摘要
"高分七号"卫星是中国首颗亚米级高分辨率传输型立体测绘卫星。星上主载荷为双线阵相机,相机探测器采用了时间延迟积分电耦合器件,该器件具有5档增益,每档增益又可以与至少6档积分级数组合供在轨成像选择使用。文章提出了一个卫星发射前,成像参数最优组合的预估方案,根据经验给出了典型目标地物反射率和灰阶值预期,再通过辐射传输仿真得到预期辐亮度,进而计算得到在轨绝对辐射定标系数预估值。相机在实验室辐射定标实验中,每个辐亮度下都获得了由5档增益和6档积分级数分别配对组合的30组输出,选择与仿真同一辐亮度的30组绝对辐射定标系数进行对比分析。结果表明,以前视相机为例,第二档增益与第四档级数的组合最符合在轨预估。将这一组参数作为默认参数以使在轨第一时间获得高品质图像。卫星发射后,对真实的在轨图像数据进行检验。灰阶统计发现图像动态范围利用比较充分,目标亮度与背景具有明显的差异可以区分,目视评价图像层次分明,灰阶统计和目视评价均表明文章提出的成像参数组合预估方案有效。文章研究的内容对于相关遥感相机在轨合理使用具有一定参考价值。
GF-7 satellite is China’s first sub-meter level stereo mapping satellite.The camera on board uses Time Delayed Integration Coupled Charged Device(TDICCD),which has multiple levels of integration and gain.Before launch,researchers proposed a prediction solution of optimum parameters combination,i.e.inputting empirical target refraction and image digital number(DN) to radiative transfer model to output the target radiance expected,and thus obtaining an expected absolute radiometric coefficient by calculation with target DN.This coefficient was compared with 30 coefficient records at the same radiance input from laboratory calibration.The result showed that combination of gain at level 2 and integration at level 4 matched expectation best.This combination was set as default in orbit at the beginning.After launch,on-orbit images were checked and the solution proposed in this paper was proved to be proper both statistically and visually.This paper could be helpful for rational use of relevant earth observation cameras.
作者
王殿中
齐文雯
谭伟
何红艳
WANG Dianzhong;QI Wenwen;TAN Wei;HE Hongyan(Beijing Institute of Space Mechanics&Electricity,Beijing 100094,China;Beijing Key Laboratory of Advanced Optical Remote Sensing Technology,Beijing 100094,China)
出处
《航天返回与遥感》
CSCD
2020年第2期122-128,共7页
Spacecraft Recovery & Remote Sensing
基金
国家自然科学基金(41871278)
高分辨率对地观测系统重大专项(50-Y20A07-0508-15/16)。
关键词
立体测绘
预估成像参数
光学遥感
“高分七号”卫星
stereo mapping
imaging parameter prediction
optical remote sensing
GF-7 satellite
