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Proceedings Paper

Ultra High Resolution Science Data Extraction For The Gravity Probe-B Gyro And Telescope
Author(s): Richard A. Van Patten; Ray DiEsposti; John V. Breakwell
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Paper Abstract

In 1960, Leonard Schiff predicted, using Einstein's General Theory of Relativity, that a gyroscope in orbit about the Earth would experience a precession of its spin axis relative to the "fixed stars". Two relativistic precessions are predicted: a "geodetic" precession associated with the orbital motion of the gyro about the Earth, and a "motional" precession due to the Earth's rotation. For a gyro in a 650 km altitude polar orbit with its spin axis initially pointed towards an inertial reference, in this case the star Rigel, and lying in the orbital plane, the geodetic precession is 6.6 arcsec/yr north , and the motional precession is 0.042 arcsec/yr east. This scenario is illustrated in Figure 1. To detect these relativistic drifts, a gyro is currently being developed whose absolute Newtonian drift rates are less than 10-3 arcsec/yr. Even with such a "perfect" gyro, however, the question arises: Can the relativistic drifts be detected in the presence of random measurement noise, and other error sources such as satellite attitude control system errors, Rigel proper motion uncertainty, drifts due to gyro suspension forces, drift of electronic parameters such as instrument scale factors due to thermal effects, etc.? This paper describes an all-digital data flow simulation that demonstrates the Kalman Filter data reduction process for detection of the relativistic drifts. The simulation demonstrates successful optimal estimation of the relativity effects in the presence of the expected measurement noise and consistent with the experiment lifetime, and the other above-mentioned effects.

Paper Details

Date Published: 18 July 1986
PDF: 9 pages
Proc. SPIE 0619, Cryogenic Optical Systems and Instruments II, (18 July 1986); doi: 10.1117/12.966649
Show Author Affiliations
Richard A. Van Patten, Stanford University (United States)
Ray DiEsposti, Stanford University (United States)
John V. Breakwell, Stanford University (United States)

Published in SPIE Proceedings Vol. 0619:
Cryogenic Optical Systems and Instruments II
Ramsey K. Melugin, Editor(s)

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