Research On Direct Position Determination For Passive MIMO Radar

Passive MIMO radar is a passive multistatic radar system consisting of multiple noncooperative transmitters and multiple receivers.Compared with SISO passive bistatic radar,the passive MIMO radar can obtain additional space and frequency diversity gain,reducing the probability of miss caused by the time domain discontinuity,time-varying power and bandwidth of the non-cooperative transmitters.The increase of observation information can also obtain higher target positioning accuracy,which has practical application value.The direct position determination method of passive MIMO radar centralized processing directpath signals and target-path signals received by all receivers by building a mathematical model of the system scene.This centralized processing method detects and locates targets directly in the Cartesian coordinate space.Instead of two steps of parameter estimation and location equation solution,the direct position determination method derives the target’s position directly from the direct-path and target-path signals by building a mathematical model.The direct position determination method of centralized processing not only makes use of the correlation between the reference channel and the surveillance channel intrareceiver,but also makes use of the correlation between the reference channel and the surveillance channel,and the correlation between the surveillance channel and the surveillance channel inter-receiver.However,the global grid search method for direct position determination greatly increases the computational complexity,which makes it difficult to apply in practice.Therefore,around the above problems in passive MIMO radar direct position determination,this paper carries out relevant research,the main research results are as follows:1.This paper considers a scene in which a target is directly positioned by a passive MIMO radar network composed of multiple non-cooperative transmitters and multiple receivers using planar array antennas in three-dimensional space.The element-level signal models of multiple direct-path and target-path signals in the passive MIMO radar network are established,and then the above signal models are represented concisely and uniformly by a matrix method.2.Based on the method of generalized likelihood ratio test,the cost functions of SS-GLRT and RS-GLRT are constructed respectively.The performance of the two direct position determination methods is simulated and analyzed.Then,to reduce the computational complexity of global grid search using SS-GLRT and RS-GLRT,a three-dimensional iterative grid search method is proposed.3.By analogizing the ambiguity function of radar signals,the ambiguity characteristics of the SS-GLRT direct position determination method which only uses the target-path signal,and the RS-GLRT direct position determination method which uses direct-path and targetpath signal are analyzed.This paper mainly discusses the factors that affect the ambiguity characteristics and the relationship between the waveform ambiguity function of the transmitter signal,then combines a case when Link16 signal with undesirable waveform ambiguity function is used for direct position determination,analyses the impact of imperfect waveform ambiguity function on direct position determination of passive MIMO radar,and presents a neighborhood mismatched filter algorithm to solve the above problem.