I download Sentinel-1 GRD products from https://search.asf.alaska.edu/. The original Geotiff image contains a lot of ground control points (GCPs) but not georeferenced. I georeference the images using GCPs by the following code
It seems that the GRD products on https://search.asf.alaska.edu/ did not go through terrain correction. We can not just use the GCP to geocoding them but need to use GCP and DEM to do the terrain correction.