Understanding the Altimeter
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
It Is Quite Common for Confusion to Arise About the Process Used During a Hydrographic Survey When GPS-Derived Water Surface
It is quite common for confusion to arise about the process used during a hydrographic survey when GPS-derived water surface elevation is incorporated into the data as an RTK Tide correction. This article explains a little about the process. What we are discussing here might be a tide-related correction to a chart datum for coastal surveying – maybe to update navigational charts, or it might be nothing to do with tides at all. For example, surveying a river with the need to express bathymetry results as a bottom elevation on the desired vertical datum – not simply as “depth” results. Whether it is anything to do with tidal forces or not, the term “RTK Tide” is ubiquitous in hydrographic-speak to refer to vertical corrections of echo sounding data using RTK GPS. Although there is some confusing terminology, it’s a simple idea so let’s try to keep it that way. First keep in mind any GPS receiver will give the user basically two things in terms of vertical positioning: height above the GPS reference ellipsoid surface and height above Mean Sea Level (MSL) where ever he or she is on the Earth. How is MSL defined? Well, a geoid surface is a measure of the strength of gravity which in turn mostly controls the height of the sea; it is logical to say that MSL height equals the geoid height and vice versa. Using RTK techniques to obtain tide information is a logical extension of this basic principle. We are measuring the GPS receiver height above a geoid. -
Meyers Height 1
University of Connecticut DigitalCommons@UConn Peer-reviewed Articles 12-1-2004 What Does Height Really Mean? Part I: Introduction Thomas H. Meyer University of Connecticut, [email protected] Daniel R. Roman National Geodetic Survey David B. Zilkoski National Geodetic Survey Follow this and additional works at: http://digitalcommons.uconn.edu/thmeyer_articles Recommended Citation Meyer, Thomas H.; Roman, Daniel R.; and Zilkoski, David B., "What Does Height Really Mean? Part I: Introduction" (2004). Peer- reviewed Articles. Paper 2. http://digitalcommons.uconn.edu/thmeyer_articles/2 This Article is brought to you for free and open access by DigitalCommons@UConn. It has been accepted for inclusion in Peer-reviewed Articles by an authorized administrator of DigitalCommons@UConn. For more information, please contact [email protected]. Land Information Science What does height really mean? Part I: Introduction Thomas H. Meyer, Daniel R. Roman, David B. Zilkoski ABSTRACT: This is the first paper in a four-part series considering the fundamental question, “what does the word height really mean?” National Geodetic Survey (NGS) is embarking on a height mod- ernization program in which, in the future, it will not be necessary for NGS to create new or maintain old orthometric height benchmarks. In their stead, NGS will publish measured ellipsoid heights and computed Helmert orthometric heights for survey markers. Consequently, practicing surveyors will soon be confronted with coping with these changes and the differences between these types of height. Indeed, although “height’” is a commonly used word, an exact definition of it can be difficult to find. These articles will explore the various meanings of height as used in surveying and geodesy and pres- ent a precise definition that is based on the physics of gravitational potential, along with current best practices for using survey-grade GPS equipment for height measurement. -
Beforethe Runway
EDITORIAL Before the runway By Professor Sidney dekker display with fl ight information. My airspeed is leaking out of Editors Note: This time, we decided to invite some the airplane as if the hull has been punctured, slowly defl at- comments on Professor Dekker’s article from subject ing like a pricked balloon. It looks bizarre and scary and the matter experts. Their responses follow the article. split second seems to last for an eternity. Yet I have taught myself to act fi rst and question later in situations like this. e are at 2,000 feet, on approach to the airport. The big So I act. After all, there is not a whole lot of air between me W jet is on autopilot, docile, and responsively follow- and the hard ground. I switch off the autothrottle and shove ing the instructions I have put into the various computer the thrust levers forward. From behind, I hear the engines systems. It follows the heading I gave it, and stays at the screech, shrill and piercing. Airspeed picks up. I switch off altitude I wanted it at. The weather is alright, but not great. the autopilot for good measure (or good riddance) and fl y Cloud base is around 1000 feet, there is mist, a cold driz- the jet down to the runway. It feels solid in my hands and zle. We should be on the ground in the next few minutes. docile again. We land. Then everything comes to a sudden I call for fl aps, and the other pilot selects them for me. -
NORWAY LOCAL SINGLE SKY IMPLEMENTATION Level2020 1 - Implementation Overview
LSSIP 2020 - NORWAY LOCAL SINGLE SKY IMPLEMENTATION Level2020 1 - Implementation Overview Document Title LSSIP Year 2020 for Norway Info Centre Reference 20/12/22/79 Date of Edition 07/04/2021 LSSIP Focal Point Peder BJORNESET - [email protected] Luftfartstilsynet (CAA-Norway) LSSIP Contact Person Luca DELL’ORTO – [email protected] EUROCONTROL/NMD/INF/PAS LSSIP Support Team [email protected] Status Released Intended for EUROCONTROL Stakeholders Available in https://www.eurocontrol.int/service/local-single-sky-implementation- monitoring Reference Documents LSSIP Documents https://www.eurocontrol.int/service/local-single-sky-implementation- monitoring Master Plan Level 3 – Plan https://www.eurocontrol.int/publication/european-atm-master-plan- Edition 2020 implementation-plan-level-3 Master Plan Level 3 – Report https://www.eurocontrol.int/publication/european-atm-master-plan- Year 2020 implementation-report-level-3 European ATM Portal https://www.atmmasterplan.eu/ STATFOR Forecasts https://www.eurocontrol.int/statfor National AIP https://avinor.no/en/ais/aipnorway/ FAB Performance Plan https://www.nefab.eu/docs# LSSIP Year 2020 Norway Released Issue APPROVAL SHEET The following authorities have approved all parts of the LSSIP Year 2020 document and the signatures confirm the correctness of the reported information and reflect the commitment to implement the actions laid down in the European ATM Master Plan Level 3 (Implementation View) – Edition 2020. Stakeholder / Name Position Signature and date Organisation -
TCAS II) by Personnel Involved in the Implementation and Operation of TCAS II
Preface This booklet provides the background for a better understanding of the Traffic Alert and Collision Avoidance System (TCAS II) by personnel involved in the implementation and operation of TCAS II. This booklet is an update of the TCAS II Version 7.0 manual published in 2000 by the Federal Aviation Administration (FAA). It describes changes to the CAS logic introduced by Version 7.1 and updates the information on requirements for use of TCAS II and operational experience. Version 7.1 logic changes will improve TCAS Resolution Advisory (RA) sense reversal logic in vertical chase situations. In addition all “Adjust Vertical Speed, Adjust” RAs are converted to “Level-Off, Level-Off” RAs to make it more clear that a reduction in vertical rate is required. The Minimum Operational Performance Standards (MOPS) for TCAS II Version 7.1 were approved in June 2008 and Version 7.1 units are expected to be operating by 2010-2011. Version 6.04a and 7.0 units are also expected to continue operating for the foreseeable future where authorized. 2 Preface................................................................................................................................. 2 The TCAS Solution............................................................................................................. 5 Early Collision Avoidance Systems................................................................................ 5 TCAS II Development .................................................................................................... 6 Initial -
Is Mount Everest Higher Now Than 100 Years
Is Mount Everest higher now than 155 years ago?' Giorgio Poretti All human works are subject to error, and it is only in the power of man to guard against its intrusion by care and attention. (George Everest) Dipartimento di Matematica e Informatica CER Telegeomatica - Università di Trieste Foreword One day in the Spring of 1852 at Dehra Dun, India, in the foot hills of the Himalayas, the door of the office of the Director General of the Survey of India opens. Enters Radanath Sikdar, the chief of the team of human computers who were processing the data of the triangulation measurements of the Himalayan peaks taken during the Winter. "Sir I have discovered the highest mountain of the world…….it is Peak n. XV". These words, reported by Col. Younghausband have become a legend in the measurement of Mt. Everest. Introduction The height of a mountain is determined by three main factors. The first is the sea level that would be under the mountain if the water could flow freely under the continents. The second depends on the accuracy of the elevations of the points in the valley from which the measurements are performed, and on the mareograph taken as a reference (height datum). The third factor depends on the amount of snow on the summit. This changes from season to season and from year to year with a variation that exceeds a metre between spring and autumn. Optical measurements from a long distance are also heavily influenced by the refraction of the atmosphere (due to the difference of pressure and temperature between the points of observation in the valley and the summit), and by the plumb-line deflections. -
A Seamless Vertical-Reference Surface for Acquisition, Management and Display (Ecdis) of Hydrographic Data
SEAMLESS VERTICAL DATUM A SEAMLESS VERTICAL-REFERENCE SURFACE FOR ACQUISITION, MANAGEMENT AND DISPLAY (ECDIS) OF HYDROGRAPHIC DATA A report prepared for the Canadian Hydrographic Service under Contract Number IIHS4-122 David Wells Alfred Kleusberg Petr Vanicek Department of Geodesy and Geomatics Engineering University of New Brunswick PO. Box 4400 Fredericton, New Brunswick Canada E3B 5A3 FINAL REPORT (DRAFT) November 22, 2004 Page 1 SEAMLESS VERTICAL DATUM Final Report 15 July 1995 FINAL REPORT (DRAFT) November 22, 2004 Page 2 SEAMLESS VERTICAL DATUM TABLE OF CONTENTS Table of contents...........................................................................................................................2 Executive summary.......................................................................................................................5 Acronyms used in this report ........................................................................................................6 1. Introduction...............................................................................................................................8 1.1 Problem statement.......................................................................................................8 1.2 The role of vertical-reference surfaces in navigation..................................................8 1.3 Vertical-reference surface accuracy issues..................................................................9 1.3.1 Depth measurement errors .........................................................................10 -
Accuracy of Flight Altitude Measured with Low-Cost GNSS, Radar and Barometer Sensors: Implications for Airborne Radiometric Surveys
sensors Article Accuracy of Flight Altitude Measured with Low-Cost GNSS, Radar and Barometer Sensors: Implications for Airborne Radiometric Surveys Matteo Albéri 1,2,* ID , Marica Baldoncini 1,2, Carlo Bottardi 1,2 ID , Enrico Chiarelli 3, Giovanni Fiorentini 1,2, Kassandra Giulia Cristina Raptis 3, Eugenio Realini 4, Mirko Reguzzoni 5, Lorenzo Rossi 5, Daniele Sampietro 4, Virginia Strati 3 and Fabio Mantovani 1,2 ID 1 Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, 44122 Ferrara, Italy; [email protected] (M.B.); [email protected] (C.B.); fi[email protected] (G.F.); [email protected] (F.M.) 2 Ferrara Section of the National Institute of Nuclear Physics, Via Saragat, 1, 44122 Ferrara, Italy 3 Legnaro National Laboratory, National Institute of Nuclear Physics, Via dell’Università 2, 35020 Legnaro (Padova), Italy; [email protected] (E.C.); [email protected] (K.G.C.R.); [email protected] (V.S.) 4 Geomatics Research & Development (GReD) srl, Via Cavour 2, 22074 Lomazzo (Como), Italy; [email protected] (E.R.); [email protected] (D.S.) 5 Department of Civil and Environmental Engineering (DICA), Polytechnic of Milan, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; [email protected] (M.R.); [email protected] (L.R.) * Correspondence: [email protected]; Tel.: +39-329-0715328 Received: 7 July 2017; Accepted: 13 August 2017; Published: 16 August 2017 Abstract: Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial radionuclides measured during airborne surveys. -
FSF ALAR Briefing Note 3.2 -- Altitude Deviations
Flight Safety Foundation Approach-and-landing Accident Reduction Tool Kit FSF ALAR Briefing Note 3.2 — Altitude Deviations Altitude deviations may result in substantial loss of aircraft • The pilot-system interface: vertical separation or horizontal separation, which could cause – Altimeter setting, use of autopilot, monitoring of a midair collision. instruments and displays; or, Maneuvers to avoid other aircraft often result in injuries to • The pilot-controller interface: passengers, flight crewmembers and, particularly, to cabin crewmembers. – Communication loop (i.e., the confirmation/ correction process). Statistical Data Altitude deviations occur usually as the result of one or more of the following conditions: An analysis by the U.S. Federal Aviation Administration (FAA) and by USAir (now US Airways) of altitude-deviation events1 • The controller assigns an incorrect altitude or reassigns showed that: a flight level after the pilot was cleared to an altitude; • Approximately 70 percent of altitude deviations were the • Pilot-controller communication breakdown — mainly result of a breakdown in pilot-controller communication; readback/hearback errors such as the following: and, – Controller transmits an incorrect altitude, the pilot • Nearly 40 percent of altitude deviations resulted when does not read back the altitude and the controller does air traffic control (ATC) assigned 10,000 feet and the not challenge the absence of a readback; flight crew set 11,000 feet in the selected-altitude – Pilot reads back an incorrect altitude, but the window, or when ATC assigned 11,000 feet and the flight controller does not hear the erroneous readback and crew set 10,000 feet in the selected-altitude window. does not correct the pilot’s readback; or, Defining Altitude Deviations – Pilot accepts an altitude clearance intended for another aircraft (confusion of call signs); An altitude deviation is a deviation from the assigned altitude • Pilot receives, understands and reads back the correct (or flight level) equal to or greater than 300 feet. -
Radar Altimeter True Altitude
RADAR ALTIMETER TRUE ALTITUDE. TRUE SAFETY. ROBUST AND RELIABLE IN RADARDEMANDING ENVIRONMENTS. Building on systems engineering and integration know-how, FreeFlight Systems effectively implements comprehensive, high-integrity avionics solutions. We are focused on the practical application of NextGen technology to real-world operational needs — OEM, retrofit, platform or infrastructure. FreeFlight Systems is a community of respected innovators in technologies of positioning, state-sensing, air traffic management datalinks — including rule-compliant ADS-B systems, data and flight management. An international brand, FreeFlight Systems is a trusted partner as well as a direct-source provider through an established network of relationships. 3 GENERATIONS OF EXPERIENCE BEHIND NEXTGEN AVIONICS NEXTGEN LEADER. INDUSTRY EXPERT. TRUSTED PARTNER. SHAPE THE SKIES. RADAR ALTIMETERS FreeFlight Systems’ certified radar altimeters work consistently in the harshest environments including rotorcraft low altitude hover and terrain transitions. RADAROur radar altimeter systems integrate with popular compatible glass displays. AL RA-4000/4500 & FreeFlight Systems modern radar altimeters are backed by more than 50 years of experience, and FRA-5500 RADAR ALTIMETERS have a proven track record as a reliable solution in Model RA-4000 RA-4500 FRA-5500 the most challenging and critical segments of flight. The TSO and ETSO-approved systems are extensively TSO-C87 l l l deployed worldwide in helicopter fleets, including ETSO-2C87 l l l some of the largest HEMS operations worldwide. DO-160E l l l DO-178 Level B l Designed for helicopter and seaplane operations, our DO-178B Level C l l radar altimeters provide precise AGL information from 2,500 feet to ground level. -
Advisory Circular
AC 4302B DATE 10/16/80 ADVISORY CIRCULAR DEPAl<TI\IEST OF TiL4SSPOlCTATiON Federal Aviation Administration Washington, D.C. .Srr bjecrt : MINIMUMMOmY FDR CLIEMTIONAND TEST OFAIMOS~RIC PRESSUPEINSTRUMENTS 1. PURPOSE. This advisory circular (AC) provides guidance material &ich may be used to determine the adequacy of barometers used in the calibration of aircraft static instruments. It explains barometric accuracy requirements and provides general information pertaining to altitude and atmospheric pressure rneasursnent Additional information concerning the general operation, calibration, and Wntenance of barmeters is presented. 20 CANCEIILATION. AC 43.2A, Minimum Barametry for Calibration and Test of Atmospheric Pressure Instruments, dated August 22, 1974, is cancelled. 3 BACKGROUND.'Ihe Federal Aviation Administration (FAA) has long recognized the direct relation that exists between altimeter accuracy and the efficiency with which the available airspace can be utilized. Accurate altimetry contributes to collision avoidance and terrain clearance. To improve safety in this area, the agency adopted rules prescribing periodic tests of aircraft altimeter systems. Following is a general discussion of each of the major areas of barometry &ich concern persons using barameters in aviation. 4 RASIC PEFERENCE. The National Bureau of Standards of the Department of Cknerce published Monograph 8 entitled "kkrcury Barometers and Emcxneters." This excellent publication ms prepared to fill the need of manufacturers and use& of barometers for information &ich was scattered through the literature and, in some cases, ws unpublished. 'Ihe definitions and terminology used in the mnograph will be used in this AC. kbnograph 8 describes the variety of design elements &ich are critical in obtaining precision and accuracy from these instruments. -
Mercury Barometers and Manometers
NBS MONOGRAPH 8 Mercuiy Barometers and Manometers U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS THE NATIONAL BUREAU OF STANDARDS Functions and Activities The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau's unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau's work take the form of either actual equipment and devices or pub- lished papers. These papers appear either in the Bureau's own series of publications or in the journals of professional and scientific societies. The Bureau itself publishes three periodicals available from the Government Printing Office: The Journal of Research, published in four separate sections, presents complete scientific and technical papers; the Technical News Bulletin presents summary and pre- liminary reports on work in progress; and Basic Radio Propagation Predictions provides data for determining the best frequencies to use for radio communications throughout the world.