Health monitoring approach for transport infrastructure and bridges by satellite remote sensing Persistent Scatterer Interferometry (PSI)

The satellite PSI Interferometry is a radar-based remote-sensing technique, which is capable of monitoring and measuring displacements with a high precision of the Earth's surfaces by means of multi-temporal acquisitions. These are collected without interfering in any way with the operating conditions of the transport infrastructure as opposed to the common non-destructive survey methodologies (e.g. GPS, accelerometer, total stations). Nowadays, the use of medium ground-resolution SAR-datasets, acquired by C-Band sensors (operating at a frequency of 5.4 GHz), allow to conduct computationally affordable analyses, detecting displacements with a centimeter accuracy of the measurement. Furthermore, the use of images acquired by the new generation of high-resolution X-Band radar sensors (operating at a frequency of 9.6 GHz), allow to increase the ground-resolution and achieve a millimeter displacement-resolution This study aims at demonstrating the potential of the PSI remote-sensing technique to develop and formulate an innovative health-monitoring methodology and approach for structural assets such as bridges, using a multi-frequency satellite resolution. For this purpose, in this study C-Band Sentinel-1A SAR products provided by the European Space Agency (ESA), and X-Band COSMO-Skymed products provided by the Italian Space Agency (ASI) were acquired and processed. Furthermore, a PSI analysis was developed to monitor and detect structural displacements of a bridge of historical values. Outcomes of this investigation outlined the presence of various PS over the inspected bridge, which were proven useful to achieve a more comprehensive health monitoring and the assessment of the structural integrity of the bridge. This research paves the way for the development of a novel interpretation approach relying on the integration between remote-sensing data and non-destructive information collected on-site (e.g., GPR surveys and Laser Scanner), to improve and optimize current maintenance process of transport assets.