Remote sensing of vital signs using an ultra-wide-band radar

Remote vital signs monitoring and tracking are of great importance for various applications including but not limited to baby monitoring, elderly care, human activity behind barriers, bio-medical and more. This paper deals with the extraction of micro-Doppler (uDoppler) signatures of a person’s respiration and heart-beat using a single transmitter (TX), single receiver (RX) Ultra Wide Band (UWB) impulse radar. The received spectrum contains the respiration and heart fundamental beat frequencies and their corresponding integer multiplicity harmonies as well as their mutual inter-modulations that appears due to the micro-Doppler frequency-modulation of the sinusoidal nature of the moving torso and heart, a fact that poses a difficulty in extracting the correct heart-beat fundamental harmony. Moreover, the commonly used Discrete Fourier Transform (DFT) is insufficient for differentiating close proximity spectral components, thus, an adaptive, real-time, novel, spectral estimation algorithm is proposed and experimental results are given.