中国科学院云南天文台机构知识库

传统一元定标法测量红外天空亮度,面临诸多困难,如测量易受环境温度变化影响、仪器动态范围不足等。提出增加积分时间为自变量的二元定标模型,解决了仪器动态范围不足的问题;然后通过改变环境温度的系列实验,掌握了二元定标模型中仪器辐射随环境温度变化的规律;基于此,提出再增加环境温度为自变量的三元定标模型。实验数据表明,三元模型与实测数据拟合程度很高,相关系数为1.000,模型参数a、b、d,95%置信度的相对不确定度均小于0.82%,当环境保持某一温度不变时,三元模型退化为二元模型,各模型参数稳定,其相对偏差小于0.6%。最后,通过红外天空亮度实测,验证并比较了三元和二元定标模型;结果表明,三元模型定标测量法使用条件宽泛,既扩大了仪器动态范围,又不受环境温度变化影响;更重要的是,不再需要现场定标,提高了测量精度和测试效率。 

The traditional univariate calibration method used in measuring infrared sky brightness is confronted with many issues, and two main issues are the insufficient dynamic response of the measuring instruments as well as the influence of the ambient temperature on the measurement result. In order to extend the dynamic response of the measuring instruments, a bivariate calibration model at the constant temperature was demonstrated in the paper, and its independent variables were radiance and exposure time. Then with the experiment data acquired in many temperatures, the variation of the bivariate calibration model in different temperature was analyzed. Thus trivariate calibration model was presented at the last part, and the goodness of the fit of the model and the experiment data was best. R -square is 1.000, and the relevant uncertainties in 95% confidence degree of a, b and d, parameters of the trivariate calibration model, were all less than 0.82%, trivariate model can be degraded to bivariate at some certain temperature, the deviation of all of parameters of degraded model were less than 0.6%; Finally, with the outfield experiment of infrared sky brightness, bivariate and trivariate calibration model were validated and compared. The benefit of this trivariate calibration model is that it can extend the dynamic response of the measuring instruments, and the precision of its measuring result is not affected by the variation of ambient temperature. Hence this model can be widely used and can achieve high-precision and highefficiency measurement without in-situ calibration.