A geoid and world geodetic system based on a combination of gravimetric, astrogeodetic, and satellite data

A world‐wide estimate of the gravity field was combined with an estimate of the geoid and with variations in satellite orbits in least‐squares adjustment which was generalized by taking correlation into account. The gravity‐field estimate was based on all available gravimetry and was extended by using correlation with elevation in a Markov analysis. The estimated geoid was based on astrogeodetic data covering 19 per cent of the earth. Secular and long‐period variations of the 1957β and 1958 β satellite orbits were used. The value obtained for the quadratic sum indicated that the estimates of variance and covariance should be increased about 44 per cent. Results obtained include Equatorial radius: 6,378,163±21 meters. Flattening: 1/298.24±0.01. Equatorial gravity: 978,043.6±1.2 milligals (Potsdam system). Datum shifts (with three‐dimensional standard deviation) for the Americas system (±35 m); Europe‐Africa‐Siberia‐India system (±38 m); Japan‐Korea‐Manchuria system (±68 m). Coefficients in the spherical harmonic expression of the gravity field up to the eighth degree. World‐wide geoid heights having standard deviation varying from ±10 to ±22 m.