Estimating Bridge Natural Frequencies Using Phase Time-Series Micro-Doppler Analysis with Dwell-Mode Satellite SAR

This study explores the feasibility of estimating the natural frequency of bridge structures using ICEYE Dwell-mode synthetic aperture radar (SAR) data. Sub-aperture imaging was employed to construct a complex image time series for analyzing the vibration-induced micro-Doppler components. To ensure precision, residual errors were mitigated through registration between the sub-aperture images and low-order polynomial detrending of multi-scatterer phase signals. The estimated frequency was found highly consistent with accelerometer-based measurements. These findings demonstrate the viability of satellite SAR as a remote, non-contact tool for structural health monitoring (SHM).