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The WGS 84 datum surface is an oblate spheroid with equatorial radius a = 6 378 137 m at the equator and flattening f = 1 ⁄ 298.257 223 563. The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is GM = 3.986 004 418 × 10 14 m 3 /s 2. The angular velocity of the Earth is defined to be ω = 72.921 15 × ...
The first EGM, EGM84, was defined as a part of WGS84 along with its reference ellipsoid. WGS84 combines the old GRS 80 with the then-latest data, namely available Doppler, satellite laser ranging, and Very Long Baseline Interferometry ( VLBI ) observations, and a new least squares method called collocation. [ 3 ]
On 7 January 2024 move to IGS20 happened, so WGS 84 is now aligned with ITRF2020, including PSD (post-seismic deformation), also called G2296. On the other hand GLONASS is using PZ-90.11, which is close to ITRF2008 at epoch 2011.0 and is using 2010.0 epoch (that means when you use reference transformation to PZ-90.11 you will get January 2010 ...
As noted above, the iterative solution to the inverse problem fails to converge or converges slowly for nearly antipodal points. An example of slow convergence is (Φ 1, L 1) = (0°, 0°) and (Φ 2, L 2) = (0.5°, 179.5°) for the WGS84 ellipsoid. This requires about 130 iterations to give a result accurate to 1 mm. Depending on how the inverse ...
EPSG:3857 - Web Mercator projection of WGS 84, used for display by many web-based mapping tools, including Google Maps and OpenStreetMap. EPSG:9989 - International Terrestrial Reference Frame 2020 (ITRF2020) for 3D coordinates (latitude, longitude, ellipsoidal height) with subcentimeter accuracy, used for monitoring continental drift among others.
For comparison, the data of the modern World Geodetic System WGS84 are shown, which is mainly used for modern surveys and the GPS system. Bessel ellipsoid 1841 (defined by log a and f): a = 6 377 397.155 m; f = 1 / 299.152 812 85 [1] [2] [3] b = 6 356 078.962 822 m. Earth ellipsoid WGS84 (defined directly by a and f): a = 6 378 137.0 m; f = 1 / ...
The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.
[1] [2] [3] The GRS80 gravity model has been followed by the newer more accurate Earth Gravitational Models, but the GRS80 reference ellipsoid is still the most accurate in use for coordinate reference systems, e.g. for the international ITRS, the European ETRS89 and (with a 0,1 mm rounding error) for WGS 84 used for the American Global ...