Research On Signal Processing And Algorithm Of Bistatic MIMO Radar

In recent years,the introduction of multi-input multi-output(MIMO)technology has brought new opportunities for the further development of radar system.Bistatic MIMO radar combines the advantages of MIMO technology and bistatic radar system,and has good technical and tactical performance,which has attracted wide attention of the researchers at home and abroad.In this dissertation,the signal processing and related algorithms of bistatic MIMO radar are studied.The main works and contributions are as follows:(1)In this dissertation the basic configuration of bistatic MIMO radar system is given,and the signal models are established,including the uniform linear array model and plane array model.Based on the radar signal model and combined with actual work process,the basic signal processing algorithm and the flow of bistatic MIMO radar are proposed,and the special signal processing schemes for bistatic MIMO Radar such as beam forming,matched filtering processing in different working processes and accumulation processing are introduced;and meanwhile,this dissertation analyzes the effects of common interferences and non ideal factors on the performance of bistatic MIMO radar.Then the basic simulation platform architecture for bistatic MIMO radar is put forward.(2)The search for targets is one of the basic functions of radar.Bistatic MIMO radar has the work mode of wide transmit beam and wide receive beam,and with the digital beam forming(DBF)and long time accumulation technology it can solve the contradictions between the fast search in airspace and the accurate measurement for a specific target in conventional radar system.However,the high complexity in the search process and the matched filter output loss caused by the equivalent transmit beamforming misalignment has a certain effect on the performance of the radar.In this dissertation,the "distance-angle" coupling of the stepped frequency division linear frequency modulation(SFDLFM)signal is analyzed and disscused,through which the search processing structure of bistatic MIMO radar is optimized;and using the coupling effect,two-dimensional and three-dimensional distance division methods in search processing of bistatic MIMO radar is proposed,which can reduces the loss of the matched filter output.(3)For bistatic MIMO radar,the information fusion techlogy can enhance the measuring accuracy of the target parameters and the detection and tracking ability in complex condition;and the data association is the precondition of the information fusion.Based on the nearest neighbor association algorithm,a data association decision using the transmit angle and range parameter as decision statistics is proposed in this dissertation,and the association probability is derived.The method can effectively avoid the association false caused by the directional error of transmit array,and can improve the correct probability of the data association between the two receive stations.In addition,by comparing with the phased array radar,the excellent performance of the bistatic MIMO radar data association is verified.(4)Bistatic MIMO radar uses separated transmit array and receive array,and transmit orthogonal detection signal waveform,which has many advantages and potential in the interference confrontation.In this dissertation,aiming at the the direct wave and multipath interference,the CLEAN algorithm is applied to bistatic MIMO radar signal processing,and the spatial linearly constrained minimum variance(LCMV)algorithm is combined with the CLEAN algorithm to suppress the direct wave and multipath interference.For range deception jamming,two different method aiming at different location methods are proposed.One of the methods recognizes the deception jamming through the comparation between the range parameters from different ways;and the other method is constructing a binary detector using the least squares fitting error to distinguish the target echo and jamming.These two methods can recognize the deception jamming effectively with few additional burdens on the system.(5)In practical engineering applications,the existence of various array errors will seriously affect the performance of radar parameters estimation and tracking.To solve this problem,this dissertation proposes a joint calibration method for amplitude and phase error and mutual coupling error of the transmit array and the receive array of bistatic MIMO radar.This method deformes the error matrixs,and then uses the iterative algorithm to estimate the array errors.And meanwhile,the dissertation uses the nonlinear least squares method to jointly compensate the transceiver array pointing error of bistatic MIMO radar.The simulation results show that the proposed methods have good estimation accuracy.(6)The structure and the realization of the space,time and frequency synchronization system of bistatic radar are complex,and the performance of the synchronous system will directly affect the performance of the parameter measurement.The function demand of bistatic MIMO radar synchronous system is studied in this dissertation,and the influence of synchronization error on bistatic MIMO radar are analyzed,and then this dissertation comprares multiple synchronization schemes and makes a choice for bistatic MIMO radar.(7)In addition to the theoretical analysis and simulation experiment,the hardware experimental platform is also indispensable to perfect the function of a radar system and the application test.At the end of this dissertation,the hardware experiment platform of bistatic MIMO radar is introduced.The basic structure,working principle and working flow are introduced;some experimental results are demonstrated,which verify the target detection performance of the bistatic MIMO system.