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An Empirical Method for Determining the Lunar Gravity FieldA method has been devised to determine the spherical harmonic coefficients of the lunar gravity field. This method consists of a two-step data reduction and estimation process. In the first step, a weighted least-squares empirical orbit determination scheme is applied to Doppler tracking data from lunar orbits to estimate long-period Kepler elements and rates. Each of the Kepler elements is represented by an independent function of time. The long-period perturbing effects of the earth, sun, and solar radiation are explicitly modeled in this scheme. Kepler element variations estimated by this empirical processor are ascribed to the non-central lunar gravitation features. Doppler data are reduced in this manner for as many orbits as are available. In the second step, the Kepler element rates are used as input to a second least-squares processor that estimates lunar gravity coefficients using the long-period Lagrange perturbation equations.
Document ID
19720015209
Acquisition Source
Headquarters
Document Type
Thesis/Dissertation
Authors
Ferrari, A. J. (Bellcomm, Inc. Washington, DC, United States)
Date Acquired
September 2, 2013
Publication Date
September 1, 1971
Subject Category
Space Sciences
Report/Patent Number
NASA-CR-126149
TM-2014-1
Accession Number
72N22859
Funding Number(s)
CONTRACT_GRANT: NASW-417
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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