Research On Multi-person Positioning And Vital Signs Detection Technology Based On FMCW Radar

Multi-person location and vital signs detection technology has a wide range of application requirements in the fields of medical monitoring,emergency rescue,and home health monitoring.Imaging technology based on video and infrared can distinguish human targets from the environment to be measured,but it is susceptible to interference from environmental factors such as light intensity and temperature,and cannot give accurate vital sign information.Radar-based multi-person location and vital signs detection technology is not restricted by environmental conditions,and can achieve long-term,uninterrupted monitoring,which has important research significance.This paper proposes a multi-person location and vital signs detection algorithm and system based on single-transmit multiple-receive FMCW radar,which can realize the two-dimensional spatial location of multiple human targets and obtain the corresponding target's respiration and heartbeat signals.The main research contents are summarized as follows:(1)Introduced the basic principles of FMCW radar ranging and vital signs detection,studied the basic principles of multi-person location and vital signs detection based on DBF,simulated and verified the non-adaptive DBF algorithm based on vector space.(2)According to the application requirements of this article,a set of single-transmit and multiple-receive FMCW radar system was designed,and each unit module of the system was introduced,including the antenna,transmitting and receiving unit,sampling unit,control and data transmission unit;The receiving channels'amplitude and phase correction experiment eliminated the inherent error of each channel and improves the accuracy of the DBF technology.(3)A multi-person location and vital sign signals detection algorithm was proposed:firstly,the distance and angle information of each human target was obtained based on the DBF angle scan;then based on the improved A~2RC algorithm,the energy that the interferential human target angle range was suppressed and the vital sign signals of each human target were extracted;finally,based on the improved VMD algorithm,the endpoint effect problem was overcome,and the respiration and heartbeat signals of each human target were accurately separated.(4)An experimental platform for single-transmit and multiple-receive FMCW radar system was built,and the effectiveness of the multi-person location and vital sign signals detection algorithm proposed in this paper was verified through two-person and three-person experiments.In the two-person experiment,the maximum error of ranging was 0.162m,the maximum error of angle measurement was 2°,and the maximum measurement error of the frequency of respiration and heartbeat signals was 0.024Hz;in the three-person experiment,the maximum error of ranging was 0.142m,the maximum error of angle measurement was4.7°,and the maximum measurement error of the frequency of respiration and heartbeat signals was 0.0244Hz.