Movement-immune respiration monitoring using automatic DC-correction algorithm for CW Doppler radar system

Doppler radar has the capability to remotely monitor human respiration. However, in real applications random body movements during measurement will cause drift of “DC” level in the experiment results. Also, the dc level will shift slowly with the temperature change of the radar circuit. Those DC drifts will cause inaccurate measurement results. To solve the dc drift issue during the experiments, an automatic DC-correction algorithm is developed. Experiment results show that this algorithm eliminates undesirable DC drifts and offset while recovering useful information of the original respiration signal. It is able to provide reliable respiration measurement even if there are large body movements that otherwise overwhelm the desired signal.