Research On Target Detection Method Of Millimeter Wave Security Radar

With the development of society,we pay more attention to the security precaution,and the security market has gradually prospered.The demands for intrusion detection around sensitive areas is the most concerned,while millimeter-wave radar is a kind of high resolution radar with advantages such as all-weather operation ability,strong antiinterference ability,small volume,wide application,excellent moving target detection ability and can be a research hotspot in intrusion detection field.Based on the 77 GHz millimeter-wave radar,this thesis studies the related algorithms of security radar,designs and improves the algorithm process,and verifies the algorithm on the IWR1642 platform.The main work of this thesis is as follows:1)The system structure and working principle of linear frequency modulated continuous wave(LFMCW)radar are introduced.Based on the characteristics of two modulation modes of LFMCW radar signal,the LFMCW signal modulated by multiperiod sawtooth wave is determined as the transmitting signal.The principle of ranging,velocity and angle measurement under this modulation mode and the problem of spectrum leakage in the process of solving target information are studied.2)The appropriate clutter simulation method is selected to simulate the ground clutter in the security scene,and the applicable conditions of various classical Constant False Alarm Rate(CFAR)detectors is analyzed by simulation.It is convenient to select the appropriate CFAR detector for the scheme of moving and static target separation and detection of LFMCW radar.The fractal dimension CFAR detection is used to replace the original two-dimensional CFAR detection on the 2D-FFT spectrum to reduce the computational complexity.3)The clutter suppression technology in LFMCW radar is studied.The angular resolution is improved by the multi-input multi-output method based on time division multiplexing,and the phase offset caused by the target motion in this method is compensated.The radial moving target and tangential moving target are detected respectively,and the detection ability of low radial velocity target is increased without affecting the detection of tangential moving target of LFMCW radar.4)The chip structure and software architecture of IWR1642 are studied,and the signal processing flow is improved by combining the above algorithm.The basic parameters of radar are configured according to the set performance index.On the basis of the simulated beat signal model and ground clutter model,the rationality of parameter configuration and the effectiveness of the whole signal processing flow are verified.Finally,the whole algorithm process is implemented on the platform IWR1642 and the function of the system to detect intrusion targets is tested.The detection results are displayed by the GUI interface on the PC side.