations ; if the value exceeds GREENWICH 180° and is less than 360°, the value to be used HA in computations is 360° minus the local hour angle; if the value above exceeds 360°, the HA value to be used in computations is the local hour angle minus 360°. For example, suppose that an observation is taken on Altair from longitude 94° 39' 14" W at 0200 hours central RA LONG standard time (CST) on 1 April 1961. VE GREENWICH MERIDIAN GREENWICH OBSERVER'S SIDEREAL TIME LONGITUDE GREENWICH HOUR ANGLE OBSERVER Figure 140. Determining the local hour angle (star) (observer in west longitude). LOCAL HOUR ANGLE b. The local hour angle for observations on A-—STAR the sun is determined by subtracting the longi- RIGHT ASCENSION tude of the observer from the Greenwich hour VERNAL EQUINOX angle (which is Greenwich apparent time plus Figure 139. Determining the local hour angle (star) or minus 12 hours). (observer in east longitude). Example: Hours Minutes Seconde LMT of observation , 9 30 22 Correction for time zone (73° 13' 43" W) +5 00 00 GMT of observation 14 30 22 Equation of time at O'1 (23 July 1961) - 06 22 Correction for daily change for GMT - 01 GAT of observation 14 23 59 -12 00 00 GHA of sun 2 23 59 Degrees Minutes Seconds GHA of sun in arc 35 59 45 Longitude of observer (W) -73 19 43 LHA of sun for observer -37 19 58 c. In both cases in a and b above, east longi- tracting a minus quantity or value. If the re- tude is understood to be minus and west longi- sult is negative, the celestial body is east of the tude to be plus; therefore, in subtracting east observer, and, if the result is positive, the longitude, it would mean algebraically sub- celestial body is west of the observer. 206 366. Determining mannerAzimuth asin forSouth the observer in the Northern Latitude Hemisphere. b. The polar distance is determined by If the observer is in the Southern Hemi- algebraically adding the declination of the sphere, there are different techniques for de- celestial body to 90° with due regard to the termining parts of the PZS triangle and the algebraic sign of the declination. azimuth determined will be based on the south c. The azimuth determined will be based on pole. the south pole. The azimuth is corrected for convergence, and 180° is either added to or a. The coaltitude, subtractedthe colatitude, from andthe azimuththe to determine the local hour angle are determined in the same azimuth based on grid north. Section III. STAR IDENTIFICATION 367. General means used to locate Polaris, the North Star, Astronomic observations for azimuth require when followed in the opposite direction from that the personnel engaged in performing the Leo. Figure 141, however, does not make this fieldwork be capable of readily locating and apparent because of distortion in the polar identifying any of the stars listed in the Army areas. Unfortunately, star charts, like maps, Ephemeris, TM 6-300-61. These stars can be have to be printed on flat sheets of paper, and identified by using either (or both) of the two some of their relative positions are bound to be identification aids discussed in paragraphs 368 disturbed on the world star chart. Except for and 369. the stars near the celestial equator, the distor- tions on the world star chart are greater than 368. Star Chart they would be on a hemisphere star chart, but The world star chart (fig. 141) based on the the world star chart is very useful because the equator system shows most of the brighter declinations and right ascensions are shown stars in the heavens. All of the stars listed in graphically. The star chart indicates the TM 6-300-61 are shown as well as many others relative position of the stars as viewed in the which aid the observer in locating these stars. sky. The approximate right ascension and declina- tion can be obtained from this chart and can b. The first efforts should be concentrated be used as arguments to enter the chart. on learning a half dozen stars in each 6 hours of the right ascension, which would be useful 369. Identification of Stars for observing' on or near the prime vertical or a. Proficiency in star identification is usually as east and west stars. For instance, there are based on a working knowledge of the constella- several stars just east of the constellation Orion tions (star groups) and their relative locations. forming a large pentagon with the œ Canis Starting with such familiar constellations as Minor (Procyon). near the center. Greek let- Orion (a kite-shaped figure on the celestial ters were originally assigned in each constel- equator visible during the winter months), or lation to the stars in order of the relative Ursa Major (the Big Dipper), anyone should magnitude; these were only relative, but the soon be able to lead himself from constellation o: stars are nearly always bright and many of to constellation across the sky. If, for example, them have special names. The stars are rated one follows the arc of the Big Dipper on in order of brightness from first magnitude to around, it will lead him directly to the star fifth or sixth, which are the dimmest that are Arcturus and eventually to Spica in the con- ordinarily visible without a telescope. On the stellation Virgo. Also, the end stars in the star chart, the magnitude is indicated by con- bucket of the Big Dipper (Dubhe and Merak, ventional signs, and it is also shown in TM fig. 141) will lead the observer directly to Leo. 6-300-61. After learning the locations of These two stars are often referred to as the Castor, Pollux, Regulus, Alphard, Sirius, and pointers since they are the most common other stars in this part of the heavens, it is 207 easy to include others coming up from the east, b. Determine the orientation angle as fol- as the night or season advances. lows: (1) Estimate the watch time at which the 370. Star Identifier observations are to begin. i The star identifier (fig. 142) based on the (2) Determine the orientation angle, using horizon system is issued to all artillery units DA Form 6-21 (par. 371). that are issued a transit or a theodolite. It c. Set the arrow on the template over the assists in locating stars by providing the ap- orientation angle. proximate true azimuth and altitude to each d. Read the approximate true azimuth and given star. (It can also be used to identify the approximate altitude of any star on the stars of which the approximate true azimuth base that is within the observer’s field of vision and altitude are known.) All stars shown on (stars having altitudes between 20° and 45° the star identifier are listed in the table, and azimuths between 60° and 120° or between “Alphabetical Star List,” in TM 6-300-61 and 240° and 300° should be selected). are shown in figure 141. The star identifier e. Orient the star finder so that the pointer consists of a base and ten templates. Nine on the template is pointing approximately to- templates are used in star identification and ward true south. The stars will then appear one template with moon and planet data is at the approximate altitudes read from the star not used in artillery survey. One side of the finder; the approximate azimuth to the star is base, marked N is used in the Northern Hemi- as read from the star finder in the Northern sphere. The other side of the base, marked S Hemisphere or equal to the azimuth read from is used in the Southern Hemisphere. A template the star finder minus 180° in the Southern is furnished for each 10° difference in latitude Hemisphere. from 5° through 85°. One side of each template is used for the given latitude in the Northern 371. Use of DA Form 6—21, Computation Hemisphere. The other side is used for the and Instructions for Use With Star same latitude in the Southern Hemisphere. The Identifier template constructed for the latitude nearest Figure 143 shows the entries made on DA the latitude of the observer must be used. To Form 6-21 for determining data in finding and « use the star identifier— identifying stars. Instructions for the use of a. Select the proper template andthe correctlyform are contained on the reverse side of place it on the appropriate side of the base. the form (fig. 144). Figure HI. World star chart. (Located in back of manual) 208 « » • «npotxftTH ,v\'Y' JS' •a?j '"h f// "h »»re»# <$■ o N / O % Ö G O oos UT1TAJ AAC 35C LA AS OÎ.Î 35° ■stf »e« 0120 G o S8 o QSm» \« ■* ~9 G / & Zf v# jth *■« lio % Oft tao % Ü* VS ’‘to 4». vtf vw" 4 v\' %>/,/ /,/o stf \ Figure 142. Star identifier. 209 COMPUTATION AND INSTRUCTIONS FOR USE WITH STAR IDENTIFIER (FU €-ttQ) TIME LATITUDE LONGITUDE ZOME OF STATION OF STATION ?ik rs /? SCHEDULE 1 SCHEDULE 2 SCHEDULE S SCHEDULE 4 4 PRESELECTED LOCAL DATE /¿>/9Pn¿/ PRESELECTED VATCH TIME «2 OOO LONGITUDE OF STATION EAST + WEST- i> tr LONGITUDE OF CENTRAL MERIDIAN EAST- t (FROM TABLE I ON REVERSE) WEST* a ?o ALGEBRAIC SUM (3) AND (4) a /* (FROM TABLE 11 ON REVERSE) CORRECTION TO (4) FOR WATCH TIME (FROM TABLE III ON REVERSE 3o/ V So S' ALGEBRAIC SUM (•) AND (9) ¥J¿2Z_ »F 10 ISL I* <-> 360° (10) Sùo 0° TO 340* REPEAT (10) MORE THAN 360* (10) - 360* ORIENTATION ANGLE ¿2JL SET POINTER OF APPROPRIATE TEMPLATE ON ORIENTATION ANGLE (SEC CUIDE ON REVEUSE) 13 NAME OF STAR Ai.ne.BAXaiu APRX AZIMUTH OF STAR CONVERT (13) TO MILL IF NECESSARY APRX ALTITUDE OF STAR 37 16 CONVERT (IS) TO MILL IF NECESSARY 13 NAME OF STAR BELLfiTRl'j € APRX AZIMUTHOF STAR J5S CONVERT (13) TO MILS, IF NECESSARY APRX ALTITUDE OF STAR 3* 1« CONVERT (IS) TO MILL IF NECESSARY NAME OF STAR Serpee u* APRX AZIMUTH OF STAR as/ CONVERT (13) TO MILL IF NECESSARY APRX ALTITUDE OF STAR. sr CONVERT OS) TO MILL IF NECESSARY 13 NAME OF STAR A*CT APRX ALTITUDE OF STAR \*3 n 16 CONVERT (IS) TO MILL IP NECESSARY DA i nr» 6.21 PREVIOUS EDITIONS OF THIS FORM ARE OBSOLETE. Figure US. Entries made on front of DA Form 6-SI 210 « mm TABLE TABLE W < ! TABLE II I ■ III TORT TMI OP DAY DAY PATCH OP OP ZOMI Mini* OIAN MONTH MONTH TIME BAST L0M6 100* 1W* 210* 140* 40* VEST LOMC V, GIVEN: Time zone of area of operation. Latitude and longitude of station to nearest degree. Preselected local date of observation. Preselected watch time of observation to nearest hour. GUIDE: When observation is to be made at other than preselected watch time ((2) of computation), increase orientation angle ((11) of computation) 1 degree for each 4 minutes of elapsed time after the hour or decrease orientation angle 1 degree foLeach 4 minutes of time before the hour. Select stars between 20 and 45 degrees (60 degrees if a special eyepiece is available) above horizon and within 30 degrees of a 90-degree or 270-degree azimuth (east - west line) to use the altitude method. Select four stars for each schedule, two in the east and two others in the west. Read APRX AZIMUTH and APRX ALTITUDE of stars from template of star identifier to nearest degree. When using a mil-graduated instrument, convert APRX AZIMUTH and APRX ALTITUDE to mils using table III b of TM 6-230. LIMITATIONS: The altitude and hour-angle methods should not be used when the sur is more than 60 degrees above horizon. RESULT* APRX AZIMUTH and APRX ALTITUDE for four schedules of four stars each at preselected watch times. Figure Instructions for use of DA Form 6-21. 211 i CHAPTER 22 THE ALTITUDE METHOD Section I. GENERAL 372. General and is always applied to altitude observations made on the sun. The altitude method of astronomic observa- tion requires the solution of the astronomic b. Refraction. Owing to the density of the triangle for the value of the azimuth angle. earth’s atmosphere, a ray of light from space The three sides of the triangle are used in the is bent downward to the earth as it passes computations (polar distance, coaltitude, colati- through the atmosphere. Therefore, an ob- tude). The solution of this triangle has been server on the earth sees the celestial body simplified by the use of Department of the higher in the heavens than it actually is. The Army forms for the computations. The alti- refraction correction varies according to the tude method gets its name from the most criti- air temperature and the altitude of the celestial cal element in the solution of the triangle— body observed. The refraction correction is the corrected vertical angle to the celestial always minus and is obtained from the ephe- body or the true altitude. meris by using the air temperature at the sta- tion and the observed vertical angle to the celestial body. 373. True Altitude In the solution of the altitude method of 374. Required Field Data astronomic observations, the true altitude of The field data which must be obtained to de- the celestial body must be determined. The termine direction by the altitude method of vertical angle to the celestial body can be deter- astronomic observation are as follows: mined by the observer but this is not the true a. Mean horizontal angle from an azimuth altitude because the observer is located on the mark to the celestial body (sun or star). earth’s surface and also because of the earth’s b. Mean vertical angle to the celestial body. atmosphere (b below). There are two correc- c. Date and mean time of observation (cor- tions—parallax and refraction. rect to nearest 5 min). a. Parallax. Because the sun d.is Airso closetemperature. to the earth, there is a difference between the e. Geographic coordinates of station. vertical angle to the celestial body at the earth’s /. UTM (UPS) coordinates (whenever pos- surface and the vertical angle to the celestial sible) . body at the earth’s center. This difference is g. Approximate azimuth to the azimuth called parallax and is equal to the angle at the mark. center of the sun between the center of the earth and the observer. This difference is 375. Selection of Astronomic Observation negligible on vertical angles to the stars be- Station cause they are so far from the earth. The cor- When other survey operations do not deter- rection that is to be applied in artillery survey mine the location of the point at which astro- to the vertical angle observed on the sun is nomic observations must be made, a point with +07 seconds (0.04 mil) ; this is a mean value known geographic coordinates should be se- 212 « lected. If that is not possible, a point with selected which can easily be located on a large- known grid coordinates should be selected. If scale map; i.e., a point which is easily identi- neither of these is possible, a point should be fiable both on the map and on the ground. Section II. DETERMINING FIELD DATA 376. General the final pointing is made on the azimuth mark, Field data for determining azimuth by astro- the mean data can now be determined. nomic observation consist of the horizontal Caution: Do not view the sun directly angle between an azimuth mark and the ob- through the telescope unless the sun filter has served celestial body, the vertical angle to the been affixed to the eyepiece. body (altitude method only), the time of the observation, the temperature at the time of the observation (altitude method only), and the location of the observing station in both geographic and grid coordinates. 377. Determining Horizontal and Vertical Angles The instruments used to observe celestial bodies are the T16 theodolite or the T2 theo- dolite. Angles are determined in much the same manner as in any other method of sur- vey; i.e., the angle is determined by comparing the mean pointing on one station with the mean pointing on another. Since celestial bodies appear to be moving, the technique of pointing is slightly modified. Also, since the sun presents such a large target, special tech- niques must be employed to determine its center. 378. Use of the T16 Theodolite in Astronomie Observations a. The T16 theodolite is equipped with a solar circle on its reticle (fig. 145). This per- Figure 1A5. T16 theodolite reticle with solar circle. mits an observer to view the sun in such a manner that the vertical and horizontal cross- b. Stellar observations with the T16 theodo- lines of the instrument are directly over the lite are performed as outlined in a above except center of the sun. The initial pointing on the that the intersection of the single vertical azimuth mark is made with the telescope in crossline and the horizontal crossline is used the direct position. The telescope is then rather than the solar circle. This intersection pointed toward the sun. The sun is placed in is placed just ahead of the apparent path of the solar circle and tracked by using both the the star. The star then moves into the inter- horizontal and vertical tangent screws. When section by its own apparent motion, at which the sun is as nearly centered in the solar circle time the operator announces TIP. as possible, the observer announces TIP, levels the collimation level bubble, and reads the ver- 379. Use of the T2 Theodolite in tical and horizontal circle readings. The tele- Astronomic Observations scope is then plunged and the process repeated a. The T2 theodolite is not equipped with a with the telescope in the reverse position. solar circle for pointing on the center of the With the telescope still in the reverse position, sun (fig. 146). To achieve measurements to 213 the center of the sun, measure the angles to motion. If the sun is placed tangent to the one side of the sun with the telescope direct horizontal crossline, it is brought into tangency and then to the other side of the sun with the with the slow vertical motion. Because of the telescope in the reverse position. The resulting double vertical crossline, the sun must be i mean angle is the angle to the center of the placed in one of the two quadrants separated sun. This method of determining the center of by the single vertical crossline. the sun is called the quadrant method and can b. For stellar observations, the T2 theodo- be used either when the sun is viewed directly lite is used in the same manner as discussed in through a sun filter or when the image of the paragraph 378b for the T16 theodolite. sun is projected onto a card held to the rear of the eyepiece of the telescope. To determine the correct quadrant in which to place the image of the sun, first determine the direction the sun is moving. If the motion of the sun is MEAN HORIZONTAL ANGLE through the first and third quadrants (from HORIZONTAL first to third or from third to first) as viewed through the telescope or on the card, the image of the sun should be placed in the second and fourth quadrants. If the motion of the sun is through the second and fourth quadrants MEAN CENTER OF SUN MEAN VERTICAL (from second to fourth or from fourth to ANGLE second), the image of the sun should be placed in the first and third quadrants. The leading edge of the sun is always tracked with one of the crosslines and tangency is obtained with HORIZONTAL the other through the sun’s movement. Point- ings on the sun with the T2 theodolite are shown in figures 147 and 148. If the sun is placed tangent to the vertical crossline, it is Figure 1^6. Method of observing to determine the G brought into tangency with the slow horizontal mean center of the sun. TEL REV TEL DIR PM AM Dl TE EV APPARENT NOON Figure 1A7. Quadrants used in Northern Hemisphere for observation with Wild T2 theodolite (direct observation with dark filter). 214 € APPARENT J NOON TEL DIR TEL REV TEL DIR TEL REV AM MOVEMENT ON CARD Figure H8. Quadrants used in Northern Hemisphere for observation with the Wild T2 theodolite (card method). 380. Time it is necessary to know only the date and time of observation with an error of not more than a. The times at which pointings are made on the sun or a star are read and recorded to 5 minutes. Time correct to 5 minutes can- be the nearest second for both methods of astro- obtained from the message center clock. b. The watch used by the artillery surveyor nomic observation. With the altitude method, to measure time for astronomic observations it is not necessary to know time to this ac- should be a reliable watch with a sweep second curacy, but recording the time to the nearest hand. second will give the recorder additional prac- c. Watch times are based on standard time tice in reading and recording time for the zones, each of which covers a portion of the hour-angle method. Time recorded to the earth. In a zone of operations, survey per- nearest second will also provide survey person- sonnel using astronomic observations must nel a means for detecting errors from examina- know the time zone on which their watch time tion of field data. When the altitude method is is based. The time zone on which a watch is used for observing a star, it is necessary to based can be determined from the message cen- know only the date of observation. When the ter. (Time zone corrections are given in altitude method is used for observing the sun, table I.) Table I. Time Zone Corrections, Local Mean Time to Greenwich Mean Time Correction Correction Time Zone (honre) Time Zone (hours) z . 0 z . A - 1 N + B . - 2 O . + C . - 3 P . + D . - 4 Q - + E . - 5 R . + F . - 6 S - + G . - 7 T . + H - 8 U + 8 I _ - 9 V . + 9 K . -10 w + 10 L . -11 X . + 11 M -12 Y . + 12 Note. Time zone Q corresponds to eastern daylight saving time. Time zone R corresponds to eastern standard time and central day- light saving time. Time zone 5 corresponds to central standard time and to mountain daylight saving time. Time zone T corresponds to mountain standard time and to Pacific daylight saving time. Time zone U corresponds to Pacific standard time. » 215 381. Time of Observation grid coordinates of the station are not known, the location of the station must be plotted on Because of the apparent motion of a celestial the map by careful map inspection. body, the watch time at which each pointing is made on the celestial body should be read b. If the geographic coordinates of the sta- and recorded to the nearest second. To obtain tion are not known and a large-scale map is not the accurate time of observation the instrument available but the accurate grid coordinates are operator announces “Ready” a few seconds be- known, the geographic coordinates must be fore the star is at the intersection of the cross- determined by conversion of the grid coordi- hairs or before the sun is tangent to the cross- nates (ch. 27). hairs. He announces “Tip” and stops tracking c. If the geographic coordinates cannot be at the exact instant of tangency. The recorder determined by any means, azimuth cannot be reads and records the time corresponding to determined by the altitude or hour-angle the exact second that the operator announces method of astronomic observation. “Tip.” The times corresponding to the direct (first) reading and the reverse (second) read- 384. UTM Grid Coordinates of the ing are meaned. This is the mean time of Astronomic Observation Station observation. The UTM grid coordinates of the astronomic observation station should be known in order to 382. Temperature compute convergence through both geographic and UTM grid coordinates. For the altitude method, it is necessary to know the air temperature at the time of ob- servations in order to determine a refraction 385. Approximate Azimuth to Azimuth correction. The temperature should be deter- Mark mined within an accuracy of 5° F. The tem- The approximate azimuth to the azimuth perature can be determined by using the mark should be determined and recorded to psychrometer in a surveying altimeter, or it detect large errors in computations. This azi- can be obtained, by prior arrangement, from muth may be determined by using an M2 com- a meteorological or weather section. In an pass or the compass of an aiming circle or by artillery unit, the temperature can be obtained scaling the azimuth from a large-scale map. from the thermometer used to obtain powder temperature in a gun section. 386. Recording Field Data Field data for astronomic observations are 383. Geographic Coordinates of the recorded as discussed in paragraph 206. Astronomic Observation Station The geographic coordinates (latitude and 387. Determination of Final Azimuth longitude) of the astronomic observation sta- a. Fifth-order astronomic azimuths are tion must be known for the hour-angle method. determined by using the T16 theodolite. To The latitude of the station must be known for achieve a fifth-order astronomic azimuth, ob- the altitude method. For both methods, it is serve and compute at least three sets of obser- desirable to know the geographic coordinates vations—each set, one position. Mean the azi- for the computation of convergence. (The muths and reject any set which varies from geographic coordinates of trig points can the mean by more than 0.3 mil. At least two usually be obtained from trig lists issued by sets must remain and be remeaned to deter- the Corps of Engineers.) mine final azimuth. The considered accuracy a. If the geographic coordinatesof ofa fifth-orderthe sta- astronomic observation is ± tion are not known, they are determined, if 0.3 mil. possible, by measuring, from a large-scale map. b. Fourth-order astronomic azimuths are If the grid coordinates of the station are determined by using the T2 theodolite. To known, they should be used to accurately plot achieve a fourth-order astronomic azimuth, ob- the location of the station on the map. If the serve and compute at least three sets of obser- 216 vations—each set one position. Mean the azi- 389. Limitations muths and reject any set which varies from a. For best results with the altitude method, the mean by more than 30". At least two sets the celestial body is observed within 30° (azi- must remain and be remeaned to determine muth) of the prime vertical (60° to 120° and final azimuth. The considered accuracy of a 240° to 300° in azimuth). The vertical angle fourth-order astronomic observation is ±30". is the critical element in the altitude method but an error in vertical angle has less effect on 388. Azimuth Checksthe and final Improvements azimuth throughout this band. A Azimuths may be checked and improved by celestial body should not be observed at alti- using the following methods : tudes less than 20° because the refraction cor- a. A final azimuth determined from observa- rection is very great. tions on the sun before noon may be checked b. Vertical angles of less than 20° have a and improved by determining another final large and uncertain refraction correction. (A azimuth on the sun in the afternoon. The same 5° vertical angle at 80° F. has a refraction observer’s position and azimuth mark are used. correction of 9' 06".) Refraction corrections The two final azimuths are meaned. for vertical angles less than 20° are not tabu- b. Another method of improving or check- lated in TM 6-300-61. Do not attempt to ob- ing an azimuth is to use an east and a ivest serve a celestial body above 45° without special star and mean the final azimuths. astronomical equipment. Section III. COMPUTATIONS 390. Computation of Astronomic Azimuth (3) Latitude. 30° 16' 21" N. Computations for determination of astro- (4) Longitude. 97° 36'42" W. nomic azimuth by the altitude method are (5) Area. Round Hill. entered on DA Form 6-11 (Computation- (6) Approximate azimuth to the azimuth Astronomic Azimuth by Altitude Method, Sun mark. 3650 mils. or Star (figs. 149 and 150)). This astronomic (7) Local date. 29 May 1961. azimuth can be converted to grid azimuth by (8) Temperature. 94° F. using DA Form 6-20 (Computation-Conver- gence (figs. 151 and 152) (par. 392)). (9) Watch correction. 13 seconds slow ( +138). 391. Use of DA Form 6-11 (10) Mean time of observation. 15h 22m a. Determination of azimuth by the altitude 12s (S). method depends on solution of the astronomic (11) Mean vertical angle. 477.3 mils. (PZS) triangle when the three sides—polar distance, colatitude, and coaltitude—are known (12) Mean horizontal angle. 954.8 mils. (par. 363). DA Form 6-11 provides a con- c. Under certain conditions, auxiliary com- venient step-by-step means for computing the putations are required to determine data for azimuth angle (par. 3645) required. The hori- entry on DA Form 6-11. Spaces for these com- zontal angle measured from the azimuth mark putations are provided on the reverse side of to the celestial body observed is applied to the the form. computed azimuth during the last steps to de- (1) When observations are made with a termine true azimuth to the mark. The formula mil-graduated instrument, latitude solved and a guide for use of the form are and longitude of the observation sta- shown on the back of the form. tion are converted to mils in the space 5. Entries are made on the form as shown provided. in figures 149 and 150. The data given below (2) When the sun is the celestial body are taken from the field notes. observed, an auxiliary computation (1) Station. BnSCP. for declination at Greenwich mean (2) Azimuth mark. Station Oak. time of observation is necessary to 217 SUN OR COMPUTATION-ASTRONOMIC AZIMUTH DY ALTITUDE METHOD. SUN OR STAR TABLE NRS REFER TO TM 6-300. 19. 6l STAR NAME AND NR (TAfiLE 9) SUV LCNGITUDt 30 °| l6'i OP STATIOM 97 "136 te "¿fro»1.1. U030^ I »,‘¿9 MAY 6l ffSk OAK TlMPCOATURI / 9^ hi ml I I r MC AM WATCH Tlal OP OCSIRVATIOM 3.5 ig 112 9. 936 I 326 WATCH CMRICTIOH ' 13 9- 950 i 573 I- ALOCUAK SUM Ml AMO III 22_^ Q, flfig . fiOO TlMl ZOMC CORRICTIOM i 6 LOC COS (20) a, 66l|-371 ALOCMAK SUM (J) AMD <4> 21 22 , 35 3; CRCINWICH DATE . 29 KM ..61 24 00 00 24 00 00 24 00 00 9 659 I 283 2; 1 3? CRIKNWICH MEAN TIME (GMTI 21 22 ,35 9 - 772 i 381s 77 , 3 1)0)4. IQ.COO MM + 07 SECONOS OR •9 - 772,381s PARALLAKSUH MLY) 4Q.W MILS +.0L 9l 886,192 POR SUM. (7)4.(ll POO STAR. REPEAT 17) 77 i 34 ANGLE HAVING LOG ( .1 02) 7 ,05 ,7 IIPIACT4N ITAELC I OR >>MIL1> 0 , 52 Ik 111 i ‘s (•)—<10) TRUC ALTITUDE (h) 76 , 82 i h Liur-A.iMi «»«►•iiSoJ 6U |00 ! o 85 %8 C«I*TI* TKâ» 11*1 IIAItllMI 4—H rr j» UTiim »nt »MoÜjCjl-mi H mm Ils ,11 , Is tus tfww OR isooje^ H h 16 00 tua.)-"- ls9 ,88 16 REPEAT (12) WITH SIGH REVERSED H h H 1- 85 MEAN HORIZONTAL ANGLE % 9 15i) i 8 ALGERRAIC SUM«II) AHO MO £>12 ■+—+■ ,52 17 (11) - (U) S ASTRONOMIC AZIMUTH TO MARK IsO .33.8 iim i UL 76 Tse 16 ai.,3^ [(171 OP CONVERSION TO MILS 1 NORTH + ¡TOMP ON REVERSE IP USMC MILSJ SOUTH @ 5 38 ,17 Sun ALGERRAIC SUMII7) AW Ml) 22 29 51 «L JJt-Oè REPEAT MSI 12 3* ,52 SURTRACT SMALLER, (20) OR OIL SIGN ALWAYS 11 |Hs i 76 PROM LARGER. (21) OR (20), PLUS + ■99 ' ?6 l Stn Oak ■fc IP IS) IS. GREENWICH DAT! (4) I Si ( + I AMD LI IS THAN 24 NRS LOCAL DATE SAME AS O) ( + )AW MORE THAN 24 HRS LOCAL DATE-PI OAT >“ 24 HRS SHIE^ OP 2*hiit> LOCAL DATE - 1 OAT HRS - (I) SMITH JOBSS RKPLACKa IDITtOM OP 1 SCP 1*. WHICH IS OBSOLETE bA/Dr..6-i1 Figure H9. Entries made on front of DA Form 6-11 for computing true azimuth from observations on the sun (altitude method) 690 996677 219 V Cos Lat Cos h mil values. values. are computed using hundredth-mil horizon. a. Less than 20 degrees or more than 60 degrees above azimuth (east-west line). b. More than 30 degrees from a 90-degree or 270-degree are computed using tenth-mil values. d. (23) through (37) of'computation are computeo using hundredth-mil values. a. (7) through (22) of computation COMPUTATION are computed using hundredth- b. (6) through (14) of AUXILIARY through (17) of CONVERSION TO MILS COMPUTATION c. (2) through (9) and (11) A value of astronomic azimuth for each set of observations. than fourth-order are This form should not be used when accuracies greater or star is-- The altitude method should not be used when the sun the UTM grid azimuth. Continue computations using DA Form 6-20 to obtain required. block marked. E 1 Enter observed field data in azimuth to azimuth mark. Value in (37) should be about equal to approximate or west of meridian, A - astronomic azimuth of sun or star measured east and watch correction. Mean watch time of observation instrument,-- When using a mil-graduated longitude of station. Latitude and mark and to sun or star (sketch). Approximate azimuth to azimuth Local date of observation. Temperature at time of observation. from azimuth mark to sun. Horizontal clockwise angle s = 1/2 sum of polar distance, latitude, and true altitude, area of operation. Time zone of of selected star(s). Sun or name(s) and number(s) angle to) sun or star. Observed altitude of (vertical h = true altitude of celestial body. p ? polar distance of celestial body. Lat s latitude of station. , Cos 1/2 As /Cos a Cos (a-p) RESULTS: FORMULA: LIMITATIONS: j GUIDE: GIVEN: FIELD DATA: ■ 00 X 7d 2 1 96 33 33. ill? I 81 6375 5 138 11? X60 X x 618 4 1 -h X60 X els 4 I 16375 ANO ON DA FORM 1-20 I SUM OF mi THROUGH IHI [ENTER IM (III ON FRONT! 22^ 2 ; and instructions on back of DA Form 6-11. Figure 150. Auxiliary computations 2%5 2 -75 20 101 22 k X60 2L. 1178 8189 1202 1260 36 ,1)2 ' 21)11)1) 00 loo 6l8 4 I Í6375 J5J32. p: urejra o' ^BSiSsae ? 107 1888 29 MAT 6l ^ ^ 185 I »*8 & 5" _l6 JX _2L DATE AND GMT AT GREENWICH TABLE III b OF TM 6-230) CONVERSION TO MILS COMPUTATION (USE OF SUN DECLINATION COMPUTATION FOR APPARENT AUXILIARY UMBER OF MINUTES IN IT) *1 IN HUNDREDS OF OR (111 CONVERTED TO MINUTES AND SECONDS (II) IN MILS [USE SICNOF (♦)] LOC OF CONSTANT in + m + m CMT {HOURS ANO MINUTIS IN I«) OF COMPUTATION] 3 NUMtERS OF HOURS IN OI X *0 [«> OF COMPUTATION] \ ORCtMalCH DATE determine the value to be entered on north) for the observer’s location is performed line 12 of DA Form 6-11. The Army on DA Form 6-20 (figs. 151 and 152) from Ephemeris (table 2) tabulates data geographic and, if possible, from grid coordi- for declination of the sun at 0h GMT nates. This convergence is algebraically added for each day of the year and the daily to the astronomic (true) azimuth computed on change from one day to the next. An DA Forms 6-10, 6-10a, and 6-11 to convert interpolation is performed to deter- that azimuth to grid azimuth. mine the fraction of daily change cor- b. The data necessary to compute the con- responding to the difference between h vergence are the geographic and grid coordi- 0 GMT and GMT of observation. A nates of the observer’s location. The con- space is provided on the reverse side vergence for the problem computed in figures of the form for this interpolation. The 151 and 152 is computed from the following following formula is solved: data: Change in declination = (1) Station. BnSCP. GMT of observation x daily change (seconds or mils) (2) Azimuth mark. Station Oak. 1,440 (minutes in a day) (3) Latitude. 30° 16' 21" N. 392. Use of DA Form 6-20 (4) Longitude. 97° 36'42" W. a. Computation for determining the conver- (5) UTM grid coordinates (nearest 100 gence (difference between grid north and true meters). (633600-3349600). 220 COMPUTATION - CONVERGENCE (ASTBOHOMIC AZIMUTH TO UTM GRIL AZIMUTH) (T*bi» Numb0r* Mmfmr to Tit Ä - 300 - 19 SX ) ( r* 6-no) AZIMUTH MARK Bn SCP mmm OMC E UTM GRID LONGITUDE OP STATION EASTING OP STATION X7.35,32 ZONE 633 . 600 1 I LATITUDE OP STATION NORTHING OP STATION 3 i 3^ , 600 ! 1 LONGITUDE OP STATION EASTING OP STATION 17 ,35 ,32 633 , 600 LONGITUDE OP CENTRAL MERIDIAN (PROM TABLE ON REVERSE) 17 [60 I oo 500.000 133 |60Q MORE THAN (2) (1) -(2) 17 |3ñ 132, MORE THAN (12) (11) - (12) LESS THAN (2) (2) —- ( I) LESS THAN (12) (12)-01) ^ ■« 133 I 600- IP (1) IS IN DEGREES, USE (fl ) OP REPEAT (12) WITH DECIMAL CONVERSION COMP ON REVERSE IP (I) IS IN MILS. REPEAT (3) 2k .66 POINT MOVED LEPT SIX PLACES o • 133 i 600 1 392| 3^5 <» 12S| 8o6 LOG OP PUNCTION XV LOG SIN LATITUDE OP STATION (TABLE 6} 9 . 702, 5^ UfiazkL jr^ 66k 1 1, . ogly, 689 3j i(fli| 67fL NUMBER HAVING LOG (7) « T LOG CONVERSION 7 PIRST TERM IN SECONDS OR MILS .12 M SECONDS TO MILS 7 6 9 3:575 SECOND TERM (TABLE 8 OR IP (I) IS IN DEGREES, REPEAT (17) 8*MJLI. USE (2) AMD LATITUDE) 00 IP (1) IS IN MILS, USE (17) + (18) L 095i 2k5 NUMBER HAVING LOG (IP) « (•14(9). COMVCRCCHCC M SCCONOtOK MS.» PIRST TERM IN SECONDS OR MILS 12 . ¿5. «MCM tTATIOM ts IM HOBTH LATITUDI AMO.. SECOND TERM (TABLE 7, USE MVZtTLOMC IMCASTLOMG IP(H il. no i». no n. (M) AMD MORTHIMG) 0 .00 MOBC TMAM (S 4 LIISTMAMU) - 4 (20)-(2I)-COHVCCGCMCC IM SCCOMOS Q MILS WMCM tTATIOM IS M SOUTH LATITUD« AMD.. •HIM STATION IS IN MOUTH LATITUM M VIST LOMO W CAST LONG IF (U IL no is. no)is. IF (11) IS. 127) IS. MORBTHAHI» - + KOBE THAN (12) — LOS TMAM <71 + - LIU THAN (1» + VMCN STATION ISM SOUTH LATITUDE 12 IF 12 -^5 IP (10) AND (22) DIPPER BY MORE THAN / C4" \ REDETERMINE COORDINATES AND RECOMPUTE ALL COMPUTATIONS 1.0.02 MJ IP (1) IS IN DECREES. USE (18) OF CONVERGENCE CONVERSION COMP ON REVERSE + If (1) IS IN MILS. REPEAT (22) ÊL ,12 .1*5 SUMMARY OF ASTRONOMIC AZIMUTHS AND COMPUTATION OF UTM GRID AZIMUTH ASTRONOMIC AZIMUTH TO AZIMUTH MARK UP i 33, 8 MEAN (SIGN 4- ) UOj 8 CONVERGENCE + REPEAT (23) 3 121 V ALGEBRAIC SUM OP (31) AND (32) = GRID AZIMUTH TO MARK UP j 211 k SHEET ^ OF ^ SHEETS SMITH JunRS NOTEBOOK REFERENCE U-B-6 ROUND ** f u. 29 MAY 1961 REPLACES DA FORM 6-20, 1 OCT 5?; AND DA FORM 6-2N, 1 SEP 52, DA ,^6-20 «HICH ARE OBSOLETE. Figure 151. Entries made on front of DA Form 6-20 for converting true azimuth to correct grid azimuth. 221 TABLE - CENTRAL MERIDIAN OF UTM GRID ZONES ZONE DECREES MILS ZONE DEGREES MILS ZONE DEGREES MILS ZONE DEGREES MILS NR W LONG V LONG NR « LONG W LONG NR E LONG E LONG NR E LONG E LONG 177 3146*67 16 87 1S46.67 S3.33 93 1553.33 171 3040.00 17 81 1440.00 32 160.00 47 1766.00 16S 2933.33 18 75 1333. 33 33 15 266.67 105 1866.67 159 2826.67 19 69 1226. 67 21 373.33 49 111 1973.33 153 272a 00 20 63 112a oo 35 27 480.00 50 117 208040 147 2613.33 21 57 1013.33 36 33 586.67 51 123 2186.67 2506.67 906.67 37 693.33 52 129 2293.33 135 240a00 23 800.00 38 45 800.00 S3 135 240a00 2293.33 24 39 693.33 39 141 2506.67 10 123 2186.67 586.67 1013.33 147 2613.33 117 208a 00 27 63 maoo 56 153 2720.00 12 111 1973.33 27 21 373.33 4:.' 1236.67 57 159 2826.67 13 105 1866.67 15 266.67 133Í.33 58 165 2933.33 14 99 p76aooS~ ua oo ir 144a00 59 171 304a00 93 1653.33 30 53.33 45 87 t$46.67 60 177 3146.67 CONVERSION COMPUTATION DEGREES. MINUTES. AND SECONDS TO SECONDS SECONDS TO DEGREES. MINUTES. AND SECONDS ÎT TT REPEAT (3) 9 REPEAT <22) OF COMPUTATION NUMBER OF DEGREES |N(I) NUMBER OF TIMES 3600 DIVIDES 10 INTO (9) s NUMBER OF DEGREES IHJ9] 11 REPEAT (9) (2) X 60 12 NUMBER IN (10) X 3600 NUMBER OF MINUTES IN (1) 13 (11)— (12) NUMBER OF TIMES 60 DIVIDES 14 (3) + (4) INTO (13) s NUMBER OF MINUTES IN (9J X60 15 REPEAT (13) (5) X 60 16 NUMBER IN (14) X 60 NUMBER OF SECONDS IN (1) 17 <15)-(16)sNUMBER OF SECONDS IN (9) (6) + (7 ) ENTER IN (4) ON FRONT r + CONVERGENCE lgl (ENTER IN (23) OM FRONT) GIVEN: UTM grid zone of area of operation. UTM grid coordinates of station to nearest meter. Latitude and longitude of station to nearest second or one*hundredth mil (DA Form 6-10, 6-10a, or 6-11). A value of astronomic azimuth for each set of observations (DA Form 6-10, 6-10a, or 6-11). GUIDE: When using a mil-graduated instrument, - - a. (1) through (5), (7) through (10), and (20) through (22) of computation are computed using hundredth-mil values. b. (6) and (24) through (33) of computation are computed using tenth-mil values. Compare (10) and (22) and, if they differ by more than 4 seconds or 0. 02 mils, redetermine coordinates and recompute all computations. LIMITATIONS: This form should not be used when accuracies greater than third-order are required. RESULTS: A value of UTM grid azimuth from the mean values of astronomic azimuth and the grid convergence at the station. FORMULAS: UTM grid azimuth = Astronomic azimuth * convergence. USING UTM GRID COORDINATES; Convergence = (XV)q - (XV (XV) = a variable function based on latitude of station (obtained from TM 6-300-19 , “Army Ephemer is for 19 "). q = 0.000 001 times the distance in meters from central meridian of UTM grid zone to station. (XVOq3 = second term of convergence computation (obtained from TM 6-300-19 , "Army ehe- rner is for 19 "). USING GEOGRAPHIC COORDINATES: Convergence - (XU)p + (XUI)p3 (XU) = 10,000 times sine of latitude of station. p = 0.0001 times distance in seconds or mils of arc from central meridian of UTM grid zone to station. (XIII)p3 s second term of convergence computation (obtained from TM 6-300-19 , "Army Ephe- meris for 19 "). Figure 152. Auxiliary computations and instructions on back of DA Form 6-20. CHAPTER 23 HOUR-ANGLE METHOD Section I. GENERAL 393. General desirable limits for the altitude method, then a celestial body which is as near as possible to a. The hour-angle method of astronomic ob- the limits should be selected and the hour-angle servation also requires the solution of the method used. astronomic triangle. The parts of the triangle that are used are the polar distance, the colati- 394. Required Field Data tude, and the local hour angle (two sides and a. The field data required for the hour-angle the included angle). method are slightly less than the altitude b. The local hour angle is determined from method. The data needed to compute the azi- the time of observation and is directly pro- muth by the hour-angle method are as follows : portional to the azimuth of the body ; therefore, (1) Mean horizontal angle from azimuth it is extremely important that it be correct to mark to celestial body. the nearest 1 second. The hour-angle method (2) Mean time of observation correct to can be used any time the altitude method is nearest second (10“ for Polaris). used, provided time is correct to the nearest (3) Geographic coordinates of observer’s second. station and when possible UTM c. The hour-angle method can be used when (UPS) grid coordinates to nearest 100 the celestial body is below 20° altitude; how- meters. ever, as the line of sight approaches the obser- (4) Approximate azimuth to azimuth ver’s horizon, an error (horizontal refraction) mark. may be introduced which cannot be corrected. b. The vertical angle is not needed for the d. If there is no celestial body within the hour-angle method. Section II. DETERMINING FIELD DATA 395. Determining Angles (Hour-Angle method (pars. 379 and 380) may be used for Method) the hour-angle method. Alternate methods of Except for the method of pointings (pars. pointing for the hour-angle method are given 379 and 380) horizontal angles are determined in paragraphs 398 and 399. for the hour-angle method in the same way that they are determined for the altitude 397. Pointings on a Star (Hour-Angle method. (A set of observations for the hour- Method) angle method consists of determining horizon- When observing a star for the hour-angle tal angles—one position for theodolites.) method, place the vertical crossline just ahead 396. Pointings on Celestial Bodies of the star so that the star will move toward (Hour-Angle Method) the crossline. Place the horizontal crossline The techniques of pointing for the altitude approximately on the star. Let the crosslines 223 remain stationary. Just before the vertical 399. Time crossline is over the star, announce “Ready”. When the hour-angle method is used, the At the instant that the crossline is over the time is not only recorded to the nearest second, star, announce “Tip”. (The recorder reads and but it must be correct to the nearest second records the watch time corresponding to the (nearest 10 seconds for Polaris). The method exact instant that the instrument operator for obtaining the correct time from radio time announces “Tip”.) signals is explained in detail in TM 5-234. The watch correction should be obtained before and 398. Pointings on the Sunafter (Hour-Angle the observations. If there is a difference, Method) the mean time of each observation must be de- When observations are made with the T16 termined by using the corrections. theodolite, the procedures for pointings on the sun are as described in paragraph 379a. When 400. Coordinates the T2 theodolite is used, either the quadrant The methods of determining geographic and method discussed in paragraph 380 or the fol- grid coordinates and their use are discussed in lowing procedures are used : Place the vertical paragraphs 384 and 385. crossline just ahead of the leading edge of the sun in the direct position and just ahead of the 401. Approximate Azimuth Mark trailing edge of the sun in the reverse posi- The methods of obtaining the approximate tion so that the sun will move into tangency azimuth to the azimuth mark are discussed in with the vertical crossline. Place the hori- paragraph 386. zontal crossline so that it approximately bisects the sun. Let the crosslines remain stationary. 402. Records of Field Data Just before tangency, the observer announces “Ready”. At the instant of tangency, he an- The method of recording field data for nounces “Tip”. (The recorder reads and re- astronomic observations (hour-angle method) cords the watch time corresponding to the is discussed in paragraph 206. exact instant the observer announces “Tip”.) Using this method, obtain tangency first with 403. Techniques the leading edge of the sun (telescope direct) The techniques for the hour-angle method and then with the trailing edge of the sun are the same as for the altitude method (par. (telescope reversed). 387) except the vertical angle is not measured. Section III. COMPUTATIONS 404. Computation of Azimuth by the nomic (PZS) triangle when two sides and the Hour-Angle Method included angle are known. The two sides re- quired are polar distance (par. 363a) and Because of the difference in solar time and colatitude (par. 363c). The included angle is sidereal time, a different form must be used the local hour angle (pars. 364c and 365). DA when the azimuth is computed using a star Form 6-10 provides a convenient step-by-step than when it is computed using the sun. The means for computing the azimuth angle (par. form used for the hour-angle method, sun, is 3645) required, when the sun is the celestial DA Form 6-10. This form is discussed in body observed. The horizontal angle measured paragraph 405. The form used for hour-angle from the azimuth mark to the sun is applied method, star, is DA Form 6-10a. This form is to the computed azimuth during the last steps, discussed in paragraph 406. to determine true azimuth to the mark. The formula on which the form is based and a 405. Use of DA Form 6—10 guide for the use of the form are shown on a. Determination of azimuth by the hour- the reverse side. angle method depends on solution of the astro- b. Entries made on DA Form 6-10 are 224 shown in figures 153 and 154. The data given hour-angle is determined from sidereal time below are taken from the field notes— and right ascension instead of from apparent (1) Station. Dunce. time. Declination of a star is obtained from (2) Azimuth mark. Water tower. the Army Ephemeris for Greenwich date of (3) Latitude. 34° 39' 48" N. observation, eliminating the auxiliary compu- tation required when the sun is observed. (4) Longitude. 98° 24' 18" W. b. (5) Area. Gunnery Hill. Entries made on the form are shown in figures 155 and 156. The data given below are (6) Approximate azimuth to azimuth taken from the field notes. The example is mark. 4,300 mils. from a fourth-order observation. Local date. (7) 12 March 1961. (1) Latitude. 34° 39'48" N. (8) Watch correction. 1 second fast (2) Longitude. 98° 24'18" W. (-01«). (9) Mean time of observation. 08h 49m (3) Approximate azimuth to mark. 240°. 48« (S). (4) Local date. 11 March 1961. (10) Mean horizontal(5) angle.Azimuth 4,085.5 mark. mils. Water tower. c. Spaces are provided on the reverse side of (6) Station. TS-7. DA Form 6-10 for the auxiliary computations (7) Star. Polaris. required. (8) Mean time of observation. 19h 58m (1) Declination of the sun at Greenwich 36« (S). mean time of observation is com- (9) Watch correction. 25 seconds slow puted as explained in paragraph (+ 25s). 391c (2) for entry on line 18 of the form. (10) Mean horizontal angle. 114° 34' 20". (2) Conversion of latitude and longitude (11) Area. Gunnery Hill. to mils is performed on the reverse c. Spaces are provided on the reverse side side, when required. of the form for certain auxiliary computations (3) A space is provided for conversion of required. time to arc, for entry on line 12 of (1) Conversion of latitude and longitude the form. to mils, when required. 406. Use of DA Form 6—10a (2) Conversion of time to arc, for entry on line 12 of the form. a. DA Form 6—10a is used to compute azi- muth by the hour-angle method when a star is the celestial body observed. The form is 407. Grid Azimuth used to solve the astronomic (PZS) triangle in DA Form 6-20 determines the convergence the same manner as DA Form 6-10. The steps to be applied to the astronomic azimuth com- performed are the same except that the local puted on DA Forms 6-10 and 6-10a. 225 226 SUN DOUCE H h 1 84 08 5311 38,4 Q11 5 00, 9115 ■Slii 57 JONES 1 .TT ,04 1^'38 ,4 14 40 , 85,5 64 43 i 06,0 ja Jl 6l G> 0 252 492 9 ' SU 1678 9 ! 764 170 9]983 !477 9 ! 780 1693 9 1 975 i 784 o'! 252 ; 492 0 228 276 9 ! 432 464 0.7<^ i 8p US ^ 6 il6 ,2k WT KJ ‘IXI SMITH MTV LATnUME SOUTH LATTTUM «»■ tfLTWI ISM ANGLE HAVING LOG TAM (IS) (»)-(40)s ASTROMOMIC AZIMUTH TO MARK RCPCAT MCI WITH OPPOWTC St6M L06 COT OA) AMGLE HAVING LOG TAN (**) MEAN HORIZONTAL ANGLE ALMUAIC SUM (II) AM> (21) LOG COS (Ml TO TM t- 300 . 19. TABLE HRS REFER IP (10) AM) (14) HAVE SAME MG NS, USE (M)-f(lT) IP (MI AMO (24) HA VC OPPOSITE SIC MS, SUBTRACT SMALLER (2» OB (17». PROM LARGER. (17)00(24) 00 00 00 00 12 24 00,00 00:00 hi mi 12 24 1UT m itari 41 84 40 4l 10 43 01 ‘ 00 28 24 itl ii 51 21 55 21 00 00 00 58 00 42. 10 49 19 16 3a. 21 3a 3a 22. 1Û. 28 2 12 6 .79 iaol ± 24 14 14 8 149 IL LOCAL DATE - I DAY LOCAL OATE + I DAY LOCAL DATE JJL ~ "1 + GREENWICH DATE (A) ISi S> 5 ? 2 <^8 149 k 10 (III OP COMPUTATION GIVEN: H fl |9? H—h Time zone of area of operation. ■ MH.f M HOURS OP (I) H h 165 I OOjOO FIELD DATA: OCORCIS AH» MINUTES OM MILS H MINUTES OP (I) Latitude and longitude of station. H—h MINUTES ANO SECONOS 0« MO.S IN SECONOS OP (I) oojso Approximate azimuth to azimuth mark. —in-prom H h Name(s) and number(s) of selected star(s). [ENTER IM (IS) QM PEONT] i*> 1^0 Local date of observation. Mean watch time of observation and watch correction to nearest second. CONVERSION TO MILS COMPUTATION (USE TABLE in b OF TM S.230) Horizontal clockwise angle from azimuth mark to star. GUIDE: LONOITUOE ^PROJ^RON^^OMI^ Enter observed field data in block marked. E i When using a mil-graduated instrument, -- a. (2) through (5) of CONVERSION COMPUTATDN are computed using hundredth- mil values. b. (2) through (9) and (11) through (17) of CONVERSION TO MILS COMPUTATION are computed using hundredth-mil values. c. (12) through (24) of computation are computed using hundredth-mil values. d. (25) through (41) of computation are computed using tenth-mil values. Value in (41) should be about equal to approximate azimuth to azimuth mark. SUM OP (11) THROUCH (It) Continue computations using DA Form 6-20 to obtain the UTM grid azimuth. rCNTER ININ (17 ) ON PRONf) [ANO ON 0OA PORN 4.20 J LIMITATIONS: This form should not be used when accuracies greater than fourth-order are required. The hour-angle method should not be used when the star is more than 60 degrees above horizon. RESULTS: A value of astronomic azimuth for each set of observations. FORMULAS: ,an l/2(A+q)=cs?ai^ft:;;^i - v*. ,an 1/2(A q> , ~ =r.V/sfat;^ i/*. A sastronomic azimuth of star measured east or west of meridian, q s parallactic angle (cancels in computations). Lat s latitude of station. Dec a declination of star. t a hour angle (less than 12^) of star. GI)V>)iNMKsr I‘HÍNTIMO VhFJCE J9SRn-«»t«St Figure 15i. Auxiliary computations and instructions on back of DA Form 6-10, 6l STAR NAME COMPUTATION - ASTRONOMIC AZIMUTH BY HOUR • ANGLE METHOD, STAR TABLE NR5 REFER TO TM <-300 - 19 AND NR (TABLE 9) FQUBJS 3* "'39'; W "(f) 98°|gl» |l8 "<4)1 21*0° 11 KAR 6l HT TB 7 hi .ml ^ I MEAN WATCH TIME OP OBSERVATION 21 REPEAT (17) g 31* ! 39 ! M WATCH CORRECTION |25 REPEAT (IB) WITH OPPOSITE SIGH ^89 05 i 07 ALGEBRAIC SUM (1) AMO (1) ALGEBRAIC SIM (21) AMO (27) 2? 19 O*LONG H H TIME ZONE CORRECTION rlW— ^6 22J* ^—h ALGEBRAIC SUM (I) AMO «> w 25 I 59 i 01 9 9^9 06l8 1 GREENWICH DATE> ..6r 24r jww00x00 i v 24 00 00 24 00 00 LOG COT (U) o ; 139 r goo » 0 ; 088 I 9702 GREENWICH MEAN TIM« (GMT) 01 I 59 I 01 9. 91*5 11276 SIDEREAL TIME AT 9*ON GREENWICH DATE ITAaLt 2) H 1 7 i 36 o! 1*3 I 5^6 +AH- CORRECTION TO ( 7 ) (TABLE <> ANGLE HAVING LOG TAN <1* > & '18.03 U)+(7H<»> [IP LESS THAN (IOL ADO U HRS] 13 116 I 57 9l 660 ; 1731 2 4lOO10 0 24 00 00 24 00 00 0 139 i 9081* 13 116 |57 9 800 0815 RIGHT ASCENMON OP STAR (TABLE »B-MÍLI, OR Ml I 15 9' 673 ! 39*^5 11 ,21 ol 126 Teero (M) CONVERTED TO ARC ÜDOP CONV COMP ON REVERSE] 170 115 |30 ANGLE HAVING LOG TAN (IS) 53 ill* 21 r p*,e (COMI .IcSS^ge jDi* |i8 $1* 118 03 ALGEBRAIC SIM (12) AM) (12) ~ 71 i 51 ,12 IP (20) AW (241 HAVE SAME SIGNS. USE - 61 i 52 i28~ - AND CNT (I) Hi I +) AND LEU THAN 14 NR~S UNE AS (S) ( ♦ I AMO HORS THAN 24 HRS (S)- 24 MS SHEET X OP I SHEETS O w 24 HRS-(2) EMITS JOSSS n A PORM Uf\ 1 JAN 86 6-lOa REPLACES EDITION OF 1 SEP 53, WHICH IS OBSOLETE. Figure 155. Entries made on front of DA Form 6-10a for computing true azimuth from fourth order observa- tion on the star Polaris, hour-angle method. 229 6U.S.GOVERNMENT PRINTING OFFICE. I4SI 0-47(0») mil values. values. are computed using hundredth-mil mil values. 1/J(A q,2 -=c-^feæ->/* COMPUTATION are computed using hundredth- a. (2) through (5) of CONVERSION through (17) of CONVERSION TO MILS COMPUTATION b. (2) through (9) and (11) are computed using hundredth-mil values. c. (12) through (24) of computation COMPUTATION are computed using hundredth- d. (6) through (14) of AUXILIARY are computed using tenth-mil values. e. (25) through (41) of computation c1/21 area of operation. Time zone of mark. Approximate azimuth to azimuth and watch correction to nearest second. Mean watch time of observation Latitude and longitude of station. Local date of observation. from azimuth mark to sun. Horizontal clockwise angle block marked. F I Enter observed field data in instrument, -- When using a mil-graduated A value of astronomic azimuth for each set of observations. the UTM grid azimuth. Continue computations using DA Form 6-20 to obtain to azimuth mark. Value in (41) should be about equal to approximate azimuth fourth-order are required. This form is not to be used when accuracies greater than sun is more than 60 degrees The hour-angle metho ' should not be used when the above horizon. “ - of meridian, A sastonomic azimuth of sun measured east or west Dec ©apparent declination of sun. q s parallactic angle (cancels in computations). Lai s latitude of station. t s hour angle (less than 12^) of sun. FIELD DATA: GIVEN: GUIDE: LIMITATÜNS: RESULTS: FORMULAS: fi- 2 67 0¡2Ó 0 !0U ll !n i 39',M -Htf + 5 ,33 6 , l6!2ir n+ X60 X X 6! 8 4 I 16375 OF SUN n. -+- X60 i 618 41 6375 ANO ON OA . Oaa t-H j SUM OP Mil TMBOUCN MAI [INTI» IN MTIOM P»OMfl 16. L&L 57,84 33 1333 and instructions on back of DA Form 6-10a. Figure 156. Auxiliary computations 22 01 21 S3Û. 12. 7 .10 X60 14 o !oU _ata_ 12 March 6l * ■ ^'^'3g sieVrissaro g 949. 390 0 ■ 844 477 è- 1 |l*g o. 98*: 2U" l8"l "■ [.‘.'..f.'»,, 17 M 1^3 1— -16 100 AT GREENWICH DATE AND GMT 5 ) COMPUTATION (TABLE CONVERSION AUXILIARY COMPUTATION FOR APPARENT DECLINATION (USE TABLE III b OF TM 6.230) CONVERSION TO MILS COMPUTATION MN.S [UU UCMOKH] •«• OP NINUTfSMI» O'CMC» O* ML» M HOUR» OP Ml OP ni auum ANO we»« oa aa.i IM UCOMOI MU OP COMPUTATION or (11 OICMIt AMO NMUTI» OO MLS m MMUTCl (iMTf » IM Mil ON PROMT) I UN OP Ml THROWCN (1) flMTIt M (I LOMCITUOI AND SECONDS OR MILS (ARC) TO DECREES, MINUTES AND SECONDS (TIME) HOURS, MINUTES (PROM POQMT OP POO»] —m«nuu gt PtftlT AMO ON QA PO— » . |j L06 OP CONSTANT Oil CONVIRTIO TO NMUTI » AMO UCCM01 O I OffMICN ©AT« [in OP COmfVTATtOm] 2 CNT CnOU»l ANO NBNffl» IN w OP CONPUTATNSN] i CHAPTER 24 AZIMUTH BY SIMULTANEOUS OBSERVATIONS 408. General the same time that he is observing a celestial Because of the great distances of celestial body. A loudspeaker, headset, or other device bodies from the earth, the directions to a celes- must be provided at each flank station so that tial body at any instant from two or more the observer can hear instructions from the close points on the earth are approximately observer at the master station while he is equal. The difference between the azimuths is pointing.) The master station reports its primarily due to the fact that the azimuths at coordinates (encoded if necessary) to each different points are measured with respect to flank station and each flank station notifies the different horizontal planes. This difference can master station when ready to observe. When all be determined. The principles in paragraph stations are ready, the observer at the mas- 409 provide a simple and rapid means of trans- ter station announces, “Ready—begin track- mitting direction between points by simul- ing—3—2—1—tip.’’ Pointings are made on taneous observations. the celestial body as explained in paragraphs 379 and 397, depending on which instrument is used. However, each flank station observer, 409. Transmission of Direction by if he is observing the sun, keeps his vertical Simultaneous Observations on crosshair (crossline) tangent to the leading Celestial Bodies edge of the sun and approximately bisects the a. A master station is established at a point sun with the horizontal crosshair (crossline). which can be identified on a large-scale map The master station observer announces “Tip” and from which the grid azimuth to an azimuth the instant the star is at the intersection of mark is known or has been determined. Flank the crosshairs or the instant the sun is tangent stations are established at points which can to both crosshairs. The master station observer be identified on a large-scale map and at which records the readings on the horizontal and it is desired to determine common grid azi- vertical scales. Each flank observer records the muths. Wire or radio communication must be reading on the horizontal scales when observ- available between each flank station and the ing the sun and the readings on the horizontal master station. An observing instrument is set up at the master station and oriented on the and vertical scales when observing a star. (The azimuth mark. An observing instrument is set vertical angle is read at the flank station (s) up at each flank station and oriented on an only as an aid for identification.) All observ- azimuth mark to which the azimuth is desired. ers then plunge their telescopes and observe (Direction can be transmitted to more than the celestial body (with the telescope in the one flank station at the same time.) A promi- reverse position), using the procedure re- nent celestial body at an altitude between 10° quired for their instrument. If observing the and 65° is selected by the observer at the sun, each flank station observer tracks with master station and identified to the observer the vertical crosshair tangent to the trailing at each flank station. (The observer at the edge of the sun. After both pointings, each master station must wear a lip or throat micro- flank station acknowledges if the observation phone so that he can transmit information at was successful. He reports “Take again” if 230 € they were not successful. After each set of at the master station (H) and the distance pointings in which one or more flank stations (D). This line will intersect the center scale tracked successfully, the horizontal angle at the (C) at a point corresponding to the correction master station, from the azimuth mark to the in seconds (or mils) to be applied to the azi- celestial body, is determined from the observed muth at the master station to determine the data. This horizontal angle is then added to the correct azimuth from the flank station to the grid azimuth from the master station to the celestial body. When the nomograph is used, azimuth mark to obtain the grid azimuth to the it may be necessary to multiply the indicated observed celestial body. This grid azimuth and value in meters by 10, 100, etc. In this case, the mean vertical angle to the celestial body the indicated correction in seconds (or mils) are transmitted to each flank station. must also be multiplied by the same number. b. At each flank station,The thecorrection locations is appliedof to the grid azimuth both stations are plotted on a large-scale map of the celestial body (determined at the master (fig. 157). A line is then drawn on the map station) in accordance with the following rules : representing the azimuth to the celestial body (1) When the flank station is to the left at the master station. The perpendicular dis- of the line from the master station tance (D) to this line from the flank station to the celestial body, the correction is then measured. is added to the azimuth. (2) When the flank station is to the right of the line from the master station N STATION A to the celestial body, the correction is \ subtracted from the azimuth. X d. The corrected azimuth obtained in c above 0 \ vyt & \ is the grid azimuth of the celestial body from the flank station. The mean of the observed horizontal angle at the flank station, from the 't \ azimuth mark to the celestial body, is then \ \ \ subtracted from this azimuth to obtain the grid MASTER /2/ azimuth to the azimuth mark. For this sub- 7 4 STATION traction, it may be necessary to add 360° or C(CORRECTION IN SECONDS) 6400 mils to the azimuth of the celestial body. e. If necessary, the master station may use an assumed starting azimuth to the azimuth mark. 410. Example of Transmission of Direction by Simultaneous Observations The following example illustrates the trans- mission of direction to one flank station by simultaneous observations : a. Mean data obtained from observations are as follows : Figure 157. Relative locations of the master station, the flank station, and the celestial body. Master station Horizontal angle = 2191.0 mils c. By using the nomograph shownVertical in figure angle = 720.0 mils 158 (also contained in TM 6-300-61, a line is Flank station drawn to connect the mean observed altitude Horizontal angle = 1715.4 mils 231 b. Given grid azimuth to e. Correct grid azimuth azimuth mark at from flank station master station = 1874.5 mils to celestial body = 4066.2 mils Mean observed hori- zontal angle at Mean observed horizontal master station = ( + ) 2191.0 mils angle at flank Grid azimuth to celestial station = ( —) 1715.4 mils body at master Azimuth to azimuth station — 4065.5 mils mark at flank c. The relative locations of the master sta- station = 2350.8 mils tion, the flank station, and the celestial body are shown in figure 157. 411. Additional Observations d. The nomograph (fig. 158) is entered by In the event of unsuccessful observations at using the mean vertical angle H from a above any flank station, the master station should and the distance D, obtained from figure 157. repeat the procedure. By establishing the num- The correction obtained from the nomograph ber of observations and the rejection limits in is +0.68 or 0.7 mil. By applying this correc- a similar manner to those established for tion to the grid azimuth from the master sta- astronomic observation, direction can be trans- tion to the celestial body, an azimuth of 4066.2 mitted through simultaneous observation with mils is obtained. This is the grid azimuth from accuracy comparable to astronomic observa- the flank station to the celestial body. tions. 232 TABLE 13. Grid Azimuth Correction, Simultaneous Observation D H METERS SECONDS MILS DEGREES MILS IOOO — 70"-^ = 60"—^ E— 0.30 ni 900 — -IIOO irf 50“—- 60° 800 - 40“-= — 0.20 rrf _ 1000 nrf 700 — 30" 600 — 900 nK 50* 20 0 .10 irf O.OÔrrf 500 — 800 nrf — — — EXAMPLE 0.08 nrf a07n^ 0.06 nrf l_ 700 nrf 400 — 10 0.05 nrf 9" 8“ 0.04 nrf -f=- 600 nrf NOTE: D = Perpendicular distance from flank station to a line representing azimuth from master 6"-=— 0.03 nrf 300 station to sun or star. 30* If 0 exceeds 1000 meters, a multiplier of 10,100, etc is used . _P- 500 rrf H s Observed altitude from master station to „ sun or star. 4 0.02 nrf C» Correction to be applied to azimuth from master station to sun or star to obtain corrected azimuth from flank sfction to 3“ sun or star. — 400 rrf Correction is plus if flank station is to the 200 left of a line from the master station to sun or star, minus if to the right. 20°— EXAMPLE o» 0.01 rrf 0*5000 meters H * 40° 30‘ (or 720 mils) With a straight edge, line up 500 on 0 scale and 40°30r(or 720 mils) on H 300 m scale. The correction 0*13.6(or 0 068)xl0* 136 seconds (or 0.66 mils). In this case 500 is multiplied by 10 to make it 5000, 15° — so the correction for azimuth from C scale must also be multiplied by 10. 0.005 rrf 200 m 100 10* 0.5" —1 Figure 158. Simultaneous observation, grid azimuth, correction nomograph. 233 CHAPTER 25 COMPARISON OF METHODS 412. General 413. Astronomic Triangle (PZS) The two methods of astronomic observations Both the hour-angle and the altitude methods used by the artillery to determine the azimuth require the solving of the PZS triangle. The solving of the PZS triangle has been simplified for survey are the altitude and the hour-angle by the use of Department of the Army forms method. An experienced observer using prop- for computations. The elements of the PZS er observing procedures can compute the re- triangle used in each method are shown in fig- quired azimuth accurately by either of these ure 159. methods. An extensive knowledge of astronomy is not required. 414. Fieldwork The fieldwork required for either the hour- angle or the altitude method is as follows : Element required Hour-angle method Altitude method Horizontal angle Yes Yes Vertical angle No Yes POLAR DISTANCE Time Yes Yes COLATITUDE Temperature No Yes Latitude Yes Yes Longitude Yes Yes 415. Hour-Angle Method COALTITUDE a. Computing Azimuth by the Hour-Angle Method. The hour-angle method of observation 0 ALTITUDE METHOD and computation for determining azimuth can be used at any time that the altitude method is used; it is always used for observing Polaris and other celestial bodies which are not in the COLATITUDE desired position for the altitude method of LOCAL HOUR- POLAR observation. The azimuth of the celestial body ANGLE DISTANCE is computed for the mean time of observation. The horizontal angle from the azimuth mark to the celestial body and the mean time of ob- servation are determined by field observations. In the computations, three elements of the PZS triangle are used—the local hour angle, co- HOUR-ANGLE METHOD latitude, and polar distance. (1) Time is the critical element in an Figure 159. PZS triangle. hour-angle observation, since it is 234 used to compute the hour angle. The observer’s meridian, and the solution elements in this determination vary becomes indeterminate at the instant with choice of the celestial body. The of apparent noon. following computations are used to determine the hour angle for the sun and stars: 416. Altitude Method a. Computing Azimuth by the Altitude Sun Method. The altitude method of observation Change LMT to GMT and computation for determining azimuth is GMT + equation of time = GAT the most common method used by the artillery. GAT rfc 12 hours = GHA The azimuth of the celestial body is computed GHA — west longitude (or + east for the mean time of observation. The hori- longitude) = LHA zontal angle from the the azimuth mark to the celestial body, the mean vertical angle to the Star celestial body, the mean time of observation, Change LMT to GMT and the temperature at the time of observation Determine GST by using the Army are determined by field observations. In the Ephemeris computations, three elements of the PZS tri- GST — RA = GHA angle are used—the coaltitude, colatitude, and GHA — west longitude (or + east polar distance. longitude) = LHA (1) The vertical angle is the critical ele- (2) Latitude is u§ed to determine the ment in an altitude observation. From colatitude. the vertical angle, the coaltitude is (3) The declination (taken from the Army determined. The vertical angle to the Ephemeris) is used to determine the sun must be corrected for parallax polar distance. (the correction is always plus), be- b. Limitations. cause the vertical angle is measured (1) The hour-angle method can be used from a point on the surface of the when the celestial body is below 20° earth and not from the center of altitude ; however, as the line of sight the earth. No parallax correction approaches the observer’s horizon, an is needed for observations on the error (horizontal refraction) which stars, because they are at such great cannot bs corrected may be intro- distances from the earth that the duced. vertical angle is the same as though (2) The celestial body should not be ob- it were measured from the center of served at a position above 45° in alti- the earth. Although the parallax cor- tude, unless special eyepieces are rection is applied to the vertical angle available for the instrument. on the sun only, the refraction correc- (3) Time accurate to 1 second is required, tion (always minus) is applied to the except when Polaris is observed (10 vertical angle to any celestial body. seconds). When a ray of light emanating from a (4) The sun should not be observed when celestial body passes through the at- it is within 2 hours of the observer’s mosphere of the earth, the ray is bent meridian. The accuracy with which downward; hence, the sun and stars the azimuth may be determined de- appear to be higher above the observ- pends on the precision of field observa- er’s horizon than they actually are. tions, the accuracy of the corrections The angle formed by the ray’s devia- in altitude, and the shape of the celes- tion from its direction on entering the tial triangle. The PZS triangle be- earth’s atmosphere to its direction at comes weak as the sun approaches the the surface of the earth is called re- 235 fraction. The magnitude of the re- muths. At least three sets of fraction correction depends on the observations must be observed, and temperature and barometric pressure sets varying from the mean by more of the atmosphere and the altitude of than 0.3 mil must be rejected. At the ray. The refraction correction least two sets must remain and be tables give corrections for a baro- meaned. metric pressure of 29.5 inches, which (3) The M2 aiming circle and the transit is assumed to be of sufficient accuracy can be used for astronomic observa- for practical purposes. The parallax tion. The procedures for measuring correction is determined and applied angles outlined in chapters 5 and 6 to the refraction correction, and the are applicable to astronomic observa- final correction is subtracted from the tion. The number of sets and the re- observed altitude. jection limits are as outlined in (2) The latitude and declination for the appendix II. determination of the colatitude and c. Azimuth Checks and Improvement. Azi- polar distance are used the same as in muths may be checked and improved by using the hour-angle method. the following methods: b. Limitations. (1) A final azimuth, as described in b ( 1 ) Polaris is never observed by using the above, determined from observations altitude method, because it is located on the sun before noon, may be near the observer’s meridian and checked and improved by determining presents a poor trigonometric solu- another final azimuth on the sun in tion. the afternoon. The same observer’s (2) Best results with the altitude method position and azimuth mark are used. can be obtained if observations are The two final azimuths are meaned. made on celestial bodies which are (2) Another method of improving or located within 30° of the prime verti- checking an azimuth is to use an east cal and between 20° and 45° in alti- and a ivest star and mean the final tude. In such cases, the celestial body azimuths. is changing faster in vertical angle than in azimuth, and any error in 418. Summary of Hour-Angle and vertical angle will make a smaller Alîitude Methods corresponding error in azimuth. (3) The body should not be observed when a. For either the hour-angle or altitude it is within 2 hours of the observer’s method, the best results are obtained when the meridian. celestial body is observed within 30° of the prime vertical and between 20° and 45° alti- 417. Accuracies and Techniques tude. a. Accuracy. Either the altitude or hour- b. When the hour-angle method is used, time angle method gives the required accuracy. accurate to 1 second is required, except when Polaris is observed (10 seconds). It is the b. Determination of Final Azimuth. best method for observations on circumpolar (1) When using the Wild T2 theodolite, stars. observe and compute at least three c. When the altitude method is used, the sets. Mean the three azimuths and celestial body must be observed within 30° of reject any azimuth which is more the prime vertical. This is the best method for than 30 seconds from the mean. At observations on an east or west star. least two azimuths must remain and d. The sun should not be observed when it be meaned to obtain an azimuth for is within 2 hours of the observer’s meridian. use with a fourth-order survey. e. For best results, a celestial body should (2) The Wild T16 theodolite is used to de- not be observed when it is less than 20° in termine fifth-order astronomic azi- altitude. 236 f. There are days, especially during . the after the body has crossed the observer’s winter months at the higher latitudes in the meridian. Northern Hemisphere, when the sun or stars do not enter the most desired position for g. If an azimuth is needed and no celestial astronomic observations. Under these circum- body is in the proper position for observation, stances, the best results are obtained by ob- the celestial body that is closest to the proper serving the celestial body at the highest point position will be observed. The hour-angle in its orbit, yet not within 2 hours before or method is used for best results. 237 « PART SIX CONVERTING SURVEY CONTROL, CONVERSION OF COORDINATES, AND TRANSFORMATION CHAPTER 26 CONVERTING SURVEY CONTROL 419. General data established by the lower echelon to the a. In order to permit the delivery of ac- grid established by the higher echelon. curate field artillery fires without adjustment and to permit the massing of fires from two 420. Variations in Starting Control or more artillery units, all field artillery units The methods by which starting control for operating under the tactical control of one field artillery survey may be obtained are listed commander should be located and oriented in a through c below, in order of preference. with respect to a single datum or grid. This a. Use of Known Coordinates and Heights grid can be based on the UTM (UPS) grid co- of Points Located With Respect to a UTM (or ordinates of points previously established by UPS) Grid. The points for which the coordi- survey, or the grid may be based on assumed nates and heights are known may be points data. established by surveys performed by the higher b. The common grid used is the one estab- echelon, or they may be points which were lo- lished by the highest survey echelon present cated by surveys performed prior to the start in the area. The headquarters which exercise of military operations. The locations of points tactical control over artillery units are bat- established prior to the commencement of talion, division, and corps. The mission of the military operations are contained in trig lists subordinate unit requires it to initiate survey prepared and published by the Corps of En- operations without waiting for survey control gineers. to be established by a higher echelon. There- b. Use of Assumed Coordinates and Heights fore, at all levels, survey is started and com- and Correct Grid Azimuth. Correct grid azi- pleted as soon as possible, and, when higher muth can be determined, in many cases, echelon survey control becomes available, the through astronomic observation or through the original data is converted to place the unit on use of a gyro azimuth surveying instrument. the grid of the higher echelon. Thus, it may be Correct grid azimuth should always be used necessary for a battalion assigned or attached whenever possible. If both higher and lower to a division artillery to operate first on the survey echelons initiate surveys by using cor- grid established by the battalion (battalion rect grid azimuths, any discrepancy which ex- grid), then on the grid established by division ists between surveys due to assumption of artillery (division grid), and finally on the coordinates will be constant for all points lo- grid established by corps artillery (corps grid). cated (fig. 160). When it is necessary to as- When survey at one or more echelons is based sume the coordinates and height of the starting on assumed data, it is necessary to convert point, they should approximate the correct co- 238 « ordinates and height as closely as possible. problem of conversion to common control. For The approximate coordinates can be deter- this reason, assumed azimuth should never be mined from a large-scale map. (Use of start- used when it is possible to use correct grid ing data determined from a map must always azimuth. be considered assumed data.) 421. Coordinates and Height Conversion (Sliding the Grid) When both a higher and a lower survey eche- ERROR IN ASSUMED AZIMUTH lon start survey operations with correct grid azimuth but one (or both) echelon (s) starts ERROR IN (start) with assumed coordinates and height, ASSUMED COORDINATES the lower echelon must apply coordinate and height corrections to the locations of each PLOT OF TRAVERSE PERFORMED USING AZIMUTH AND COORDINATES critical point to convert to the grid of the WHICH ARE CORRECT WITH RESPECT TO GRID. higher echelon. This coordinate and height PLOT OF TRAVERSE PERFORMED USING CORRECT AZIMUTH AND INCORRECT COORDINATES WITH RESPECT TO GRID conversion is commonly referred to as sliding - PLOT OF TRAVERSE PERFORMED USING INCORRECT AZIMUTH AND the grid (fig. 161) and is accomplished as fol- COORDINATES WITH RESPECT TO GRID. lows: a. Determine the difference in easting and Figure 160. Discrepancies in survey control caused by northing coordinates and the difference in use of assumed starting data. height between the assumed coordinates and height of the starting point and the common c. Use of Known or Assumed Coordinates grid coordinates and height of the starting and Assumed Azimuth. Assumed azimuth point. should be used for a starting azimuth only Easting Northing Height when azimuth cannot be determined from Assumed starting astronomic observations, a gyro azimuth sur- point 550000.00 3838000.00 400.0 Common grid start- veying instrument or computation. The as- ing point 550196.52 3837887.89 402.3 sumed azimuth should closely approximate the Corrections + 196.52 — 112.11 +2.3 correct grid azimuth when possible. The ap- proximate grid azimuth can be determined by b. The difference becomes the correction scaling from a large-scale map or with a de- when the difference is given a sign which will cimated aiming circle. If either (or both) cause the algebraic sum of the assumed data higher or lower echelon survey operations are and the correction to equal the common grid initiated with assumed azimuths, differences of data. varying magnitude will exist between the co- c. Apply the corrections algebraically to the ordinates of points located by their surveys coordinates and height (as determined by the (fig. 160). This variation complicates the lower echelon) of each station to be converted. Assumed coordinates of BnSCP Btry SCP on assumed grid Azimuth TS2 tomk rror |dN coordinates TSI IdN dN I St dE TS2 at IdN Azimuth Btry SCP tomk on common grid ^ Common grid TSI coordinates of BnSCP LdJ Figure 161. Schematic diagram illustrating sliding the grid. 239 V 422. Azimuth Conversion (Swinging the cause the algebraic sum of the correction and Grid) the assumed azimuth to equal the common grid If a unit initiates survey operations using azimuth. correct grid coordinates for the starting point b. Apply the azimuth correction to each leg but assumed azimuth, the coordinates of each of the survey. station in the survey and the azimuths deter- c. Since the azimuth of each leg has changed, mined by survey will be in error when correct the bearing angle of each leg has changed. direction is determined for the starting point. Recompute each leg of the survey by using the In order to convert the assumed data to correct corrected azimuths and new coordinates deter- grid data, all azimuths and coordinates deter- mined for each station in the survey, thus mined in the scheme must be corrected. The placing all stations on the common grid. application of the azimuth correction is com- d. If it is desired to determine the common monly referred to as swinging the grid and grid data for a specific point only, compute the procedures are as follows : azimuth and distance from the starting point a. Determine the difference betweento the designatedthe as- point (assumed data). Apply sumed starting azimuth and the azimuth given the azimuth correction to the azimuth deter- by common control. mined and recompute the location of the desig- nated point from the starting point, using the Assumed starting azimuth 160° 19' 40" corrected azimuth and the distance determined Common grid starting azimuth __ 164° 24' 20" by computation (fig. 162). Azimuth correction +4° 04' 40" e. Any orienting lines may be corrected by This difference becomes the azimuth correction applying the azimuth correction to the azimuth when the difference is given a sign which will determined through the use of assumed data. Common grid azimuth to az mk Assumed azimuth to az mk |° 52'20" azimuth error Io 52* 20" (900 meters) azimuth BnSCP - correction Btry SCP on grid started with Assumed azimuth 330° 26' 20" Common grid azimuth 332° IB1 Ad1 assumed azimuth Azimuth correction ♦ I ° 521 20" Computed azimuth BnSCP to Btry SCP 86° 17' 40" Azimuth correction « |° 52' 20" Common azimuth BnSCP to Btry SCP 88° 10'00" Btry SCP on common grid Figure 162. Schematic diagrams illustrating swinging the grid for a specific station. 240 423. Azimuth, Coordinates, and Height swinging and sliding may be accomplished at Conversion (Swinging and Sliding the same time. Only the critical points (bat- the Grid) tery centers, OP’s) are converted. The steps If either (or both) a higher or a lower sur- in swinging and sliding the grid (fig. 163) are vey echelon initiates survey operations with as follows: assumed azimuth, coordinates, and height, the a. Using the assumed coordinates, compute lower echelon must apply azimuth, coordinates the azimuth and distance from the starting and height corrections to critical locations and point to the first critical point, from the first directions to convert to the grid of the higher critical point to the second, and so on until the echelon. This technique is commonly referred closing point is reached. to as swinging and sliding the grid and both b. Determine the azimuth correction by com- Original survey on assumed grid with azimuth corrected by swinging / T\ V f ^ ^ Assumed / r \ azimuth / / X N À Correct 'i //// / azimuth x ' Jy Azimuth difference ^ 4 Assumed f Azimuth difference applied as a BnSCP / correction to each leg causes the Original survey on assumed grid to swing grid and azimuth dN Original survey corrected by swinging and sliding the grid^ !_d§ 1__ dE dN dN cr Common V Original survey on assumed grid with azimuth corrected grid BnSCP dN dN by swinging Assumed BnSCP J Difference /between common grid and assumed grid applied at starting station causes grid to slide Figure 163. Schematic diagram illustrating swinging and sliding the grid. 241 ( paring the assumed starting direction with the ever, control cannot be extended from any data common grid starting direction. Apply the obtained from a graphical solution. Normally, azimuth correction to each of the computed the graphical solution is used in conjunction azimuths determined in a above. with a firing chart. An overlay is made of the c. Using the common grid coordinates for existing critical points, including the battalion the starting point, the corrected azimuths {b survey control point and a line of direction to above), and the computed distances between the azimuth mark, and then the critical points critical points (a above), compute the coordi- are transferred to a new chart. The steps for nates of the first critical point from the start- this procedure are as follows: ing point. Using the new coordinates of the a. Plot the coordinate locations, as deter- first critical point, the corrected azimuth and mined from assumed data, for the battalion the computed distance to the second point, re- SCP and all critical points. Plot the azimuth compute the coordinates of the second critical (assumed) to the mark on the chart. point and so on until the closing point is b. Place a sheet of overlay paper over the reached. chart and prick the locations of the battalion d. Correct the height of the critical points SCP and critical points. by applying the height correction. c. Trace the line of direction from the chart to the overlay. d. Plot the common control coordinates of 424. Swinging and Sliding the Grid the battalion SCP and the common control azi- (Graphically) muth to the mark on a new chart. The procedure discussed in paragraph 423 e. Place the overlay on the new chart, alin- require considerable mathematical computa- ing battalion SCP on battalion SCP and azi- tions in order to convert to common control. muth line on azimuth line. If time is critical, a graphical solution to con- f. Prick the locations of all critical points version to common control can be used. How- shown on the overlay to the new chart. » CHAPTER 27 CONVERSION OF COORDINATES 425. General If the distance is computed from UTM coordi- It may occasionally be necessary to convert nates, the log scale factor must be applied to grid data to geographic data and/or geographic obtain ground distance. data to grid data. Occasions when this may be necessary or desirable are as follows: 427. Procedures for Conversion of Coordinates a. When coordinates are transformed from a. The procedures for converting UPS grid a UTM zone to a UPS zone or from a UPS coordinates to geographic coordinates and for zone to a UTM zone, it is necessary to convert converting geographic coordinates to UPS grid coordinates to geographic coordinates and grid coordinates are discussed in TM 5-241. then to convert the geographic coordinates to grid coordinates for the new zone. (To trans- b. In artillery surveys, UTM grid coordi- form a grid azimuth from a UTM zone to a nates are converted to geographic coordinates UPS zone or from a UPS zone to a UTM zone, and geographic coordinates are converted it is necessary to convert the true azimuth to to UTM grid coordinates by using DA Form a grid azimuth for the new zone; this is ac- 6-22 (Grid to Geographic (machine)), DA complished by subtracting the convergence Form 6-23 (Geographic to Grid (logarithm)), from the grid azimuth for the old zone and and DA Form 6-25 (Geographic to Grid applying the convergence for the new zone.) (machine) ) together with technical manuals containing data relative to the appropriate b. When only the geographic coordinates are spheroid. TM 5-241-1 contains a map showing known for a point which will be used to initiate the various spheroids. A spheroid is an as- or check survey operations, it is necessary to sumed size and shape of the earth for the convert the geographic coordinates to UTM (or purpose of computing geodetic positions. UPS) grid coordinates. (Geographic coordi- c. The spheroids and their associated techni- nates must be correct to the nearest 0.001 cal manuals are shown below— second to obtain UTM (UPS) coordinates cor- rect to 0.03 meter.) INTERNATIONAL SPHEROID (SOUTH AMERICA, EUROPE, AUSTRALIA, c. When azimuth is obtained from astro- CHINA, HAWAII, and SOUTH nomic observations, it is necessary to know the PACIFIC) : TM 5-241-3/1 and latitude and longitude of the astronomic obser- TM 5-241-3/2. vation station. If they are not known, the CLARKE 1866 SPHEROID geographic coordinates of the station can be (UNITED STATES, MEXICO, obtained by conversion from grid coordinates. ALASKA, CANADA, and GREEN- LAND) : TM 5-241-4/1 and TM 426. Conversion of Distance 5-241-4/2. To determine the distance between two BESSEL SPHEROID (JAPAN, points, the coordinates of both points must be USSR, KOREA, BORNEO, CELE- based on a common system (for example, both BES, and SUMATRA) : TM 5-241- geographic coordinates or UTM coordinates). 5/1 and TM 5-241-5/2. » 243 CLARKE 1880 SPHEROID (AFRI- geographic coordinates to UTM grid coordi- CA) : TM 5-241-6/1 and TM nates. Longitude of the central meridian (and 5-241-6/2. UTM grid zone number) (item 2) is obtained EVEREST SPHEROID (INDIA, from the table on the reverse side of DA Form TIBET, BURMA, MALAY, and 6-23. THAILAND) : TM 5-241-7. b. Logarithms entered on DA Form 6-23 must be correct to the seventh digit in the 428. Use of DA Form 6—22 (Computation— mantissa. The complete number, for which the Conversion UTM Grid Coordinates to logarithm is obtained, must be used as the Geographic Coordinates (Machine)) argument in obtaining the logarithm. The DA Form 6-22 (fig. 164) is used to convert mantissa of the logarithm must be determined UTM grid coordinates to geographic coordi- to the eighth digit and then rounded off to nates. Instructions for the use of the form are the seventh digit. Antilogarithms must be de- contained on the reverse side of the form. termined to the third digit after the decimal Figure 164 is an example of the entries that point. are made on DA Form 6-22 for converting UTM grid coordinates to geographic coordi- nates. The longitude of the central meridian 430. Use of DA Form 6—25 (Computation— (item 39) can be obtained from the UTM grid Conversion Geographic Coordinates to zone number by using the table on the reverse UTM Grid Coordinates (Machine)) side of DA Form 6-22. The UTM grid zone DA Form 6-25 (fig. 166) can also be used to number can be determined from a map or convert geographic coordinates to UTM grid from a trig list. coordinates. (DA Form 6-25 is a machine com- putation form, whereas DA Form 6-23 is a 429. Use of DA Form 6—23 (Computation— logarithmic computation form.) Instructions Conversion Geographic Coordinates to for the use of the form are contained on the UTM Grid Coordinates (Logarithms)) reverse side of the form. Figure 166 is an ex- a. DA Form 6-23 (fig. 165) is used to con- ample of the entries that are made on DA vert geographic coordinates to UTM grid co- Form 6-25 for converting geographic coordi- ordinates. Instructions for the use of the form nates to UTM grid coordinates. Longitude of are contained on the reverse side of the form. the central meridian (and UTM grid zone Figure 165 is an example of the entries that number) (item 2) is obtained from the table on are made on DA Form 6-23 for converting the reverse side of DA Form 6-25. 244 COMPUTATION - CONVERSION UTM GRID COORDINATES TO GEOGRAPHIC COORDINATES STATION UTM CRIO HEMIsm£RE:gZlNOftTH CD SOUTH Flat Top # 2 COORDINATELE. 559.855 .¿no . ^7 ■ ^10 UTM GRID ZONE NIMER ^¿j. EASTING COORDINATE OF STATION TABULAR VALUE FUHCTIOR IX OPPOSITE (Âë »eeurstmiy st kno*n) 559 1858 ,k30 LATITUDE IH(10) 391 291j 762 TABULAR DIFFERENCE FOR 1 SECOND OPPOSITE T 500 000 000 TABUUR VALUE OF FUNCTION IX INE’J) 0 1 131 I 19 TABULAR VALUE FUNCTION X OPPOSITE LATITUDE \%(tO) if (I) IS MORE THAN (1), USE (1) ■ (V ,3151 254- IF (i) IS LESS THAN (7), USE (3) -d) T (Sign atwmys + ) (+) TABULAR DIFFERENCE FOR 1 SECOND OPPOSITE 59 1858 |¿i-30 TABULAR VALUE OF FUNCTION X IN (37) 0 i 00*H 23 GRAPHIC VALUE A 2<1X) REPEAT CJ; WITH DECIMAL POINT ÍUSE (17) AS ARCUNENT. ENTER GRAPH AT (- MOVED LEFT SIX PUCES 059 1358 i^30 \ifT SIDE (Sign slwy» -jJ 001 GRAPH 1C VALUE E) = SECONOS OF ARC 003 1533 [032 |_USE STEP (4) AS ARGUMENT AT LEFT SIDE 30* OF GRAPH. USE STEP (10) AS ARGUMENT AT TOP OF GRAPHJ 000 121^ 1^75 000 1012 1838 31 216 NCftmING COORDINATE OF STATION 1 0 0 0 0 0 0 0 ALGEBRAIC SUM TW), f a*). AND (31) (+) (Sign «iw«r« + ) 391 ?-9^i 977 C<4a sceurmtëiy sa known) IF I 'HEMISPHERE IS SOUTH, USE 07) X (4) = SECONDS OF ARC 10,COO,000.COG MINUS NORTHING (+i (Sjjn a I way a + ) COORDINATE OF STATIONj 2 3521 136 "1 1 T— 3i 336 1637 i310 o. irVt TABUUR VALUE FUNCTION I NEAREST TO AND LESS THAN VALUE IN (») ÆL 3151 356 05) X (6) = SECONDS OF ARC UTITUDE IN DEGREES AND MINUTES M (Sj^n aImaya — ) OPPOSITE VALUE INf*> 3lj. 1|0 OL 068 = TABUUR DIFFERENCE FOR 1 SECOND OPPOSITE ALGEBRAIC SUM f JOJ,f JJ), AND (54) SECONDS TASUUR VALUE OF FUNCTION I INfPJ I 30 L 801 i 99 OF ARC (Sign alwmya +) ( + ) 2 I 3521 068 TABUUR VALUE FUNCTION VI I OPPOSITE i r CONVERT (57) TO DEGREES. MINUTES. SECONDS LATITUDE IN (10) li 758 i^9 OF ARC 39 |12 i 068 TABUUR DIFFERENCE FOR 1 SECOND OPPOSITE LONGITUDE OF CENTRAL kCRIO'AN OF UTM GRID ir TABUUR VALUE Of FJNC' I ON VI I IN (17) ZONE BEING USED (Uaa tsbta) Ol 01.8 , 12 99 TABUUR VALUE FUNCT ION VI11 OPPQSITE LONGITUDE OF STATION UTMUDE IN (10) 23 I 10 98159 1 60' 000 GRAPHIC VALUE Dt -SECONDS CT ARC IF (39) IS VEST LONGITUDE AND (1) IS LESS [ujE VALUE IN STEP •- A:* ARGUMENT, ENTER THAN (3), USE (38) f (39) UPAPH AT I EFT CIDE (Sign alwmya -)j {-) 39 12 068 IF (39) IS «EST LONGITUDE AND (I) IS MORE 755 il79 IMAN(7), USE(39) - (38) f IF (39) IS EAST LONGITUDE AND (1) IS LESS 2^ f517 THAN (7), USE(39) - (38) (17) + ( 10) - APPROXIMATE LAT ITUOC OF IF (J*) IS CAST LONGITUDE AND (1) IS MORE STATION IN DEGREES. MINUTES. SECONDS THAN (7), USE (38) + (39) 3^ °'\ Tj-O 24 I517 98 "l 20 I 47 [ 932 0 1 t * Obtained from UTM Grid Tables for spheroid being usad, Volum» II. li 759 1293 (70) X (3) - SECONDS OF ARC 6 ¿30^ CONVERT On TO Ml NUI ES AND SECONDS 4 OF ARC (7) X at) -StCOHDS OF ABC OiOOO '.rest ALGEBRA ic SUM OF í IS) J(/8).(77). AND —z\—n“ z 2U (73) urilUDC OT STATION IN .HfMISPHfRl SHOWN ABCVE 34 i 40 i 18j213 19 January 1961 DA 1^6-22 Figure 16A. Entries made on DA Form 6-22 for converting UTM grid coordinates to geographic coordinates (machine). 245 COMPUTArION - CONVERSION GEOGRAPHIC COORDINATES TO UTM GRID COORDINATES (Logarithms) TT L3fp[. I TUOt OF STATION 1- ( »! atcuffty •• known) 96 23 Ifr 1830 SILL Xi ►Q' ' LCNGI GRAPHIC VALUE AK ({lëe value in Stop (J) »• a & REPEAT (Ut) © Èntar Graph at laft aide) 35 622 0, 000 NUMBER HAVING LOG (57) LOG (aaeonda) LATITUDE OF STATION LU41 SIGN OF U/)J Ö ) .033 (Vaa aaeonda part of latitude of atation ■horn at top of computation) 1, 501.5796 ALGEBRAIC SUM (56) AND (59) © 35t 589 LOG (1U) LJ^8I 3761 LOG (60) ^ 551, 3158 (19) + (20) REPEAT (10) 2, 990.1^7 8, 030, 3263 REPEAT {19) 1 501 5796 (61) f (62) 581, 6421 LOG (l6) 8, Ill 2625 REPEAT (51) (+) f 2541 606 ' 161 (22) + (23) 9 612 , 8421 NUMBER HAVING LOG (5U) 26 941 REPEAT (15) ALGEBRAIC SUM (6tt) AND (65) (+) 3! 5071 616 (Jifn al maye +) (+) 254 , 581,220 NUMBER HAVING LOG (24) -T- LOG (66) IF SIGN OF 116) IS 'fl, USE SIGN (+1 Q ^ 405 8264 IF SIGN OF 116) IS (-1, USE SIGN I-l 4— 0 ..410 REPEAT (6) ALGEBRAIC SUM (2S) AND (26) 9| 343, 4421 (St^n alvaye -t ) (f) 3Í 508. 026 (67) + (66) 4 749, 2685 LOG (27) 3, 545 0633 NUMBER HAVING LOG (63) 3 LlK-g SIGN OF I6:>J © 0 382 REPEAT (9) 8, 686 8842 REPEAT (48) Ö OOO (26) t (29) 2 231 9475 ALGEBRAIC SUM (70) AND (7l) © LOG (17) 0^ 382 0. 326 9500 NUMBER HAVING LOG (69) (+) REPEAT (12) 7, 373 7684 (BI|H atway* *) 56, 139 I 494 REPEAT (72) © (31) + (32) 0 1 382 7, 700 7184 ALGEBRAIC SUM (73) AND (7a) NUMBER HAVING LOG (33) alwaya *■) ;+) 56 , 139.876 IF SIGN OF <17> 1 S <+), USE SIGN 1+) EASTING UTM GRID COORDINATE OF STATION IF SIGN OF (1)) IS l-l, USE SIGN ('>1 0 .005 6 0 0 0 0 0 IF LONGITUDE IS E¿Sr »NO Ul IS MORE THAN Cl , USt JOC,CCC.CCC + 1751 REPEAT (10) €) 0^000 IF LONGITUDE IS EAST ANO Ul IS LESS THAN ALGEBRAIC SUM (3U) AND (3S) Û o;oo5 Cl , USE 600,CCC.CCC - (7V IF LONGITUDE IS «CST «NO Ul IS MORE THAN REPEAT (13) (+) 3 832 185 r 907 (21, USE VC,CPC.an - (7V NUMBER HAVING LOG (2l) IF LONGITUDE IS WEST «NO Ul IS LESS TH *N (St$n atwaja +) 977. 588 (2), USE VC,OCO.000 + (TV 556| 139 ■ 88 NUMBER HAVING LOG (30) (Sijn alwaya +) 170. 588 a06r«in«W /rea t/Ttf OrJd Tmbtaa tor aphtrotd boJng uaed, Volume / (37) + (38) + (39) (+) 3 833, 334 083 REPEAT (36) >r 005 SPC J DOB ALGEBRAIC SUM (ao) AND (Ul) (Sign alwaya +) 3, 833 j 334 r 088 Cpl R ROE NORTHING UTM GRID COORDINATE OF STATION f- S NORTH f f 3 8331 334 ; 0<^ 1 Feb 61 DA ,5TM 6-23 Figure 165. Entries made on DA Form 6-23 for converting geographic coordinates to UTM grid coordinates (logarithms). 246 COMPUTATION - CONVERSION GEOGRAPHIC COORDINATES TO UTM GRID COORDINATES (aAcamt) lATITUCC o • - 10»GITUCI£ 0 • CZ)t«»T SILL SU 38 3I.738 93 23 lU.33Cefcl.EST WORTH T ISCUTH I TABULAR VALUE FUNCTION IV OPPOSITE LATITUK LONGITUDE (V STATIC (*m mwrmtmij mm éIIIIMI^ (Ùmir—a, minuta») OF STATION PS I IUA 330 25b 603 1158 LONGITUDE OF CENTRAL IRIDIAN OF UTM GRID TABULAR DIFFERENCE POR 1 SECOND OPPOSITE 1 1 ZONE BEING USED 99 FUNCTION IV IN (23) O t 8U8 |8t; "1 =1 TA8UUR VALUF FUNCTION V OPPOSITE S?) IF fl} IS MIRE THAN (2), USE FO-m LAT MUDE (Dmgraaa, minutma) OF STATION IF (t) IS LESS THAN (2), USE <2>-(l) 98 123 i 1U| 830 35 i 622 (Sign mimmya *) TABULAR DIFFERENCE FOR t SECOND (♦> 0 136 i U5l 170 OPPOSITE FUNCTION V IN (24) & 0 ! 001 P3 GRAPHIC VALUE B5 CONVERT (J) TO SECONDS OF ARC 22 I 05 i 17? I lift LATITUDE (Dagrmaa, minutma) AS PftSl'— ■CN1 AT TOP OF ÛRAIH. USE VALUE IN REfCAT (4) WITH DECIMAL POINT MOVED LEFT T~ SI EP (3) AS ARGUHENT AT LEFT SIDE OF FOUR PLACES Ol 220 ! 517|0 "»J 000 ? 0| 0U8 627,7 GR4BIIC VALUE A <<•> [uSC UTITUDE rS.conUaJ OF STAXMM AS ( + 1 ARGUMENT. ENTER GRAFH AT LEFT SIOEJ 0| 010 7231 003 (33) X LATITUDE (SmcoUda) OF STATION (-) 01 002 i U i 26i 9Ul 1 r TABULAR VALUE FUNCTION I OPPOSITE (23) X LATITUDE (Smeenda) OF STATION LATITUDE (Oagrmaa. mitmtaa) OF $TATION 31 8321185 1 907 & :J0| 033 TABULAR DIFFERENCE FOR 1 SECOND T 10* ALGEBRAIC SLMT34J ANO (29) o OPPOSITE FUNCTION I IN (9) 30 1801 I 82 TABULAR VALUE FUNCTION I! OPPOSITE i r 11* LATITUDE (Orngrama, mitmfm) » STATION 315071616 o —Q—I iSg .. TABULAR DIFFERENCE FOR 1 SECOND T ALGEBRAIC SIMT»;. (37), M0(2»> 12* (♦) OPPOSITE FUNCTION II INfU> ^ 012 |Qg (tigm mimara * ) 25U i 581 j 220 TABULARVALUE FUNCTION III OPPOSITE (T\ (32) X(*) 13' (*) LAT ITUOC (Dagraaa, mimitaa) OF STATION 2 i I23 (Sign almaja * ) 56 i 135 i U87 GRAPHIC VALUE A* »uiemuc SUM(«). fJi). «RDÍJ-» IN* {jJSE VALUE IN SliP (3) AS AAGUMCNI. (O Eli.» .F..7. ♦ ) ' 1 EMTEB GRAPH AT LEFT S iPtJ 0:000 56 I 139 I 869 i EASTING UTM GRID COORDINATE OF STATION (iO) x LATITUDE (Sacaba) OF STATION [*) 0 0 0 0 0 0 IF LONGITUDE IS E»ST ANO (i) IS NOAC THAN (2), 1?77 ; 588 _i r USE SOO'OCG.OGO * (34) (12) X LATI TUCE (Smeonda) OF STATION IF LONGITUDE IS EAST AMO (1) IS LESS THAN (3), O 0 , UlO USE 9OO.OOO.CCO - (34) “T 1 IF LONGITUDE IS VEST ANO (i) IS NONE THAN (3), H \— ALGEBRAIC StMCJO ANOnO USE 900.000.CCC - (34) (Sign mimar* * ) ' ’ 3,3j 508 1j 026 IF LONGITUDE IS VEST AND (i) IS LESS THAN (3), USE 900.000.000 4 (34) 556 1 139 1 87 (*) 1170 1587 ‘OBTAINED FROM UTM GRID TABLES FOR SPHEROID BE INC USED. VOLUME I O o : 00s í ALGEBRAIC SUM (9)t(i4)t(iS).(i$), Am (29) (Siga aimara * ) SFC J DOE 8^pU j 08? NORTHING UTM GRID COGROIUTE OF STATION IF HEMISPHERE OF STATION IS NORTH, REPEAT (30) Cvl R ROE IF HEMISPHERE OF STATION IS SOUTH, USE 10,000.000.000 - (20) 3 , 833,33U l 09 1 February 1961 Font DA 1 SEP 92 6-25 Figure 166. Entries mode on DA Form 6-25 for converting geographic coordinates to UTM grid coordinates (machine). 247 CHAPTER 28 TRANSFORMATION 431. General formation of coordinates involves only the When field artillery units are operating mathematical continuation of the adjacent grid across grid zone junctions, it will frequently be to the grid being used and the subsequent cor- necessary to transform the grid coordinates of rections for locations due to the change in grid points and the grid azimuths of lines from the north reference. Although the location of grid for one zone to the grid for the adjacent point P on the ground will not be changed, the zone. Special tables are available through value of its original coordinates will change Army Map Service which permit transforma- with the transformation. The value in terms of tion across several zones in a single computa- zone 15 would be less than 100,000 meters in tion. easting and greater than 3,700,000 meters in northing. It is apparent that in transformation a. The method of transforming grid coordi- there will be a major change in the easting co- nates from a UTM zone to a UPS zone or from ordinates due to the coordinate numbering a UPS zone to a UTM zone is discussed in para- system of each zone and the change in grid graph 426. north reference, but there will be only a small b. In the UTM grid system there are overlap change in northing coordinate, based only on areas east and west of zone junctions. How- the difference in the grid north reference. ever, transformation is not restricted to these overlap areas. Grid coordinates (and azi- 432. Use of TM 5-241-2 (Formerly AMS muths) can be transformed from any point in TM No. 50) one zone into terms of an adjacent zone. To understand what transpires when transforma- a. In using TM 5-241-2 to extract the func- tion is performed, refer to figure 167. Figure tion required for the formulas used in trans- 167 shows two adjacent UTM zones, 14 and 15. formation, determine first the spheroid to be In terms of northing coordinates they are num- used. This can be accomplished by referring to bered the same, since the origin of the northing the map of the world in the back of the techni- coordinate is the Equator. However, the east- cal manual, and using it as an index to de- ing coordinates from left to right are not a termine which spheroid tables should be used. continuous series of numbers, since the origin The formulas being solved in transformation of the easting coordinate for each zone is the computations are also contained in the technical central meridian for that zone and is numbered manual. 500,000. Within each zone, the coordinates will b. The tables in TM 5-241-2 are compiled increase to the east and decrease to the west for 100,000-meter intervals of easting and nor- from the central meridian. Visualize point P thing. A station is considered to be in a in zone 14. The coordinates are (800,000- 100,000-meter square, and the coordinates of 3,700,000). If the coordinates of point P were the nearest corner of this square are used for to be transformed to the adjacent grid (zone the determination of e' and n' and for the en- 15), the action taken would be the equivalent tering arguments. of superimposing the grid of zone 15 over the c. Certain procedures must be followed to grid of zone 14 as indicated. Actually, trans- insure proper extraction from the tables. 248 UTM \ ZONE JUNCTION / 43 CM ■ 43 42 ZONE 42 ZONE 41 40 •39 38 © ■ 3,700,000 4 S00.000 6 9 3 4 500,000 6 7 ZONE 14 ZONE 15 Figure 167. Schematic drawing showing transformation requirements. (1) When transforming to the east (such to-zone universal transverse mercator grid as zone 14 to zone 15), use the e value coordinates transformation is DA Form 6-36 on the right side of the table and the (fig. 168). This form is designed for use with upper of the signs where there are a computing machine. If a computing machine two shown. is not available, multiplication is performed on (2) When transforming to the west (such a separate paper by using logarithms or direct as zone 15 to zone 14), use the e value multiplication and the results are entered in on the left side of the table and the the proper spaces. The form is executed in a lower of the signs. straight numerical sequence with the values in d. In performing the computations on DA lines 11 through 18 (N0, E0, a!, a2, blf b2, c2, and Form 6-36 and considering the initial zone to c) extracted from TM 5-241-2 for the proper be A, the resulting E and N coordinates are for spheroid. the adjacent zone B. In the Southern Hemi- b. Formulas on which the form is based, are sphere the transformed northing must be sub- shown on the back of the form. tracted from 10,000,000 to compute the correct coordinate. 434. Transformation of UTM Grid 433. Use of DA Form 6—36 Azimuth from Zone-to-Zone a. The use of forms will simplify transfor- The same reasons for transforming grid co- mation computations. The form used for zone- ordinates (par. 431) are applicáble to grid 249 ZONE TO ZONE UTM GRID COORDINATES TRANSFORMATION SILL FT SUL, OKLAHOMA 14 13 CLAREE 1866 USE ONLY FOR SOUTHERN HEMISPHERE 1 0. 00 0' . 000 3,833 1334 ,09 {5) - (6) FOR E Tien* A) 556, 139, 87 SOUTHERN HEMISPHERE + (1) TO NEAREST (6) OR (7) TO NEAREST 100,000 METERS (e) 600, 000, 00 100,000 METERS = (n) 3 i 800 , OOP iQO ALGEBRAIC SUN (6) OR (7) ALGEBRAIC SUN (l) ANO (2) ^ 431 8601 13 AND (B) i 33 1334 109 REPEAT (3) WITH DECIMAL POINT REPEAT (9)WITH DECIMAL POINT MOVED LIFT FIVE PLACES = •* ¿ o|4386013 MOVED LEFT FIVE PLACES = n* 3333409 3j 8221 297 TO? Enter AUS Technical Manual No. 50 for proper 652, 499 349 spheroid using values fron linea (2) and (8) u m 100 336 277 aa arguments. When transforming to east, 532 use (e) value on right side of table and up* è _L 5 £58 per of signs; for transforming to west, use 8 904 (e> value on left side of table and lower of A 68 056 signs. ê 037 A 261 1 I (15) 904 FALSE EASTING 800 , 000 10 (io) X (17) è 012 (12) 652, 499 349 ALGEBRAIC SUM (1R) AND (20) è 916 (10) * (36) é 1, 992 486 (4) X (18) CHANGE (u) * (32) SIGN OF RESULT 114 43, 993 263 ALGEBRAIC SUM n ALGEBRAIC SUN (2l) AND (22) è 802 (37), (38), (39). AND (»0) (16) A 68 056 1, 106, 513 600 (10) X (181 e 087 tu) 3 i 822, 297 707 (») * (17) 10 016 (10) X (32) 33, 435 272 ALGEBRAIC SUN (2“). (25). ALGEBRAIC SUM AND (26) 67 951 («2) AND (43) 3 i 855, 732 979 (4) X (36) CHANGE f- (13) 1001 336 277 SIGN OF RESULT è 2, 621 662 ALGEBRAIC SUM (10) X (23) é 934 (44) ANO (45) ALGEBRAIC SUM (28) AND (29) 100 ! 333 343 3 , 853 , HI 317 (4) X (27) CHANGE T USE ONLY FOR 10, 000 ,000 SIGN OF RESULT A 21 804 SOUTHERN HEMISPHERE 92 ALGEBRAIC SUM (30) AND (3l) 100, 303 539 REPEAT (»6) (47) - (48) FOR SOUTHERN (11) A 5 1958 532 HEMISPHERE N (Zotti B) (10) X (27) ê Ï 652 (4) X (23) 861 i 1— ALGEBRAIC SUM (33). (31). ANO (35) è i 5 977 323 SFC J DOB Cpl R ROE 1 Feb 1961 DA, Ts» 6-36 Figure 168. Completed DA Form 6S6. azimuths, and the same reference tables, 436. Transformation of Coordinates for TM 5-241-2, are employed for the extractions Fourth-Order Surveys of functions. To understand what transpires For fourth-order surveys, the steps in trans- when transformation of azimuth takes place, forming the coordinates of points after having refer again to figure 167. On the UTM zone to obtained the transformed coordinates of one the left (zone 14), a line of direction has been point and the azimuth transformation correc- indicated. The azimuth of this line is repre- tion are as follows: sented by a horizontal clockwise angle from the a. Compute the azimuth and grid distance grid north for zone 14. If the azimuth of that between the point which has been transformed line is transformed to the grid of the adjacent and the point which is being transformed, zone (zone 15), the line of direction does not using for both points the old zone coordinates. change; however, due to a new grid north ref- b. Transform the computed azimuth by erence line, the azimuth of the line will in- algebraically adding the azimuth transforma- crease. From this figure, in transforming tion correction. azimuth from a west zone to an east zone, the c. Transform the computed grid distance by azimuth will increase; conversely, in trans- dividing it by the scale factor for the old zone forming azimuth from an east zone to a west and multiplying it by the scale factor for the zone, azimuth will decrease. new zone. d. Compute the differences in easting and 435. DA Form 6—34 northing between the transformed point and the point which is being transformed, using a. DA Form 6-34 is used for zone-to-zone the transformed azimuth (b above) and the UTM grid azimuth transformation (fig. 169). transformed distance (c above). This form, which is similar to DA Form 6-36, e. Apply the differences in easting and also was designed for use with a computing northing to the transformed coordinates of machine. The same procedure as used with DA the point which has been transformed. Form 6-36 is used with this form if a com- puting machine is not available. Also, values 437. Transformation of Coordinates for for lines 11 through 17 (a!, a2, bi, b2, clt and Fifth-Order Surveys c2) are extracted directly from TM 5-241-2, For fifth-order surveys it is not necessary to using the tables for the proper spheroid. transform the grid distance. The grid distance b. Formulas on which the form is based, are for the old zone can be used to compute the shown on the back of the form. differences in easting and northing. 251 ZONE TO ZONE UTM GRID AZIMUTH TRANSFORMATION SILL FT SILL, OKLAHOMA FROM ZONE A 14 13 CIARES 1866 USE ONLY FOR SOUTHERN AZIMUTH TO BE HEMISPHERE 1 O I O 0 o I OOP I o o TRANSFORMED FROM ZONE A TO ZONE 0= T, 42 i 17 13 3 . 833 ,334 ,09 —i——i (6) - (7) FOR . 556, 139,8? SOUTHERN HEMISPHERE 4- (Z) TO NEAREST (7) OR (S) TO NEAREST 100,000 METERS = (•) 100,000 METERS =(ll) 600 ! OOP i 00 3 | 800 |000 |00 ALGEBRAIC SUM ALGEBRAC SUM (2) AND (3) »3 1 860,13 (7) OR (8) AND (9) 33 1334 |09 REPEAT (U) WITH REPEAT (10) WITH T DECIMAL POINT MOVED X DECIMAL POINT MOVED LEFT FIVE PLACES = •» 0 » i 4386013 LEFT FIVE PLACES = n* »13333409 i r Enter AMS Technical Manual No. SO for proper I 100 [336 22Z. spheroid using values from Lines (3> and (9) $ 5 1958 532 as arguments. When transforming to east, use (e) value on right side of table and upper 8 90» of signs; for transforming to vest, use (e) à 168 056. value on left side of table and lower of 037 signs. 261 T (1») X 2 » (13) 17 808 è I 5,958 532 (11) X (16) X 3 99 (11) X (26) £ j_a 039 »5 269 ALGEBRAIC SUM (5) X (22) e (18) AND (19) 17 8»7 J_Z. 678 (5) X (17) X 3. ALGEBRAIC SUM 9 « CHANGE SIGN OF RESULT 3»2 (32), (33), ANO (3N) è 5 1996 123 ALGEBRAIC SUM 21 (20) AND (21) 17 505 10 0 0 0 0 0 0 0 (15) X 2 136, 112 LOG (31) 001 I 1710 (11) X (17) X 3 261 (36) - (37) 998 , 8290 (5) X (16) X 3 9 048 LOG (35) 777 18703 ALGEBRAIC SUM , (38) + (3») (23). (20). AND (25) $ 135, 803 8i 776 ,6993 ANGLE WHOSE LOG TAN IS . IT (12) 100 336 277 (40), u$E SIGN OF (35) § 25 20 (11) * (22) di J21 42 17 13 ALGEBRAIC SUM REPEAT (91), CHANGE SIGN , (27) AND (26) 100 330 442 FOR SOUTHERN HEMISPHERE O 25 20 (5) X (26) CHANGE ALGEBRAIC SUM (»2) AND («3) SIGN OF RESULT 59 563 ALGEBRAIC SUM AZIMUTH (Un* B) 91 (29) AND (30) 100 270, 879 38 51 53 SFC J DOE Cpl R ROE 1 Feb 1961 DA”" 6-34 Figure 169. Completed DA Form 6S4, 252 » APPENDIX I REFERENCES 1. Miscellaneous Publications AR 117-5 Military Mapping and Surveying. AR 220-50 Regiments; General Provisions. AR 220-60 Battalions—Battle Groups—Squadrons—General Provisions. AR 220-70 Companies—General Provisions. AR 320-5 Dictionary of United States Army Terms. AR 320-50 Authorized Abbreviations and Brevity Codes. DA Pam 108-1 Index of Army Motion Pictures, Film Strips, Slides, and Phono- Recordings. DA Pam 310-series Military Publications Indexes (as applicable). FM 6-18 Mortar Battery, Airborne Division, Battle Group. FM 6-20 Field Artillery Tactics and Techniques. FM 6-21 Division Artillery. FM 6-40 Field Artillery Cannon Gunnery. » FM 6-120 The Field Artillery Observation Battalion and Batteries. FM 6-135 Adjustment of Artillery Fire by the Combat Soldier. FM 21-5 Military Training. FM 21-6 Techniques of Military Instruction. FM 21-26 Map Reading. FM 21-30 Military Symbols, FM 21-31 Topographic Symbols. FM 30-5 Combat Intelligence. FM 44-1 Air Defense Artillery Employment. FM 44-2 Light Antiaircraft Artillery (Automatic Weapons). FM 44-4 Medium and Heavy Antiaircraft Artillery. FM 57-100 The Airborne Division. TM 5-231 Mapping Functions of the Corps of Engineers. TM 5-232 Elements of Surveying. TM 5-234 Topographic Surveying. TM 5-236 Surveying Tables and Graphs. TM 5-241 The Universal Grid Systems. TM 5-241-1 Grids and Grid References. TM 5-241-2 Universal Transverse Mercator Grid, Zone-to-Zone Transformation Tables. TM 5-241-3/1 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80°; International Spheroid (meters) Volume I, Transformation of Co- ordinates from Geographic to Grid. 253 TM 5-241-3/2 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80°; International Spheroid (meters) Volume II, Transformation of Co- ordinates from Grid to Geographic. TM 5-241-4/1 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80° ; Clarke 1866 Spheroid (meters) Volume I, Transformation of Co- ordinates from Geographic to Grid. TM 5-241-4/2 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80° ; Clarke 1866 spheroid (meters) Volume II, Transformation of Co- ordinates from Grid to Geographic. TM 5-241-5/1 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80° ; Bessel Spheroid (meters) Volume I, Transformation of Coordinates from Geographic to Grid. TM 5-241-5/2 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80° ; Bessel Spheroid (meters) Volume II, Transformation of Coordinates from Grid to Geographic. TM 5-241-6/1 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80° ; Clarke 1880 Spheroid (meters) Volume I, Transformation of co- ordinates from Geographic to Grid. TM 5-241-6/2 Universal Transverse Mercator Grid Tables for Latitudes 0° — 80°; Clarke 1880 Spheroid (meters) Volume I, Transformation of Co- ordinates from Grid to Geographic. TM 5-241-7 Universal Transverse Mercator Grid Tables for Latitudes 0° — 45° ; Everest Spheroid (meters), Transformation of Coordinates from Geographic to Grid and from Grid to Geographic. TM 5-241-8 Universal Transverse Mercator Grid. TM 5-241-9 Universal Polar Stereographic Grid Tables for Latitudes 79° 30' — 90° ; International Spheroid (meters), Transformation of Coordinates from Geographic to Grid and from Grid to Geographic. TM 5-6675-200-15 Theodolite: Directional 5.9 In. LG Telescope; Detachable Tribrach, W/Accessories and Tripod (Wild Heerbrugg Model T-16) ESN 6675-542-1683. TM 5-6675-213-12 Theodolite, Directional, 1 Sec, Graduation 5.9 In. Length Telescope, W/Tripod, Carrying Case and Accessories, Wild Heerbrugg Instru- ments, Inc., Model T-2, S/N Ranges 5602 through 17897 and 27235 through 30594 (ESN 6675-232-8972) T-2 Model S/N Ranges 50892 through 55124 (ESN 6675-587-3767). TM 5-9421 Surveying Altimeters, Wallace & Tiernan Models FA-112, FA-113, and FA-181. TM 6-230 Logarithmic and Mathematical Tables. TM 6-240 Rule, Slide, Military, Field Artillery, with Case, 10-inch. TM 6-300-(61) Army Ephemeris, 1961. TB ENG 23 Use of the Tellurometer in Military Surveying. Tellurometer Handbook, Tellurometer (PTV) Ltd, Cape Town, South Africa (issued with each unit). Instruction Manual, EM 2171, for Able (Surveying Instrument, Azi- muth, Gyro Artillery) Model XCZA System with Modified Electronic Package, Autonetics, North American Aviation, Inc. 2. DA Forms 5- 1Field39 Record and Computations-Tellurometer. 6- 1Computation—Azimuth and Distance from Coordinates. 254 6-2 Computation—Coordinates and Height from Azimuth, Distance, and Vertical Angle. 6-2b Computation—Trigonometric Heights. 6-5 Record—Survey Control Point. 6-7a Computation, Plane Triangle, Using Three Sides. 6-8 Computation—Plane Triangle Coordinates and Height from One Side, Three Angles and Vertical Angles. 6-10 Computation—Astronomic Azimuth by Hour-Angle Method, Sun. 6-10a Computation—Astronomic Azimuth by Hour-Angle Method, Star. 6-11 Computation—Astronomic Azimuth by Altitude Method, Sun or Star. 6-18 Computation—Coordinates and Height from Two-Point Resection. 6-19 Computation—Coordinates and Height from Three-Point Resection. 6-20 Computation—Convergence (Astronomic Azimuth to UTM Grid Azimuth). 6-21 Computation and Instructions for Use with Star Identifier. 6-22 Computation—Conversion UTM Grid Coordinates to Geographic Coordinates (Machine). 6-23 Computation—Conversion Geographic Coordinates to UTM Grid Coordinates (Logarithms). 6-25 Computation—Conversion Geographic Coordinates to UTM Grid Coordinates (Machine). 6-26 Observing Record and Preliminary Computation—Altimétrie Height. 6-27 Computation—Altimétrie Height (Single-Base or Leapfrog Method). 6-34 Zone to Zone UTM Grid Azimuth Transformation. 6-36 Zone to Zone UTM Grid Coordinates. 3. Other U.S. Government Publications Special Publication No. 237, Manual of (Available from The Superintendent of Doc- Geodetic Triangulation. uments, U.S. Government Printing Office, b. Department of the Navy. Washington 25, D.C.) Naval Observatory: American Ephemeris a. Department of Commerce. and Nautical Almanac (published Coast and Geodetic Survey: Special Publi- annually). cation No. 225, Manual of Reconnais- sance for Triangulation. Air Almanac (published annually). Hydro- Special Publication No. 234, Signal Build- graphic Office: H. O. No. 205, Radio ing. Time Signals (Current Series). 255 APPENDIX II i SURVEY TECHNIQUES TRAVERSE Fourth order (1:3000) Fifth order (1:1000) 1:500 T2 Theodolite T2 Theodolite Steel tape and Steel tape and Steel tape and Steel tape and Requirement 1-second 0.002 mil T2 Theodolite T16 Theodolite transit (1-minute M2 aiming (1-second) (0.2 mil) or 20-second) circle Traverse yes yes yes yes yes yes closed On second preferred preferred preferred preferred preferred preferred known point On starting acceptable acceptable acceptable acceptable acceptable acceptable point Traverse yes yes adjusted Closing error 1:3000 1:3000 1:1000 1:1000 1:1000 1:500 in position not to exceed Allowable 0.02 mil 15" 0.1 mil 15" 0.5 mil error in azi- muth per main scheme angle Initial circle 0°00'30" ± 20" 0.150( ±0.10 0°00'30" ± 20" 1.0 mil NA NA settings mil). Horizontal 1 postion 1 postion 1 position 1 position 1 D/R 2 repetitions angles Vertical 1 D/R to HI 1 D/R to HI 1 D/R to HI 1 D/R to HI 1 D/R to HI 2 readings angles Distance tellu- 2 coarse, 2 coarse, single taped single taped single taped single taped rometer) 4 fine 4 fine checked by checked by checked by checked by Distance (steel double taped double taped pacing pacing pacing pacing tape) 1:5000 1:5000. Scale factor yes yes Log tables Vega TM 6-230 Vega TM 6-230 Vega TM 6-230 (7-place) Bearing angles 10" .01 mil 10" 0.1 mil 10" 0.1 mil E and N 0.01 m 0.01 m 0.1 m 0.1 m 0.1 m 0.1 m carried to H carried to 0.1 m 0.1 m 0.1 m 0.1 m 0.1 m 0.1 m Horiztonal and 0.001 mil 1" 0.1 mil 1" 0.1 mil vertical angles re- corded to Vertical angles 10" 0.01 mil 10" 0.1 mil 30" 0.1 mil used to nearest Azimuth 1" 0.001 mil 1" 0.1 mil 1" 0.1 mil carried to 256 < TRIANGULATION—INTERSECTION—RESECTION Fourth order (1:3000) Fifth order (1:1000) 1:500 T2 Theodolite T2 Theodolite Steel tape and Steel tape and Steel tape and Steel tape and Requirement 1-second 0.002 mil T2 Theodolite T16 Theodolite transit M2 aiming (T2) (T2) (1-sec) (0.2 mil) (1 min and 20 sec) circle Closed (tied to yes yes yes yes yes yes existing control) Adjusted yes yes no no no Closing error 1:3000 1:3000 1:1000 1:1000 1:1000 1:500 in postion not to exceed Allowable 5" 0.02 mil 15" 0.1 mil 15" 0.5 mil error in azimuth per main scheme angle Initial circle 0°00'30" ±20" 0.150 0°00’30" ±20" 1.0 mil NA NA settings 270°00'30" ± 20" ( ± 0.10 mil) 4800.150 (±0.10 mil) Horizontal 2 positions 2 positions 1 position 1 position 1 D/R 2 repetitions angles Vertical 1 D/R to HI 1 D/R to HI 1 D/R to HI 1 D/R to HI 1 D/R to HI 2 readings to angles HI Distances double tape to double tape to double taped double taped double taped double taped 1:7000 or 1:7000 or 1:3000 1:3000 1:3000 1:3000 with tellu- with tellu- rometer. rometer. Scale factor yes yes no no Log tables Vega TM 6-230 Vega TM 6-230 Vega TM 6-230 (7 place) Bearing angles 1" 0.01 mil 1" 0.1 mil 0.1 mil E and N 0.01 m 0.01 m 0.1 m 0.1 m 0.1 m 0.1 m carried to H carried to 0.1 m 0.1 m 0.1 m 0.1 m 0.1 m 0.1 m Horizontal and 0.001 mil 0.1 mil 1" 0.1 mil vertical angles recorded to Vertical angles 0.01 mil 0.1 mil 30" 0.1 mil used to nearest Azimuth 1" 0.001 mil 1" 0.1 mil 0.1 mil carried to 0 Minimum dis- 22 Va“ 400 mils 22 V2 400 mils 22V2° 400 mils tance angles pref 30° pref 533 mils pref 30° pref 533 mils pref 30° pref 533 mils Minimum apex NA NA NA 150 mils NA 150 mils angle tgt area inter- section Triangle Average for Average for : 30" ±0.3 mils ±30" ±1.0 mil closure. scheme 12", scheme 0.05 max for tri- mil max for angle 15" triangle 0.06 mil 257 ASTRONOMIC OBSERVATIONS Founh order Fifth order 1-second 0.002 mil 1-second 0.2 mil 1-min or Aiming Requirement Theodolite Theodolite Theodolite Theodolite 20-sec circle* *Specifications apply for determining a fifth-order azimuth. If the direction is not to be extended from the line established by the observation, the rejection limit can be relaxed to 1.0 mil with a considered accuracy of 1.0 mit 258 APPENDIX III DUTIES OF SURVEY PERSONNEL 1. Survey Officer c. Orients party members on the survey plan. The survey officer— d. Supervises and coordinates the field opera- a. Coordinates and supervises training of tion of his survey party. survey personnel. e. Maintains liaison with the survey officer ft. Coordinates, supervises, and emphasizes or chief surveyor during field operations. the preventive maintenance program on survey /. «Supervises preventive maintenance on equipment. section equipment, to include vehicles and com- c. Coordinates, supervises, and establishes munications equipment. the survey information center (when the SIC g. Performs other duties as directed. is authorized at his echelon). d. Accompanies the commander on recon- 4. Chief Survey Computer naissance. The chief survey computer— e. Formulates and implements the survey a. Acts as principal assistant to chief of sur- plans. vey party and is capable of performing the /. Supervises and coordinates the field opera- duties of the chief of survey party. tion of survey parties under his jurisdiction. h. Maintains a stock of all required DA g. Advises the commander and staff on sur- forms for computation of surveys. vey matters. c. Supervises and assists in training mem- h. Coordinates survey operations with sur- bers of the survey party to perform survey vey officers of higher, lower, and adjacent computations. headquarters. d. Performs survey computations independ- 2. Chief Surveyor (Surveyor) ently during field operations. The chief surveyor (surveyor)— e. Actively supervises the other survey com- a. Acts as principal assistant to the survey puter during field operations. officer and when directed performs any or all /. Insures that all computations are checked of the duties of the survey officer. for accuracy. h. Supervises survey personnel in perform- g. Performs other duties as directed. ance of routine reconnaissance, communica- tions, and survey activities. 5. Survey Computer c. Performs other duties àsThe directed. survey computer— 3. Chief of Survey Party a. Assists the chief survey computer in the The chief of survey party— maintenance of required DA forms for com- a. Trains the survey party for which he is putation of surveys. the chief. h. Performs computations independently h. Implements his party’s portion of the sur- during field operations. vey plan. c. Performs other duties as directed. 259 6. Instrument Operator e. Checks taped distances by pacing. The instrument operator— /. Provides required field data to the chief a. Performs preventive maintenance on the survey computer and survey computer inde- authorized instruments. pendently. g. Performs other duties as directed. b. Operates the instrument during field oper- ations. 8. Tapeman c. Verifies vertical alinement of the range The tapeman— pole before measuring angles during field a. Maintains the fire control set, artillery operations. survey third (fourth) order. d. Reads measured values to the recorder and b. Tapes distances using proper taping tech- checks the recorder’s operation by use of a niques during field operations. read-back technique. c. Computes an accuracy ratio for taped dis- e. Familiarizes himself with fieldwork re- tance when required. quirements for all survey methods. d. Reports measured distances to the re- f. Assists tapeman in maintaining alinement corder. during taping operations. e. Operates and maintains section radio g. Performs other duties as directed. equipment. /. Performs other duties as directed. 7. Recorder Note. Rear tapeman commands the taping team. The recorder— a. Maintains an approved notebook (level, 9. Rodman transit, and general survey record book, DA The rodman— Form 6-72, or book transit, or field book) a. Maintains station marking equipment. record of all surveys performed by the survey b. Marks stations with hub and witness stake party. during field operations. b. Records survey starting data and all c. Centers and plumbs survey range poles measured data with a 4-H pencil in a neat and over survey stations as required during field legible manner during field operations. operations. c. Sketches, in the approved notebook, com- d. Assists the tapeman in maintaining aline- plete descriptions of principal stations occupied ment of the tape. during field survey operations. e. Operates and maintains section radio d. Checks, means, and adjusts angular data equipment. measured by the instrument operator. /. Performs other duties as directed. 260 INDEX Paragraphs Page A vernier, use 73, 74 34 Accessories : Aiming circle M2 52 22 Altimeter 183 95 Azimuth gyro surveying instrument 175 91 Survey 17,19-26 8,9 Taping 17, 27 8,10 Target set, surveying 166 89 Tellurometer 139 67 Theodolite, T2 108 54 Theodolite, T16 88 45 Transit 68 30 Accidental errors 46, 48 17 Accuracy: 6 4 Astronomic observation 387, 417 216, 236 Comparative, of taped distances 45 17 General 6 4 Intersection 265, 266 165 Observation battalion survey 300 179 Ratio, traverse 227 141 Resection 263 162 Traverse 211 129 Triangulation 238 147 Trilatération 268 165 Adjustment : Aiming circle 66 28 Angles, for horizon closure 77 38 Angles, for triangle closure 247 149 Theodolite, T2 108 54 Theodolite T16 102-107 51 Transit 82-87 41 Traverse (azimuth, coordinates and height) 231-233 143 Aiming qircle M2, Accessories 52 22 Care and adjustment 65, 66 28 Checking level line 66 28 Checking level vial(s) 66 28 Components 51 18 Declination 59-62 25 Scales 51 18 Leveling 54 23 Measuring: Grid azimuths, with 64 27 Horizontal angles 56 24 Vertical angles 57 24 Moving 67 29 Reading scales 51 18 Setting up 53 23 261 Paragraphs Page Aiming circle M2—Continued Taking down 55 24 Testing 66 28 Í Air Force installation, survey 13 6 Alidade 68 30 Alinement, tape 41 14 Altimeter, surveying: Care and maintenance 186 98 Comparison adjustment 191 100 Description 183 95 General 182 95 Individual instrument temperature correction 190 99 Latitude correction Principles of operation 182 95 Reading the scales 188 99 Relative humidity and air temperature correction 192 100 Altimetry : Computations 194.195 104 Forms 194.195 104 Methods 187 98 Leapfrog 195 104 Single-base (one-base) 194 104 Altitude 355, 373 199, 212 Altitude method of astronomic observation 372-392, 416 212, 235 Angle : Azimuth 362, 364 204 Mean 56, 57 24 Angles : Astronomic observation 362-365 204 377-379 213 i 395-398 223 Determining with theodolite, (See Theodolite.) Distance 242, 245, 254 148,154 Horizontal 56 24 Measuring with: Aiming circle. (See Aiming circle.) Transit. (See Transit.) Orienting 284 170 Vertical 57, 223, 249 24,134,152 Air defense artillery survey: AW battalions (batteries) 322, 323 190 General 14, 320 6.189 Gun battalions (batteries) 321 189 Missile battalions 325, 326 191 Mission 14, 320 6.189 Surveillance radars 324 191 Army Map Service technical manual (AMS TM) (See TM 5-241.) Assumed data 274, 419, 424 167, 238, 242 Astronomic observations : Accuracy 387, 417 216, 236 app II 256 Azimuth : Checks and improvement 388 217 262 4 Paragraphs Page Astronomic observations—Continued Conversion 392 220 Choice of celestial body 418 236 Comparison of methods 412-418 234 Computations 390-392, 217 404-407 224 Determining field data 376- 213 385, 395-403 223 Limitations 389, 415 217, 234 416 235 Measuring angles 377- 213 379, 379-399 213 Records of field data 206 112 Required field data 374, 394, 414 212,234 Star identification 367-371 207 Techniques 387, 388, 403, 417, app II 216,224, 236, 256 Temperature 382 216 Time 356-361, 380, 381, 399 200, 215, 224 Astronomic triangle (PZS) 362-366, 413, 415, 416 204, 234 Autumnal equinox 353 198 Azimuth : Adjustment 231 143 Computed from coordinates 225,226 134 Conversion 419-424 238 Corrections, 1:3,000 traverse 229,231 142 Determined by astronomic observation. (See Astronomic observations.) Grid 58, 61, 64, 307, 392, 407 25, 27,182, 220, 225 Mark 291 173 Transformation 431-437 248 True 390, 392 217 Azimuth Gyro Surveying Instrument: Description 176 91 Setting up 177 92 Operation 178,179 92, 93 Maintenance 181 94 Base: Intersection 265, 266 165 Resection, one-point 261-263 162 Target area 290, 294 173 Triangulation 237-250 147 Basic survey operations 5 4 Battalion and battery, observation. (See target acquisition.) Battalion and battery survey, air defense artillery. (See Air defense artillery survey.) Battalion and battery survey, field artillery: Alternate positions 281 169 Assumed data 274 167 Astronomic observation 277 168 Connection survey 278, 288 168,173 289 Converting to higher echelon grid 275 168 General 271 167 Operations 271-294 167 Divisions 278 168 Sequence 279 169 When time is limited 282/ 169 263 Paragraphs Page Battalion and battery survey, field artillery—Continued Position area survey 278, 283-287 168,170 Searchlight 280 169 4 Survey control 272-275 167 Methods 276 168 Points 12,13 6,167 273, 274 Target area: Survey 290-294 173 Battalion group 318 188 Battery center 284 170 Bearing 217-219 131 Blunders 49 17 Breaking tape 33 12 Celestial : Bodies 355 199 Pointings 378-379, 396-398 213, 223 Simultaneous observations 408, 409 230 Equator 353 198 Meridian 353 198 Sphere 353 198 Triangle 362-366, 413,415,416 204-207, 234, 235 Central-point figures 241 148 Chain of triangles 237, 240 147,148 241 Changes to survey plan 346 195 Chart, star 368 207 Chief of party 209 128 Clamping handle 17, 23, 42 8,15 Closed traverse 208 127 4 Closure : Horizon 77 38 Triangle 247 149 Coarse alinement 178 92 Coarse readings 143,154 72,81 Coast and Geodetic Survey publications app I 253 Collimation adjustments: Theodolite 129,130 64 Transit 85, 86 42, 43 Commander’s instructions 327, 328, 348 192,195 Common grid 320, 409, 419, 424 189, 230, 238, 242 Comparative accuracy of taped distances 45 17 Computations : Altimetry 194,195 104 Astronomic observations 390-392, 404, 407 217, 220, 224, 225 Coordinates 218-222, 240-250, 255, 260, 262-270 132,134,148,153,159,162,165 Declination constant 58-62 25, 26 Intersection 267 165 Quadrilaterals 255 154 Resection 260, 262 162 Traverse 218-233 132,134 Triangulation 240-250 148,153 Computers 209 128 Connection survey 288, 289 173 Constant, declination 58-62 25, 26 264 « Paragraphs Page Control : Point, survey (SCP) 12,13 6,167,183,184,188 272-274 309, 311, 317 Starting 293 174 Survey 10-14 5, 6,167,177,184, 238, 242 272, 298 312, 314 419, 424 Convergence 392 220 Conversion: Coordinates. (See also Coordinates, con- version.) : Geographic to grid 425-427 243, 244 429, 430 Grid to geographic 425—428 243, 244 Feet to meters 222 134 Survey control 419—424 238, 242 To higher echelon control 275 168 True azimuth to grid azimuth 392 220 Converting data 275 168 Coordinates: Adjustments 232 143 Computations 218-222, 240-248, 132,134,148,152,154,162 255, 260,262 Conversion 419-430 238, 244 Geographic 352, 383 197, 216 Grid 384 216 Transformation 431-437 248, 251 Coordination 10,11 5 Corps artillery survey. (See Target acquisition battalion survey.) Corrections, altimetry 189-192 99,100,128 Critical points 209, 290, 292 128,173,174 DA Forms (See Forms, DA.) Data, assumed 274, 419, 424 167, 238, 242 Data, starting 212 130 Declination 355 199 Aiming circle 58-60 25.26 Constant 58-60 25.26 Station 12,13 5 Department of Commerce publications app I 253 Department of Navy publications appl 253 Diagonals in quadrilaterals 241 148 Direction, transmission of 408-411 230, 232 Directional traverse 208 127 Distance: Angles 242, 245, 254 148,149,154 Computed from coordinates 224, 225 134 Computed from tellurometer measurement _ 151-158 78, 83 Conversion, ground to map 221 134 Division artillery survey: Accuracy 295 177' General 295 177 Operations 12, 298 5,177 Personnel 296 177 Responsibility 12 5 265 Paragraphs Page Division artillery survey:—Continued SIC 297 177 Survey control 298 177 Earth 352 197 Easting 218, 219 132, 133, 134 222 Engineer survey responsibilities 9 5 Error (s) : Accidental 46, 48 17 Caused by blunders 46, 49 17 Of closure, height 220, 233 133, 144 Systematic 46, 47 17 Taping 46—49 17 Traverse 227 141 Triangle closure 347 195 Execution of survey plan 347 195 Factor, scale 221 134 Factors affecting survey planning 329 193 Field Artillery (FA) : Battalion and battery. (See Battalion and battery survey.) Battalion-group. (See Battalion-group.) Group. (See Group, field artillery.) Missile commands. (See Missile commands.) Target acquisition battalion. (See Target Acquisition.) Field notes: Astronomic observation 206 112 General 197 110 Intersection 200 111 Notebook 197 110 Resection 201 111 Traverse 198 111 Triangulation 199 111 Trilatération 204 111 Fifth order 6, 211 4,219,256 app II Figures, strength 253 154 Fine alinement 179 93 Fine readings 144,150 72, 77, 81 153 Flash ranging observation post 13, 315 6,187 Focusing: Aiming circle M2 50 18 Theodolite, T-2 113 56 Theodolite, T-16 94 48 Transit 72 34 Forms, DA app I 253 5- 139 150-158 77, 83 6- 1 226 141 6-2 222, 224, 231 134,143 6-2b 224, 249 134,152 6-5 297,301 177,179 6-7a 269 165 6-8 248, 255, 267 152,154,165 6-10 404, 405, 407 224 6-10a 404, 406, 407 224 Paragraphs Page Forms, DA—Continued k 6-11 391 217 F 6-18 262 162 6-19 260 162 6-20 392, 407 220, 225 6-21 371 208 6-22 428 244 6-23 429 193 6-25 430 244 6-27 194.195 104 6-34 435 251 6-36 433 249 Forward : Line 250 153 Station 30-56 213 130 Fourth order 6,211 4,129,256 app II Geographic coordinates 352, 391, 425-430 197, 217, 243, 244 Conversion to grid coordinates 425-430 243, 244 Grid 8, 419 5, 238 Azimuth 58, 61, 64, 306, 392, 407 25, 26, 27, 182, 220, 225 Common 8, 320, 419-424 5, 189, 238, 242 Convergence 392 220 Sliding the 421, 424 239, 242 Swinging the 423, 424 241, 242 Grids, FA 419 238 Ground reconnaissance 339, 342 194 Group, field artillery 316, 317 188 > Hand level 17, 24, 41 8, 9,14 Handle, tension 17, 33, 42 8,12,15 Height: Adjustment 229, 233 142.144 Computations : Altimétrie 194.195 104 421 423 239 241 Difference in (dH) ’ 220 133 Error of closure of 220, 233 133.144 Of instrument (HI) 57 24 Trigonometric: Intersection 267 165 Resection 260, 262 162 Traverse 220-224 133,134 Triangulation 248 152 HI. (See Height of instrument (HI).) Horizon closure 77 38 Horizontal angles 56 24 Determining with theodolite. (See The- odolite.) Measuring with: Aiming circle. (See Aiming circle M2) Transit. (See Transit.) Horizontal scales. (See Scales, reading.) Horizontal taping ; 30-44 10,16 Hour-angle method of astronomic observation — 393, 407, 415 223, 225, 234 » 267 Paragraphs Page Hour circle 352 197 Hydrographic Office publications app I 253 4 Identifier, star 370, 371 208 Instrument: Height 57 24 Operator 209, app III 128, 259 Instruments survey 16,18 8 Intersection 237, 264-267 147,165 Accuracy 265, 266 165 Computations 267 165 •Definition 237 147 Field Notes 200 111 Limitations 266 165 Techniques 265 165 Known datum point (KDP) 321 189 Latitude, parallels 352 197- Law of sines 240 148 Leapfrog altimetry 187,195 98,104 Legs 207 127 Lenses, care 65, 80,123 25, 41, 61 Level : For level rod 17, 26 8,9 Hand. (See Hand level.) Plate. (See Plate levels.) Leveling: Altimétrie. (See also Altimetry.) 187 98 The aiming circle M2 53 23 The theodolite 92,112 47, 56 The transit 71 33 Trigonometric 249, 255 152,154 Í Lights used on ranging pole 214 130 List, trig 9, 297 5,177,179 301 Logarithmic tables 17,19 8 Longitude, meridians : 352 197 Magnetic: Needle 51, 58—64 18, 25, 27 Objects affecting 60 26 North 58, 59 25 Mains converter 139 67 Map reconnaissance : 339, 341 194 Mark, azimuth 391 217 Mean angle 56, 57 24 Measuring: Angles. (See Angles.) Distances. (See Taping.) Mercator projection. (See Projections, map.) Meridians of longitude 352 200 Meteorological station, survey 12,13 6 Methods, survey, use 276 168 Military slide rule 17,19 8 Missile command survey: Air transportable 319 189 Medium 318 188 268 « Paragraphs Pag© Mission, air defense artillery 14, 320 6,189 Mission, survey 8 5 Nadir 354 199 Naval Observatory publications app I 253 Night : Lights used with ranging pole 214 130 Taping 39 14 Northing, difference in (dN) 218, 219, 222 132, 133, 134 Notebook. (See Field notes.) Notes, field. (See Field notes.) Observation : Astronomic. (See Astronomic observations.) Post(s) 292 174 Target area : Azimuth mark 291 173 Definition 291 173 .Selection 292 174 Observer’s position 354 199 Occupied station 37, 213 13, 130 Open traverse 208 127 One-point resection. (See Resection.) One-base (single-base) altimetry 194 104 Operator, instrument 209, app III 128, 259 Orienting: Angle 284 170 Line 11, 284 5, 170 Point radar 284 170 Station 284 170 Parallax 72,109, 373 34,55,212 Parallels of latitude 352 197 Party, traverse 209 128 Pins, taping. (See Taping pins.) Plan, survey. (See Survey plan.) Planning, survey. (See Survey planning.) Plate levels 68, 71, 83, 88, 92, 103,108,126,169 30, 33, 42, 45, 47, 51, 54, 63, 89 Plumb bob 17, 20, 27, 31, 43 8, 9, 10, 11, 16 Used in taping 31, 32, 35, 37, 43, 44 11, 12, 13, 16 Used with aiming circle M2 53 23 Used with theodolite 1 88,91,108,111 45, 47, 54, 56 Used with transit 69, 70 33 Pointings 56, 77, 98, 120 24, 38, 49, 58 On celestiaL bodies 378, 379 213 Pole, ranging __1 25, 214 9,130 Tripod 26 9 Poles, north and south celestial 353 198 Position : Area survey 278, 283-287 168,170 Taken with theodolite. (See Theodolite.) Prescribed accuracy. (See Accuracy.) Psychrometer 182,184, 192 95, 97 100 Publications . app I 253 PZS triangle 362-365, 413,415,416 204, 234, 235 269 Paragraphs Page Quadrants 218,219 132 Quadrilaterals 250-256 153 R1 and R2 chains 253-255 154 Radar: Orienting point 284 170 Surveying 11, 13,287, 313 5,6,171,184 Radio time signals 399 224 Range-calibrating point, radar (ADA) 14, 321 6,189 Ranging pole 25, 214 9,130 Tripod 26 9 Ratio, accuracy, traverse 227 141 Rear station 30, 213 10,130 Reciprocal measurements of vertical angles 223, 249 134,152 Reconnaissance 341, 342 194 Triangulation 276 168 Recorder. (See also Recording.) 197,198, 209, app III 110,128, 259 Recording. (See also Recorder.) 197, 209, 210 110,128,129 Reference stake 215 131 References 3, app I 4, 259 Refraction 373 212 Registration point 290 173 Repair, tape 29 10 Resection 237, 259, 263 147,162 Accuracy 263 162 Computations 260, 262 162 Field notes 201 111 Techniques 259 162 Three-point 259, 260 162 Two-point 261, 262 162 Restricted area (ADA) 14 6 Restrictions on survey operations 329 193 Right ascension (RA) 355, 369 199, 207 Rodman 209 128 Rule, slide, military 17, 19 8 Scale factor 221 134 Scales, reading: Aiming circle 51, 52 18, 22 Altimeter 183, 188 95, 99 Theodolite, T-2 115-118 56 Theodolite, T-16 96 48 Transit 73-76 34 Schemes of triangle 237, 240, 241, 250 147,148,153 SCP. (See Survey control point.) Searchlight units 12, 13, 280 6,169 Sets, surveying 18 8 SIC. (See Survey information center.) Signs of dE and dN 218,219 132,133 Silica gel 183, 186 95, 98 Simultaneous observations on celestial bodies — 408, 411 230, 232 Sines, law 240 148 Single-base (one-base) altimetry 194 104 Single triangles, chain 243-245 149 Situation 330 193 270 Paragraphs Page Sketch 197 110 Slide rule, military 17,19 8,9 Sliding the grid 421, 424 239,242 SOP. (See Standing operating procedures.) Spherical triangle 362, 365 204, 205 Stake, reference 215 131 Standing operating procedure (SOP) 348, 349 195,196 Star: Chart 368 207 Identification 369 207 Identifier 370, 371 208 Starting: Control 420 238 Data, traverse 212 130 Station : Declination 12,13, 60, 61 6,26 Forward. (See Forward station.) Occupied. (See Occupied station.) .Orienting 284 170 Rear. (See Rear station.) Traverse 209, 213 128,130 Triangulation 241, 249 148,152 Steel arrows (taping pins) 17, 21, 44 8,9,16 Strength of figures 253 154 Surveillance radar 321, 324 189,191 Survey : Accessories 17,19-26 8,9 Control 9,14, 272,419-424 5, 6,167, 238 Point (SCP) 12, 13, 173, 274 6,167 For weapons position 286 170 Information center SIC 13, 297, 301 6,177,179 Instruments 16 8 Methods, use 276 168 Mission 327 192 Plan: Changes 346 195 17' * ; „ ^ ojrr i ntr JLJJIGVU IslUU o*± I General 344 195 Sequence 345 195 Planning: General 5,327-337 4,192 Standing operating procedure 348, 349 195 Steps in survey planning 339-343 194 Survey plan 344-347 ! 195 Purpose 8 5 Sets 18 8 Station, traverse 209-213 128 Surveying: Altimeter. (See Altimeter, surveying.) Forms. (See Forms, DA.) Swinging the grid 422-424 240 Systematic errors 46, 47 17 Tables, logarithmic 17,19 8,9 Tape: Alinement 41 14 Breaking 33 12 271 Paragraphs Pase Tape—Continued Lengths, measuring 30-32 11 Repair 29 10 Tapeman 30, 31, 209 10,11,128 Tapes : Care 28 10 Description 27 10 Taping 30-49 10 Accessories 17, 27 8,10 Alinement 41 14 Errors 46-49 17 Night 39 14 Notes 198 111 Pins 17,21,44 8, 9,16 Target acquisition battalion survey: Accuracy 300 179 Coordination and supervision 13, 303 6,181 General 300 179 Operations 304-315 181 Personnel 302 180 Responsibility 13 6 Survey information center (SIC) 301 179 Target area: Base, survey 290-293 173 Survey 290-293 173 Target set, surveying: Accessories 166 89 Adjustments 173 90 Setting up 167,168 89 Leveling 169 89 Maintenance 174 90 Operations 171,172 89 Temperature : Astronomic observations 382 216 Corrections, altimetry 190,192 99,100 Technical manual 5-241 series (formerly AMS TM series) 427, 432, 434, app I 243, 248, 249, 253 Techniques app II 256 Astronomic observations 387-389, 403, 417 216, 224, 236 Intersection 265 165 Resection 259 162 Traverse app II 256 Triangulation 238 147 Tellurometer : Accessories 139 67 Computing a distance 151-158 78 Description 139 67 Field notes 164 General 138 67 Maintenance 162,163 84 Measuring a distance 150 77 Monitoring controls 147 73 Operating controls 147 73 Operations 145-161 72 Personnel 159 83 Phase comparison 142 71 Preset controls 147 73 Principles of operation 140 70 Setting up 148 75 272 Paragraphs Pag:« Tellurometer—Continued Setting up controls 147 73 » Traverse 160 83 Trilatération 161 84 Tuning 149 76 Tension handle 17,22,42 8, 9,15 Terrain, effects of, on survey operations _ 336 194 Tests for aiming circle 66 28 Theodolite; T2 (mils) : Accessories 108 54 Adjusting for parallax 113 56 Adjustments 125-130 62 Care and maintenance 122-124 61 Circle-reading system 115-117 56 Description 108 54 Horizontal angles 120 58 Leveling 112 56 Reading scales 115-117 56 Setting up 109' 55 Taking position 120 58 Vertical angles 121 61 Theodolite, T-2 (Sexagesimal): Adjustments 137 66 Circle reading 133 65 Description 132 65 Horizontal angles 136 66 Reading scales 133,134 65 Vertical angles 136 66 Theodolite, T-16: Accessories 88 45 Adjusting for parallax 1 94 48 Adjustments 102-107 51 » Care and maintenance 99-101 51 Circle reading 96, 97 48 Description 88 45 Horizontal angles 98 49 Leveling 92 47 Reading scales 96 48 Setting up 89-91 47 Taking position 98 49 Vertical angles 98 49 Thermometers in psychrometer 182,184,192 95, 97,100 Three-point resection. (See Resection.) Time: Apparent 361 204 Available for survey operations 278, 282, 328, 359 168,169,193, 203 Mean 359, 399 203, 224 Of altimeter observation 187, 194, 195 98, 104 Of astronomic observation 381, 399 216,224 Sidereal 356, 360 200, 203 Signals 380, 399 215 Solar 356 200 Standard 359 203 Zone corrections 380 215 Training, survey 338 194 Transformation, azimuth and coordinates 431-437 248 Transit: Accessories 68 30 » 273 Paragraphs Paff« Transit—Continued Adjusting for parallax 72 34 I Adjustment of angles 77 38 ^ Adjustments 82-87 41 Care and maintenance 79-87 40 Components 68 30 Description 68 30 Horizon closure 77 38 Horizontal angles 74,77 35, 38 Leveling 71 33 Scales 73, 76 34,38 Setting up 69, 70 33 Vertical angles 75, 78 36, 39 Transit time 155 81 Transmission of direction 408, 411 230, 232 Traverse : Accuracy 6, app II 4,256 Ratio 227 141 Adjustment 229-233 142 Coordinate computations 218-223 132 Definition 207 127 Directional 208 127 Error, radial 227 141 Field notes 198 111 Height computations 220, 223 133,134 Party 209 128 Scale factor 221 134 Starting data 212 130 Stations 213 130 Techniques app II 256 Tellurometer 160 83 4 Types 208 127 Triangle, astronomic (PZS) 361-366, 413, 415, 416 204-207, 234, 235 Triangle, error of closure 247 149 Triangles, chain of 237,243, 245 147,149 Triangulation : Accuracy 238,'app II 147, 256 Checks 241 148 Angular limitations 242,246 app II 148,149, 256 Base measurement 241, app II 148, 256 Choice of side 242, 246 148,149 Computations 248, 249 152 Definition 237 147 Error of closure 247 149 Field notes 199 111 Height computations 249 152 Quadrilaterals 250-256 153 Reconnaissance 276 168 Schemes 250 153 Strength of figures 253, 254 154 Techniques 238 147 Trig: List 9, 297, 301 5,177,179 Trigonometric leveling 260, 267, 262 162,165,162 Tripod, ranging pole 26 9 True azimuth 390, 392 217, 220 Two-point resection. (See Resection.) 274 c Paragraphs Paffe Use of survey methods 276 168 Vernal equinox 352 197 Vernier(s) 73, 74 34,35 Vertical angles 57, 223 24,134 Determining, with theodolite. (See The- odolite.) Measuring, with: Aiming circle. (See Aiming circle M2.) Transit. (See Transit.) Vertical scales. (See Scales, reading.) Weapons position, field artillery 286 170 Weather: Considerations in altimetry 187 98 Effects of, on survey operations 337 194 Zenith 354, 362 199, 204 Zone to zone transformation 431-437 248 275 BY ORDER OF THE SECRETARY OF THE ARMY : G. H. DECKER, General, United States Army, Official : Chief of Staff. R. V. LEE, Major General, United States Army, The Adjutant General. Distribution : Active Army: DCSPER (2) ARADCOM Rgn (1) ACSI (2) LOGCOMD (1) DCSOPS (2) Armies (5) DCSLOG (2) Corps (3) ACSRC (2) Div (2) CRD (1) Div Arty (3) COA (1) Bde (1) CINFO (1) FA Gp (5) TIG (1) FA Bn (5) TJAG (1) USAAMS (900) TPMG (1) Units organized under following TOE : Tech Stf, DA (1) 6-37 (2) ARADCOM (2) 6-577 (5) NG: Same as Active Army except allowance is one copy to each unit except TOE 1-7, 1-17 (1); 6-100, 6-300 (4); 6-401, 6-501, 7-2, 17-2 (2). USAR: Same as Active Army except allowance is one copy to each unit. For explanation of abbreviations used, see AR 320-50. ¿T U. S. GOVERNMENT PRINTING OFFICE: 1961 59877B/O002A 276 460583 0-58 (Face p. 276) e e SOTT». I■!^Wifhi-rrr 40 80° 30’ 50° 60° 70° 10 10' 90‘ 50° 20» 80’ 70° e 0 24h 23h22h21h20h19h18h17 4- + VernOl Eau _a + + \l + -O V Fbmalhout + 9'' '®i Al Nair y'QRUS u AOUARI JS^ l(Octantis) eneb i tI + • + / \ + AlMir \j AC UILA® Cl / SAGITTARIUS Nunkj ^ßC^ N---. _±_i. 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