Development and calibration of infrared standard radiometer

Accuracy of blackbodies' reference source radiance is one of the crucial factors that determine the accuracy of infrared sensor's absolute radiometric calibration. To improve the measurement accuracy of blackbodies' radiance, a infrared standard radiometer was developed to calibrate blackbodies' radiance directly. The principle and the opto-mechanical design of the instrument were described in detail, and the radiometer was calibrated against a high accuracy water-bath blackbody. The experimental results demonstrate that radiometer's instability is less than 0.03% with in one hour and the uncertainty is less than 0.22%. This corresponds to a brightness temperature uncertainty of 73 mK at 308 K. The radiometer possesses the advantages of system-level measurement and high-precision tracing standard, and by which the blackbodies' radiance can be traced to the radiant standard in lab.