Harmonic Path (HAPA) algorithm for non-contact vital signs monitoring with IR-UWB radar

We introduce the Harmonic Path (HAPA) algorithm for estimation of heart rate (HR) and respiration rate (RR) with Impulse Radio Ultrawideband (IR-UWB) radar. A well known result is that a periodic movement, such as the lung wall or heart wall movement, induces a fundamental frequency and its harmonics. IR-UWB enables capture of these spectral components and frequency domain processing enables a low cost implementation. Most existing methods try to identify the fundamental component to estimate the HR and/or RR. However, often the fundamental is distorted or cancelled by interference, such as RR harmonics interference on the HR fundamental, leading to significant error for HR estimation. HAPA is the first reported algorithm to take advantage of the HR harmonics, where there is less interference, to achieve more reliable and robust estimation of the fundamental frequency. Example experimental results for HR estimation demonstrate how our algorithm eliminates errors caused by interference.