The Study of Metrology and Measurement Technology of Spaceborne Microwave Radiometer Hot Calibration Target

The hot calibration target provides the standard radiation brightness temperature signal with high accuracy and stability for spaceborne microwave radiometer. It can be used for the real-time calibration of the microwave radiometer on-orbit, and widely applied in the microwave detection payloads of meteorological and ocean observation satellite, such as FY-3 and HY-2. Therefore, the calibration technologies of physical temperature and microwave emissivity for hot calibration target is important, which is directly related to the validity and accuracy of satellite detection data. Focusing on the performance evaluation requirements of hot calibration target, the measurement technologies of the thermal and electromagnetic characteristics were studied. The paper summarized and analyzed the current test methods and results of the key parameters, mainly including the measurement and control precision of physical temperature, temperature non-uniformity and stability, microwave emissivity and frequency range, etc. The technical realization ways and development trends of the hot calibration target with better performance were analyzed and forecasted, according to the requirements of China's remote sensing satellite quantification, and the on-orbit calibration of microwave remote sensing payloads of next generation meteorological satellite.