The determination of high degree potential coefficient expansions from the combination of satellite and terrestrial gravity information
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Date
1984-12
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Ohio State University. Division of Geodetic Science
Abstract
This report reviews several methods that can be used for the combination of satellite and terrestrial gravity data for the ultimate purpose of computing high degree spherical harmonic expansions of the earth's gravitational field. Special attention is given to the use of surface gravity anomalies in combination solutions, and to the elimination of the spherical approximation assumption that is made in some solutions. A recommended procedure for handling the terrestrial gravity data is to upward continue the anomalies from the surface of the earth to a bounding sphere. This upward continued data set is then used in a combination procedure. Calculations were made that showed that errors in computed geoid undulations made by not carrying out the upward continuation can be on the order of 10 cm at low ( <10) degrees and on the order of 2 cm at higher degrees. Recommendations are made in this report on how a new combination solution could be accomplished using existing satellite data, 30' x 30' mean anomalies in ocean areas, and 30' x 30' mean values in some land areas. This combination could lead to spherical harmonic expansions to degree 360.
Description
Prepared for National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland: NASA Grant No. NGR 36-008-161, OSURF Project No. 783210