中国科学院遥感与数字地球研究所-高光谱遥感应用技术研究室

【作者】              陈正超                                                                                                                                                  

【导师】              童庆禧；郑兰芬

【 学位年度 】    2005

【论文级别】      博士    

【关键词】          DMC，灾难监测星座，在轨测试，图像评价，定标

【Key words】   DMC, Disaster Monitoring Constellation, on-orbit test, image evaluation, calibration  

【中文摘要】

卫星在轨测试是监测卫星平台及其遥感器在轨运行情况及性能衰减程度的有效手段，也是卫星数据处理和应用的前提与基础。本文将从系统工程的角度研究我国DMC（Disaster Monitoring Constellation，灾难监测星座）小卫星在轨测试内容和方法，用来指导对我国DMC小卫星在轨测试，同时也为国内外其他类似卫星提供参考。

    本文研究的我国DMC小卫星是参与国际卫星星座组网的微小型卫星，无论是卫星自身特点上还是其操作运行方式，都区别于我国已经发射的卫星。该卫星的研制和发射都由英国萨瑞大学负责，卫星在发射成功并入轨调整后再交付给我国有关方面，所以对该小卫星进行在轨测试，不仅是评价卫星在轨性能和卫星数据处理和应用的基础，而且是我方验收小卫星的技术依据和基础，这就要求对我国DMC小卫星的在轨测试必须系统化、标准化、国际化。同时，对我国DMC小卫星在轨测试是国家航天局航天遥感论证中心工作的一部分，对我国DMC小卫星的在轨测试研究有助于建立我国完善的航天遥感论证体系。

    本文正是基于以上出发点，研究建立我国DMC小卫星在轨测试的内容和方法体系，同时为我国其他类似卫星的在轨测试提供参考。围绕这个目的，本文将我国DMC小卫星的在轨测试总结为四个方面，即对遥感器及其图像的几何特性、辐射特性、光谱特性、图像的综合质量及其应用潜力分析。对遥感器及其图像的几何性能的评价内容包括：卫星姿态和轨道参数的评价、相机指向精度和侧摆能力、图像的外部和内部几何精度、波段配准和图像分辨率等。对卫星遥感器及其图像的辐射性能的评价内容包括：调制传递函数、信噪比、相对辐射定标、绝对辐射定标、辐射稳定性、动态范围和响应线性度、CCD阵列的均匀性等。由于我国DMC小卫星的波段数少，光谱分辨率低，对其遥感器及图像的光谱性能的评价，只能定性的分析遥感器的波段设置情况和光谱响应函数的变化情况。除了对遥感器及其图像的上述工程参数的评价，本文还从数据应用的角度来提出评价图像综合质量的技术指标，并分析我国DMC小卫星图像数据的应用潜力。

     本论文的最大贡献在于：根据我国DMC小卫星的特点和性能参数设计，在系统、详细分析每一个评价参数的必要性、常用方法和实施步骤的基础上，建立我国DMC小卫星在轨测试内容和方法体系。同时，本文提出的我国DMC小卫星在轨测试内容和方法体系也是国内首次全面建立的该类卫星的在轨测试体系，能够适用于推扫式对地观测卫星的在轨测试，对这类卫星的在轨测试具有很大指导意义。本文在一些测试方法上进行了深入的研究，提出或改进一些具有创新意思的测试算法。主要包括：在图像几何精度评价方法方面，本文在图像相关的基础上，提出一种高精度波段配准精度检验方法，该方法具有匹配速度块、精度高的特点；在图像辐射性能评价方法方面，本文提出一种利用“加权均值和方差”来计算相对辐射校正增益系数的辐射校正方法，并给出了“加权均值和方差”的计算公式。本文提出的“加权均值和方差”也用于对图像信噪比的计算中。 

【Abstract】

Satellite on-orbit test is a useful way to monitor satellite platform, on-orbit status and attenuation degree of sensors, and is the premise and base for satellite data’s processing and application. The article studies the contents and methods of small satellite on-orbit test from systems engineering in our country, which is used to direct our DMC（Disaster Monitoring Constellation）small satellite on-orbit test, and also as a reference for other similar satellite in our country.

      The satellite studied in the article participates in international satellite constellation network. Compared with other satellites of our country, this satellite has its own characteristics and operation manner. The satellite is developed and launched by SSTL（Surrey Satellite Technology Limited，Surrey Space Centre University），which is handed over to China when on-orbit test period. The on-orbit test not only evaluates satellite platform, on-orbit status and attenuation degree of sensors, which provides the necessary parameters for satellite data’s processing and applications, but also the technical base for our checking and accepting the small satellite. So this requires the systematization, standardization, and internationalization of the DMC small satellite on-orbit test in our country. At same time, this job is also a part of Demonstration Center for Spaceborne Remote Sensing, CNSA, which is helpful to establish the system of our spaceborne remote sensing demonstration.

      Based on above points, the article aims to establish the system of the contents and methods of our DMC small satellite on-orbit test, and also as a reference for other similar satellite in our country. We think that the DMC small satellite on-orbit test includes four aspects: geometic characteristics of sensor’s image, radiomatic characteristics of image, spectral characteristics of image, image general quality and its application potential.The evaluation of s geometric characteristics of its image includes: satellite pose, evaluation and adjustment of orbit parameters, directing precision of camera and its wavering performance, interior and exterior geometry precision of image, band matching, image resolution, and so on. The evaluation of radiomatic characteristics includes: MTF, SNR, relative radiometric calibration, absolute calibration, radiometric stability, dynamic range, the linearity of spectral response, and uniformity of CCD etc,. Because of few bands and low spectral resolution of our DMC small satellite, we only analyze band setting of sensors and change of spectral responding function qualitatively when evaluating the spectral performance of image. In addition, the article brings forward technical guideline for evaluating general image quality from data application, and analyzes application potential of our DMC small satellite image data.

      The most contribution of the article is to establish the contents and method system of our DMC small satellite on-orbit test based on the characteristics and performance parameter design of our DMC small satellite, and summary of foreign similar satellite on-orbit test. It is the first system in our country that is applicable to push-broom, earth observing satellite, and has great directive significance for similar satellite on-orbit test. Furthermore, the article makes deep research in test methods, and advances some creative test methods, mainly including: a highly precise matching algorithm to test errors of bands matching; a method to calculate relative radiometric calibration.The aim of the article is to establish the system of the contents and methods of our DMC small satellite on-orbit, not an innovation of evaluation methods. Because our DMC small satellite is planned to be launched in May, 2005, it is impossible to get necessary test data. So the article is focused on experiment and analysis of some content and method of evaluation. However, the article summarizes the necessary data and documents in our DMC small satellite on-orbit, and advances the whole scheme and implementing method, which is meaningful to actual satellite on-orbit test.