Sentinel-1 GRD products erroneous geocoding information

1

Hi,

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

gdalwarp s1a-iw-grd-hh-20150117t091102-20150117t091131-004209-0051d2-001.tiff -tps 20150117.tif.

However, the geocoding information of different images is inconsistent after georeferencing.

I wonder what is the problem. Do I use the wrong command?

Best,
Enze

2

Have you checked GeoTiffs stored on AWS Public Dataset?
https://registry.opendata.aws/sentinel-1/
These should be georeferenced.

3

Thanks for your suggestion. I will try it first. But it is strange that I can not get consistently georeferenced images from ASF. Hope that I can fix that problem or know what is wrong later.

4

I have solved the problem.

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.

Thanks for your kind help.