S1A Terrain correction frustration

Microwave Toolbox
#1

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:

S1A_EW_GRDM_xxxxxxxxx.SAFE

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.

#2

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.

#3

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.

#4

Yes it’s already done by TC.