Calibration of Interferometric ENVISAT/ASAR Image Mode Products

Abstract

The robust and automatic use of complex products for InSAR data processing requires careful calibration and validation. Interferometric calibration comprises geometric and phase accuracy aspects. With respect to geometry, orbit and timing parameter have to be calibrated in order to allow accurate geo-coding and optimal processing of the interferometric products. Phase accuracy of the underlying complex products is an important prerequisite for the interferometric measurement technique. This paper describes methods for location accuracy determination and reports the preliminary results obtained during the ongoing calibration/ validation phase of ENVISAT/ASAR. The paper includes a first ENVISAT/ASAR interferogram obtained with DLR’s value added land processing system for interferometry. The data sets were acquired over a test site near Berlin. This interferogram is compared to the result from ERS for the same season of year. In addition, for verification of timing parameters a new method is proposed based on the cross-calibration of ERS and ENVISAT/ASAR. As a test site serves the Flevo Polder site in The Netherlands. Several ESA transponders are located on this site adjusted for ENVISAT/ASAR calibration.