External DEM for SLC data coregistration

[ABraun]

@delia

You are right, for coregistration maybe a dem with 1m resolution is not necessary but then, when i will use the topographic phase removal, i suppose that i will have the same problem.

I used ACE30 for the BackGeocoding and later the 2m DEM (I reported in the other topic) and this worked fine.

DEM-based coregistration tries to find patterns which exist both in the DEM and the backscatter intensity. If the images are not of equal size or resolution these patterns cannot be found and no GCP are created and the coregistration fails.