Vibration Environment Reconstruction for FMCW Radar Using a Radar-Performance-Oriented Spectral Operator

Tracked vehicles operating under off-road conditions subject onboard frequency-modulated continuous-wave (FMCW) radars to broadband and impulsive vibration, making vibration-environment reconstruction important for repeatable laboratory evaluation of vibration-induced sensing degradation. Conventional reconstruction methods mainly target vibration-signal characteristics, such as power spectral density (PSD), root mean square (RMS), and higher-order statistics, without explicitly accounting for the frequency-selective influence of vibration components through the radar processing chain. This study proposes a radar-performance-oriented spectral operator for FMCW radar velocity measurement and incorporates it, together with vibration PSD and higher-order statistical features, into the reconstruction process. Numerical simulations assess reconstruction performance, and shaker tests assess laboratory implementation and consistency with a model-based radar reference. Compared with reconstruction based on PSD and higher-order statistics, the proposed method reduces the mean relative L2 error of the sensitive-band effective-energy vector from 38.07% to 16.95%. In simulation, the reconstructed main-peak broadening and spurious-peak center position are 1.26m/s and 0.68m/s, corresponding to relative errors of 4.13% and 1.45%, respectively, with respect to the simulated original-vibration response. In shaker tests, the corresponding measured values are 1.133m/s and 0.637m/s, with relative deviations of 6.36% and 7.68%, respectively, from the simulation reference obtained using the original measured vibration input. The results support improved agreement with the model-based reference in the evaluated cases while maintaining comparable vibration statistical characteristics. Accuracy relative to actual field radar degradation remains unverified because an independent field-measured radar baseline is unavailable.