Radar-based remote sensing monitoring of roads

This paper provides a brief description of two powerful radar-based remote sensing techniques to monitor the deformations of roads, their associated infrastructures and, more in general, their surroundings. The first technique is the satellite radar interferometric technique. In this work a specific technique, named Persistent Scatterer Interferometry (PSI), is considered. This technique has wide-area coverage capability (e.g. covering thousands of square kilometres at the time) and, at the same time, is sensitive to very subtle displacements. The second technique, named groundbased radar interferometry is based on a terrestrial instrument. From the viewpoint of the deformation measurement principle this second technique is very similar to the first one. However, it can be used to cover much smaller areas but offering a very dense temporal sampling capability (e.g. one measurement every a few minutes). This is typically used to monitor critical deformation phenomena, e.g. very active landslides that may represent a high risk for a given road, etc. This work provides, for both techniques, a concise description with several references to major works related to them. In addition, it illustrates some examples of the results that can be achieved with both techniques.