Multivariate Correlation of Higher Harmonics for Heart Rate Remote Measurement Using UWB Impulse Radar

Ultra wideband impulse (UWB) radars are getting much attention in the application of remote sensing of heart rate. UWB radar measures the heart rate by mean of the motion of thorax in the heartbeat activities. However, the signal of heartbeat is usually much smaller than the harmonics signal of respiration, then be easily perturbed. Thus, this paper proposed a multivariate correlation method (MCM) to improve the signal-to-noise ratio (SNR) of the heartbeat. The MCM is applied in the bandwidth of higher harmonics rather than the fundamental of heart rate to minimize the affection of the respiration signal. The experiments showed that the second harmonic of heart rate is good at minimizing the affection of the respiration signal, and the MCM is efficient to improve the SNR about 83.7 dB than the continuous wavelet transform method. The heart rate could be estimated with an average error of 2.54% compared with a referenced photoplethysmography sensor.