Radiometric normalization not available

Microwave Toolbox
#1

In SNAP 4.02 (S1TBX 4.0.3) , I get an error message (in blue): “Warning: Radiometric normalization currently is not available for - products” when terrain correcting Sentinel-1 dual-pol GRDH products. SNAP then opts to write input bands instead of the radiometrically normalized ones. These bands also seem to be garbage in the output file (the incidence angle seems OK). I don’t remember having seen that before. Is this normal ? Somehow SNAP reports to use java version 1.8.0_60 even though my default java is 1.8.0_102-b14.

#2

Normalization from the Terrain Correction is not available for Sentinel-1 products because they use a look up table for calibration. Instead use radiometric calibration or terrain flattening.

SNAP uses it’s own JRE regardless of other versions installed.

#3

OK, I will try “terrain flattening”. I don’t see why the use of look-up table in calibration is an obstacle for radiometric normalisation in terrain correction. Especially when the help for “Range Doppler Terrain Correction” says for Radarsat-2:

    In case of "USE projected angle from the DEM" selection, the 
    radiometric normalisation is performed applying the product LUTs and 
    multiplying by (sin DEM/sin el), where DEM is projected local 
    incidence angle into the range plane and el is the incidence angle 
    computed from the tie point grid respect to ellipsoid.

As “they” obviously adapted the LUT format of Sentinel-1 products from the LUT format of Radarsat-2, I don’t see why processing Sentinel-1 products has been made more difficult for the user (requiring one extra processing step in the graph) than Radarsat-2 processing.