For TSX-1 EEC products, the radar brightness is derived from the image pixel values or digital numbers (DN) applying the calibration ('calFactor' in product metadata) which is polarization dependant. Sigma nought is derived from beta nought in function of the local incidence angle.
TSX-1 L1B EEC acquisitions are calibrated using SNAP, the open source common architecture for ESA Toolboxes ideal for the exploitation of Earth Observation data.
The TSX-1 calibration SNAP graph is depicted below:
The SNAP graph relevant parameters are listed in the table below:
The input is an ingested TSX product, see details here.
The output is a STAC item geojson ... including the assets ...
[RD01] Airbus Space and Defence Radiometric Calibration of TerraSAR-X datato Beta Noughtand Sigma Nought, TSXX-ITD-TN-0049-radiometric_calculations_022019_v2, issued: 2019.02.05