Multiple-Target Vital Signs Sensing using 77GHz FMCW radar

In this paper, a commercial FMCW radar sensor working at 76 to 81GHz is used on single objects and multiple objects to obtain the IF signal containing vital signs information. Heartbeat and respiratory raw waveform are obtained after a series of digital signal preprocessing methods including Fast Fourier transform (FFT) and differential denoising. Later, three classical spectral estimation algorithms for extracting heart and respiration rate and period are used, including peak interval method, autocorrelation function, and Discrete Fourier transformation algorithm. We then implemented simultaneous measurements and calculations for multiple individuals, which is based on analyzing the range and angle information using MIMO antennas. Heartbeats and respiration movement of the target can be estimated by analyzing the frequency distribution of the extracted phase signals over the bands of 0.2-0.8Hz and 12 Hz. and experimental results show that this method can better identify the respiration and heartbeat information of multiple targets.