Research On Radar Multi-Target Tracking Technology For Space Detection

With the continuous development of astronautical technology and ballistic missiles,space is becoming more and more important in both civilian and military fields and therefore becomes a strategic fulcrum of major powers' competition.Effective space surveillance is the significant basis of exploiting space and protecting national security.As the most important equipment in space target detection,radar has advantages such as ultra-long range,all-weather and all-time capabilities and so on.Target tracking technology is the prerequisite of realizing continuous measurement for radar,it mainly consists of two subfields: data association and tracking filter.Radar's echo will be put into the signal processor firstly to get multiple targets' plots,then these plots will be processed by data processor to get stable and high-accuracy multiple targets' tracks through association and filter operation.This thesis emphasizes two specific problems in radar target tracking for detecting space targets: one is the filtering of space target's measurements and another is the discriminating and tracking of closely-spaced targets.Both of the two problems have practical application background.Linear least-square filter is widely used in engineering because of its simplicity and robustness.But for space targets,especially low orbit objects,the linear least-square filter based on polynomial model does not work well because of their high dynamic.This paper investigated sliding-window residual least-square algorithm and its improvement.It first gets a reference orbit using orbit extrapolation method,then gets the residual by subtracting reference orbit from measurements and finally filters the residual to reduce random error.Both Simulation and practical data proves this algorithm has good effects.For modern ballistic missiles,defense penetration capability is a basic requirement.One of the frequently-used ways for defense penetration is releasing decoys in the free flight stage.Because the relative speed of decoys and warhead is small,they are closely-spaced in a long time after separation,which brings difficulties for radar in discriminating and tracking of multiple targets.For this problem,the thesis proposed a discrimination approach based on coherent integration and an association method based on range-velocity joint processing.This method mainly uses radar's high velocity resolution ability when it works in coherent integration mode,so those targets which cannot be resolved in space resolution cells can be separated in Doppler dimension.Simulation result shows this approach can significantly promote the radar's ability for discriminating andtracking closely-spaced targets,thus it especially suits for measuring the targets' separation process.