Optical correlator for star identification and tracking

Abstract

Star tracker is one of the most important spacecraft attitude sensors which can achieve accuracies within several arc-seconds utilizing star identification and star tracking. The refresh rate and accuracy of star tracker are constrained as there are so many stars in the sky. A novel star identification and tracking method for star tracker using optical correlator is proposed to solve this problem of star map comparing and identification. The proposed optical correlator can optically execute the correlation operation between current star map and the standard star map constructed from the star catalog. The whole sky star identification can be completed within 100ms due to the inherent parallel computing ability of optical correlator. Star map motion can be tracking with an accuracy of up to 1/100 pixel. Computer simulations and experiments indicate that this method has great robustness to small signal-to-noise ratio, and improve the performance of star tracker remarkably. © 2009 Springer-Verlag Berlin Heidelberg.