Least squares collocation applied to local gravimetric solutions from satellite gravity gradiometry data

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1985-08

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Ohio State University. Division of Geodetic Science

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Abstract

An autonomous spaceborne gravity gradiometer mission is being considered as a post Geopotential Research Mission project. The introduction of satellite gradiometry data to geodesy is expected to improve our solid earth gravity models. This study explores the possibility of utilizing gradiometer data for the determination of pertinent gravimetric quantities on a local basis. The analytical technique of least squares collocation is investigated for its usefulness in local solutions of this type. It is assumed, in the error analysis, that the vertical gravity gradient component of the gradient tensor is used as the raw data signal from which the corresponding reference gradients are removed to create the centered observations required in the collocation solution. The reference gradients are computed from a high degree and order geopotential model. The solution can be made in terms of mean or point gravity anomalies, height anomalies, or other useful gravimetric quantities depending on the choice of covariance types. Selected for this study were 30' x 30' mean gravity and height anomalies. Existing software and new software are utilized to implement the collocation technique. It was determined that satellite gradiometry data at an altitude of 200 km can be used sucessfully for the determination of 30' x 30' mean gravity anomalies to an accuracy of 9.2 mgal from this algorithm. It is shown that the resulting accuracy estimates are sensitive to gravity model coefficient uncertainties, data reduction assumptions and satellite mission parameters.

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Prepared for National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland: NASA Grant No. NGR 36-008-161, OSURF Project No. 783210

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