First Results of the Sentinel-1A In-Orbit Antenna Characterization Performed by DLR

Sentinel-1A is the first of two new C-band SAR-system satellites commissioned by the ESA. The high demands on radiometric stability and accuracy that are made for Sentinel-1 constitute a challenge for the calibration concept. An integral part of this concept is the antenna model, which was validated on-ground to a remarkable accuracy. To guarantee the image quality, the model needs to be verified in-orbit during the commissioning phase. The methodology of the in-orbit antenna characterization by DLR are presented in this paper. Results could not be described as Sentinel-1A had not been launched at the time of this article's submission.