Image to image georeferencing using optical and radar data?

hello All!

recently for geometric correction i just made image to image georefencing using envi application with optical and radar data. basicly warped the sentinel 1-data radar data using GCP’s picked on optical sentinel 2-A. Then i realized i didnt use any DEM on radar data. So does it mean i couldnt remove the SAR geometry distortions such as Foreshortening? if the answer is yes is there any way the remove those effects without using range doppler terrain correction?

Thank you all in advance

I’d say that depends on the topography in your scene. If it is flat, coregistration with your optical data could work. If you have ridges and slopes, image to image referencing cannot remove foreshortening or overlay effects. Or it will simply not be able to find matching points in these areas.

Short answer is yes and no. You need to do the range-doppler terrain correction.