S1A Terrain correction frustration

Dear all,

I am pretty new in the forum and in the SAR topic and need some help to clear the things up. I am trying to process the following products:


My Regions Of Interest (ROI) are mainly polar regions where there is no DEM available. Usually those ROIs contain only ocean or is a mixture of ocean and land. I would like to perform the following process:

1 Radiometric correction
2 Speckle filter
3 Terrain correction
4 Mosaicking

(Please let me know at this point if more process needs to be done for the GRD products)

As far as I understand Terrain correction should do also a re-projection to a targeted CRS? My problem is that I am not sure what I miss to perform a correct Terrain correction or/and re-projection. Since TC needs DEM, at polar regions there is no such information apart maybe from the ASTER product. How should I proceed? Reference code you may find under my topic in the python forum http://forum.step.esa.int/t/s1a-product-terrain-correction-frustration/5123.

Many thanks for your help.

I believe there is ASTER DEM data at ± 30 lat. If you data is within that range then you could download the ASTER tiles and place them in the folder C:\Users\lveci.snap\auxdata\dem\ASTER 1sec GDEM
If not, then you could check if the GETASSE30 is good enough for your purposes. For areas away from mountain ranges it should be ok.

Many thanks for your reply. I will play with the DEM and see how it looks like the TC. Just for my understanding, By performing a TC is this kind of equivalent to a re-projection? I mean if I do a TC do I still need to re-project to a target CRS or this is already done in the TC? Many thanks in advance.

Yes it’s already done by TC.