自校准光谱辐射计信号采集及系统控制设计

发布时间：2018-01-18 13:24

本文关键词：自校准光谱辐射计信号采集及系统控制设计　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：针对传统辐射定标精度已不能满足定量应用和气候变化研究的迫切需求,课题组计划研制一种基于自发参量下转换,具有自校准和辐射观测两种工作模式的光谱辐射计。本文主要解决该辐射计自动化定标及采集软件精度验证方面的问题。根据测量需求设计了自校准辐射计数据采集系统控制方案,基于LabVIEW语言编写了自校准辐射计数据采集系统控制软件。自校准模式能够自动定标多个通道探测效率,观测模式能够同时获得多个通道μs间隔的光子计数。自校准模式时,利用355nm激光泵浦BBO晶体,使用编写的自校准模式软件定标了APD在736nm波长点的量子效率为67.3%,测量的不确定度优于0.71%,和APD出厂数据的相对偏差为1%;观测模式时,使用编写的软件采集0.1s时间内APD输出计数值,并和994计数器输出值比较,平均相对偏差为0.22%,可以证明编写的控制软件能够满足系统的功能要求。设计了辐射计自校准原理有效性验证实验方案,基于LabVIEW语言编写了对应的控制软件。通过向光路中插入不同倍率的衰减片来模拟系统的衰变,选择积分球出射的单色均匀光作为观测光源,利用编写的控制软件测量不同衰减对应的入瞳相对光谱辐亮度,相对偏差为2.39%,证明设计的自校准辐射计反演的光谱辐亮度不随系统的衰变而发生变化,系统具有自校准功能。研制的自校准光谱辐射计的最终目标是作为可见～近红外波段空间光学遥感器的辐射基准,对其它光学遥感器进行定标。因此论文最后分析了当前数据采集系统的精度限制和体积限制,提出了一种基于时间数字转换(TDC)的高精度和小型化的数据采集系统设计方案。
[Abstract]:In view of the traditional radiometric calibration accuracy can no longer meet the urgent needs of quantitative applications and climate change research, the team plans to develop a kind of down-conversion based on spontaneous parameters. Spectral radiometer with two working modes of self calibration and radiation observation. This paper mainly solves the problems of automatic calibration of radiometer and precision verification of acquisition software. According to the requirement of measurement, the data of self calibration radiometer is designed. Control scheme of acquisition system. The control software of data acquisition system of self-calibrating radiometer is programmed based on LabVIEW language. The self-calibration mode can automatically calibrate the detection efficiency of multiple channels. In the self-calibrating mode, the BBO crystal is pumped by 355nm laser at the same time. The self-calibration mode software is used to calibrate the quantum efficiency of APD at 736nm wavelength, and the uncertainty of measurement is better than 0.71%. And the relative deviation of APD data is 1. In the observation mode, the APD output count value is collected in 0.1 s by using the software, and the average relative deviation is 0.22% compared with the output value of the 994 counter. It can be proved that the control software can meet the functional requirements of the system. An experimental scheme to verify the validity of the radiometer self-calibration principle is designed. The corresponding control software is compiled based on LabVIEW language. The decay of the system is simulated by inserting attenuation slices of different rates into the optical path, and the monochromatic uniform light emitted from the integral sphere is selected as the observation light source. The relative spectral radiance of different attenuation was measured with the control software, and the relative deviation was 2.39%. It is proved that the spectral radiance of the self-calibrated radiometer does not change with the decay of the system. The system has the function of self-calibration. The ultimate goal of the self-calibrated spectrometer is to be the radiation reference of the space optical remote sensor in the visible ~ near infrared band. Other optical remote sensors are calibrated. Finally, the accuracy and volume limitations of the current data acquisition system are analyzed. A design scheme of high precision and miniaturization data acquisition system based on time digital converter (TDC) is presented.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH74;TP274;TP311.52

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