Autonomous, all-stellar attitude determination experiment - Ground test results

An all-stellar instrument is designed to demonstrate five-arcsec autonomous attitude determination on a NASA Spartan spacecraft. The instrument includes a charge-coupled device (CCD) star camera that provides centroid measurements of up to five simultaneous star images with an update rate of 10 per second. At slue rates less than 0.1 degrees per second the camera accuracy varies from 5 to 15 arcsec per image, depending on star magnitude. The instrument processor matches measured stars with a 9000 entry catalog and then computes a single-frame and Kalman-filter estimate of Spartan attitude and attitude rate each second. By using multiple star images for attitude determination, an accuracy of a few arcsec can be obtained.