Estimation for IF signal frequency of FMCW LIDAR based on Hilbert-Huang Transform

This letter proposes an improved method to estimate intermediate frequency (IF) signal frequency of FMCW LIDAR. This method extracts characteristics of IF signal from FMCW LIDAR and optimizes the selection and solution of intrinsic mode functions (IMFs). The main contribution of the proposed solution, namely refined modal variation Hilbert-Huang transform (RMV-HHT), relies on the extraction of characteristics from the specific IMF of the IF signal decomposed by variational mode decomposition (VMD). Considering non-stationary interference and environmental noise, the RMV-HHT and four competitive methods are evaluated. Calculating distance after signal processed by different methods, the RMV-HHT achieves the highest SNR and lowest mean absolute error at different distances. Results demonstrate that the proposed RMV-HHT method is superior to traditional methods in FMCW LIDAR signal processing.