Attitude Determination Method of Satellite Based on Star Tracker and Gyroscope

An attitude determination method of satellite based on star trackers and gyroscope was proposed for the requirements of high precision attitude information for remote sensing satellite. The QUEST algorithm was improved according to the principle of solving eigenvectors by power method to solve the problem that QUEST algorithm can’t judge whether quaternions are positive or negative. On this basis,according to the extended Kalman filter( EKF) principle,the quaternion difference between the star sensor and the gyro output was used as the quantitative measurement of EKF to compensate the gyro drift.It not only obtains the continuous optimal solution of the vector information of the star sensor,but also compensates the drift error of the gyroscope, and improves the accuracy of attitude determination.Simulation results show that this method makes the attitude angle error and angular velocity error converge to zero and the accuracy of attitude angle error estimation is 0. 003°,and the accuracy of angular velocity error estimation is 0. 03°/h.

Conclusion

This article proposes a satellite attitude determination algorithm based on a star tracker/gyroscope combination to meet the demand for high-precision attitude information in remote sensing satellites. Firstly, improve the QUEST algorithm to accurately determine the positive and negative of quaternions, thereby outputting continuous quaternions. The attitude quaternion obtained from the star sensor’s star light vector processed by the improved QUEST algorithm is used as the measurement data of EKF to correct the drift of the gyroscope. Numerical simulations have verified that this algorithm can achieve high attitude estimation accuracy for the system.