Multi-target vital signs detection using frequency-modulated continuous wave radar

Abstract

Respiration and heartbeats rates are important physiological assessment indicators that provide valid prior-knowledge for the diagnosis of numerous diseases. However, most of the current research focuses on the vital signs measurement of single target, and multi-target vital signs detection has not received much attention. In this paper, we use frequency-modulated continuous wave (FMCW) radar to measure the vital signs signals of multi-target. First, we apply the three-dimensional fast Fourier transform (3D-FFT) method to separate multiple targets and get their distance and azimuth information. Subsequently, the linear constrained minimum variance-based adaptive beamforming (LCMV-ADBF) technique is proposed to form a spatially distributed beams on the targets of interest directions. Finally, a compressive sensing based on orthogonal matching pursuit (CS-OMP) method and rigrsure adaptive soft threshold noise reduction based on discrete wavelet transform (RA-DWT) method are present to extract the respiratory and heartbeat signals. We perform tests in a real experimental environment and compare the proposed method with reference devices. The results show that the degrees of agreement for respiratory and heartbeat are 89% and 87%, respectively, for two human targets. The level of agreement for respiratory and heartbeat is 87% and 85%, respectively, for three human targets, proving the effectiveness of the proposed method.

Radar-Based Monitoring of Vital Signs: A Tutorial Overview

“…In the last few years, increasing attention is being paid to MIMO radar systems, mainly because they make range and DOA estimation of multiple targets possible. The use of MIMO FMCW, IR-UWB, and CW radar systems for the monitoring of vital signs has been investigated in [62], [76], [77], [78], [79], [80], [81], and [82]. More specifically, the use of MIMO FMCW radars operating at 77 and 120 GHz has been studied in [62], [76], [77], and [79], whereas the simultaneous use of two FMCW radars, each endowed with single ULA, but one operating at 24 GHz and the other one at 77 GHz, has been investigated in [78].…”

“…The use of MIMO FMCW, IR-UWB, and CW radar systems for the monitoring of vital signs has been investigated in [62], [76], [77], [78], [79], [80], [81], and [82]. More specifically, the use of MIMO FMCW radars operating at 77 and 120 GHz has been studied in [62], [76], [77], and [79], whereas the simultaneous use of two FMCW radars, each endowed with single ULA, but one operating at 24 GHz and the other one at 77 GHz, has been investigated in [78]. Nosrati et al [82], instead, focused on the use of beamforming in MIMO CW radar systems.…”

Radar-based Monitoring of Vital Signs: A Tutorial Overview

“…In the last few years, increasing attention is being paid to MIMO radar systems, mainly because they make range and DOA estimation of multiple targets possible. The use of MIMO FMCW, IR-UWB and CW radar systems for the monitoring of vital signs has been investigated in [54][55][56][57][58], [59,60] and [61] respectively. More specifically, the use of MIMO FMCW radars operating at 77 GHz and at 120 GHz has been studied in [54][55][56] and [58], respectively, whereas the simultaneous use of two FMCW radars, each endowed with single ULA, but one operating at 24 GHz and the other one at 77 GHz, has been investigated in [57].…”

“…The use of MIMO FMCW, IR-UWB and CW radar systems for the monitoring of vital signs has been investigated in [54][55][56][57][58], [59,60] and [61] respectively. More specifically, the use of MIMO FMCW radars operating at 77 GHz and at 120 GHz has been studied in [54][55][56] and [58], respectively, whereas the simultaneous use of two FMCW radars, each endowed with single ULA, but one operating at 24 GHz and the other one at 77 GHz, has been investigated in [57]. Reference [61], instead, focus on the use of beamforming in MIMO CW radar systems.…”

Contact-Free Vital Sign Estimation Using Ultra-Wide Band Radar

“…Vital signs are measured continuously and noninvasively to obtain basic parameters of a patient's health status. Breathing and heartbeat signals are significant bio-signals that not only give information about patients' physical health but also help various public health systems manage their everyday operations [1]. The resting heart rate can indicate coronary heart disease and has strong links to non-cardiovascular disorders, including stroke and sudden death [2].…”