Life Detection Radar Based On Chaotic Correlation And Phase Measurement

China is one of the countries that earthquakes are most active and earthquake disasters are most server,since 2008,large earthquake frequently occurred which caused huge economy lose and casualties.To locate and rescue the trapped people in time is the most important task of disaster relief.Life detection radar has the advantages of non-contact and penetrability,and it is widely used in rescuing for survivors after disaster.Therefore,it is of great significance to research life detetion radar for improving our country's emergency rescue capability and protecting the safety of people's life.Life detection radars are mainly divided into two systems: impulse radio ultra-wideband and continuous wave.The former has principle contradiction that the range resolution and detecting depth cannot be improved simultaneously.The ultra-wideband chaotic radar based on correlation method can solve this problem,with advantages of natural anti-interference capability and good performance in radar network application.However,it cannot obtain phase information and hence it was unable to detect micro-doppler signal of vital sign.This paper has developed a hybird life detction radar system which combines ultra-wideband chaotic signal and single-tone signal,the chaotic correlation method is used for high precision target localization and meanwhile the interference phase detection based on microwave sensor is used for weak vital sign detection.The system can achieve life detection and localization simultaneously.The main research works includes:1.The development in radar system and extraction method of life signal detection were summarized,and the testing principle of life detection radar were described in detail,then the feature extraction technique of vital sign was researched by simulation.2.The state microwave sensor integrating a Schottky diode and a split ring was designed and fabricated,by using the Michelson interference phase detection method,the doppler life detection radar system based on this sensor was constructed.Furthmore,a rapid identify algorithm for human status was proposed.Experimental results in free space and in through-wall scenarios demonstrate that the proposed radar system can realize real-time human vital sign detection,and automatically distinguish different human status.3.The radar characteristic of ultra-wideband chaotic was analyzed,and the through-wall radar system based on chaotic signal was constructed.Experimental results demonstrate that the system can realize human localization and moving target tracking.4.A hybird life detection radar system which based on ultra-wideband chaotic signal and single-tone was proposed.The two waveforms are transmitted simultaneously,which are independent and will not influence each other.Experimental results in free space and in through-wall scenarios demonstrate that the frequencies of breathing and heartbeat can be obtained in real-time,and the image of target can be achieved simultaneously.Moreover,the system can automatically recognize the human status(no human,static human,moving human),and can detect the moving target and multiple target.The proposed system has a range resolution of 10 cm and a large dynamic range,about 35 dB for the respiration signal detection and 25 dB for the heartbeat signal detection.