Space Early Warning System On The Target Positioning And Forecasting

Space early warning system is an important part of ballistic missile defense system. In this dissertation,according to the establishment of space early warning system,location and prediction problems of ballistic missile are studied,using angel of arrival measurement from space-based infrared sensors. It is one of key technology of space early warning information processing.The main efforts and results of this dissertation consist of three issues:Chapter II studies kinematic modeling and state (i.e. position and velocity) estimation problem of ballistic missile during boost phase. Firstly linear polynomial kinematic model and constrained nonlinear kinematic model are presented. Simulation results show that the improved gravity turn model proposed in this dissertation more closely reflects the ballistic missile motion during boost phase. Then,Gauss-Newton algorithm is improved by use of angel measurement decoupling. And,according to two different ways,estimation problem of kinematic state during boost phase is solved.Chapter III studies tactical parameters estimation of boost phase and impact position prediction problems based on prior trajectory profile. Firstly a simple and practical method is proposed that prior trajectory profile and corresponding tactical parameters are used in modeling trajectory of boost phase. Then,improved Gauss-Newton algorithm is proposed to solve nonlinear estimation problem of tactical parameters by means of nonlinear projection transform. And,prediction algorithms of burnout and impact position are proposed and error is analyzed.Chapter IV studies trajectory estimation problem of ballistic missile during free flight phase with low Earth orbit satellites. Taking into account poor target motion observability,feasibility and limitation of Levenberg-Marquardt algorithm is analyzed. In order to conquer the limitation of L-M algorithm,two new simple and robust improved algorithms are proposed as follows:only position constrained filter algorithm,velocity and position filtering in turn algorithm.To sum up,Chapter II and Chapter III solve early warning problems of ballistic missile with only geostationary satellites. Chapter IV solves trajectory estimation problems of ballistic missile after burnout with low Earth orbit satellites. All of these methods and results can be used in practical space early warning information processing directly.