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Optimum data weighting and error calibration for estimation of gravitational parametersA new technique was developed for the weighting of data from satellite tracking systems in order to obtain an optimum least squares solution and an error calibration for the solution parameters. Data sets from optical, electronic, and laser systems on 17 satellites in GEM-T1 (Goddard Earth Model, 36x36 spherical harmonic field) were employed toward application of this technique for gravity field parameters. Also, GEM-T2 (31 satellites) was recently computed as a direct application of the method and is summarized here. The method employs subset solutions of the data associated with the complete solution and uses an algorithm to adjust the data weights by requiring the differences of parameters between solutions to agree with their error estimates. With the adjusted weights the process provides for an automatic calibration of the error estimates for the solution parameters. The data weights derived are generally much smaller than corresponding weights obtained from nominal values of observation accuracy or residuals. Independent tests show significant improvement for solutions with optimal weighting as compared to the nominal weighting. The technique is general and may be applied to orbit parameters, station coordinates, or other parameters than the gravity model.
Document ID
19900003669
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Lerch, F. J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1989
Subject Category
Geophysics
Report/Patent Number
NAS 1.15:100737
NASA-TM-100737
REPT-89B00158
Accession Number
90N12985
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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