Study On Location Technology For Space Non-Cooperative Target Based On The Extended Kalman Filter

All the aerospace countries want to achieve a target which to control all thespace. Motion states estimation( position and velocity estimation ) of a spacenon-cooperation target is the foundation and precondition. Space non-cooperationtarget means satellites and ballistic missiles from hostile countries. Space-basedsystem has the advantage to track and observe of the space non-cooperation target.In the space-based system, space maneuver vehicle is an effective means ofanti-satellite and space-based infrared system is the important part of ballisticmissile defense system. The main research included in this paper is algorithms ofmotion states and orbit parameters estimation of non-cooperation satellite andballistic missile.Motion states estimation belongs to navigation area. The Extended Kalmanfilter (EKF) method linearized by optimal state is studied firstly. Then twoapplications using extend Kalman filter are studied as below:First one, motion sates and orbit parameters estimation of the non-cooperationsatellite.According to the relationship of the relative motion between the chaser aircraft(the space maneuver vehicle) and the non-cooperation target aircraft within adistance of 40 kilometers, a relative navigation algorithm was proposed to estimatethe position and velocity. It was based on the measurement information of VisualNavigation Camera and Laser Ranger Finder. The target aircraft's orbit parametersare accounted at last. Simulation results verify the validity of the navigationalgorithm and show higher navigation accuracy relatively.Second one, motion sates estimation of the ballistic missile.The dynamic functions of the ballistic missile are built firstly, which includedthe boost phase, ballistic phase and reentry phase. Using the tracking infraredcamera, the relative position of the missile and the early-warning satellite are got asmeasurement information. The missile's motion states are estimated using EKFfinally. An improving gravity turn model was adopted in boost phase, and earthgravitational field model with perturbing term was adopted in ballistic phase. In thesimulation, STK (satellite tool kit) was used to make the early-warning satellitessystem and the target ballistic missile, which enhances the reliability greatly.Simulation results verify the validity of the former algorithm and show higherestimation accuracy relatively.