Realtime Multi-target Vital Sign Detection with 79GHz FMCW Radar

In this paper, multi-target vital signs are detected by a 79GHz frequency modulation continuous wave (FMCW) radar. Compared with existing methods, this system could track multitarget vital signs accurately in real time with cost-effective and simple method. In order to avoid interference of static objects, moving target indication (MTI) is implemented to subtract background clutter. In addition, variable detection threshold is adopted which changes inversely with detection range, so that distant target can be detected even though its amplitude attenuates greatly. After target detection and tracking, phase information is extracted from corresponding range bins. Two simple but efficient methods including fast Fourier transform (FFT) and autocorrelation are implemented and their confidence degrees are calculated to determine the final breath and heart rate. Experiments show that this novel signal processing can achieve high accuracy and real-time performance for multi-target vital sign detection.