Techniques for the Derivation and Evaluation of Truncated Gravitational Models for Special Applications
DEFENSE MAPPING AGENCY AEROSPACE CENTER ST LOUIS AFS MO
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In many applications, it is necessary to use a truncated gravitational model because of limitations in computer hardware and software or mission requirements. Consequently, studies have been performed to evaluate the effect of truncation and also to determine the best method for the derivation of eighth and 12th degree and order gravitational models. Three methods were used for their derivation truncation by chopping the original more complete model, suppression of parameter corrections for all harmonic coefficients above the desired degree and order, and by not allowing as parameters any gravitational model coefficients above the desired degree and other limitation. The procedures for the derivation and subsequent analysis were applied to both the Department of Defense World Geodetic System 1972 and the 1969 Smithsonian Standard Earth II gravitational models.