Terrasar X-band Insar Observations in Urban Areas

SAR (Synthetic Aperture Radar) has ability to detect subtle surface movement at the scale of millimeter to centimeter. TerraSAR-X is new radar satellite operated at X-band, multi polarization, and multi beam mode. Compared with C-band or L-band SAR, the X-band system inherently suffers from more temporal decorrelation due to short wavelength (3.1 cm), but is more sensitive to surface deformation monitoring due to short wavelength and high spatial resolution (1m-3m). Many urban areas are experiencing land subsidence due to water, oil and natural gas withdrawal, underground construction, sediment compaction, and so on [1-3]. Monitoring of surface deformation, especially in urban areas, is valuable for effectively limiting damage areas [4]. In addition high accuracy and spatially dense subsidence map can be achieved by Xband InSAR observation, promoting identification and separation of various subsidence processes and leading to enhanced understanding via mechanical modeling. The Roi_Pac was utilized for interferometric processing of TerraSAR-X SSG data. Although the Roi_Pac was originally developed and distributed by JPL [5], we modified many steps in order to improve the performance, to make it more robust in very flat area and mountainous area, and to deal with the data with inaccurate orbit such JERS-1 and RADARSAT-1. Fig. 1 shows the flowchart of the modified Roi_Pac, which was used for all steps of radar interferometry using TerraSAR-X data. The most special consideration on the