Accuracy Assessment and Improvement of FMCW Radar-based Vital Signs Monitoring under Practical Scenarios

Acquisition of human vital signs through radar is a very promising technology that can address the shortcomings of the traditional contact-based measurement devices and enable the move toward a contactless vital monitoring system. This research is focused on monitoring breath rate (BR) and heart rate (HR) via a frequency modulated continuous wave (FMCW) radar. Currently, the two approaches used for BR and HR estimation are filter-based and decomposition-based, such as variational mode decomposition (VMD) for high-quality signal separation. We propose an adaptive VMD (AVMD) to address the problem of setting the number of segmentation levels required by the VMD algorithm. Various experiments are conducted under practical scenarios in terms of distance, angle, posture, and activity as well as the existence of a nearby person and fan. We have made a comprehensive assessment of accuracy change and impact in these scenarios. The experimental results show clearly that the proposed AVMD gives higher accuracy compared to the filter-based and VMD-based. A real-time BR-HR monitoring system using the proposed AVMD and the TI’s IWR1843Boost radar board has been implemented to demonstrate its practical uses