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Gravitational spectra from direct measurementsA simple rapid method is described for determining the spectrum of a surface field (in spherical harmonics) from harmonic analysis of direct (in situ) measurements along great circle arcs. The method is shown to give excellent overall trends (smoothed spectra) to very high degree from even a few short arcs of satellite data. Three examples are taken with perfect measurements of satellite tracking over a planet made up of hundreds of point masses using (1) altimetric heights from a low-orbiting spacecraft, (2) velocity (range rate) residuals between a low and a high satellite in circular orbits, and (3) range rate data between a station at infinity and a satellite in a highly eccentric orbit. In particular, the smoothed spectrum of the earth's gravitational field is determined to about degree 400(50-km half wavelength) from 1 x 1 deg gravimetry and the equivalent of 11 revolutions of GEOS 3 and Skylab altimetry. This measurement shows that there is about 46 cm of geoid height (rms worldwide) remaining in the field beyond degree 180.
Document ID
19790064519
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Wagner, C. A.
(NASA Goddard Space Flight Center Geodynamics Branch, Greenbelt, Md., United States)
Colombo, O. L.
(NASA Goddard Space Flight Center Geodynamics Branch, Greenbelt, Md.; Ohio State University, Columbus, Ohio, United States)
Date Acquired
August 9, 2013
Publication Date
August 10, 1979
Publication Information
Publication: Journal of Geophysical Research
Volume: 84
Subject Category
Geophysics
Accession Number
79A48532
Distribution Limits
Public
Copyright
Other

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