为了满足航天器对轻小、价廉，性能可靠的自主导航系统的要求，设计了广角静态红外地平仪系统。该系统选择辐射稳定的14~16.25 μm作为工作波段，并设定全视场角为136°，F数为0.61；采用反远距结构，使系统后工作距达到15 mm;利用f-θ镜头设计原理，并合理地选用非球面对广角系统进行优化设计,使系统的线性特性的相对误差<0.5%；在空间频率为15 lp/mm处，系统的调制传递函数＞0.6，接近衍射极限；在半径为20 μm的圆内，系统径向能量>85%。另外，采用了像方远心光路，提高了像面的照度均匀性，实现了整个像面照度均匀性>99%。设计结果表明，该镜头结构简单、体积小、后工作距大，很好地解决了广角镜头轴外像差平衡问题，实现了地平仪系统的高精度设计。

In order to meet the requirements of spacecrafts for autonomous navigation systems with light small,cheap and reliable performance,a wide-angle static infrared horizontal system was designed.The system chose the operating wavelength range of 14 to 16.25 μm to keep a stable radiation,and its full field of view was set as 136° and F number as 0.61.By using a retrofocus structure in image space,the back working distance has been 15 mm in the optical system.On the basis of the design principle of a f-θ lens, the aspheric surface was used to rationally optimize the wide-angle system,then the related error of linear characteristics of the f-θ len is less than 0.5%,and the modulated transfer function is higher than 0.6 at 15 lp/mm in the image plane(approaches diffraction limit).In a circle with radius of 20 μm,the radial energy is higher than 85%.Furthermore,a telecentric optical path was used in the system,which improves the relative illumination to more than 99%.These results show that the designed lens has the advantages of simplicity,compactness and long back working distance,and can balance the correctness of off-axis aberrations.