Research On UAV Target Detection Method Based On LFMCW Radar

Linear Frequency-modulated Continuous Wave(LFMCW)radar has the characteristics of high resolution,no range blind zone,simple structure and low cost,making it widely used in many fields.Due to the low flying height,slow speed,and small radar cross-sectional area,detection of UAV targets is difficult in the clutter background.However,LFMCW radar has unique institutional advantages in the field of anti-UAV,especially for large-scale applications in complex environments.Range of high-precision detection.This thesis mainly studies the UAV target detection technology of LFMCW radar.The content of this thesis mainly consists of three parts.The first part introduces the working principle and signal processing method of LFMCW radar.The LFMCW radar range velocity coupling phenomenon and the actual system range resolution problem are studied,and the factors affecting the coupling error and system resolution are analyzed using simulation data.The design of the LFMCW radar signal processing scheme is described,and the data simulation analysis and discussion on the key points that affect the system performance indicators are done.The second part studies the application of the Empirical Mode Decomposition(EMD)method in the azimuth estimation of the three-coordinate machine scanning LFMCW radar target.The modal aliasing problem of the EMD method is analyzed in detail,and a modal de-aliasing method based on spectrum rearrangement is proposed,which uses the idea of spectrum rearrangement to adjust the spectrum interval of mixed signals.Simulation data shows that this method can be used.Effectively solve the problem of modal aliasing caused by mutual interference between signals.Aiming at the problem of UAV target azimuth estimation under clutter background,this thesis combines the data-driven adaptive characteristics of EMD decomposition,and proposes a radar target azimuth estimation method based on modal decomposition,which can effectively suppress clutter interference while simultaneously The complete signal component is retained.The simulation data shows that this method can effectively improve the target azimuth measurement accuracy of the three-coordinate machine scanning LFMCW radar in the clutter background.The third part completed the design and implementation of the LFMCW radar signal processing system in conjunction with a scientific research project,and carried out field experiments,mainly responsible for the design of the FPGA module of the signal processing system and the analysis and processing of the measured data.The system performance and key indicators were tested and verified using actual environmental data.The results proved that the system is in different scenarios.It has real-time detection and tracking capabilities for UAV targets.