Precise Geolocation of Persistent Scatterers Aided and Validated by a Lidar DTM
Chang, Ling; Dheenathayalan, Prabu; Hanssen, Ramon
Delft University of Technology, NETHERLANDS

Persistent Scatterers (PS) interferometry results in the deformation history of time-coherent scatterers. Although several applications focus on smooth, spatially correlated signals, we aim for the detection, identification and analysis of single anomalies. These targets can be indicative of, e.g. strain in structures, potentially leading to the failure of such structures. For the identification and analysis it is of the greatest importance to know the exact position of the effective scattering center, to avoid an improper interpretation of the driving mechanism. Here we present an approach to optimize the geolocation of important scatterers, when necessary aided by an a priori lidar-derived DTM with a 50 cm resolution. The DTM is also used to validate the geocoding. We apply techniques developed for a high resolution sensor such as TerraSAR-X [1] also for the medium resolution systems of ERS, Envisat and Radarsat. This involves orbit improvement, timing correction, earth tides and tectonics, and atmospheric correction. As the lower resolution hampers the geolocation precision, we use information from the Lidar DTM as additional constraint. Three-dimensional confidence intervals are produced to geolocate the effective scattering centers. We implement our approach on a near-collapse of a shopping mall in Heerlen, the Netherlands, to unravel its driving mechanism.
[1] X. Cong, Balss, U., Eineder, M. and Fritz, T., Imaging Geodesy-Centimeter-Level Ranging Accuracy With TerraSAR-X: An Update, Geoscience and Remote Sensing Letters, IEEE Volume: 9, Issue 5, 2012, Page(s): 948 - 95