Ground Calibration of Flight Models of Reference Radiometer of MIRAS

In this paper we present the calibration approach and a collection of results of the on-going ground characterization campaign of the reference radiometer (noise injection radiometer, or NIR) of MIRAS (Microwave Imaging Radiometer using Aperture Synthesis), which is the instrument on ESA's (European Space Agency) SMOS (Soil Moisture and Ocean Salinity) mission. Currently the characterization is in a phase in which the antennas are mounted on the units and several parameters have been measured without the antenna