In October 2013 Omnisys was awarded the ESA contract for a 875 GHz Receiver Front-End for an Airborne Icecloud Imager Demonstrator for the International Sub-Millimetre Airborne Radiometer Instrument, or ISMAR.

ISMAR is an instrument currently under development which will measure radiation in the 200-1000 GHz frequency range. It will act as an airborne demonstrator for a possible future ESA satellite instrument, called Ice Cloud Imager (ICI), monitoring ice clouds and precipitation in the atmosphere.

Omnisys will design and manufacture two receiver chains including horn antennas, mixers, the LO chain, LO source and an IF amplifier. The critical Front-End components are based on a low noise GaAs Schottky membrane and unique InP HEMT MMIC receiver technology from Chalmers University of Technology in Gothenburg. The complete ISMAR instrument will be developed by the UK Met Office to monitor the climate and measure surface precipitation.


  • Odin-SMR became the first satellite instrument observing our atmosphere using microwaves with frequencies above 300 GHz. Some other limb sounders have used similar frequencies, but the frequency region has so far not been used by satellites dedicated to weather observations.
  • The Ice Cloud Imager, to be launched around 2022 as part of the Metop Second Generation satellite series, will use these frequencies in regular operations.
  • ICI will operate at frequencies between 183 and 664 GHz. ISMAR has a similar set of channels as ICI, but will also be used to test even higher frequencies, such as 875 GHz.


  • As ICI will be the first of its kind, a demonstrator system is required. This is the main reason for developing the ISMAR airborne instrument.
  • ISMAR is of particular value to develop the required scientific algorithms, as an airborne instrument offers a possibility to perform detailed test measurements, which will not be possible with the future ICI.
  • The frequency range that ISMAR and ICI handles is especially suitable for measuring the mass of clouds consisting of ice particles. This is a quantity of fundamental importance for weather, and thus also for our climate, that today is poorly handled by existing observation systems.
  • ICI will also provide additional information on water vapour and help to forecast surface precipitation.