Remote Heart Rate Measurement Using UWB Radar via Multistage Adaptive Estimation

Radar technology is widely recognized for its ability to monitor biological signals without contact. However, heart rate (HR) monitoring accuracy is often compromised by interference from respiratory harmonics, especially when their frequencies overlap with heartbeat signals. To solve this challenge, we propose an adaptive HR measurement method using impulse-radio ultra-wideband (IR-UWB) radar. This method employs a multistage process to enhance heart rate estimation (HRE). First, we selectively intercept phase information within the effective range and apply weighting factors to suppress the multipath interference effect. Second, we dynamically adjust the notch filter bandwidth based on respiratory asymmetry and pause duration between breaths, preventing excessive suppression of frequencies near respiratory harmonics. Third, we separate the heartbeat and its second harmonic to examine their correspondence and use historical data as prior information for robust HRE. Experimental results on real-world data demonstrate that the proposed method outperforms existing noncontact HR measurement techniques.