A Constant-Gain Satellite Attitude Determination Method Based on Projection

Since the Extended Kalman Filter (EKF) algorithm requires computing Jacobi matrix and gain matrix on-line, a constant-gain Kalman filter algorithm based on projection is applied to satellite attitude determination system in this paper. Firstly, in order to avoid the calculation of Jacobi matrix, a projection method is used to obtain the time-invariant measurement matrix. Then, the gain matrix of EKF is replaced by the constant gain matrix, which is obtained when the filter get stable. So the real-time performance and stability have been improved greatly. The simulation results show that the method not only has the advantage of saving computation time, high stability, but also ensure high accuracy of attitude determination.