Monitoring terrain movements by means of sparse SAR differential interferometric measurements

Synthetic aperture radar differential interferometry is a powerful technique that allows, in principle, the measurement of very small movements of the terrain over time. Unfortunately, SAR differential interferograms are often rather noisy. A recently proposed phase unwrapping approach allows sparse data to be processed, and therefore extraction of the available information from noisy data sets. The authors test the potential of this method on several SAR differential interferometric data sets. In particular, the subsidence phenomena happening in Bologna (Italy) and in the surrounding area from 1993 to 1999 are analyzed. Unwrapped phases corresponding to different pairs are finally combined to perform a full space-time analysis of the considered phenomena.