Uncertainty Quantification of Satellite InSAR‐monitoring of Bridges: a Case Study

Traditional structural health monitoring (SHM) systems provide accurate and objective information to assess the condition state of bridges; however, they are expensive and typically installed only on strategic bridges. Innovative technologies offer a potential solution. Interferometric Synthetic Aperture Radar (InSAR) takes multiple satellite radar images of a given area over time and extracts displacement time series of reflective point targets on the ground. The literature on InSAR‐based SHM of bridges lacks systematic studies aiming at quantifying the metrological uncertainty of the displacements measured. Furthermore, the topographic context and the magnitude of displacements of these structures between successive satellite passes significantly impact the uncertainty of results. This paper aims to evaluate the effectiveness of InSAR‐based SHM of bridges by comparing displacement time series obtained from InSAR with those from an on‐site topographic system. Displacements are measured from a prestressed concrete bridge in the Alpine region. Moreover, this study models the deformed shape of the bridge based on satellite and on‐site measurements and compares the results to determine whether bridge distortions can be reconstructed using satellite data alone.