DOCSLIB.ORG

Information to Users

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Information to Users INFORMATION TO USERS This manuscript has been reproduced horn the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely, event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. Ml 48106-1346 USA 313-'761-4700 800/521-0600 ANALYSIS OF GPS DATA PROCESSING TECHNIQUES: IN SEARCH OF OPTIMIZED STRATEGY OF ORBIT AND EARTH ROTATION PARAMETER RECOVERY DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Graduate School of The Ohio State University By Dorota A. Grejner-Brzezinska, M.S., M.S. ***** The Ohio State University 1995 Dissertation Committee: Approved by John D. Bossier Clyde C. Goad Ivan L Mueller Adviser Department of Geodetic Science and Surveying UMI N um ber: 9612187 OMI Microform 9612187 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 To my daughter Bogna ...who always keeps my spirit up... ACKNOWLEDGMENTS First and foremost, I wish to express my deepest appreciation and thanks to my husband Robert and my daughter Bogna for their patience, constant support and unshakable faith in me during the difficult and long but certainly fruitful years of my graduate studies. To my daughter, Bogna, I thank you for understanding my frequent absences. Very special thanks go to my mother, my sister and my mother-in-law in Poland, for their encouragement, support and belief in me. I wish to express my deep gratitude to my adviser, Dr. Clyde C. Goad, for his professional guidance and assistance, and the valuable help throughout my graduate studies at the Department of Geodetic Science and Surveying, and during the course of my doctoral research. His support, understanding and encouragement are greatly appreciated. I am also very thankful and truly indebted to Dr. Ivan I. Mueller, for his valuable guidance, expert advice and constant encouragement. I want to thank him for his support and understanding, for many stimulating discussions, and also for permission to use his invaluable and unique personal library. My gratitude and appreciation go to Dr. John D. Bossier, for the stimulating and constructive discussions and valuable suggestions which greatly enhanced the quality of this dissertation. In addition, I wish to acknowledge the invaluable contribution of all the faculty of the Department of Geodetic Science and Surveying to my education. Special thanks are also due to my fellow students, past and present: Dr. David Chadwell (now at Scripps Institution of Oceanography, La Jolla), Dr. Ming Yang (now at National Cheng Kung University in Tainan, Taiwan) and Jarir Saleh (now at the University of the West Indies, Trinidad), for their help, valuable comments and stimulating discussions during all the years we spent together in Cockins Hall. My deep appreciation goes to Mrs. Irene Tesfai, “expert grammarian and dialectician,” for her help and advice during the typing of this manuscript. VITA March 10,1963 ....................................... Bom, Poland 1986 ........................................................ M.S., Agricultural and Technical University of Olsztyn, Poland 1986-1990 ............................................... Agricultural and Technical University of Olsztyn, Poland 1995 ................ ........................................ M.S., The Ohio State University, Columbus, Ohio 1990-present ............................................Graduate Teaching Associate & Graduate Research Associate, The Ohio State University, Columbus, Ohio PUBLICATIONS Goad, C. C., Grejner-Brzezinska, D. A , Yang, M., Determination of High-Precision GPS Orbits Using Triple Differencing Technique, submitted to Bulletin Geodesique/manuscripta geodaetica/Journal o f Geodesy, June 1995. Grejner, G., Grejner-Brzezinska, D. A , New Methods in Land Information Data Gathering, Proceedings of International Conference of Young Scholars, Olsztyn, Poland, September 1990. Grejner, D. A , Successors of the Transit System. GPS - Future of the Space Methods for Positioning, Przeglad Geodezyjny 61(1), pp. 3-9, 1989. Grejner, D. A, Precise Relative Positioning with GPS Phases - Accuracy Analysis, Acta Academiae AC Technicae Olstenesis 19, pp. 19-29,1989. FIELDS OF STUDY Major Field: Geodetic Science and Surveying • Studies in Geodetic Astronomy, Satellite Geodesy, Geodynamics: Prof. Ivan I. Mueller • Studies in Physical Geodesy, Geometric Geodesy: Prof. Richard H. Rapp • Studies in Global Positioning System, Advanced Satellite Geodesy, Geometric Geodesy: Prof. Clyde C. Goad • Studies in Adjustment Computations: Prof Burkhard Schaflrin TABLE OF CONTENTS DEDICATION.................................................................................................... ii ACKNOWLEDGMENTS.................................................................................... iii VITA.................................................................................................................. v LIST OF FIGURES.............................................................................................. xi LIST OF TABLES.............................................................................................. xv CHAPTER PAGE I. INTRODUCTION................................................................................... 1 n . GLOBAL POSITIONING SYSTEM. GENERAL OVERVIEW AND DATA MODELING................................................................................ 8 2.1. GPS System and Signal Description .................................................... 8 2.2. GPS Data Modeling .......................................................................... 15 2.2.1. Types of Observables: Pseudoranges, Carrier Phases and Their Combinations ....................................................... 15 2.2.2. Correlation Between Differenced Observations .................... 21 2.3. GPS Observation Error Sources and Corrections ................................ 23 2.3.1. Ionospheric Refraction ......................................................... 28 2.3.2. Tropospheric Refraction ...................................................... 32 m . REFERENCE FRAMES AND TIME SYSTEMS..................................... 39 3.1. Conventional Celestial Reference System ............................................ 40 3.2. Conventional Terrestrial Reference System ......................................... 41 3.3. Transformation Between Terrestrial and Celestial Reference Systems.. 44 3.4. Relativistic Effects on Reference Frames and Time ............................. 47 3.5. Time Systems.................................................................................... 50 3.5.1. Sidereal and Solar Time Systems .......................................... 51 3.5.2. Atomic Time Scale............................................................. 53 3.5.3. Dynamical Time Scale .......................................................... 53 vii IV. MODELING OF THE MOTION OF THE EARTH ORBITING SPACECRAFT; TERRESTRIAL SITE DYNAMICS.............................. 56 4.1. Equations of Motion and Variational Equations of the Earth Orbiting Satellite ............................................................................... 56 4.2. Numerical Integration of Equations of Motion and Variational Equations .......................................................................................... 59 4.2.1. Adams Type Predictor/Corrector Formulae .......................... 60 4.3. Total Perturbation Model .................................................................. 61 4.3.1. Noncentral Gravitational Potential of The Earth ................... 62 4.3.2. Third-Body Attraction and the Indirect Oblation Effect 66 4.3.3. Direct Solar Radiation Pressure ............................................ 67 4.3.3.1. Solar Radiation Pressure Model for GPS Satellites: ROCK4 and ROCK42 ........................................ 68 4.3.3.2. Acceleration due to the 7-bias ............................ 70 4.3.3.3. Effect of the Eclipse on the Modeling of the Motion of GPS satellites ..................................... 71 4.3.3.4. Spacecraft Attitude Model .................................. 77 4.3.4. Earth Radiation (Albedo) ...................................................
Load more

Recommended publications
  • WWVB: a Half Century of Delivering Accurate Frequency and Time by Radio
    Volume 119 (2014) http://dx.doi.org/10.6028/jres.119.004 Journal of Research of the National Institute of Standards and Technology WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio Michael A. Lombardi and Glenn K. Nelson National Institute of Standards and Technology, Boulder, CO 80305 [email protected] [email protected] In commemoration of its 50th anniversary of broadcasting from Fort Collins, Colorado, this paper provides a history of the National Institute of Standards and Technology (NIST) radio station WWVB. The narrative describes the evolution of the station, from its origins as a source of standard frequency, to its current role as the source of time-of-day synchronization for many millions of radio controlled clocks. Key words: broadcasting; frequency; radio; standards; time. Accepted: February 26, 2014 Published: March 12, 2014 http://dx.doi.org/10.6028/jres.119.004 1. Introduction NIST radio station WWVB, which today serves as the synchronization source for tens of millions of radio controlled clocks, began operation from its present location near Fort Collins, Colorado at 0 hours, 0 minutes Universal Time on July 5, 1963. Thus, the year 2013 marked the station’s 50th anniversary, a half century of delivering frequency and time signals referenced to the national standard to the United States public. One of the best known and most widely used measurement services provided by the U. S. government, WWVB has spanned and survived numerous technological eras. Based on technology that was already mature and well established when the station began broadcasting in 1963, WWVB later benefitted from the miniaturization of electronics and the advent of the microprocessor, which made low cost radio controlled clocks possible that would work indoors.
    [Show full text]
  • Reference System Issues in Binary Star Calculations
    Reference System Issues in Binary Star Calculations Poster for Division A Meeting DAp.1.05 George H. Kaplan Consultant to U.S. Naval Observatory Washington, D.C., U.S.A. [email protected] or [email protected] IAU General Assembly Honolulu, August 2015 1 Poster DAp.1.05 Division!A! !!!!!!Coordinate!System!Issues!in!Binary!Star!Computa3ons! George!H.!Kaplan! Consultant!to!U.S.!Naval!Observatory!!([email protected][email protected])! It!has!been!es3mated!that!half!of!all!stars!are!components!of!binary!or!mul3ple!systems.!!Yet!the!number!of!known!orbits!for!astrometric!and!spectroscopic!binary!systems!together!is! less!than!7,000!(including!redundancies),!almost!all!of!them!for!bright!stars.!!A!new!genera3on!of!deep!allLsky!surveys!such!as!PanLSTARRS,!Gaia,!and!LSST!are!expected!to!lead!to!the! discovery!of!millions!of!new!systems.!!Although!for!many!of!these!systems,!the!orbits!may!be!poorly!sampled!ini3ally,!it!is!to!be!expected!that!combina3ons!of!new!and!old!data!sources! will!eventually!lead!to!many!more!orbits!being!known.!!As!a!result,!a!revolu3on!in!the!scien3fic!understanding!of!these!systems!may!be!upon!us.! The!current!database!of!visual!(astrometric)!binary!orbits!represents!them!rela3ve!to!the!“plane!of!the!sky”,!that!is,!the!plane!orthogonal!to!the!line!of!sight.!!Although!the!line!of!sight! to!stars!constantly!changes!due!to!proper!mo3on,!aberra3on,!and!other!effects,!there!is!no!agreed!upon!standard!for!what!line!of!sight!defines!the!orbital!reference!plane.!! Furthermore,!the!computa3on!of!differen3al!coordinates!(component!B!rela3ve!to!A)!for!a!given!date!must!be!based!on!the!binary!system’s!direc3on!at!that!date.!!Thus,!a!different!
    [Show full text]
  • Sentinel-1 Constellation SAR Interferometry Performance Verification
    Sentinel-1 Constellation SAR Interferometry Performance Verification Dirk Geudtner1, Francisco Ceba Vega1, Pau Prats2 , Nestor Yaguee-Martinez2 , Francesco de Zan3, Helko Breit3, Andrea Monti Guarnieri4, Yngvar Larsen5, Itziar Barat1, Cecillia Mezzera1, Ian Shurmer6 and Ramon Torres1 1 ESA ESTEC 2 DLR, Microwaves and Radar Institute 3 DLR, Remote Sensing Technology Institute 4 Politecnico Di Milano 5 Northern Research Institute (Norut) 6 ESA ESOC ESA UNCLASSIFIED - For Official Use Outline • Introduction − Sentinel-1 Constellation Mission Status − Overview of SAR Imaging Modes • Results from the Sentinel-1B Commissioning Phase • Azimuth Spectral Alignment Impact on common − Burst synchronization Doppler bandwidth − Difference in mean Doppler Centroid Frequency (InSAR) • Sentinel-1 Orbital Tube and InSAR Baseline • Demonstration of cross S-1A/S-1B InSAR Capability for Surface Deformation Mapping ESA UNCLASSIFIED - For Official Use ESA Slide 2 Sentinel-1 Constellation Mission Status • Constellation of two SAR C-band (5.405 GHz) satellites (A & B units) • Sentinel-1A launched on 3 April, 2014 & Sentinel-1B on 25 April, 2016 • Near-Polar, sun-synchronous (dawn-dusk) orbit at 698 km • 12-day repeat cycle (each satellite), 6 days for the constellation • Systematic SAR data acquisition using a predefined observation scenario • More than 10 TB of data products daily (specification of 3 TB) • 3 X-band Ground stations (Svalbard, Matera, Maspalomas) + upcoming 4th core station in Inuvik, Canada • Use of European Data Relay System (EDRS) provides
    [Show full text]
  • Circular Orbits
    ANALYSIS AND MECHANIZATION OF LAUNCH WINDOW AND RENDEZVOUS COMPUTATION PART I. CIRCULAR ORBITS Research & Analysis Section Tech Memo No. 175 March 1966 BY J. L. Shady Prepared for: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION / GEORGE C. MARSHALL SPACE FLIGHT CENTER AERO-ASTRODYNAMICS LABORATORY Prepared under Contract NAS8-20082 Reviewed by: " D. L/Cooper Technical Supervisor Director Research & Analysis Section / NORTHROP SPACE LABORATORIES HUNTSVILLE DEPARTMENT HUNTSVILLE, ALABAMA FOREWORD The enclosed presents the results of work performed by Northrop Space Laboratories, Huntsville Department, while )under contract to the Aero- Astrodynamfcs Laboratory of Marshall Space Flight Center (NAS8-20082) * This task was conducted in response to the requirement of Appendix E-1, Schedule Order No. PO. Technical coordination was provided by Mr. Jesco van Puttkamer of the Technical and Scientific Staff (R-AERO-T) ABS TRACT This repart presents Khe results of an analytical study to develop the logic for a digrtal c3mp;lrer sclbrolrtine for the automatic computationof launch opportunities, or the sequence of launch times, that rill allow execution of various mades of gross ~ircuiarorbit rendezvous. The equations developed in this study are based on tho-bady orb:taf chmry. The Earch has been assumed tcr ha.:e the shape of an oblate spheroid. Oblateness of the Earth has been accounted for by assuming the circular target orbit to be space- fixed and by cosrecring che T ational raLe of the EarKh accordingly. Gross rendezvous between the rarget vehicle and a maneuverable chaser vehicle, assumed to be a standard 3+ uprated Saturn V launched from Cape Kennedy, is in this srudy aecomplfshed by: .x> direct ascent to rendezvous, or 2) rendezvous via an intermediate circG1a.r parking orbit.
    [Show full text]
  • Some of the Scientific Miracles in Brief ﻹﻋﺠﺎز اﻟﻌﻠ� ﻲﻓ ﺳﻄﻮر English [ إ�ﻠ�ي - ]
    Some of the Scientific Miracles in Brief ﻟﻋﺠﺎز ﻟﻌﻠ� ﻓ ﺳﻄﻮر English [ إ���ي - ] www.onereason.org website مﻮﻗﻊ ﺳﺒﺐ وﻟﺣﺪ www.islamreligion.com website مﻮﻗﻊ دﻳﻦ ﻟﻋﺳﻼم 2013 - 1434 Some of the Scientific Miracles in Brief Ever since the dawn of mankind, we have sought to understand nature and our place in it. In this quest for the purpose of life many people have turned to religion. Most religions are based on books claimed by their followers to be divinely inspired, without any proof. Islam is different because it is based upon reason and proof. There are clear signs that the book of Islam, the Quran, is the word of God and we have many reasons to support this claim: - There are scientific and historical facts found in the Qu- ran which were unknown to the people at the time, and have only been discovered recently by contemporary science. - The Quran is in a unique style of language that cannot be replicated, this is known as the ‘Inimitability of the Qu- ran.’ - There are prophecies made in the Quran and by the Prophet Muhammad, may God praise him, which have come to be pass. This article lays out and explains the scientific facts that are found in the Quran, centuries before they were ‘discov- ered’ in contemporary science. It is important to note that the Quran is not a book of science but a book of ‘signs’. These signs are there for people to recognise God’s existence and 2 affirm His revelation. As we know, science sometimes takes a ‘U-turn’ where what once scientifically correct is false a few years later.
    [Show full text]
  • Principles and Techniques of Remote Sensing
    BASIC ORBIT MECHANICS 1-1 Example Mission Requirements: Spatial and Temporal Scales of Hydrologic Processes 1.E+05 Lateral Redistribution 1.E+04 Year Evapotranspiration 1.E+03 Month 1.E+02 Week Percolation Streamflow Day 1.E+01 Time Scale (hours) Scale Time 1.E+00 Precipitation Runoff Intensity 1.E-01 Infiltration 1.E-02 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Length Scale (meters) 1-2 BASIC ORBITS • Circular Orbits – Used most often for earth orbiting remote sensing satellites – Nadir trace resembles a sinusoid on planet surface for general case – Geosynchronous orbit has a period equal to the siderial day – Geostationary orbits are equatorial geosynchronous orbits – Sun synchronous orbits provide constant node-to-sun angle • Elliptical Orbits: – Used most often for planetary remote sensing – Can also be used to increase observation time of certain region on Earth 1-3 CIRCULAR ORBITS • Circular orbits balance inward gravitational force and outward centrifugal force: R 2 F mg g s r mv2 F c r g R2 F F v s g c r 2r r T 2r 2 v gs R • The rate of change of the nodal longitude is approximated by: d 3 cos I J R3 g dt 2 2 s r 7 2 1-4 Orbital Velocities 9 8 7 6 5 Earth Moon 4 Mars 3 Linear Velocity in km/sec in Linear Velocity 2 1 0 200 400 600 800 1000 1200 1400 Orbit Altitude in km 1-5 Orbital Periods 300 250 200 Earth Moon Mars 150 Orbital Period in MinutesPeriodOrbitalin 100 50 200 400 600 800 1000 1200 1400 Orbit Altitude in km 1-6 ORBIT INCLINATION EQUATORIAL I PLANE EARTH ORBITAL PLANE 1-7 ORBITAL NODE LONGITUDE SUN ORBITAL PLANE EARTH VERNAL EQUINOX 1-8 SATELLITE ORBIT PRECESSION 1-9 CIRCULAR GEOSYNCHRONOUS ORBIT TRACE 1-10 ORBIT COVERAGE • The orbit step S is the longitudinal difference between two consecutive equatorial crossings • If S is such that N S 360 ; N, L integers L then the orbit is repetitive.
    [Show full text]
  • Preparation of Papers for AIAA Technical Conferences
    DUKSUP: A Computer Program for High Thrust Launch Vehicle Trajectory Design & Optimization Spurlock, O.F.I and Williams, C. H.II NASA Glenn Research Center, Cleveland, OH, 44135 From the late 1960’s through 1997, the leadership of NASA’s Intermediate and Large class unmanned expendable launch vehicle projects resided at the NASA Lewis (now Glenn) Research Center (LeRC). One of LeRC’s primary responsibilities --- trajectory design and performance analysis --- was accomplished by an internally-developed analytic three dimensional computer program called DUKSUP. Because of its Calculus of Variations-based optimization routine, this code was generally more capable of finding optimal solutions than its contemporaries. A derivation of optimal control using the Calculus of Variations is summarized including transversality, intermediate, and final conditions. The two point boundary value problem is explained. A brief summary of the code’s operation is provided, including iteration via the Newton-Raphson scheme and integration of variational and motion equations via a 4th order Runge-Kutta scheme. Main subroutines are discussed. The history of the LeRC trajectory design efforts in the early 1960’s is explained within the context of supporting the Centaur upper stage program. How the code was constructed based on the operation of the Atlas/Centaur launch vehicle, the limits of the computers of that era, the limits of the computer programming languages, and the missions it supported are discussed. The vehicles DUKSUP supported (Atlas/Centaur, Titan/Centaur, and Shuttle/Centaur) are briefly described. The types of missions, including Earth orbital and interplanetary, are described. The roles of flight constraints and their impact on launch operations are detailed (such as jettisoning hardware on heating, Range Safety, ground station tracking, and elliptical parking orbits).
    [Show full text]
  • International Earth Rotation and Reference Systems Service (IERS) Provides the International Community With
    The Role of the IERS in the Leap Second Brian Luzum Chair, IERS Directing Board Background The International Earth Rotation and Reference Systems Service (IERS) provides the international community with: • the International Celestial Reference System and its realization, the International Celestial Reference Frame (ICRF); • the International Terrestrial Reference System and its realization, the International Terrestrial Reference Frame (ITRF); • Earth orientation parameters (EOPs) that are used to transform between the ICRF and the ITRF; • Conventions (i.e., standards, models, and constants) used in generating and using reference frames and EOPs; • Geophysical data to study and understand variations in the reference frames and the Earth’s orientation. The IERS was created in 1987 and began operations on 1 January 1988. It continued much of the tasking of the Bureau International de l’Heure (BIH), which had been created early in the 20th century. It is responsible to the International Astronomical Union (IAU) and the International Union of Geodesy and Geophysics (IUGG). For more than twenty-five years, the IERS has been providing for the reference frame and EOP needs of a variety of users. Time The IERS has an important role in determining when the leap seconds are to be inserted and the dissemination of information regarding leap seconds. In order to understand this role, it is important to realize some things regarding time. For instance, there are two different kinds of “time” being related: (1) a uniform time, now based on atomic clocks and (2) “time” based on the variable rotation of the Earth. The differences between uniform time and Earth rotation “time” only became apparent in the 1930s with the improvements in clock technology.
    [Show full text]
  • Role of the IERS in the Leap Second Brian Luzum Chair, IERS Directing Board Outline
    Role of the IERS in the leap second Brian Luzum Chair, IERS Directing Board Outline • What is the IERS? • Clock time (UTC) • Earth rotation angle (UT1) • Leap Seconds • Measures and Predictions of Earth rotation • How are Earth rotation data used? • How the IERS provides for its customers • Future considerations • Summary What is the IERS? • The International Earth Rotation and Reference Systems Service (IERS) provides the following to the international scientific communities: • International Celestial Reference System (ICRS) and its realization the International Celestial Reference Frame (ICRF) • International Terrestrial Reference System (ITRS) and its realization the International Terrestrial Reference Frame (ITRF) • Earth orientation parameters that transform between the ICRF and the ITRF • Conventions (i.e. standards, models, and constants) used in generating and using reference frames and EOPs • Geophysical data to study and understand variations in the reference frames and the Earth’s orientation • Due to the nature of the data, there are many operational users Brief history of the IERS • The International Earth Rotation Service (IERS) was created in 1987 • Responsible to the International Astronomical Union (IAU) and the International Union of Geodesy and Geophysics (IUGG) • IERS began operations on 1 January 1988 • IERS changed its name to International Earth Rotation and Reference Systems Service to better represent its responsibilities • Earth orientation relies directly on having accurate, well-defined reference systems Structure
    [Show full text]
  • NIST Time and Frequency Services (NIST Special Publication 432)
    Time & Freq Sp Publication A 2/13/02 5:24 PM Page 1 NIST Special Publication 432, 2002 Edition NIST Time and Frequency Services Michael A. Lombardi Time & Freq Sp Publication A 2/13/02 5:24 PM Page 2 Time & Freq Sp Publication A 4/22/03 1:32 PM Page 3 NIST Special Publication 432 (Minor text revisions made in April 2003) NIST Time and Frequency Services Michael A. Lombardi Time and Frequency Division Physics Laboratory (Supersedes NIST Special Publication 432, dated June 1991) January 2002 U.S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary TECHNOLOGY ADMINISTRATION Phillip J. Bond, Under Secretary for Technology NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY Arden L. Bement, Jr., Director Time & Freq Sp Publication A 2/13/02 5:24 PM Page 4 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY SPECIAL PUBLICATION 432 (SUPERSEDES NIST SPECIAL PUBLICATION 432, DATED JUNE 1991) NATL. INST.STAND.TECHNOL. SPEC. PUBL. 432, 76 PAGES (JANUARY 2002) CODEN: NSPUE2 U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 2002 For sale by the Superintendent of Documents, U.S. Government Printing Office Website: bookstore.gpo.gov Phone: (202) 512-1800 Fax: (202)
    [Show full text]
  • Concern on UTC Leap Second Schedule Announcements
    Concern on UTC Leap Second Schedule Announcements Karl Kovach 15 Aug 19 © 2019 The Aerospace Corporation UTC & Leap Seconds • International Earth Rotation Service (IERS) – The “keeper’ of UTC • The ‘decider’ of UTC leap seconds • U.S. Naval Observatory (USNO) – Contributes to IERS for UTC • Follows IERS for UTC leap seconds • U.S. Department of Defense (DoD) – Follows USNO for UTC & UTC leap seconds • Global Positioning System (GPS) – Should be following USNO for UTC & UTC leap seconds 2 UTC Leap Second Announcements • IERS announces the UTC leap second schedule – USNO forwards the IERS announcements • DoD uses the IERS leap second announcements – GPS should simply follow along… 3 IERS “Bulletin C” Announcements Paris, 6 July 2016 – Bulletin C 52 4 IERS “Bulletin C” Announcements Paris, 9 January 2017 – Bulletin C 53 5 IERS “Bulletin C” Announcements Paris, 06 July 2017 – Bulletin C 54 6 IERS “Bulletin C” Announcements Paris, 09 January 2018 – Bulletin C 55 7 IERS “Bulletin C” Announcements Paris, 05 July 2018 – Bulletin C 56 8 IERS “Bulletin C” Announcements Paris, 07 January 2019 – Bulletin C 57 9 IERS “Bulletin C” Announcements Paris, 04 July 2019 – Bulletin C 58 10 UTC Leap Second Announcements • IERS announces the UTC leap second schedule – USNO forwards the IERS announcements • DoD uses the IERS leap second announcements – GPS should simply follow along… • GPS also announces a UTC leap second schedule – Should be the same schedule as IERS & USNO 11 GPS Leap Second Announcement WNLSF DN ΔtLSF 12 GPS Leap Second Announcement Leap
    [Show full text]
  • Leap Second Application Anomaly
    PRESS RELEASE Leap Second Application Anomaly Affected products The following models will not properly apply the leap second coming 31 December 201 6. Model 1 084A/B/C Model 1 093A/B/C Model 1 1 33A Model 1 088A/B Model 1 094B Model 1 092A/B/C Model 1 095B/C What is a leap second? A leap second is the second added to or subtracted from the UTC time reference when the difference between UTC and UT1 approaches 0.9 seconds. By adding an additional second to the time count, clocks are effectively stopped for that second to give Earth the opportunity to catch up with atomic time. What does this mean, UTC, UT1 , et cetera? There are many time references in use. There is time based on atoms. There is time based on the Earth's rotation. Then there is time that we civilians use. • International Atomic Time (TAI). TAI is a statistical atomic time scale based on a large number of clocks operating at standards laboratories around the world with the unit interval of the SI second. • Universal Time (UT1 ). UT1 is also known as Astronomical Time and is the non-uniform time based on the Earth’s rotation. • Coordinated Universal Time (UTC) is a widely used standard for international timekeeping of civil time and differs from TAI by the total number of leap seconds. • Global Positioning System (GPS) Time is the atomic time scale implemented by the atomic clocks in the GPS ground control stations and the GPS satellites themselves. GPS time was zero at 0h 6 January 1 980 and does not include leap seconds.
    [Show full text]