Beacon-assisted spacecraft attitude control systems and methods

摘要

Control systems and methods are provided which enhance acquisition range, transient response and offset pointing accuracy in beacon-assisted orientation of a spacecraft to a desired spacecraft attitude Adsrd. The methods receive a beacon signal with antennas that are arranged in a fixed angular relationship to thereby form an attitude error signal Serr whose magnitude is a measure of the attitude difference between a current spacecraft attitude Acrnt and the desired spacecraft attitude Adsrd. A sum power PSIGMA that is the sum of the signal powers from the antennas is sensed and a signal modifier Smod is generated that increases with decreases in the sum power PSIGMA. The attitude error signal Serr is then modified with a term (1+Smod) to form an enhanced attitude error signal Serrenhd. In one embodiment, the signal modifier Smod is n|Pmax-PSIGMA|m wherein n and m are positive numbers and Pmax is the sum power PSIGMA when the attitude error is zero.