Vital signs detection via Dopper radar and CFAR in complex environment

Generally speaking, it is hard to identity the vital signs of injured people in the complex environment. In this paper we present a Doppler contactless system-using a commercial Doppler radar. The proposed algorithm can identify the vital signs such as the heart beat and breathing accurately. The chest vibration caused by the breathing and heartbeat is regarded as harmonic vibration. According to the principle of Doppler effect, the vital signs can be detected by the periodic vibration caused by harmonic vibration. First, advanced data preprocessing techniques are used to extract the vital signs in the complex environment. Next, the IIR filters are used to separate the signals. Finally, the results are presented based on the FFT transform, non-coherent matched filter and MLE. The proposed approach is firstly validated using a set of synthetic data generated by simulation for Doppler radar. Further, it is demonstrated using the laboratory experiments data including the Vector network analyzer and this system. The results show that with the combination of Doppler radar and our proposed data processing algorithms, it is effective to detect the vital signs in the medicine service and rescue.