Ellipsoidal corrections for geoid undulation computations
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Date
1981-03
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Ohio State University. Division of Geodetic Science
Abstract
The computation of accurate geoid undulations is usually done combining potential coefficient information and terrestrial gravity data in a cap surrounding the computation point. In doing this a spherical approximation is made that can cause errors that are investigated in this paper. The equations dealing with ellipsoidal corrections developed by Lelgemann and by Moritz are used to develop a computational procedure considering the ellipsoid as a reference surface. Terms in the resulting expression for the geoid undulation are identified as ellipsoidal correction terms. These equations have been developed for the case where the Stokes function is used, and for the case where the modified Stokes function is used. For a cap of 20° the correction can reach -33 cm. Ellipsoidal corrections were also computed for the Marsh/Chang geoids. These corrections reach -45 cm for a cap size of 20°. Global maps are given showing the distribution of the corrections so that more accurate geoid undulations can be found.
Description
Prepared for National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland: Grant No. NGR 36-008-161, OSURF Project No. 783210