Research On Human Target Recognition Technology Based On Variable Speed SAR

The identification and positioning of human targets plays a very important role in postdisaster relief work.Currently,the search and rescue methods which we mainly used include manual search,life detector detection and radar vital sign detection.Among them,advantages of radar vital sign detection are extremely obvious.It has the superiority of high efficiency,allweather working condition and wall penetration capability.The existing vital sign detection radar can perform SAR imaging,identification or positioning work.However,it is difficult for the radar to keep running at a constant speed in actual work,which will cause problems such as inaccurate positioning and fuzzy SAR imaging.Designing a radar system which can perform the above work simultaneously when the radar moves at variable speed is of great significance to applications in the field of post-disaster rescue and security.This paper constructs a human target recognition system based on variable-speed FMCW SAR.The algorithm can extract and detect the vital signs in the target area while the radar vehicle is running at variable speed using the human identification radar system.It can identify and locate the human target at the same time.Finally,the algorithm can complete the imaging of human target in the detected region combined with the variable SAR imaging results.The main work contents are as follows:1.The basic theory and radar system of FMCW radar are introduced.The basic principle of vital sign detection is described.The validity of vital sign detection method using FMCW radar was verified by simulation and actual experiments.2.The basic theory of FMCW SAR imaging is introduced.Two common imaging algorithms,RD and ?K,are deduced in detail.The two algorithms are compared by simulation.Then the variable-speed FMCW SAR imaging algorithm is introduced.Considering the multidomain applicability requirements of variable-speed imaging algorithms,this paper proposes a time-domain interpolation array transformation algorithm which can complete the reconstruction of non-uniform data in the un-transformed time domain.Finally,the accuracy of the variable-speed imaging algorithm is verified by simulation.3.The human target identification radar system is constructed.The method of extracting vital signs from variable speed SAR mode is proposed.The vital sign signal modeling based on body breathing model is proposed.The method of human target recognition and localization is carried out in combination with the method of extracting vital signs and respiratory body modeling.The algorithm can complete the vital sign detection,identification and localization of human targets in the variable-speed SAR mode.Finally,the accuracy and effectiveness of the algorithm are verified by simulation experiments.4.We set up an identification radar system platform and design the experimental plans.Firstly,the variable-speed FMCW imaging experiment based on the time-domain interpolation array transformation algorithm was carried out.The SAR imaging of simple indoor environment and complex indoor environment was imaged under the condition of dramatic change of radar speed.Then the human body target recognition based on variable speed FMCW SAR imaging was carried out.Single human target recognition,multi-human target recognition and outdoor complex human body target recognition were completed.Human target can be located accurately and re-imaged in the experiments.The experimental results show that the proposed algorithm can detect the vital signs,identify and locate the human targets in the detection area,and can clearly image the human targets under the condition of radar shifting motion.