ERS tandem InSAR processing for DEM generation, glacier motion estimation and coherence analysis on Svalbard

This paper describes the unique InSAR (Interferometric Synthetic Aperture Radar) processing algorithms at Norwegian Defence Research Establishment (FFI) and how ERS (European Remote Sensing Satellite) tandem data are used to prove the high performance of the processing chain. The InSAR baselines are estimated from the high precision orbit data only, without using ground control points in the Svalbard test area. The flattening of the interferograms is of high quality and the interferograms are used to generate InSAR DEM (Digital Elevation Model) by using an existing DEM from Svalbard. The root mean square (rms) of the InSAR DEM is between 10 and 20 m in the selected test area. Although one day interferograms with removed terrain fringes were used, a combination of field measurements, photogrammetric methods and interferometry are necessary to obtain a complete pattern of ice velocities on a fast-moving glacier like Kronebreen (maximum 2 m day(-1)), where parts of the glacier are heavily crevassed. The study also demonstrated that considerable decorrelation may occur during one day over snow and glaciers due to changing weather conditions.