A Novel Heart Rate Estimation Method Exploiting Heartbeat Second Harmonic Reconstruction via Millimeter Wave Radar

Millimeter wave radar has been extensively exploited in heart rate estimation tasks, but there is still potential for improvement in estimation accuracy. At present, the interference of the second and third harmonics of respiration has become a significant problem that hinders further improvement of heart rate estimation accuracy. To handle this problem, we propose a novel method to estimate heart rate based on reconstructing the heartbeat second harmonic. This method can cleverly solve the problem that the second and third harmonics of respiration overlap with the heartbeat signal frequency and are difficult to be separated. The proposed method is verified by real experiments with ten volunteers, and the results show that the method is capable of providing precise and robust heartbeat estimation. The mean relative error of this method is 2.924%.