Simultaneous Monitoring of Cardiopulmonary Signals Unobtrusively : A Dual Radar based approach

Recent interest in unobtrusive life signs detection has turned heads towards microwave based sensing, especially Doppler radars. Among these, Continuous Wave (CW) radars are preferred for physiological signal detection because of its low hardware and signal processing complexity. Use of a uniquely spatially separated dual CW radar system counters the null-optimum detection problem of a single channel CW radar. This paper presents a novel approach for simultaneous monitoring of cardiopulmonary signals for such a dual radar system; it uses a combination of different time domain and frequency domain techniques based on the received signal quality to simultaneously determine the breathing rate (BR) and heart rate (HR). The proposed technique computes BR and HR with mean accuracies(± SD) of 94.6%(±2.06) and 94.9%(±2.21) respectively, and heart rate variability with a mean accuracy of 94%(±2.94) on an external cohort.