Full Calibration of the SMAP-R Dataset

SMAP-R is the first polarimetric GNSS-R dataset collected from the space. The reception of the Horizontal and Vertical components of an incident circular polarized signal allows to retrieve the Full-Stokes parameter of this hybrid compact polarimetry radar configuration. In this manuscript, the Stokes parameters of the reflection scenario are defined and calculated. The first Stokes is calibrated to retrieve the normalized bistatic radar cross section as main observable. The SMAP-R dataset is validated by collocating it to CYGNSS measurements. The results show a good agreement with CYGNSS normalized bistatic radar cross section, with an unbiased root-mean-square error of 3.3 dB for a 6 months period, showing also larger sensitivity over vegetated areas.