| The work in this dissertation demonstrates the feasibility of using Doppler radar for life signs monitoring under the noise and interference constrains as can be expected in real life applications. The criteria used to determine the feasibility was the accuracy of extracted physiological signals. It was demonstrated that heart rate can be extracted with an accuracy of 1 beat per minute, even in the presence of interference signals with an order of magnitude larger amplitude. Contributions to the field of electrical engineering include novel hardware and software techniques that overcome the effects of noise, interference and distortion in Doppler radar life signs monitoring devices. Innovative hardware approaches, including the sensor node concept, the analog linear demodulator and the coherent Low-IF receiver architecture were introduced and validated as potential solutions to the noise and distortion issues. The use of an advanced signal processing techniques, Empirical Mode Decomposition, was shown effective in removing unwanted signal interference and extracting heart signals with 99% accuracy. These new approaches may enable wireless life sign detection and monitoring for a wide range of applications, including remote health monitoring, search and rescue, and vehicle occupant monitoring. |
