In-orbit correction and optimization design of the calibration assembly for HY-2 microwave radiometer

The HY-2 microwave radiometer containing nine channels, whose operational frequencies range from 6.6 GHz to 37 GHz, is one of the four microwave payloads deployed on the HY-2 satellite. After launch, both the hot blackbody counts and cold sky counts are processed before producing the Level 1b data, and the influence on cold sky observation resulted by main reflector draws special attention. Moreover, it is verified that the fluctuation mentioned above can be up to 2.4 K at 6.6 GHz, and this effect is corrected through processing the acquired data. In view of the realistic problem, some corresponding improvements have been carried out in the subsequent satellite´s design phase. This paper describes characteristics of the instrument, and the corrections to cold sky counts are also provided. Finally, the optimization design is presented and evaluated.