Micro-motion Target Detection And Parameter Estimation For Distributed Radar

The micro-motion target detection based on radar mainly uses the Doppler effect brought by human's respiration,heartbeat and other micro-motions,so as to realize target detection and parameter estimation.It has shown great application value in the fields of counter-terrorism activities,disaster relief and medical monitoring,and is a research hotspot at home and abroad.The traditional micro-motion target detection of single view,limited by its poor source of information,is usually difficult to obtain the information of all targets in complex environments.However,with the distributed radar system,targets can be detected from multiple perspectives,and multi-node data can be fused to obtain more comprehensive target information in complex environments.In this thesis,based on the idea of stepping from single angle detection to multi-perspective detection,the following research work has been carried out on the estimation of position parameters and frequency parameters of micro-moving targets.1,In the target distance estimation of single view,aiming at the problem that traditional algorithms have difficulty in detecting occluded targets,a novel method based on modified correlation entropy is proposed,which improves the radar's ability to detecting occluded targets effectively.2,In the target position estimation with the distributed radar system,in order to improve the imaging results of the traditional logic-based fusion algorithm,an image fusion algorithm based on the connected domain is proposed.Then in consideration of the “micro-motion frequency”,the essential characteristics of the micro-motion target,an innovative image fusion algorithm based on the frequency weighted sum is further proposed.Significant improvement is shown on false alarms which can hardly be avoided with several existing traditional image fusion metheds.3,In the target frequency estimation of single view,a novel time-frequency analysis algorithm based on envelope extraction is proposed.By analyzing the frequency spectrum of the Doppler frequency caused by the micro-motion,it solves the problem that the traditional Fourier transform is restricted by the radar carrier frequency effectively.4,In the target frequency estimation with the distributed radar system,by considering the angle between the radar and the target moving direction,the traditional micro-motion model is improved.Based on the analysis of the model,three methods are proposed to fuse the frequency estimation results of different nodes from multiple perspectives: arithmetic average method,max Doppler frequency selection method,and Doppler frequency weighted average method.Theoretical analysis proves that these methods can effectively reduce the frequency estimation error's variance of the micro-motion target,thereby improving the accuracy and robustness of the frequency estimation.The above micro-motion target detection and parameter estimation algorithms have all been verified by experiments and have been proven to be used in actual scenes with single or multiple stationary human targets,and achieve better results than traditional algorithms.