The technology has been in use since the early / mid-2000s, and is a useful supplement to various monitoring systems or as stand-alone monitoring of exposed mountain sides. Campaigns repeated over a certain period can quantify both size and movement pattern in unstable mountain sides or subsidy / sentences. The radar can also be used for continuous monitoring of unstable mountain sides, so that any acceleration in the movement can be detected and notified.
Similar to satellite-based radar surveillance (InSAR), the differences in the radar signal between scenes taken at different times are used to detect displacement. Ground-based radar has, in contrast to satellite-based, a fixed location for all measurements at a locality, so that there is no contribution from the terrain in the radar signal. This reduces the sources of error in the measurements and enables the use of all the data over a long period of time.
GPRI at NGI
NGI's activities related to ground-based interferometric radar are mainly focused on the detection of movements on steep mountain slopes. The aim is to identify areas with displacement, quantify the size of this displacement and to monitor any accelerations. It is also possible to monitor infrastructure and other types of structures.