As far as I can tell, the process of calibrating to sigma0 involves thermal noise removal and speckle filtering. However, SNAP does not support ICEYE calibration to sigma0 because, I believe, the incidence angle is not available, and sigma0 is the radar cross section that accounts for the incidence angle derived from the meta data.
Yes, I did, but I believe there is something amiss in this. First of all the thermal noise removal doesnât support ICEYE in SNAP, then, as I shared in previous post the sigma0 requires incidence angle. In other words I think SNAP doesnât support what is mentioned.
So, If I understand well @mengdahl, radiometric calibration for Iceye GRD product is not supported?
In that case, why Iceye mention in the document you shared above, the following: âFor amplitude scenes, a conversion to sigma0 has already been applied using the incidence angle calculated from the ellipsoid model.â
How should we understand this statement? And how should I interpret the âsigma0â band that I get when I apply the SNAP âradiometric calibrationâ operator with an ICEYE GRD product? (because I do get such sigma0 band as outputâŚ)
Well, if the product is ânot supportedâ by the operator, the outputs cannot be trusted and arguably an error should be thrown. We should make sure sigma0 conversion with ellipsoid does not take place twice.
Perhaps @jun_lu could investigate?
Thank you so much for your kind support. While the teams at ICEYE and Bayanat had different perspectives at the time, science is science, and the facts remain the same after almost a year.