测绘一号卫星相机的光谱和辐射定标  

Spectral and radiometric calibrations for mapping satellite-1 camera

作　　者：万志[1] 李葆勇[1] 刘则洵[1] 刘洪兴[1] 任建伟[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《光学精密工程》2015年第7期1867-1873,共7页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.61108066);吉林省科技发展计划资助项目(No.20130101028jc)

摘　　要：对测绘一号卫星相机的各个光谱通道进行了光谱定标和辐射定标以验证其光谱辐射性能是否达到设计指标要求。进行光谱定标时,利用单色仪分光谱扫描波长提供准直单色辐射照明,同时同步采集定标图像数据;然后将图像灰度值与已经过校准的参考标准探测器的输出进行比对和数据处理,得到相机各个谱段的相对光谱响应函数曲线,从而进一步获得各项光谱特性参量。辐射定标时,采用近距离面源法充满相机的孔径和视场进行端对端的绝对和相对辐射定标。星上内定标则采用经老炼和筛选过的发光二极管(LED)作为星上定标光源,对焦平面阵列探测器及其成像电路的状态和辐射响应性能变化进行在轨监测,在必要的情况下予以校正。定标结果显示:测绘一号卫星相机的各项光谱和辐射性能均达到了设计指标要求,经过相对辐射校正后响应非均匀性由1.93%下降到0.22%,相机全色谱段信噪比超过90倍,多光谱各通道信噪比优于180倍;发射后在轨星上内定标数据与发射前实验室测试结果的比对显示相机的辐射响应性能未发生明显变化,暂时无须校正。The spectral calibration and radiometric calibration were performed for every waveband of the Mapping Satellite-1 camera to validate its spectral and radiometric performance. In spectral calibration, a collimated monochromatic light source was provided by wavelength scan using a monochrometer and a collimator. Meanwhile, the camera acquired calibration images, and then compared image＇s digital number and the output of calibrated standard reference detector to obtain relative spectral responsive curve by data analysis and processing. Furthermore, spectral characteristics were acquired. In radiometric calibration, the nearest emitting source method was used to perform the end to end relative and absolute radiometric calibrations with irradiating the whole aperture and the field of view. In the on-orbit inner calibration, the aged and picked up LEDs were employed as on-orbit inner calibration light sources to monitor the changes and status of focal plane detector array and its imaging electric circuit at post launch, and they were corrected in necessary conditions. Spectral calibration and radiometric calibration results indicate that all the spectral performance and radiometric performance of the Mapping Satellite-1 camera meet design requirements, non-uniformity of the camera is decreased from 1.93% to 0.22% after relative radiometric calibration. The typical Signal to Noise ratios （SNRs） of panchromatic and multispectral cameras are beyond 90 times and 180 times respectively. The compared results from the on-board inter calibration after launching and the tested data from a la boratory before launching show that radiometric responsive performance of the camera has not changed during this period, and not need to be corrected.

关 键 词：测绘相机 光谱定标 辐射定标 星上内定标 

分 类 号：V447.3[航空宇航科学与技术—飞行器设计] P414.4[天文地球—大气科学及气象学]