Short-Time Remote Heart Rate Measurement Based on mmWave FMCW Radar Frame Structure

This letter presents a novel method to reduce measurement time for remote heart rate measurement using millimeter-wave frequency-modulated continuous wave (FMCW) radar. The proposed method is based on the sampling theory and the frame structure of recent FMCW radar systems. The range displacement from heartbeat is measured by 60 GHz FMCW radar with a fixed frame interval, 50 ms. With additional chirp repetition in each frame, the heartbeat signal can be sampled with increased or decreased interval. By adopting three different sampling rates from a single radar measurement, the resolution of heart rate measurement is improved in a short time, 2.5 s. The proposed method is evaluated with a commercial off-the-shelf FMCW radar system and three different human subjects, for no respiration and natural status. To evaluate the performance of the proposed method, the heart rate result is compared with electrocardiogram (ECG) sensor and conventional signal processing method. The results show that the proposed method estimates the heart rate with lower error and shorter measurement time.