Study Of Measurement Principle And Key Technology Of On-orbit Calibration In Situ Blackbody

According to the Planck’s radiation law, the radiance emitted by a blackbody source is determined by the temperature and the emissivity of blackbody cavity. A new scheme of calibration blackbody on-orbit with high emissivity is proposed. It can be applied in infrared remote instrument calibration on-orbit. Controlling of temperature and dissemination of the value method with high accuracy is founded using fixed point defined by ITS-90 through blackbody, temperature sensor and miniature phase change fixed point device. It realizes the blackbody source emissivity measurement on-orbit based on the controlling surrounding radiation.The miniature phase change fixed point apparatus is designed, and the experimental apparatus is developed. The experimental results show the phase change temperature keep stability during the whole dissolution progress. The standard deviation of measurement results better than 10 m K. It also presents that the longer duration melts have plateaus that more closely approach the gallium melt temperature.The theoretical model of blackbody source emissivity measurement method based on controlling surroundings radiation is presented. The measurement results of blackbody source emissivity agree well with the theoretical modeling result, and the standard deviation of measurement results better than 0.1 %.The demands of calibration in infrared remote sensing of China are stated, the research status of blackbody on-orbit, phase change fixed point and emissivity measurement in certain countries is presented. The research progress and experimental results are described in detail of National Institute of Metrology in temperature calibration through phase change fixed point and emissivity measurement on-orbit based on controlling surrounding radiance. All the works aim at raising the infrared remote sensing calibration accuracy of China.