Study On Radar Target Detection Technology Based On Passive Bistatic Radar

The passive bistatic radar(PBR)is an important application of the bistatic radar.The radar itself does not transmit radio signal outside.Instead,it detects,locates and tracks target by receiving the reflected wave of the signal emitted by external radiation source in the air.Different external radiation source signals have different characteristics.Generally,the PBR using mobile communication signals has good detection capability for low-altitude targets.Therefore,the PBR has a good application value.LTE signal is a new generation mobile communication signal.It has the characteristics of stability and wide distribution,etc.Therefore,it has a lot of excellent characteristics as an external radiation source that can be utilized.The paper discusses the moving target detection technology of PBR based on LTE signal.The main contents of this paper are summarized as follows:Firstly,the basic characteristics of LTE signal are analyzed and the range resolution and speed resolution of actual sampled signal are discussed in this paper.According to the ambiguity function theory,we analyze the distance blur and velocity blur of the LTE signal.In this paper,the main parameters of LTE signal and other external radiation source signal are compared and the results show that the target detection capability of LTE signal is stronger,and the feasibility analysis of PBR based on LTE signal is completed.Secondly,we compare the performance of commonly used clutter suppression algorithms.In the multi-target,strong direct wave and strong multi-path environment.we discuss the clutter suppression capabilities of LMS,NLMS,RLS,and ECA algorithms and the ability to detect targets,and the response and convergence characteristics of the algorithms themselves.Comparing the characteristics of various aspects,the ECA algorithm was finally selected as the direct wave cancellation algorithm of the system.After that,the influence of main parameters of ECA algorithm(the number of segments and the reference distance)on clutter suppression is discussed.Finally,we discuss the system design of PBR based on LTE signal and introduce the system design of each sub module.The effectiveness of the system is verified by simulating different intensity targets,direct waves,and different numbers of multipath signals.Then we discuss the FPGA implementation of the clutter suppression module and details the simplified clutter suppression module based on the extended cancellation algorithm and the computation of complexity,and focuses on the implementation of various calculation sub-modules,such as the correlation matrix module,inverse module and so on.Finally,the actual test shows that the clutter suppression module can effectively suppress the clutter.