Research On High-precision Attitude Measurement Of Agile Satellite

Agile satellite covers attitude agile control technology,control technology of high precision imaging technology and rapid response in the integration of satellite.It can point to the strength and stability in the process of motor ability,and can complete in a single satellite of multi-objective collaborative imaging,bar area splicing imaging and 3D imaging and a series of multiple points of view more fusion task.High accurate is needed by agile satellites and orbit measuring considering that the existing satellite on board with a primary measuring element of star sensor,the star map recognition and attitude determination algorithm is the core of the high precision attitude measuring problem and the traditional method is difficult to meet the needs of agile motor,so it is necessary to carry out the dynamic process of the agile map quickly identify method and attitude determination research method.This paper mainly study the followings:Firstly,this paper built agile satellite attitude determination and attitude control model,and the attitude dynamics model and the attitude kinematics model,respectively,to define common coordinate system,and defines the description of the satellite attitude.Based on the analysis of the kinematics and dynamics model,this paper analyzed the influence of agile satellites' fast maneuver to sensors and attitude determination algorithm.The fast maneuver will enlarge the measuring error of gyroscope.And there is aberration in star sensor which reduce the success rate of star identification.Meanwhile fast maneuver has an effect on the accuracy of attitude determination.This paper study the core technology of star sensor,and the star map recognition technology,analysis the disadvantage of the existing algorithm.This paper put forward a improved algorithm based on pattern recognition,throughout the earth within the scope of random simulation map to verify this algorithm,the results show that the proposed algorithm of star map identification can meet the requirements of agile satellites of quickness,at the same time,the location and magnitude noise had stronger robustness,and it also had strong anti-interference ability to the vibration of the flexible components.Finally,the paper analyzed the attitude determination algorithm based on multiple sensor information fusion,using star sensor to measure information and mutual compensation and gyroscope to measure information fusion,on the basis of the model,EKF filtering algorithm was analyzed on the problems existing in the satellite attitude estimation,EKF can be the linearization of the system in agile satellites introduce significant error under the condition of rapid change,Therefore according to the problem,this paper put forward the improvement of NPF-EKF filtering algorithm,introducing approximation algorithm for the system model of real-time estimation error,improving the accuracy of estimating the pose.The simulation results proved that NPF-the attitude of EKF estimation precision can meet the requirements,at the same time it can meet the fast working mode of agile satellite.