Generalized dynamic motion compensation technology for star tracker on rotating spacecraft with acceleration

The influence of acceleration resulting from spacecraft maneuvering on star spot positioning and hereafter dynamic motion compensation technology are addressed. Firstly the pattern of the smeared star-spot image under maneuvering condition and the locating error are investigated. It is found that instead of following a symmetrical shaped pattern, the smeared star spot under acceleration is twisted. Simulation verifies that the position error is far beyond Cramer Rao Lower Bound(CRLB) of photoelectric devices under uniform velocity. Then a novel scheme to derive the more general accurate motion compensation is proposed. In this case, an approximate CRLB is derived to give a baseline to measure the performance of any positioning algorithm and motion compensation technique on star tracker. The theory and corresponding simulations show the novel general compensation approach is better than the conventional compensation strategy and close to the approximate CRLB. Therefore, a CRLB position accuracy of star spot is expected to be realized by using the generalized dynamic compensation method on maneuvering spacecraft.