Multitarget Respiration Monitoring Based on Cumulative Phase Gradient Approach

Simultaneous measurements of multitarget vital signs have been quite challenging for radar-based noncontact vital signs monitoring. This letter presents a novel cumulative phase gradient approach (CPGA) for accurate estimates of multitarget respirations without either range or beam discrimination in a single-input single-output (SISO) radar sensor. The signal model of multitarget respiration is first provided, and then a CPGA is developed to accurately estimate multitarget respirations from the observed mixtures by exploiting the underlying periodicity of the respiration waveforms. The proposed method provides average estimated error rates around 3% in the experiment with closely located three human targets within range resolution, and demonstrates its significant superiorities over other methods.