Abstract: To raise the precision of post attitude determination, the rauch tung striebel (RTS) filter algorithm is introduced based on EKF. Currently the errors are usually used as state variables in EKF to determine the attitude. Via calculating the data obtained from EKF, the RTS smooth filter is successfully applied to post attitude determination, and at the same time, the singularity of the error covariance matrix is evitable. The simulation results indicate that the RTS smooth filter algorithm is significantly better than EKF in post attitude determination.

Key words: star sensor, gyro, post attitude determination, RTS smooth filter algorithm