Cancellation of unwanted motion in a handheld Doppler radar used for non-contact life sign monitoring

Human life signs can be monitored at a distance using mono-static Doppler radars operating in the CW mode. Such systems rely on phase modulation of the radar’s reflected signal due to physiological motion. If the antenna is also moving, this motion will combine with and might obscure physiological motion. In a hand-held radar the antenna motion must be compensated to enable life signs extraction. It will be shown that prior knowledge of antenna’s unwanted motion can be used to overcome this problem. A signal model has been developed and experimental results confirm that it is possible to extract heart signal in the presence of antenna motion with proper compensation.