Attitude Determination Algorithm Of Spacecraft Based On Star Sensor

The attitude determination of spacecraft in orbit is a basic problem in spacecraft system engineering and also the foundation for spacecraft to carry out various space missions.Whether the spacecraft orbital attitude maneuver,rendezvous and docking,or earth observation and orientation to the sun,spacecraft system needs to have accurate control of its real-time attitude.Traditional attitude determination methods of spacecraft are mainly based on the principle of space coordinate transformation or data fusion of various attitude sensors.The former cannot restrain or overcome the attitude error caused by the observation noise of the attitude sensor,while the latter makes the system structure more complicated and brings a lot of inconvenience to the design of the system.In order to improve these problems,a new joint attitude determination algorithm based on single star sensor is designed and proposed in this paper.The performance of the algorithm is verified by computer simulation.Aiming at the research content and expected goal,a joint attitude determination algorithm is designed and proposed.After deeply studying the dynamics and kinematics of the spacecraft,the attitude determination system of the spacecraft is modeled by using the nonlinear filter theory.Based on the Unscented Kalman Filter algorithm,this paper makes a local improvement on the algorithm by using the principle of two-vector attitude determination,and the joint attitude determination algorithm is designed.As a supplement and extension of the joint attitude determination algorithm,an attitude correction algorithm is designed and proposed to cope with the special situation that may occur during the operation of spacecraft.Based on the previous system state estimation,the environmental disturbance moment of the spacecraft was curve-fitted.The numerical solution of spacecraft attitude is obtained by numerical integration,and then corrected by using the incomplete star sensor data.The effectiveness of the algorithm design is verified by MATLAB computer simulation.The joint attitude determination algorithm has a higher attitude determination accuracy,a faster convergence speed of attitude estimation error,and a good real-time performance.The attitude correction algorithm can effectively correct the attitude estimation of the system,greatly delay the rising rate of the estimation error,and ensure the error of attitude determination within the acceptable range in a short time.