GPS Based Star Sensor Aiding for Attitude Determination in High Dynamics

Christian Arbinger, Werner Enderle and Otto Wagner

Abstract:	The applications of GPS in space, such as orbit and attitude determination, offer several advantages, e.g. complete navigation information on board, low weight, volume and power consumption. GPS used for attitude determination in space has many important advantages like the fast and reliable initial acquisition, the resistance against high spin rates and the fact, that at least two satellites for deterministic attitude determination are visible for most of the duration of the mission. GPS could also be used as a safe mode sensor. Therefore GPS based attitude determination seems very promising. Due to the achievable accuracy, depending on the baseline length and the signal noise figure, a GPS attitude sensor cannot be used for missions were high accurate attitude measurements are needed and the baseline lengths are restricted. A particular field of interest is the broad and evolving area of earth observation missions and their corresponding requirements for a high position and attitude accuracy related to image processing. For these missions, a star sensor will be the adequate attitude sensor. Star sensors are highly accurate and well established algorithms are available. The disadvantages using star sensors are e.g. restricted field of view, operation only at low angular rates, sensor performance degradation and sensitive to problems related to star pattern recognition. Taking all these individual advantages and disadvantages into account, the combination of a GPS attitude sensor and a star sensor seems extremely promising, because such a sensor combination can be applied to a broad area of missions and their requirements of a high accurate attitude. The GPS attitude sensor aids the star sensor within the star pattern recognition process, resulting in improvement of accuracy and robustness with respect to the attitude solution. This can even be achieved in scenarios with high angular rates. Due to the fact that the star sensors used in this research did not support the input of reference attitude data for aiding, a software simulation approach was set up. GPS based attitude measurements are fed into the star sensor software model in order to increase the area of applicability.
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:	2952 - 2971
Cite this article:	Arbinger, Christian, Enderle, Werner, Wagner, Otto, "GPS Based Star Sensor Aiding for Attitude Determination in High Dynamics," 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. 2952-2971.
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