Calibration of Sentinel-1 data, when?

[adamoferro]

I answer to myself and maybe also to @felix regarding the aforementioned posts…
As usual, after searching, then asking… you find the solution somewhere else:

SLC to GRD processing?

Is there a good, up-to-date tutorial on processing SLC files to GRD products, including what steps to do, what files specifically are needed, etc., that someone can point me to? I’m having problems getting it to work. I have this file: S1A_IW_SLC__1SDV_20150918T230756_20150918T230823_007776_00AD0C_989D.SAFE When I try Radar->Complex to Detected GR, and just click Run, I get an error “3-SRGR: Source product should first be deburst.” When I try Radar->Sentinel-1 TOPS->S-1 SLC to GRD and click…

where @lveci reports an example of SLC to GRD processing chain.
Calibration is the very first step.

Can we assume that it should be always like this?
If so, maybe it would be worth to not allow the user to perform calibration after debursting of Sentinel-1 data?
E.g., regarding the first ref. post above, I was supposing it was not necessary to calibrate at the beginning (with the ellipsoid) because I was doing “normalization” (with the DEM) at the end in the terrain correction step.

Finally, this should solve also the problem with dual-pol data reported in the second ref. post. Tomorrow I’ll give it a try.

Thanks again!
Adamo