Spacecraft Attitude and Body Rate Estimation with Four Star Sensor Heads: Concepts and Ground and On-Orbit Verification Results

We have developed a star sensor system with four heads as a prototype of a future small and low-priced satellite attitude controller. To reduce size and cost of the controller, we integrate attitude sensors into star sensors with medium resolution and medium sensitivity and adopt Commercial Off-The-Shelf (COTS) electrical parts for key parts such as CPU and CCD. Newly developed computer architecture is introduced for high reliability with COTS parts under the harsh space environment. In this paper, we will focus on the new star identification algorithm dedicated for the proposed four-head star sensor system and evaluate it with ground test and on-orbit check-out data.