Driver’s heartbeat interval estimation with millimeter-wave sensor

Abstract

This paper presents a millimeter-wave (MMW) radar based vital-signs sensor to estimate driver’s heartbeat interval (HBI) in contact-free for comfort. The HBI is here estimated from driver’s chest surface movement using the received MMW echo. The MMW sensor is sensitive to small cardiac movement of 1mm or less because of the higher frequency and wider bandwidth available, thereby the movement would be estimated even while driving an automobile. The received MMW echo contains not only the chest surface movement, but also driver’s body movement, automotive body vibration and multipath fading. Therefore, the HBI would be extracted from the received chest surface movement data using a range-bin diversity, multi-resolution analysis, and Burg algorithm-based spectrum analysis. This paper discusses the effect of driver’s operating condition and sensor installation location on the HBI. Measurement was conducted while driving an automobile and the result is also compared with a PPG (photo-plethysmograph) sensor to verify the validity. As a result, it is found that the estimated HBI is in good agreement with the PPG.