Lessons learned from PSIC4: improving PS-InSAR results for a constrained test site.
Sami Samiei Esfahany(1), Freek van Leijen(1), Petar Marinkovic(1), Gini Ketelaar(1) and Ramon F.Hanssen(1)
(1) Delft University of Technology, Kluyverweg 1, 2629 HS Delft, Netherlands
In the PSIC4 experiment, eight different processing approaches for time series analysis of InSAR data were applied to a data set containing an unknown deformation signal. The experiment proved to be highly successful, as it clearly indicated that different approaches resulted in different results, in terms of spatial point density, temporal deformation behavior, phase ambiguity resolution, and precision and reliability. Results showed a trade-off between one or more of the above characteristics, and a high sensitivity to chosen threshold values. As PSIC4 was a blind experiment, where no a priori information on the location, magnitude, temporal behavior, and other characteristics of the deformation was available, it raises the question to what extent a priori information can and should be used in PSI processing. Information, or assumptions, either on temporal or spatial behavior appear to be very important in the processing results.
At TUDelft, the results of the PSIC4 study have been used to evaluate algorithm performance and assess which approaches are most important to retrieve reliable deformation parameters at a high spatial density. This includes an analysis of type-I errors (falsely rejected PS) due to imperfections in the functional model (e.g., imperfection due to high-order deformation, sub-pixel position of the scatterer), or in the stochastic model (e.g. imperfection due to atmospheric errors, orbit errors, geometrical decorrelation). We investigate the type-I errors and present significant improvements in their identification, leading to improved deformation estimates.
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,