Proper way of combining S1A and S1B data

[ABraun]

@aleksilc

(From my knowledge only Range-Doppler terrain correction normalizes some sigma nought in regard to the incidence angle by multiplying the ellipsoid value with the ratio of the DEM incidence angle to the ellipsoid incidence angle)

Actually, Range Doppler Terrain Correction only reduces geometric distortions in the images which result from foreshortening of the signa. In turn, Terrain Flattening reduces radiometric distortions based on the different areas (per pixel) illuminated by the sensor due to topography. This completely removes the impact of incidence angles in your image. I don’t know how to normalize backscatter for a defined incidence angle, but these things have been discussed in these topics:

• Backscatter normalization to a pre-defined incidence angle for S-1 GRD HH channel data
• Incidence angle_Sentinel 1 image - #17 by chauncey