Long-term subsidence monitoring of urban areas using differential interferometric SAR techniques

Subsidence monitoring of areas affected by low velocity displacements is an extremely useful application of SAR (synthetic aperture radar) techniques. However, the required long time-baselines reduce the quality of the information stored in differential interferograms, adding difficulties to their processing. Typical characteristics of these interferograms are the presence of coherent areas that correspond to urban zones and totally incoherent areas of vegetation. A partial reconstruction of the subsidence map can be achieved by means of DInSAR (differential interferometric SAR) techniques based on the processing of coherent patches. On the other hand, PS (permanent scatterers) techniques can deal with incoherent areas, generating subsidence information of the whole image. A comparison of both techniques using ERS data is presented in this paper