Research On System Technology Of Vital Sign Detection Radar

In recent years,the number of deaths caused by sudden cardiopulmonary diseases has increased year by year.In order to ensure the safety of people's lives and property,it is necessary to carry out real-time monitoring for the people.When an emergency occurs,it can timely alarm and provide treatment.The accurate measurement of vital signs has a great significance for the judgment of health,such as respiration and heartbeat.The radar RF front-end system,the signal processing algorithm and the performance and realizability of system all are studied and analyzed in thesis.Through the digital signal processing of the echo,it can detect the small chest movement caused by breathing and heartbeat,and extract the high-precision breathing and heartbeat frequency.Based on the above research,the vital signs monitoring system based on a millimeter wave radar and FPGA is designed.Firstly,there are huge market and broad application prospect for the non-contact vital sign detection radar system,which shows that the system has important research value;The characteristic and mathematical modeling of chest motion caused by respiration and heartbeat are analyzed,In order to reduce the impact of the signal frequency and environmental noise,these factor have been conducted a further study on the detecting vital signs system,Then the basic principle of vital signs detection based on LFMCW signal is introduced,at the same time,the mathematical derivation is used to verify that LFMCW radar has the ability to detect weak vital signs signals with multiple targets in range.The digital signal processing of the vital signs detection system is the main research content in thesis,which mainly includes MTI differential filter,range dimension FFT gating,frequency accumulation,phase extraction and phase deentanglement and FIR filter etc.The different types of these module's performance are studied and the most appropriate type is selected to form the vital signs detection system finally.In order to obtain high-precision and real-time respiratory frequence and heartbeat frequence,these basic principles of frequency estimation algorithm are studied respectively,such as the STFT algorithm,MUSIC algorithm and Morlet wavelet transform algorithm.The three algorithms are simulated with different conditions,such as signal-to-noise ratio(SNR)and signal time length,and compared with test data.Finally,Morlet wavelet transform that has high frequency estimation accuracy and good real-time performance is selected to realize frequency estimation in the system.Finally,the vital sign detection system and the Morlet wavelet transform based on AWR1642 millimeter wave radar and FPGA are research,at the same the resource utilization of FPGA is also analyzed.Through timing analysis,the error percentage of heartbeat frequency and respiratory frequency calculated by FPGA is about 4%,which verifies the accuracy and feasibility of the system designed in thesis.