Time-frequency analysis of terahertz radar signal for vital signs sensing based on radar sensor

In this paper, we studied how to use radar sensing technology to monitor the human target and extract the heartbeat and breath rates of human beings using terahertz bandwidth. Specifically, a type of nonlinear time frequency analysis for the detection of weak signals, i.e., the Smoothed Pseudo Wigner Ville Distribution, is presented. First, the echo model of a human target is established. Second, by combining the over-sampling technique with the T-F analysis method, the accurate speed information is obtained to solve the problem of the micromovement feature extraction signal-to-noise ratio. Finally, the frequencies corresponding to heartbeat and breath, respectively, are obtained by down-sampling based on further analysis. Our experiment results show that the detection efficiency by Terahertz radar is better than that by short time Fourier transform and radar networking technology effectively in dynamic tracking and monitoring of the human body.