| LFMCW(Iinear Frequecy Modulated Continuous Wave) radar life detection technique is an organic combination of the vital signs monitoring techniques and the LFMCW radar techniques. It conquers the disadvantages of the prevenient life detection techniques, can not only obtain the range and doppler information, but also enhance the spatial resolution, the penetration depth, the detection range and the anti-jamming capability. So it can be used in any special occasions.The article firstly analyses the modeling of the life signal and noise. The analyzing results indicate that we must adopt an radar system in life detection which can realize high space resolution or time resolution to acquire high resolution and muti-target detection. LFMCW radar principle and the ambiguity function of LFMCW radar signal is analyzed to deduce its high resolution and muti-target detection capability. The article also expatiates the LFMCW radar specialty for life detection.The collection, processing and identifying of the life signal are the emphases of the research. The article discusses many aspects of signal processing technology, such as two dimensional fast Fourier transform(2-FFT), the property of equivalent quadrature channels by its single channel structure, MTI and MTD, suitable window function and life signal detection technologies. Based on the researches above, an detailed signal processing frame is formed. The article also argues the choice of radar parameters and sets up a practical signal processing system.To actualize high range resolution, simple hardware and quick detection, the article put forward a system of initiative range measurement of LFMCW radar with double DDS, which can perform initiative measurement on one range unit, shorten detection time, lower the lever of signal processing hardware and reduce the interact of the different range units. The system was successfully used in a life detetion radar and realized quick and efficient life detection. |
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