Sensitivity of GPS-based LEO Satellite Attitude Determination

Werner M. Rupp

Abstract:	The use of GPS for attitude determination of LEO satellites poses several problems to the satellite designer. One concerns the mounting of the GPS antennas which constitute the baselines for differen- tial phase measurements. For optimum performance, the orientation of the baseline vectors has to be such that they provide the best possible sensitivity of atti- tude determination. Sensitivity is defined as the root- mean-square of the weighted changes in differential range for a given small-angle rotation about all three body frame axes of the satellite’s attitude from its no- minal state. Secondly, the field of view from the ze- nith platform of an Earth-oriented satellite is usually limited to less than the hemisphere by appendages such as antennas and solar panels. A smaller field of view means a smaller number of simultaneously “vi- sible” GPS satellites which can be used for attitude determination. Several computer graphs are presented which demon- strate the influence of baseline orientation and num- ber of baselines on the achievable sensitivity and its variance over time. Moreover, the influence of a limi- ted field of view is shown. In oder to correlate sensiti- vity with attitude determination, additional computer graphs show the errors of determining the rotation angles as a result of errors in the differential ranges for several baseline configurations and for different fields of view.
Published in:	Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996) September 17 - 20, 1996 Kansas City, MO
Pages:	1091 - 1099
Cite this article:	Rupp, Werner M., "Sensitivity of GPS-based LEO Satellite Attitude Determination," Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996), Kansas City, MO, September 1996, pp. 1091-1099.
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