Deformation Monitoring using SAR Interferometry on the Azores within Exupéry Project

Abstract

Radar interferometry is widely used for deformation mapping. But its ability is limited by various sources of decorrelation, like tropospheric disturbance and temporal decorrelation due to vegetation. In order to ensure the coherence for interferometric point measurements, corner reflectors, which could provide strong and stable target response during a long time span, are often utilized. In Exupéry project a campaign with multi-sensor in Azores was conducted from April to August 2009. Two corner reflectors, which were designed for X-band with transportable size, were successfully installed for TerraSAR-X on test site Lagoa do Fogo (Sao Miguel, Azores). 11 TerraSAR-X Strip-map scenes were gathered consequently. InSAR technique was applied for processing the time series. The resulting interferograms, differential interferograms and coherence images will be delivered to the center database in Hannover and will be published instantly on the Exupéry Website. With the highly accurate orbit information, the phase measurements of the corner reflectors could be directly extracted from the interferograms using the geographical coordinates and were used for detecting the probable changes due to ground movement, atmospheric delay or other noises. Other coherent, natural scatterers and their phase values are used for further PSI analysis.