Vital Sign Quality Assessment Based on IR-UWB Radar Sensor

Impulse radio ultra-wideband (IR-UWB) radar measures vital signs such as respiration and heart rates based on the body's fine movement due to breathing or heartbeat. The conventional IR-UWB radar-based vital sign measurement algorithms measure respiration and heart rates mainly based on the frequency spectrum corresponding to the respiration and heart rates. This frequency domain approach has the advantage of being able to measure respiration and heart rates whatever the signal is, but does not consider the state of the time domain signal. Sometimes the signal may be distorted to such an extent that it cannot measure vital signs due to movement, and there may be no vital signs in the signal because there is no one within the detection range. If we can quantify how well the current measured radar signal is suitable for measuring vital signs before measuring the respiration and heart rates in the frequency domain, this can give information about the degree of reliability of the vital signs to be measured. In this paper, we propose a method to estimate the reliability or quality of a signal used for measuring vital signs. The proposed method is based on the periodicity analysis using autocorrelation. To verify the validity of the proposed method, we compared the scoring results with the accuracy of the measured vital signs.