Help regarding SLC preprocessing for polarimetric analysis

I am trying to preprocess Sentinel 1 SLC IW data in order to calculate the Radar Vegetation Index (RVI) in SNAP. However I am facing an issue during the generation of polarimetric matrix, with the error message that an SLC product is required. I am following the process in the paper for single swath single date preprocessing. I preprints201911.0393.v1 (6).pdf (571.2 KB)

Did you maybe write the data to GeoTiff or another format instead of BEAM DIMAP?
Also, did you check the “complex output” during the calibration module? If you calibrated to Sigma0, you can no longer apply polarimetric tools.

I calibrated it into sigma0. Sorry was not aware of this. Thanks for pointing that out. What calibration should I use instead ?

please see here:

There is a checkbox to select “complex output”

Thanks
I followed all the preprocessing steps, but I am stuck at module 4 which deals with the export of the data as PolSarPro. I am getting this error. Help would be appreciated.

We talked about this here: Error while exporting SNAP to PolSARPro