Design And Development Of Life Detection Radar System

In the 1970 s,continuous wave-based life detection technology was first proposed as an emerging life detection technology.Compared with other life detection methods,it has non-contact and is not susceptible to the detection environment.Therefore,it is widely used in military,post-disaster relief,security,anti-terrorism and medical treatment.At present,the life detection radar system's transmission signals mainly include sinusoidal continuous wave signal(CW),step frequency continuous wave signal(SFCW),linear frequency modulated continuous wave signal(LMFCW),ultra-wideband pulse signal(UWB)and random signals.Different transmit signals have their own advantages and disadvantages.The power spectrum of the physical random code is wide and flat,and the amplitude is high.The autocorrelation curve is similar to the function and has strong anti-interference ability,which is very suitable for spatial distance detection.The sinusoidal continuous wave signal is used for life detection and extraction algorithm.Simple and sensitive.Therefore,this paper introduces the physical random code into the traditional Doppler life detection radar,and designs a random code-Doppler life detection radar system.The sinusoidalcontinuous wave signal modulated by random code is used as the transmitting signal to detect the life information and position information.The main research work includes:1.The hardware system structure of the existing life detection radar is summarized and the advantages and disadvantages of different structures are analyzed.The life detection techniques based on different transmitted signals are summarized and the advantages and disadvantages of different detection signals for life detection are analyzed.The existing life signal extraction algorithm is analyzed.The research status of the research is summarized.It is proposed to introduce the physical random code signal into the traditional Doppler life detection radar,and design a random code-Doppler life detection radar system.2.The principle of radar life detection system is expounded.The random code-Doppler life detection radar system uses continuous wave based on Doppler effect for life detection.The physical random code signal is used to detect the position of the target through correlation positioning.Information,using the experimental instrument to build a traditional Doppler life detection radar system to collect echo signals,and using the experimental echo signals to analyze the life signal processing methods.3.The hardware system of random code-Doppler life detection radar is designed,which mainly includes the selection of the overall scheme of the hardware system,the selection of the working frequency band of the systemsignal source and the design and manufacture of the transceiver antenna.Based on FPGA,a 200 MHz physical random code generator is realized.Experiments show that the amplitude of the physical random code signal can reach 2V,its power spectrum is wide and flat,and the autocorrelation curve is pin-shaped,which has good correlation characteristics and anti-interference ability.4.The software system of random code-Doppler life detection radar is designed,which mainly includes acquisition card acquisition module and data processing module.The operation interface of the random code-Doppler life detection radar system is designed.5.The performance of the designed random code-Doppler life detection radar system was tested in the laboratory environment,mainly testing the detection distance,penetration ability and resolution of the system.Experiments show that the system can detect 20 cm thick cinder brick wall.The respiratory frequency and position of the human target within 5m can penetrate the 60 cm thick cinder brick wall to detect the target respiratory frequency and locate it.The system resolution is 0.75 m,which is basically consistent with the theoretical resolution of the signal bandwidth.