论文部分内容阅读
地球资源卫星上的多光谱扫描器(MSS)有两种型式:一种具有四条光谱带,从0.5到1.1微米,另一具有五条光谱带,即增加了10.4-12.6微米的一条。本文介绍其光学设计和性能。仪器有一物空间平面扫描镜,其运动近于线性,并有一灵敏的光学位置监控器,测定扫描镜的角位置。孔径为22.9厘米的望远镜将景物成象于纤维光学阵列上,于是将景物的能量分解并传送到光电倍增管(对于带1、2、3)和硅光电二极管(对于带4)上。带5的能量通过纤维后再成象于以辐射冷却的碲化汞镉(HgCdTe)探测器。带1至4以一内装灯和太阳来校准。带5则使用一个内装黑体和一个冷参考。这就是对探测器的自身观察。在907仟米高轨道上运行的四带扫描器一次扫过的地面为185仟米时提供的数据记录从一带到另一带可优于50米,而所分辨的花样为80米。经过一年的时间,辐射率测量表明变化小于2％。
There are two types of MSSs on Earth Resources satellites: one with four bands from 0.5 to 1.1 microns and the other with five bands, an increase of 10.4-12.6 microns. This article describes its optical design and performance. The instrument has a space-scanning mirror that moves nearly linearly and has a sensitive optical position monitor that measures the angular position of the scanning mirror. Telescopes with a 22.9 cm aperture image the scene onto a fiber optic array, whereupon the scene’s energy is resolved and transmitted to the photomultiplier tubes (for strips 1, 2 and 3) and the silicon photodiodes (for strip 4). The energy of the ribbon 5 is passed through the fiber and imaged on a radiation-cooled mercury cadmium telluride (HgCdTe) detector. Bands 1 to 4 are calibrated with a built-in lamp and sun. Band 5 uses a built-in bold and a cold reference. This is the observation of the detector itself. The four-zone scanner operating on the 907-kilometer high orbit sweeps 185 millimeters of the ground at one time and provides data records that range from one belt to another, with the resolution of 80 meters. After a year, emissivity measurements showed a change of less than 2%.