Optical window of remote sensing system has thermal exchange with ambient environment and it causes non-uniformity thermal distribution, including system average temperature shift as well as circumferential, radial and axial temperature differences, which degrade the image quality. A new method was presented to analyze this effect on the optical system wavefront error by building segments made up of complex pupils. Each segment can be effectively analyzed because of only the radial temperature being processed by non-sequential ray trace. Then all the separate impacts of the segments were calculated on the entire optical window. An example of the optical window is given, and the result shows that the method is feasible, the optical system quality is reduced by this effect and its MTF can not be completely compensated by focus shift.%空间相机光学窗口与周围环境进行热交换,导致窗口的温度发生不均匀变化,包括整体温度水平的变化以及产生径向温差、周向温差和抽向温差.这些温度梯度将影响相机的光学系统质量.针对某相机光学窗口温度分布不均匀的特点,提出利用非顺序光路建立复杂光瞳的方法对光学窗口进行分区,在各子区域上建立温度的径向分布特征,然后将各子区域的变化再统一到整个元件中,进而评判对整个系统的影响.结果表明,新方法合理可行,温度周向不均匀分布会降低光学系统质量,并且不能完全通过离焦来补偿.
展开▼
