外部杂散光对风云三号晨昏轨道气象卫星中微光成像仪的影响

Effect of External Stray Light on Low-Light Imager Loaded in Fengyun-3 Day/Night Orbit Meteorological Satellite

在介绍风云三号E星(FY3E)晨昏轨道气象卫星和微光成像仪特点的基础上,利用Satellite Tool Kit仿真技术并根据FY3E轨道参数,针对FY3E所搭载的遥感器(微光成像仪)可能受到来自太阳和月球的外部杂散光的情况进行模拟分析,并设计了遮光方法来抑制外部杂散光。分析结果表明,2006-12-18当天太阳矢量与遥感器底部窗口法向量的夹角最小,遥感器受太阳杂散光的影响最大。进一步分析了遥感器可能受月球杂散光的影响,发现只要满足太阳遮挡条件,月球就不会对遥感器产生杂散光。因此,设计遮光板时只要考虑太阳矢量与遥感器窗口法向量的夹角即可。目前的遥感器视场角为55°,遮挡杂散光的效率较低。将遥感器视场角减小到50°,同时减小遮光板尺寸,可以提高对杂散光的遮挡效率且不影响其应用。

Based on the introduction of the characteristics of Fengyun-3 E star （FY3E） day/night orbit meteorological satellite and low-light imager and according to FY3E orbit parameters, the Satellite Tool Kit （STK） simulation technology is used to simulate and analyze the external stray light, which comes from the sun and the moon and enters into the remote sensor （low-light imager） loaded in FY3E. The method of light shield is proposed to suppress the stray light. The results indicate that the stray light has the greatest impact on the remote sensor on 2016-12-18 when the angle between the sun vector and the normal vector of remote sensor bottom window is minimal. The effect of stray light caused by the moon on remote sensor is further analyzed, and it can be avoided when the sun shade condition is satisfied. Therefore, when we design the shade, the angle between the sun vector and the normal vector of remote sensor bottom window is only needed to consider. At present, the field-of-view of lhe remote sensor is 55°, and the efficiency of shading stray light is low. To improve the shading efficiency of stray light and not affact application, the field-of view of the remote sensor should be reduced to 50° and the size of the light shield should be decreased.