High-amplitude motion cancellation method for handheld UWB Doppler radar

UWB Doppler radar is capable of monitoring vital signs of human beings in a non-contact way by detecting the changes in the time of flight of narrow pulses emitted by the radar and reflected from the human chest. However, the received signal may be corrupted when there is a random motion if handheld UWB radar is used, especially when the amplitude of motion is higher than that of the thoracic motion. In this paper, a random motion cancellation method using an embedded system is proposed for recovering the real vital signs similar to image stabilization in optical cameras. The proposed embedded system is attached to the receiving antenna and used to collect the data of motion acceleration. The correlation between the data collected by the UWB system and embedded system is analyzed and a Finite Impulse Response (FIR) model considering the time delay between these two systems is developed as well. Experiments show that the respiration rate of a subject can be accurately recovered by motion cancellation method even in the presence of a high-amplitude motion of the receiver.