Signal Processing And Realization Of Millimeter Wave Vehicle Inspection Radar

With the rapid development of social economy,vehicles have become an important part of human's life.The huge amount of vehicles bring increasingly serious traffic stress while they make us convenient.The emergence of intelligent transportation system(ITS)reduces the traffic stress obviously.As an important part of ITS,vehicle detectors have great researching value.Compared to other vehicle detectors,microwave radar vehicle detectors have many advantages such as convenient installation,great ability of detection,good anti-interference etc.,and thus implying better application potential.This thesis is focused on the LFMCW(Linear frequency modulated continuous wave)radar system of millimeter-wave radar vehicle detectors.The algorithm of signal processing has been investigated and implemented by DSP.The main researches of this work are listed as follows:Firstly,algorithm of LFMCW radar is investigated in this work.It introduces the working diagram and principle of detection of LFMCW radar.The time domain and frequency domain of beat signal are modeled by mathematical method and analyzed in detail.The ambiguity function of LFMCW radar modulated by single periodic triangular wave is carried out with the resolution of range and velocity.Furthermore,this work analyzes the MTD(Moving Target Detection)-frequency domain matching method.A multi-target detection method by a FSK(Frequency-shift keying)+LFM modulation waveform and a method of multi-target detection with a variable periodic FMCW+CW modulation wave are given.These three methods are simulated and compared with each other.Finally,the flow of beat signal processing including windowing FFT,CFAR detection and discrete spectrum correction is presented.Some kinds of window functions,a variable index CFAR detection and an auto correction of discrete spectrum are analyzed,respectively.The methods above are verified by the simulation results.Secondly,the radar signal processing is implemented by DSP.First,the flow chart of software design of signal processing is given.Then the designing process of DAC module,ADC module and serial port communication module are introduced.Finally,the radar system is tested by combining the DSP board and radar sensor,which verifies effectively the validity of the algorithm.