I’m working on a multi-temporal S1 IW-GRD pair.
I tried applying Terrain Correction on the SIGMA0 calibrated image for mitigating the SAR distortions. I both considered Range Doppler TC and SAR Simulation TC. For both, I used the SRTM1Sec DEM (I guess it should take into account the gravitational model of the Earth too) ; the DEM interpolation was conducted with either BiSinc or Biinear, while resampling with either Bilinear or NN, respectively.
The output corrected map, anyway, show some strange artefacts on the sloped regions. I’d like to mitigate them as possible. Is there any TC optimal setting for it? I am afraid that this would sensibly impact on the multi-temporal analysis of the scene.
Thanks. Kind regards.
The artefacts you describe are largely unavoidable and result from correction of strong foreshortening or layover.
Your best shot at the moment for reducing terrain-effects is to run Radiometric Terrain Flattening with the best DEM you have, before Terrain Correction. You should do this in SNAP 6.0 beta as it has been improved over the previous version. We are planning to improve this further in upcoming SNAP versions.