ITRF
The International Terrestrial Reference System (ITRS) describes procedures for creating frame of reference, reference frames suitable for use with measurements on or near the Earth's surface. This is done in much the same way that a Standard (metrology), physical standard might be described as a set of procedures for creating a ''realization'' of that standard. The ITRS defines a Geocentric coordinate system, geocentric system of coordinates using the SI system of measurement. An International Terrestrial Reference Frame (ITRF) is a realization of the ITRS. Its origin is at the center of mass of the whole earth including the oceans and atmosphere. New ITRF solutions are produced every few years, using the latest mathematical and surveying techniques to attempt to realize the ITRS as precisely as possible. Due to experimental error, any given ITRF will differ very slightly from any other realization of the ITRF. The difference between the latest as of 2006 World Geodetic System, WGS ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Terrestrial Reference Frame
A geodetic datum or geodetic system (also: geodetic reference datum, geodetic reference system, or geodetic reference frame, or terrestrial reference frame) is a global datum reference or reference frame for unambiguously representing the position of locations on Earth by means of either geodetic coordinates (and related vertical coordinates) or geocentric coordinates. DatumsThe plural is not "data" in this case are crucial to any technology or technique based on spatial location, including geodesy, navigation, surveying, geographic information systems, remote sensing, and cartography. A horizontal datum is used to measure a horizontal position, across the Earth's surface, in latitude and longitude or another related coordinate system. A '' vertical datum'' is used to measure the elevation or depth relative to a standard origin, such as mean sea level (MSL). A three-dimensional datum enables the expression of both horizontal and vertical position components in a unified for ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Geodetic Datum
A geodetic datum or geodetic system (also: geodetic reference datum, geodetic reference system, or geodetic reference frame, or terrestrial reference frame) is a global datum reference or reference frame for unambiguously representing the position of locations on Earth by means of either geodetic coordinates (and related vertical coordinates) or geocentric coordinates. DatumsThe plural is not "data" in this case are crucial to any technology or technique based on spatial location, including geodesy, navigation, surveying, geographic information systems, remote sensing, and cartography. A horizontal datum is used to measure a horizontal position, across the Earth's surface, in latitude and longitude or another related coordinate system. A ''vertical datum'' is used to measure the elevation or depth relative to a standard origin, such as mean sea level (MSL). A three-dimensional datum enables the expression of both horizontal and vertical position components in a unified form. Th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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World Geodetic System
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also describes the associated Earth Gravitational Model (EGM) and World Magnetic Model (WMM). The standard is published and maintained by the United States National Geospatial-Intelligence Agency. History Efforts to supplement the various national surveying systems began in the 19th century with Friedrich Robert Helmert, F.R. Helmert's book (''Mathematical and Physical Theories of Physical Geodesy''). Austria and Germany founded the (Central Bureau of International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, John Fillmore Hayford, Hayford 1910 and 1924). A unified geodetic system for the whole world became essential in the 1950s for several reasons: * International space science and the beginning of as ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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WGS 84
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also describes the associated Earth Gravitational Model (EGM) and World Magnetic Model (WMM). The standard is published and maintained by the United States National Geospatial-Intelligence Agency. History Efforts to supplement the various national surveying systems began in the 19th century with F.R. Helmert's book (''Mathematical and Physical Theories of Physical Geodesy''). Austria and Germany founded the (Central Bureau of International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, Hayford 1910 and 1924). A unified geodetic system for the whole world became essential in the 1950s for several reasons: * International space science and the beginning of astronautics. * The lack of inter-continental ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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International Earth Rotation And Reference Systems Service
The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups. History The IERS was established in its present form in 1987 by the International Astronomical Union and the International Union of Geodesy and Geophysics, replacing the earlier International Polar Motion Service (IPMS) and the Earth rotation section of the Bureau International de l'Heure (BIH). The service began operation on January 1, 1988. Since its inception, the IERS has established new bureaus including the GPS Coordinating Centre in 1990, the DORIS Coordinating Centre in 1994 and the Global Geophysical Fluids Centre in 1998. The organization was formerly known as International Earth Rotation Service until 2003 when it formally changed its name to its pr ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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EPSG
EPSG Geodetic Parameter Dataset (also EPSG registry) is a public registry of geodetic datums, spatial reference systems, Earth ellipsoids, coordinate transformations and related units of measurement, originated by a member of the European Petroleum Survey Group (EPSG) in 1985. Each entity is assigned an EPSG code between 1024 and 32767, along with a standard machine-readable well-known text (WKT) representation. The dataset is maintained by the IOGP Geomatics Committee. Most geographic information systems (GIS) and GIS libraries use EPSG codes as Spatial Reference System Identifiers (SRIDs) and EPSG definition data for identifying coordinate reference systems, projections, and performing transformations between these systems, while some also support SRIDs issued by other organizations (such as Esri). Common EPSG codes * EPSG:4326 - WGS 84 datum ensemble for 2D (latitude, longitude) coordinates with 2 meter accuracy, used by the Global Positioning System among others. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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PZ-90
PZ-90 (short for ''Parametry Zemli 1990 goda'', in ) is a geodetic datum defined for use in the GLONASS GLONASS (, ; ) is a Russian satellite navigation system operating as part of a radionavigation-satellite service. It provides an alternative to Global Positioning System (GPS) and is the second navigational system in operation with global cove ... system. Revisions PZ-90.02 Creation date - 2005; Epoch - 2002.0; Absolute positional accuracy - from 0.3 to 0.5 m; Relative positional accuracy - from 2 to 3 cm PZ-90.11 Creation date - 2011; Epoch - 2010.0; Absolute positional accuracy - 5 cm; Relative positional accuracy - from 0.5 to 1 cm PZ-90.11 is described as "closest to ITRF2000" by the ESA's Navipedia. It converts to ITRF2008 with only a shift vector; no rotation or scaling is needed.{{cite web , title=Reference Frames in GNSS , url=https://gssc.esa.int/navipedia/index.php/Reference_Frames_in_GNSS , website=Navipedia References * GLONASS Geography o ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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GLONASS
GLONASS (, ; ) is a Russian satellite navigation system operating as part of a radionavigation-satellite service. It provides an alternative to Global Positioning System (GPS) and is the second navigational system in operation with global coverage and of comparable precision. Satellite navigation devices supporting both GPS and GLONASS have more satellites available, meaning positions can be fixed more quickly and accurately, especially in built-up areas where buildings may obscure the view to some satellites. Owing to its higher orbital inclination, GLONASS supplementation of GPS systems also improves positioning in high latitudes (near the poles). Development of GLONASS began in the Soviet Union in 1976. Beginning on 12 October 1982, numerous rocket launches added satellites to the system until the completion of the Satellite constellation, constellation in 1995. In 2001, after a decline in capacity during the late 1990s, the restoration of the system was made a government p ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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International Celestial Reference System And Its Realizations
The International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU). Its origin is at the barycenter of the Solar System, with axes that are intended to "show no global rotation with respect to a set of distant extragalactic objects". This fixed reference system differs from previous reference systems, which had been based on Catalogues of Fundamental Stars that had published the positions of stars based on direct "observations of heir equatorial coordinates, right ascension and declination" and had adopted as "privileged axes ... the mean equator and the dynamical equinox" at a particular date and time. The International Celestial Reference Frame (ICRF) is a realization of the International Celestial Reference System using reference celestial sources observed at radio wavelengths. In the context of the ICRS, a reference ''frame'' (RF) is the physical realization of a reference ''system,'' i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Earth Orientation Parameters
In geodesy and astrometry, earth orientation parameters (EOP) describe irregularities in the rotation of planet Earth. EOP provide the rotational transform from the International Terrestrial Reference System (ITRS) to the International Celestial Reference System (ICRS), or vice versa, as a function of time. Earth's rotational velocity is not constant over time. Any motion of mass in or on Earth causes a slowdown or speedup of the rotation speed, or a change of rotation axis. Small motions produce changes too small to be measured, but movements of very large mass, like sea currents, tides, or those resulting from earthquakes, can produce discernible changes in the rotation and can change very precise astronomical observations. Global simulations of atmosphere, ocean, and land dynamics are used to create effective angular momentum (EAM) functions that can be used to predict changes in EOP. Components Universal time Universal time ( UT1) tracks the Earth's rotation in time, which ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Earth-centered, Earth-fixed Coordinate System
The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a Cartesian coordinate system, cartesian spatial reference system that represents locations in the vicinity of the Earth (including its Geoid, surface, interior, atmosphere, and surrounding outer space) as ''X'', ''Y'', and ''Z'' measurements from its center of mass. Its most common use is in tracking the orbits of satellites and in satellite navigation systems for measuring locations on the surface of the Earth, but it is also used in applications such as tracking Crust (geology), crustal motion. The distance from a given point of interest to the center of Earth is called the geocentric distance, , which is a generalization of the ''geocentric radius'', , not restricted to points on the reference ellipsoid surface. The geocentric altitude is a type of altitude defined as the difference between the two aforementioned quantities: ; it is not to be confused for th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |