碳卫星CO_2探测仪发射前的漫反射板定标

为了提高CO_2探测仪的在轨辐射定标精度,建立了在轨辐射校正原理,并对关键环节漫反射板的制备、BRDF定标和应用进行了系统的研究。根据CO_2探测仪的工作原理与系统组成,介绍了星上定标设备和在轨辐射定标策略,确定了漫反射板的制备方法和优化工艺参数,制定了以标准灯和标准探测器为传递链路的漫反射板BRDF的精确定标方法。对漫反射板基准BRDF、角度修正因子和半球反射率进行了测试,对其实验室定标精度进行了分析,并通过在轨初期的应用结果予以验证。发射前的定标结果表明,漫反射板在760nm、1 610nm和2 060nm 3个波段的定标精度均优于3%。在轨初期的测试结果表明CO_2探测仪1 610nm波段在轨绝对辐射定标精度优于5%。CO_2探测仪漫反射板的定标结果满足仪器辐射定标对漫反射板定标的精度要求。

Preflight diffuser's calibration of carbon dioxide spectrometer of TanSat

In order to improve the on-orbit calibration accuracy of a CO₂ spectrometer, the principle of on-orbit radiation correction was established, and key aspects such as the fabrication, BRDF calibration, and application of a diffuser were systematically studied. Based on the working principle and system composition of the CO₂ spectrometer, the device and strategy for performing the on-orbit radiation calibration were introduced, and the fabrication method and optimization of the process parameters of the diffuser were established. Next, an accurate calibration method with lamps and detectors as transmission standards for the diffuser's BRDF are developed. The reference BRDF, angle correction factor, and hemispherical reflectivity of the diffuser were tested. In addition, the calibration accuracy in the laboratory was analyzed and subsequently verified by the application results obtained during the initial stage of the orbit. The results obtained before the launch show that the calibration accuracy of the diffuser was better than 3% for all three bands at 760 nm, 1 610 nm, and 2 060 nm. The initial test results on orbit indicate that the accuracy of the absolute radiation calibration of the CO₂ spectrometer at 1 610 nm was better than 5%. These results can satisfy the accuracy requirements for the diffuser radiation calibration of the CO₂ spectrometer.