Satellite Attitude Determination Technology Based On Star-sensor And Gyro

Satellite attitude determination is the base of satellite attitude control and space mission complete. With the developing of spaceflight technology and space mission complication, there has higher request for satellite attitude precision and stability, how to use the limited resource on satellite to improve satellite attitude determination precision has become an importance studying task. These days, attitude determination combination star-sensor with gyro can reach the high precision, because the measure identity of two kinds of attitude sensors are difference, combination star-sensor with gyro can overcome shortcoming of each other, these combinations can reach of high precision satellite attitude determination. This paper mainly researches on satellite attitude determination technology based on star-sensor and gyro. The main work of this paper is concluded as follows.Firstly, study of mending EKF attitude determination algorithm. typical satellite attitude determination algorithm based on star-sensor and gyro use gyro drift error estimation information to modify gyro angle velocity, but this method operation complexity. Satellite attitude determination algorithm based on predigest error correction with star-sensor/gyro was proposed to solve this problem. By predigest correcting the angular velocity of gyro, the states variables and complexity of filter were reduced. Simulation results indicate that the proposed algorithm provides effective performance in the computational complexity and instantaneity when it performances as the same as the typical algorithm in attitude determination precision.Secondly, study of EKF algorithm based on MRPs. Satellite attitude determination algorithm based on MRPs correction with star-sensor/gyro is based on quaternion attitude determination algorithm. Simulation the attitude determination precision and computational complexity of MRPs algorithm. Comparing the performance of MRPs algorithm with the quaternion algorithm.Lastly, study the influence of dithering to satellite attitude determination precision. Satellite in the orbit exist dithering because of control system and load mechanism movement. This dithering leads to the decrease of attitude sensor measurement precision. Establishing the attitude dithering model through analyzing the principle of measurement error. Dithering could be classified different kinds based on their frequency and scope. Many kinds of attitude determination projects have been put forward for different dithering. Simulation analysis the influence of dithering to satellite attitude determination precision using primary attitude determination algorithm. Designing the calculate of attitude error algorithm and validating its validity.