REVIEW OF PS-InSAR-BASED LONG-SPAN BRIDGES STRUCTURAL DEFORMATION MONITORING

The implementation of a lightweight structural health monitoring with continuous spatiotemporal coverage and high cost-effectiveness is of great practical significance for ensuring the bridge operation safety and realizing Intelligent Bridge and Intelligent Transportation System. The fundamental principles, technical features, application scope and research progress of the Permanent Scatterer Synthetic Aperture Radar Interferometry (PS-InSAR) technique are comprehensively summarized from three aspects: key technology, bridge structural deformation monitoring, and influencing factors. Regarding the key technology, the latest research results of image co-registration, PS points detection, phase unwrapping, and deformation recovery were systematically summarized. The application of the PS-InSAR in LOS (line of sight) deformation monitoring and three-dimensional deformation inversion were reviewed. The influence of bridge direction, surface scattering characteristics, phase unwrapping accuracy and thermal dilation model on the measurement accuracy of this technology were analyzed. The technology was further used to monitor the structural deformation of a steel arch bridge, and the feasibility of the proposed method are verified. The research on bridge deformation monitoring by the PS-InSAR technology is summarized, and possible future directions are discussed. The literature review indicates that the PS-InSAR-based method for monitoring bridge deformation has significant advantages and vast application prospects, which is expected to provide technical support for the operation and risk management of long-span bridges.