Reducing the DEM Error Effect in Differential Interferometry

Andrew Sowter(1) and Mark Warren(1)

(1) University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom


The quality of any standard 2-pass differential interferometry (DInSAR) result is affected by the quality of the digital elevation model (DEM) used as reference. In this paper we show that, under certain circumstances, a 3-pass approach can improve upon a 2-pass result when we apply a simple phase screening process similar to that already applied to the production of DEMs from single interferograms. The level of improvement depends on the quality and resolution of the DEM and the coherence of the reference interferogram. It is shown that there may be benefits in this approach when using the 90m SRTM DEM over areas of moderate to high coherence. The result is demonstrated using the ENVISAT-1 ASAR data of the 2003 earthquake in Bam, Iran.


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