I have ALOS-2 quad-pol data over the moderate topographical region. I am facing problem in calculating accurate sigma naught (backscatter coefficient). I have performed following processing steps. Kindly guide what’s the correct progressing sequence and where I have gone wrong in my processing. In my case, sigma naught values are very low ranging from ~-28 to -55 db. Line profile of sigma naught for HV is shown in the picture below.
- Slant Range to Ground Range Conversion
- Computing Sigma naught using 10*log10(I^2+Q^2)-83
- Ranger Doppler Terrain Correction