Array Radar Signal Processing Technology Based On LFMCW System

The LFMCW system array radar combines the working mode and performance advantages of the LFMCW radar and array radar.It has the advantages of high ranging resolution,no range dead zone,strong anti-interception ability,and relatively low cost.With the rapid development of modern digital signal processing technology,the LFMCW system array radar has been widely used in military and civilian fields.This thesis closely combines the characteristics of the radar system and focuses on the signal processing methods applied to the radar system.This thesis can be divided into four parts.In the first part,the LFMCW signal model is introduced.In combination with the working principle of the LFMCW radar,the method of extracting the distance and velocity information of the LFMCW signal is derived in detail.A method for decoupling distance-velocity coupling of the linear frequency modulated sawtooth wave signal is proposed.The application of sparse Fourier transform algorithm in LFMCW signal processing is introduced.In addition,the effect of factors on range resolution is discussed,and the advantages and disadvantages of LFMCW radar are discussed.In the second part,the signal model of LFMCW signal in array radar is introduced,and the threedimensional pattern function of any array is derived;the principle of cylinder array pattern synthesis is studied,and the influence of many factors on the beam forming of cylinder array is explored with the simulation example;a method of array radar target detection based on feature analysis is proposed,which can reduce the false alarm rate.The third part introduces the factors that should be considered in the design of the radar system,the general signal processing scheme of the array radar of the LFMCW system is introduced in detail,and the key steps in the signal processing scheme are analyzed theoretically and by simulation.Two signal processing optimization methods for LFMCW array radar are proposed: the first method is digital beamforming method based on the noise power of array radar,which can improve the efficiency of beam synthesis and the signal-to-noise ratio of target;the second method is dense false target elimination method based on improved DBSCAN algorithm,which can reduce the impact of interference and strong clutter on target detection.In the fourth part,a self-developed LFMCW array radar system is introduced.The system architecture and signal processing system design are briefly introduced.Combined with the measured data and radar real-time display screen,it is verified that LFMCW array radar system has the ability of real-time detecting low slow small targets in the urban background.