Validating a Star Tracker Algorithm and Measuring Its Accuracy Through Suburban Night Sky Observations

Star trackers determine the attitude of objects by identifying stars in space and matching them to a catalog of stars. To validate the effectiveness of a star tracker, stellar images must be obtained, and real night sky observations offer results that are close to actual in-orbit situations. Measurement of absolute accuracy requires accurate camera orientation; however, determining the actual orientation of a camera during on-ground experiments is challenging. This study proposed a method to provide an orientation as close to the actual one as possible that considers both astronomical factors and mounting offsets. The efficacy of a star tracker algorithm, especially its background thresholding function, was evaluated using night sky images captured in a suburban area with interference from stray light and thin clouds. The star tracker algorithm provided continuous and stable attitude estimates with arcminute-level accuracy.