High precision attitude estimation algorithm using three star trackers

This paper presents an attitude estimation algorithm for the satellite with three star trackers. The attitude estimation accuracy can be improved by modifying attitude matrix with measurement data from other star trackers. The attitude determination algorithm with two star trackers was reviewed firstly, then a modified attitude estimation algorithm using three star trackers is proposed to enhance the precision of the attitude estimation. The extended Kalman filter is used to estimate the attitude of the nonlinear satellite system, and a federated configuration is adopted to process the estimated states and covariance matrices for high accuracy attitude estimation. Using the proposed algorithm, the satellite can perform missions continuously. A mathematical simulation is performed to verify the effectiveness of the adoption attitude estimation algorithm, using a designed PD controller and five reaction wheels as the attitude control system; three star trackers mounted with a titled angle as the measuring system and federated extended Kalman filters as the attitude determination system.