Research On Spacecraft Attitude Determination Algorithm Based On Federal Filter

We need to research on federal filter theory and application more, for ensure that the spacecraft mission successful completed, and for improve the accuracy and the reliability of spacecraft attitude control system. To improve precision and fault-tolerant of spacecraft attitude control system, In this paper, we will study multi-sensor information fusion filter algorithm, for multi-sensor of aircraft attitude control system, on sensor normal, attitude angular sensor fault and attitude angular rate sensor fault, three conditions. This paper includes:Establish the measurement models of sensors, according to the configuration of attitede control system; combine with federal filter principle, design the structure of the federal filter, establishing federal filter system equations and design federal filter based on spacecraft attitude kinematics equation; in recent years many scholas study on information-sharing coefficient of federal filter and research on the affect to sub-filters and main filters of different information-sharing coefficient, through theoretical analysis and simulation.Research on fusion strategy of the federal filter with one attitude angle sensor occurred gradient-type'soft failure'condition. First of all, research on the affect of pollution to nomal sub-filters with different information-sharing derived by theory, when one sub-filters fault caused by the attitude angle sensor fault; Second based on the affect of select information-sharing coefficient to nomal sub-filter pollution, put forward a failure probability based expert system for robust federal information sharing coefficient filter allocation, for reduce the affect of fault sub-filter to normal sub-filter, before the fault are detected, in order to made fast reconstruction's convinience.Research on federal filter information fusion strategy, when attitude gyro angular rate sensor fault. when attitude gyro angular rate sensor fault, federal filter can not work cause of benchmark lost. So, adapt the diference of the first two steps prediction attitude angle to replace the attitude angular velocity, in order to made the federal filter can work. Then, because of the lack of attitude angle rate measurement, we can not use conventional PID control method to control the spacecraft attitude. So, a control method based on angular momentum conservation is designed.Theoretical analysis and simulation results show that the federated filter can improve the accuracy of attitude determination. Adjusted coefficient of information sharing, can reduce the normal sub-filter's pllute. Then made the spacecraft degradation work, with improved federal filter and angular momentum control.