Usage of Coordinate Reference System for Terrain Correction

Dear forum community,
while handling S1-images for most purposes applying of terrain correction is a must.
I was wondering, wether SNAP-algorithm is able to cope with usage of variable Coordinate reference Systems (CRS) , e.g. S1-image comes in EPSG 3587 or 4326 , is it mandatory to apply DEM in the same EPSG-Code as the native CRS of the satellite image ? Or produces the algorithm distortions while applying Transformation of the CRS?

Thanks for your help!

You can choose to reproject S-1 from native (non EPSG) coordinates into the coordinate-system of your choosing, in the (mandatory) terrain correction step.

Dear Marcus, thanks for your reply.
The coordinate system of the required DEM has to be the same EPSG-Code as the desired output of the terrain corrected S1-Image, to carry out the process properly?

Thank you

if you use an external DEM, it must be stored as GeoTiff in WGS84 (EPSG:4326), regardless of the desired output of the terrain correction.