【作者】 刘丽莹；

【导师】 李野；

【作者基本信息】 长春理工大学 ， 电子科学与技术， 2019， 博士

【摘要】 光谱辐射计作为一个高数据维和多参数维的精密光电仪器系统,仪器精度的评估与优化需要建立在高通量数据统计与矩阵数据分析的基础上。仪器系统中各种微分模型的降维和积分模型的升维需要测试分析并进行反复迭代运算,导致系统量化表征模型复杂、数据运算量大。基于多维参数和高维数据的光谱辐射计系统表征模型的发展滞后于核心器件及系统的研制,是制约光谱辐射测量系统精度提高的根本原因。随着计算机在测控与数据分析中的应用发展,光谱辐射测量相关的仪器建模及计量分析研究也日益增加,但是准确评估和优化光谱辐射计定标精度研究仍然存在一些亟待深入研究的关键问题。针对光谱辐射计多维参数误差特性中杂散光量化表征建模、CCD非线性模型的双参数相关影响特性建模以及计量定标不确定度评估中关键参数误差特性等问题,开展了以下研究工作:(1)为获取完整的系统参数信息用于实现参数调控,设计了光谱辐射计,为误差特性表征与定标研究提供了仪器基础。对接收函数特性、杂散光特性、狭缝耦合特性几个关键影响环节进行了分析研究和优化设计;为消除因体积减小而加强的杂散光影响,采用线性渐变滤光片和优化杂散光陷阱的方法分别对带内高阶杂散光与带外漫射杂散光进行了杂散光抑制优化。(2)在获取光谱辐射计系统参数基础上,对光谱辐射计误差特性中的杂散光特性进行了量化表征建模并计算不确定度的评估值。在杂散辐射矩阵测量数据基础上,以关键几何特征点为基础,构建了基于带外抑制和背景杂散辐射的杂散光特性量化表征模型。定量给出了所设计的光谱辐射计的杂散光特性评估结果:带外抑制小于0.1%,背景杂散辐射上限小于0.01%,统计均值约为0.001%。该结果表明所设计的光谱辐射计中的杂散光抑制设计有效,达到了单色仪系统的杂散光抑制水平。进一步结合谱段范围和光谱分辨带宽,计算出杂散光对测量不确定度的评估值为2%,为合成不确定度的定量计算提供依据。(3)为了准确评估及抑制光谱辐射计的非线性误差影响,进行了CCD非线性特性量化表征、建模校正及计算不确定度的评估值。对CCD探测器的积分时间和光强灰阶2个关键参数的非线性参数依赖特性进行了实验与建模研究,给出CCD的非线性量化表征函数,并以此为基础实现了测量过程中的CCD多尺度非线性修正。采用该模型进行非线性校正后与监测功率计数据进行比较,得出该模型能够将CCD非线性相对偏差从18%降低至2%以内,有效地降低了光谱辐射计的非线性误差,得到不确定度评估值2%,为合成不确定度的定量计算提供依据。(4)通过建立杂散光和非线性误差模型,解决了光谱辐射计系统误差量化表征问题,可以进一步对光谱辐射计进行精确定标。在波长定标中对数据处理组合算法进行了参数优化,实现了波长定标精度达到1/10像素波长间隔;在辐射定标不确定度的评估中,通过积分时间调控实验证明精度的波长依赖特性实际上是信噪比依赖,提出了以信噪比作为示性参数的逐像素调控定标方法,解决了定标精度的波长依赖问题。数据表明,卤钨灯光源定标系统在2小时内的不确定度评估结果小于0.5%。然后,在定标系统不确定度测试评估结果基础上,结合杂散光和非线性的误差特性表征计算给出的不确定度评估值,最终计算出合成不确定度3.8%作为仪器精度,达到了系统设计要求,可进行外场测试评估。(5)为了验证误差特性评估模型及精度优化的有效性,进行了应用验证实验及对比测试分析。首先进行了太阳辐射观测应用实验验证研究,测试结果显示精密光谱辐射计能够有效用于地基气象光谱辐射的业务观测,提供精细的太阳光谱分析数据。之后与日本EKO公司的MS700型太阳光谱辐射计(MS700是目前全球气象光谱辐射测量的标准仪器)进行室外观测比对分析。测试结果显示,所设计的SVG光谱辐射计定标精度(3.8%)优于MS700标称的定标精度(4%),通过与ISO9845标准太阳光谱比较,SVG型光谱辐射计波长分布偏差的标准差比MS700低1%左右。SVG型光谱辐射计的定标精度和分辨带宽误差均优于MS700,验证了误差特性表征模型与定标参数优化结果的有效性。通过对光谱辐射计误差特性表征及优化调控方法研究,使光谱辐射计的精度(3.8%)优于标准精度要求(<5%),所涉及的建模及分析评估方法研究为光谱辐射计量仪器精度的进一步提高提供了有效手段。更多还原

【Abstract】 Spectroradiometer is a precise electro-optic instrument system with high data dimension and multi-parameter dimension.The evaluation and optimization of instrument accuracy are based on high-throughput data statistics and matrix data analysis.The repeated iterations of various analytical testing process in the instrument system,which include of differential models reducing dimension and integral models adding dimension,make the characterization model complex and data computation heavy.The development of spectroradiometer system characterization model based on multi-dimensional parameters and high-dimensional data lags behind the development of core devices and systems,which is the fundamental reason that restricts the improvement of spectroradiometer system accuracy.With the development of computer application in measurement,control and data analysis,instrument modeling and statistical metrological analysis related to spectroradiometer are increasing.However,there are still some key problems to be studied urgently in order to accurately evaluate and optimize the calibration accuracy of spectroradiometer.In order to solve the problems of multi-dimensional parameter error characteristics,such as stray light quantization characterization modeling,two-parameter correlation influence characteristic modeling of CCD non-linear model,and error characteristics of key parameters in uncertainty evaluation of metrological calibration,the following research has been carried out:(1)In order to obtain complete system parameter information for parameter control,a precision spectroradiometer is designed,which provides an instrument foundation for error characterization and calibration.The key influence links,such as receiver function,stray light and slit coupling,are analyzed and optimized.In order to eliminate the effect of stray light enhanced by volume reduction,linear variable filter and stray light trap are separately used to suppress in-band high-order stray light and out-of-band diffuse stray light.(2)On the basis of acquiring the system parameters of spectroradiometer,the stray light characteristics in the error characteristics of spectroradiometer are quantitatively characterized and modeled,and the uncertainty is evaluated.Based on the measured data of stray radiation matrix and the key geometric feature points,the out-of-band suppression and background stray radiation characterization model are constructed.The evaluation results of the stray light characteristics of the designed spectroradiometer are given quantitatively.The out-of-band suppression is less than 0.1%,the upper limit of background stray radiation is less than 0.01%,and the statistical mean is about 0.001%.The results show that the design of stray light suppression in the spectroradiometer is effective and achieves the stray light level of the monochromator system.Furthermore,combining the spectral range and spectral resolution bandwidth,the evaluation value of stray light for measurement uncertainty is calculated to be 2%,which provides a basis for quantitative calculation of composite uncertainty.(3)In order to accurately evaluate and suppress the influence of non-linear errors of spectroradiometer,quantitative characterization of non-linear characteristics of CCD,modeling correction and evaluation value of uncertainty are carried out.The nonlinear parameter dependence characteristics of integration time and intensity gray scale of CCD detector are experimental analyzed and modeled.The non-linear quantitative characterization function of CCD is given.On this basis,the multi-scale non-linear correction of CCD in the measurement process is realized.The model is compared with the monitoring power meter data after non-linear correction,the results show that it can reduce the non-linear relative deviation of CCD from 18% to less than 2%,effectively reduce the non-linear error of spectroradiometer,and get the evaluation value of uncertainty of 2%.It provides a basis for quantitative calculation of composite uncertainty.(4)By building stray light and non-linear error models,the problem of quantifying the systematic errors of spectroradiometer is solved,and the spectroradiometer can be calibrated accurately.In the wavelength calibration,the parameters of the data processing combination algorithm are optimized,and the wavelength calibration accuracy reaches 1/10 pixel wavelength interval.In the evaluation of the uncertainty of radiation calibration,the integration time control experiment proves that the accuracy’s wavelength dependence is actually signal-to-noise ratio dependence,and the signal-to-noise ratio is proposed as an indicator parameter.Pixel-by-pixel calibration method solves the problem of wavelength dependence of calibration accuracy.The data show that the uncertainty of halogen tungsten lamp source calibration system in 2 hours is less than 0.5%.Then,on the basis of the uncertainty test and evaluation results of calibration system,combined with stray light and non-linear error characterization,the composite uncertainty is calculated.Finally,the composite uncertainty 3.8% is regard as the instrument accuracy,which meets the design requirements of the system and can be used for outdoor test and evaluation.(5)In order to validate the effectivity of model evaluation and accuracy optimization of error characteristics,application experiments and comparison test analysis are carried out.Firstly,the experiment of solar radiation observation is carried out.The analysis results show that the precise spectroradiometer can be effectively used for operational observation of ground-based meteorological spectral radiation and provide fine data for solar spectral analysis.After that,the outdoor comparison test analysis is carried out with the MS700 solar spectroradiometer of EKO Company in Japan(MS700 is the standard instrument for global meteorological spectral radiometry at present).The test results show that the calibration accuracy of the SVG spectroradiometer(3.8%)is better than that of the MS700(4%).Compared with the ISO9845 standard solar spectrum,the standard deviation of the wavelength distribution error of the SVG spectroradiometer is about 1%,which is lower than that of the MS700.The calibration accuracy and resolution bandwidth error of SVG spectroadiometer are better than MS700.The effectivity of error characterization model and calibration parameters optimization results is validated.By the study of error characterization and optimization control methods of spectroradiometer,the measurement accuracy(3.8%)of spectroradiometer is better than the standard accuracy requirement(<5%).The study of modeling and analysis evaluation methods provides an effective means for further improving the accuracy of spectroradiometer.更多还原