Error in geomteric correction for polarimetric decomposition

I’m working on RISAT 1A quad pol dataset for polarimetric decomposition. In the preprocessing, I’ve done radiometric calibration>> matrix generation>>speckle filtering>> terrain correction(as I needed local incidence angle for decomposition step). I’m performing preprocessing in SNAP and decomposition in MATLAB. But I’m facing problem in generating local incidence angle by terrain correction. My output files are blank. what would be the reason?
Thank you