星上比辐射定标器及性能评估方法研究

发布时间：2017-12-31 14:07

本文关键词：星上比辐射定标器及性能评估方法研究　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：高精度的星上定标是实现遥感数据定量化的重要途径之一。以太阳照明反射特性已知的聚四氟乙烯漫射板作为光源,采用比值辐射计进行漫反射板响应率衰减的监测和修正,实现对遥感器全光路、全视场、全口径的高精度绝对辐射定标,是当前可见短波红外波段星上定标技术的主要发展趋势。星上比辐射定标器性能评估准确与否直接影响其在轨应用性能。在此背景下,本论文开展了星上比辐射定标器及其性能评估方法研究。论文介绍了星上比辐射定标器工作原理,详细阐述了各关键环节设计方案。根据定标器原理和物理模型,分析得出星上定标不确定度主要来源为漫射板BRDF实时量值的不确定度,其关键在于比值辐射计对漫射板在轨衰减的修正精度。对星上比辐射定标器性能参数测试需求进行了分析,识别出太阳观测几何因子波段比、辐射比、动态范围和信噪比等比值辐射计的关键表征参数。建立了定标器测试方案和流程,并在实验室内完成了比值辐射计、漫反射板以及星上比辐射定标器整机级的性能参数测试。以卤钨灯作为测试光源,获取了比值辐射计太阳观测几何因子波段比查找表,不确定度优于0.18%;通过灯-板模拟系统完成了辐射比验证,预估在轨辐射比测量不确定度优于0.4%;使用已标定的大口径、多能级积分球光源对比值辐射计的动态范围、信噪比和稳定性进行了测试。结合漫射板和定标器整机测试结果,比值辐射计对漫反射板稳定性监视不确定度优于1.3%,漫射板BRDF实时量值不确定度优于1.76%,星上比辐射定标器的绝对辐射定标总不确定度优于3%。本论文系统性地对星上比辐射定标器性能评估方法进行了研究,提出了定标器测试方法以及测试流程,通过对星上比辐射定标器部件级以及整机级参数的测试,获取了定标器各项定标参数,完成星上定标不确定度的评估,验证了星上定标器设计以及性能评估方法的合理性,可以为定标器在轨应用以及定标精度预评估提供有效数据支撑。
[Abstract]:High-precision on-board calibration is one of the important ways to realize the quantification of remote sensing data. The PTFE diffuse plate which has known solar illumination reflection characteristics is used as the light source. The ratio radiometer is used to monitor and modify the response rate attenuation of the diffuse reflector to achieve the high-precision absolute radiometric calibration of the remote sensor in all optical path, all field of view and all caliber. It is the main development trend of on-board calibration technology in visible and short-wave infrared band at present. The performance evaluation of on-board specific radiation calibrator has a direct impact on the performance of on-orbit applications. In this paper, the on-board specific radiation calibrator and its performance evaluation method are studied, and the working principle of onboard specific radiation calibrator is introduced. According to the principle of the scaler and the physical model, it is concluded that the main source of the onboard calibration uncertainty is the uncertainty of the BRDF real time value of the diffuse plate. The key point lies in the correction accuracy of the ratio radiometer to the attenuation of the diffuse plate in orbit. The requirements of the performance parameters of the onboard specific radiation calibrator are analyzed and the spectral band ratio and the radiation ratio of the geometrical factors observed by the sun are identified. The dynamic range and signal-to-noise ratio (SNR) are the key parameters of the radiometer. The testing scheme and flow chart of the calibrator are established, and the ratio radiometer is completed in the laboratory. The performance parameters of diffuse reflector and onboard specific radiation calibrator are tested. The ratio radiometer solar observation geometric factor band ratio look-up table is obtained with halogen tungsten lamp as the light source. Uncertainty is better than 0.18; The radiation ratio is verified by the lamp-plate simulation system, and the uncertainty of the measurement of the estimated in-orbit radiation ratio is better than 0.4. The dynamic range, signal-to-noise ratio (SNR) and stability of the calibrated large aperture, multi-level integrated sphere light source are measured. The uncertainty of the ratio radiometer for the stability monitoring of the diffuse reflector is better than 1.3 and the uncertainty of the real-time BRDF value of the diffuse plate is better than 1.76%. The total uncertainty of onboard specific radiation calibrator is better than 3. In this paper, the performance evaluation method of onboard specific radiation calibrator is systematically studied, and the testing method and flow chart are put forward. By testing the component level and the whole machine level parameters of onboard specific radiation calibrator, the calibration parameters are obtained, and the uncertainty of onboard calibration is evaluated. The rationality of the on-board scaler design and performance evaluation method is verified, which can provide effective data support for the application of the calibrator in orbit and the pre-evaluation of calibration accuracy.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP73

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