Recent sensor designs for Earth observation

The large number of missions associated with ESA’s Copernicus program has necessitated several new image sensor designs for earth observation (or living planet) applications as each instrument needs to be highly optimized. Whilst the majority of these sensors have utilised CCD technology, the use of CMOS is starting to increase. New CCD designs and technology trends for hyperspectral applications such as Sentinel 4, Sentinel 5, Sentinel 5 precursor (TropOMI), Flex and 3MI are described. In these the sensor design has been optimized to provide highest possible signal levels with lowest possible noise in combination with higher frame rates and reduced image smear. CMOS sensors for MTG (Meteosat Third Generation) and METImage are then described. Both use extremely large pixels, up to 250μm square, at high line rates. Radiation test data and key performance measurements are shown for MTG and for a test device that has been made for METImage. Finally, newer developments including back-illumination and means for achieving a TDI function in standard-processed CMOS are briefly described.