Satellite Attitude Determination Based On Star Sensor And Gyro System With Multiplicative Noise

Satellite attitude determination is one of the key issues in satellite technology. It directly affects the accuracy of performance of satellites. For the sake of the re-quirement of satellites'high precision and reliability, the satellite attitude measure-ment system with star-sensors and gyroscopes has become the prevalent pattern. star-sensor is a high-precision instruments, there are several error sources, we con-sider the model error which is introduced into star-sensor measurement equation. This model error in the measurement equation performances as the form of multi-plicative noise affecting the accuracy of satellite attitude determination. Based on the star-sensor and gyros pattern attitude determination system with multiplica-tive noise, a algorithm is optimal in the sense of linear minimum-variance according to the concept of the linear minimum variance and the projection formula. This method can be more effective to overcome the effect to the attitude determination caused by multiplicative noise. The main research work are as follows:1. Multiplicative noise in the model:Firstly, the source of multiplicative noise is analyzed, then we can derive its form of measurement equation.2. Satellite Modeling:Firstly, a variety of reference coordinates and the con-version between them, attitude representation methods are generalized and ana-lyzed systematically. Then the attitude dynamic model are developed employing Quaternion and Euler-Angles representation. Under the condition that the star-sensor's measurement model contains multiplicative noise, we can establish the star sensor measurement equation with multiplicative noise. Then the measure-ment equation with multiplicative noise and the equation of state basing on error quaternion are proposed.3. Satellite attitude determination algorithms:Based on the star-sensor and gyros pattern attitude determination system with multiplicative noise, a attitude determination algorithms is suited to deal with multiplicative noise. This algo-rithm can effectively inhibit the effect to the attitude determination caused by multiplicative noise. Simulation results show that this algorithm is better than EKF not to deal with multiplicative noise, this algorithm perform well in satellite attitude determination.