Threat Object Information Handover In Ballistic Missile Defense System

This work does a research on the threat object information handover from the ground based radar to onboard infrared (IR) sensor in ballistic missile defense system (BMDS). It will reduce the difficulty of IR target identification and save more time for interceptor if IR sensor uses radar handover information correctly for target selecting.The work in this paper includes the establishment of threat object information handover model in BMDS, the preprocessing of radar handover information, and information handover method, etc. The feasibility and availability of the method are tested and verified by the results of simulations.Firstly, the intercepting flow is analyzed accepting the information handover technology. The position measurements are selected for handover by analyzing the radar and IR object characteristics. Then the threat object information handover models of mono-target, multi-target, and target group are established. Multi-target handover problem is modeled as multi-target assignment problem. Target group handover problem is modeled as group assignment problem.Secondly, radar handover information is preprocessed include abnormal value removal, temporal and spatial alignment, aimed at the difference between radar and IR measurements. The validity of the association data and the accuracy of handover are ensured by the preprocessing. As the radar measurement error enlarging nonlinearly through special coordinate transform, model and analysis of error transformation are presented. The presence of bias will destroy the correct handover, we formulate the change of bias with coordinate transform.Thirdly, on the basis of information handover model, object correlation algorithms are analyzed. The coarse gating of radar and IR object correlation is discussed in order to reduce the difficulty of object correlation. The formula of cost is derived by the generalized likelihood ratio test. Methods such as Hungary algorithm, nearest neighbor method, element discrimination value allocation method, and auction algorithm are designed to solve the multi-target assignment problem. Some modified methods are obtained aimed at the incomplete methods. The modified nearest neighbor method is found with good performance and less operation time by simulation, and the method is selected as the principal assignment method for the BMDS. The information handover simulation in BMDS is developed. The influences for correctly information handover of the changing of the interceptor's line of sight and different sensors configures are analyzed.Lastly, summary of this dissertation is made and the present problems and further research are pointed out.