Hello, there!
I try to run this operator, but I either get the DEM resolution error (Radiometric Terrain Flattening - Hot solve low DEM resolution?)
or with re-grid method unchecked I get “Product without incidence angle tie point grid”.
Prior to RTF I applied the Orbit File, then Radiometric | Calibrate.
I am working on this image:
S1A_IW_SLC__1SDV_20160512T160748_20160512T160815_011228_010FA8_7878
I work with SNAP 5.0
In the Calibration Step I output to Beta0 band.