Obtaining 3-Axis Attitude Solutions From GPS Signal to Noise Ratio Measurements

Jared Madsen

Abstract:	This paper investigates the performance of an algorithm which uses Kalman filtered signal to noise ratio (SNR) measurements from two GPS antennas at differing angles to derive a full 3 axis attitude solution for a rigid body such as a spacecraft. This algorithm could be used by low-earth orbiting satellites which have rather coarse attitude requirements, or could be utilized as a back-up method of attitude determination when more accurate, but less robust methods, fail. Performance of the algorithm is investigated during static attitude states as well as during periods of attitude maneuvers. Evaluations are also done on the effects of varying the constants used by the filter as well as the effects of varying the offset angle between the antennas. Finally, the impact of various expected error sources are investigated. The analysis demonstrates that a Kalman filtered SNR algorithm can provide surprisingly accurate measurements of attitude from GPS signal sources. Additionally, the results show that this approach is relatively robust in the presence of many types of error sources.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2927 - 2936
Cite this article:	Madsen, Jared, "Obtaining 3-Axis Attitude Solutions From GPS Signal to Noise Ratio Measurements," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2927-2936.
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