Filtering of interferometric SRTM X-SAR data

In February 2000, the Shuttle Radar Topography Mission acquired a global digital elevation model (DEM) within only 11 days. During the years 2000 and 2001, extensive testing and calibration activities followed at DLR. One of the questions during that phase was, which kind of interferogram filtering should be performed. We analyzed different types of filters from the perspective of an operational DEM processing chain. Our paper describes the filters investigated and the arguments that finally led us to the decision to implement a relatively simple Gaussian smoothing in the time domain. This filter performed best in many disciplines and produced the smallest artifacts.