DEM resolution influence on S1 TOPS corregistration quality


I was wondering how the quality (resolution) of the DEM used for back-geocoding during the S-1 TOPS Coregistration affects the accuracy of the of the process.

I have to work over an area in Finland and of course SRTM is not available. I am considering using ASTER or the DEMs provided by a national authority (2, 10, 25 or 200m)

Any idea on that? From my experience, the DEM resolution should be as closed as possible to the pixel size of the image.


Even a very coarse DEM like the the GETASSE30 is sufficient - there is no degradation of accuracy.

@mengdahl, If the DEM is used to provide better prediction of the offset vectors (pixel by pixel correspondence between master and slave acquisitions using using orbital data and a reference DEM).

Why the resolution of the DEM is not relevant if the process is done pixel by pixel?