The Flexible Combined Imager on board MTG: from design to calibration

摘要

The Meteosat Third Generation (MTG) Programme is being realised through the well-established and successful cooperation between EUMETSAT and ESA. It will ensure the continuity with, and enhancement of, operational meteorological and climate data from Geostationary Orbit as currently provided by the Meteosat Second Generation (MSG) system. The industrial Prime Contractor for the Space segment is Thales Alenia Space (France) with a core team consortium including OHB-Bremen (Germany) and OHB-Munich (Germany. This contract includes the provision of six satellites, four Imaging satellites (MTG-I) and two Sounding satellites (MTG-S), which will ensure a total operational life of the MTG system in excess of 20 years. A clear technical baseline has been established for both MTG-I and MTG-S satellites, and confirmed through a rigorous Preliminary Design Review (PDR) process that was formally concluded during 2013. Dedicated reviews have been held for all the main elements including the core instruments (Flexible Combined Imager (FCI) and Infrared Sounder (IRS)), the Platform (which is largely common for the two satellites), the Lightning Imager (LI) and the MTG-I and MTG-S satellites as a whole. The satellites and instruments are at the moment in preparation for the Structural and Thermal Models (STM). The FCI is designed to provide images of the Earth every 10 to 2.5 minutes in 16 spectral channels between 0.44 and 13.3 μm, with a ground resolution ranging from 0.5 km to 2 km. The on-board calibration is based on the use of a Metallic Neutral Density (MND) filter for VIS/NIR channels and a blackbody for the IR channels. This paper introduces the overall FCI design and its calibration concept covering VIS/NIR and IR domains and it describes how the use of the MND makes it possible to accurately correct the medium and long term radiometric drifts of the IR3.8 μm channel.