Monitoraggio DInSAR di infrastrutture tramite corner reflectors surrogati: validazione e possibilità di impiego. = Infrastructure monitoring using DInSAR with surrogate corner reflectors: validation and potential applications.

Due to the problem of ensuring structural safety of the European civil infrastructures’ heritage, nowadays affected by the aging phenomena of materials and by the increasing severity of natural phenomena linked with climate change, the market is asked for new tools for broad and efficient monitoring of structures. Among them the remote monitoring technique InSAR (Interferometric Synthetic Aperture Radar), using satellite active observation of Earth, represents nowadays a possible answer to this request. The wide space resolution gained with synthetic antenna allows to detect centimetric or even millimetric displacements and settlements of specific points on the Earth surface. This feature makes this technology useful for the purpose of building and infrastructure monitoring in a cheaper and more widespread way compared to traditional human survey or direct monitoring. Nevertheless, many problems linked to data usage and interpretation are still far from being solved. The lack of persistent scatters (PSs) in some areas for multiple reasons and the grouping of these points around nonstructural elements are significant problems underlined also in the guidelines proposed by ReLuis. The case study of Ponte del Risorgimento Bridge in Rome is an exceptional example of these issues that affect many monumental and historical buildings. The purposes of the thesis are to validate the effective usability of the grouped non-structural points and to highlight, extending the study to other bridges, the relation between displacement time series of the PSs with the main environmental parameters such as medium daily temperature, RH and hydrometric indices. The final goal is to show up a common pattern in the correlation of measurements to give the basis for a further depuration instrument of the signal, based on physical consideration as an alternative to the conventional signal theory techniques. Finally, a method for the estimation of displacement trends based on the direct observation of the line of side displacement time series (DOL approach) is proposed.