Research On The Combined Attitude Determination Method Based On Star Sensor And Gyro

Star sensors and gyroscopes are high-precision attitude measurement equipment.They are deployed on remote sensing satellites to acquire attitude information of satellite imagery at the moment of shooting.This is an important guarantee for achieving high-precision target positioning without ground control.With the continuous improvement of the positioning accuracy of remote sensing satellites,the requirements for the accuracy of attitude determination have become higher and higher.This paper aims to obtain high-precision attitude information by using star sensor and gyro measurement data,and focuses on the key algorithms of star sensor and gyro combination attitude determination techniques.A large number of experiments have been conducted using simulation test data.The work and major innovations completed by the dissertation include:(1)Combing the development status of star sensors and gyroscopes,introducing the basic principles of the dynamic filtering estimation algorithms in star sensor and gyro combination determination algorithms,and analyzing the features of typical state estimation filtering algorithms such as the extended Kalman filter,unscented Kalman filter,nonlinear predictive filter and particle filter,and the recent research progress of each filtering algorithm are introduced.(2)The basic coordinate system involved in satellite orbit parameters and attitude determination is introduced.Analyze the characteristic of two typical attitude described methods include methods Euler angles described method and quaternions described method.The equator kinematics equations based on Euler angles and quaternions are studied separately.Then,the basic principles of star sensor and gyro data simulation are analyzed,and the implementation flow of star sensor and gyro data simulation based on satellite orbital parameters is designed,and simulation data is produced.(3)The basic principle and characteristics of the extended Kalman filter algorithm are studied.The star sensor and gyro combined attitude determination algorithm based on extended Kalman filter is designed and implemented.The combination of star sensor and gyroscope with different precision and frequency is carried out.Analyze the effects of the accuracy and frequency of the star sensor and gyro on the attitude accuracy,and improve the accuracy of the star sensor or improves the gyro frequency can obviously improve the precision of the combined attitude.(4)The basic principle of the unscented Kalman filter algorithm is introduced,the characteristics of the unscented Kalman filter are analyzed.The characteristics of the unscented Kalman filter are analyzed.The realization process of the combination of star sensor and gyro based on the unscented Kalman filter is designed,and the combination of the star sensor and the gyroscope with different precision and frequency is carried out.The combined attitude of star sensor and gyroscope based on extended Kalman filter and unscented Kalman filter is compared and analyzed.The simulation experiment results show that the two filtering algorithms have good filtering stability and ideal position accuracy,and the convergence speed and precision of the method based on unscented Kalman filter are faster and higher.It has a good application prospect.