光学有效载荷高精度绝对辐射定标技术研究

An Advanced Technology of Absolute Radiometric Calibration for Optical Remote Sensors

随着多波段、多平台、高光谱分辨率遥感仪器的迅速发展,要求光谱辐射定标技术具有前所未有的高精度和长期测量稳定性。目前,传统辐射定标方法的精度已逐渐难以满足定量遥感应用的需求。本文提出了一种新型基于辐亮度标准探测器的高精度光谱辐射定标先进方法和技术,由于该方法可直接溯源至低温绝对辐射计,其绝对精度和长期稳定性优于传统的基于标准光源法,是提高中国目前光学遥感器实验室、星上和场地替代定标精度的有效途径。该方法已两次成功应用于中国“FY-2”气象卫星04和05星发射前外场定标,实际应用效果表明,它能够有效提高中国卫星遥感器的外场定标精度,对改善中国当前卫星遥感器各阶段定标精度,具有潜在的应用价值。

For sensor radiometric calibration, there are source-based radiometry which is based on blackbody physics referenced to the freezing temperature of gold, and detector-based radiometry which is based on electrical substitution radiometer at cryogenic temperatures respectively. The source-based radiometry is a traditional method with poor accuracy compared to detector-based radiometry owing to the difficulty of high accuracy measurement of blackbody temperature. With the development of multi-spectrum, multi-platform and high-resolution response remote sensors, the traditional absolute radiometric calibration technology source-based is facing the challenge since it accuracy doesn＇ t meet the remote sensing application requirements. In this paper, a new calibration method and its application technology based on radiance standard detector are presented in detail. The absolute accuracy of the new calibration technology is far higher than before, since it can directly trace to the cryogenic absolute radiometer which measures the radiant power with the lowest uncertainties currently. The new calibration method has been successfully used to FY-2 No. 04 and No. 05 satellite sensor preflight absolute calibration two times in KunMing in 2004. The results show that the new method can effectively improve the calibration accuracy of satellite sensors and has potential applications in preflight, on-board and vicarious calibration of sensors.