Extraction of vital signs from frequency modulated continuous wave radar based on moth-flame optimized successive variational mode decomposition

Vital signs are extracted from frequency modulated continuous wave (FMCW) radar devices, taking into account that respiratory and heartbeat signals are non-stationary and non-linear, as well as their susceptibility to interference from respiratory harmonics, intermodulation waves, and noise signals, and the issue of manually selecting the balancing parameter for the successive variational mode decomposition (SVMD). A vital signs extraction method based on moth flame optimization algorithm (MFO) optimizing SVMD and variance contribution rate (VCR) screening criteria is proposed. The method first preprocesses the radar raw echo signal by performing range dimension fast Fourier transform (FFT), static clutter filtering, selecting range cells through the maximum range gate, and processing the phase to obtain vital signs; then decomposes the vital sign using MFO-SVMD, optimizes the balancing parameters through MFO to avoid information loss and redundancy caused by unsuitable balancing parameters; subsequently filters out suitable modal components as respiratory and heartbeat signals using VCR; finally, extracts respiratory and heartbeat frequencies using FFT peak detection. Results of research indicate that the suggested approach can adaptively optimize the balancing parameter in SVMD and accurately extract respiratory and heartbeat information.