High-Accuracy Heart Rate Estimation By Half/Double BBI Moving Average and Data Recovery Algorithm of 24GHz CW-Doppler Radar

Due to the new trend on non-contact monitoring of vital signs and cardiopulmonary activity, Doppler radar is getting more attention as a promising technology. This medical radar tracks small movements on the human's body-surface to measure several vital parameters such as heart rate and respiration rate. However, because radar signals are susceptible to body movement and breathing effects, using simple signal processing methods can be challenging to provide accurate results. In this study, we propose a time-domain signal processing algorithm that combines Digital filters and a zero-crossing algorithm to extract the heart rate accurately. This algorithm comprises two processes: Heart rate extraction by Half/Double beat-to-beat intervals (BBIs) Moving average filters and Heartbeat refinement by IIR filter, zero-crossing detection and Data recovery algorithm. To evaluate the algorithm's accuracy, we measured the cardiopulmonary information of 10 healthy subjects in the supine position, and these subjects also wore an electrocardiograph (ECG) contact sensor to provide reference data. The proposed method has considerable advantages due to the compact model and low computational cost while still providing a significant correlation compared with ECG when the coefficient R = 0.998.