Error while processing two S1 IW SLC data

Microwave Toolbox
#1

Hi guys,

i try to compare two sets to derive an Interferogram and Displacements:
S1B_IW_SLC_1SDV
S1B_IW_SLC_1SDH

i stock within the first step while i try to make

Radar->Corregistration->S1 Top Corregistration->S1 Top Corregistration

I get the Error Msg…:

Has it something to do with the difference of this parameter (i dont know what it is) 1SDV vs. 1SDH ??
In the TOPSAR-Split Register i choose VV on both.
I use the Version 5.0 of Snap

Thank you for help!
Greetings

#2

Thanks for reporting, this could be a bug that should be easy to fix. Also I don’t see a reason why the polarisation could not be different. @cwong could you take a look?

#3

1SDV is a combination of VV and VH polarizations and 1SDH one of HH and HV, hence, you have indeed different polarizations which throw the error. I would be surprised if that would be considered to be a bug because one would expect phase coherence to require the same polarization.

#4

Yes, true for phase coherence but not for co-registration, which should still work, unless the software blocked it.

#5

The Back-Geocoding operator is performing the check for same polarization and it is by design.

Back-Geocoding on its own does not require same polarization. However, since the processing step after Back-Geocoding is almost always interferogram (which requires same polarization) and Back-Geocoding is the most time consuming operator, it is better to alert the user to the same polarization requirement earlier than later.

#6

@cwong I think a warning should be sufficient. There are some users who do intensity-based work but start from SLCs, and they might need to co-register non-matching polarisations.

#7

This will be fixed (i.e., issue warning instead of raise an exception if different polarization is detected) in a future version.