Retrieval of Discontinuous Deformation Induced by Thermal Expansion and Contraction of Bridges with Adaptive MTInSAR

The application of multi-temporal interferometric synthetic aperture radar (MTInSAR) technology in bridge structural health monitoring often encounters considerable challenges due to the intricate nature of bridge structures. Notably, the thermal expansion and contraction (TEC) of bridges can lead to prominent interferometric phase jumps at the expansion joints. When the magnitude of the phase jump exceeds π, the continuity assumption required for phase unwrapping is no longer valid. To address this limitation, we propose an adaptive MTInSAR method that can partition the bridge into independent segments and concurrently estimate deformation from multiple reference points. We validate the effectiveness of the method using 23 TerraSAR-X images of the Shanghai Yangtze River Bridge. The results demonstrate the successful detection of expansion joints and reliable phase unwrapping in PS sub-networks.