The Internal and External Calibration of the Sentinel-1 CSAR

The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. This paper describes the in-orbit calibration aspects for the Sentinel-1 mission. It provides an overview of the calibration requirements, and a potential technical concept for the implementation.