AAS 98-159
TOWARD THE MOST ACCURATE ATTITUDE DETERMINATION SYSTEM USING STAR TRACKERS
D. Mortari - Universita degli Studi "La Sapienza" di Roma, Italy; T. C. Pollock, J. L. Junkins - Texas A&M University
Abstract
An application of the Attitude Error Estimator Algorithm (AEEA), here fully developed, to evaluate the gain in attitude accuracy obtainable by a new star sensor idea, is here presented. The AEEA, which is based on the right definition of the attitude error and on the spatial displacement of the observed directions, allows an accurate estimation of the attitude accuracy obtainable with a given attitude data set (sensors' error and observed directions). The attitude error statistical parameters, such as the expectation, the standard deviation and the variance, are shown to be related to the maximum value only. The application shows that, with respect to the classical star sensors, the proposed new star sensor achieves a substantial gain in the obtainable attitude accuracy, which is also shown to be almost independent of both the number of observed stars and the sensor field of view. In general, the AEEA can be applied to establish which attitude determination system, among a given set of attitude sensor allocations, is the most accurate.
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