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InSAR quality control: analysis of five years of corner reflector time series

Petar Marinkovic(1), Gini Ketelaar(1), Freek van Leijen(1) and Ramon Hanssen(1)

(1) Delft University of Technology, Kluyverweg 1, 2629HS, Delft, Netherlands


Quality control for InSAR and PS-InSAR measurements is notoriously difficult, due to the lack of a well-defined effective scattering center, the absence of redundant measurements, and the phase ambiguity estimation problem. Only using a heuristic approach, based on assumptions on ergodicity in space and/or time, it is possible to derive estimates and retrieve quality parameters.

Corner reflectors are the only option to retrieve a well known scattering center, making them very useful for validation purposes. In the Delft Corner Reflector experiment five corner reflectors have been deployed since early 2003, oriented towards a descending track of Envisat and ERS-2. During these years, the reflectors have been leveled manually with high precision, to build a strong validation archive and ground water table measurements have been performed for better interpretation of the results. Quality assessment is performed, both for the (PS) InSAR as well as the leveling data, showing an RMS of fit of less than 2 mm. We will report on the deformation behavior of the reflectors related to ground water variations and temperature, the use of tandem ERS-2/Envisat acquisitions, the use of high-Doppler ERS-2 data and associated sub-pixel position estimation. Moreover, the performance of different strategies for the construction of a PS-InSAR reference network are investigated. The study is based on geodetic error propagation theory and realized through an integration of corner reflectors and neighboring "natural" persistent scatterers. We will conclude on the attainable accuracy levels and the performance of InSAR/PS-InSAR processing and estimation methodology for deformation monitoring.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry