星载多波段红外光学系统的杂散辐射分析

引入反向蒙特卡罗法与双向蒙特卡罗法对红外光学系统的杂散辐射进行分析,基于光谱辐射传递因子导出了焦平面辐射能流计算式.以某星载多波段红外光学系统为例,在检验计算可靠性的基础上,模拟了各波段辐射能从地球背景和光机内壁面到焦平面的传播过程,分析了壁面吸收率与温度的影响.结果表明,采用双向蒙特卡罗法可有效地模拟辐射能从地球向星载光学系统焦平面的传播过程,采用反向蒙特卡罗法可容易地分析光机内部热辐射的影响;光机内壁面吸收率对视场外杂散辐射的传播有很大影响,温度高于250 K的光机内壁面热辐射成为主要的杂散光源.

Analysis on Stray Radiation of Multi-Spectral Infrared Remote Sensor

The backward Monte Carlo method and the bidirectional Monte Carlo method were introduced to analyze the stray radiation of an infrared remote sensor. The formulae of radiation flux reaching the focal plane have been derived on the basis of spectral radiative transfer factors. After verifying the calculation reliability, a spaceborne multi-spectral infrared optical system was taken as an example, and the radiative propagation from the earth background to the focal plane which from its internal structure were simulated numerically. The effects of wall absorptance and temperature on the stray radiation have been analyzed. The investigation indicates that the bidirectional Monte Carlo method is flexible for analyzing the radiation transfer from the earth to the focal plane and the backward Monte Carlo method can be easily used to analyze the effects of inner thermal radiation. The results also show the significant influence of wall absorptance on the propagation of stray radiation outside viewing field, and the thermal emission of internal structure will become the main stray radiation at its temperature higher than 250K.