离轴反射系统具有不产生色差、无中心遮拦、结构紧凑等特点，但受其非对称结构影响，其视场常常为线视场。基于Zemax设计了一种大对称视场的离轴三反系统，视场为13°×13°，相对孔径为1/5，焦距为800 mm，波长为400 mm~1 000 mm，主镜和三镜为自由曲面，次镜为二次曲面。设计结果表明:对称视场离轴三反系统的点列图直径均方根小于5 μm，80%能量在一个像元内，光学传递函数接近衍射极限，各项指标满足应用要求。

遥感相机的扫描镜通常位于光学系统的最前端，容易受到在轨外热流的影响产生非规则的面型变化，进而影响相机的成像质量。针对该问题设计了基于扫描镜温度值，以神经网络算法为基本，通过温度场变化反演扫描镜面型变化的扫描镜热变形测试方法。以该方法得出的扫描镜的面型变化可以作为后续成像系统面型修正的依据。该方法能够有效地提升遥感相机在轨的温度适用性，延长遥感相机的可用时间。通过该方法计算出的面型变化与理论面型变化的差值优于RMS 12.6 nm，具有较高的面型还原精度，验证了通过扫描镜温度值变化反演其面型变化的可行性。

随着空间光学遥感器地面分辨率逐步提高，长焦距、大口径相机成为重点研究方向。为了克服重力变化、复合材料变形等因素带来的天地不一致性的问题，次镜调整成为校正光学遥感器离焦和主次镜相对位置变化的关键技术之一。将次镜柔性支撑、精密直线驱动与柔性铰链传动技术相结合，设计了一套高精度次镜调整机构。首先介绍了该套机构的光机构成、工作原理及传动链路，然后对超轻次镜、高精度直线致动、高精度调焦传动等设计分别进行了阐述，最后介绍了力学环境试验后的调整精度测试情况。试验结果表明，该套精密调整机构实测调整行程大于±120 μm，轴向调整步距精度0.18 μm (3σ值)，调整行程内次镜的最大平移误差为1.30 μm，最大倾斜误差为1.93″，具有调整范围宽、调整精度高的特点，满足空间光学遥感器精密次镜调整的要求，已成功在轨应用于北京三号B卫星0.5 m级高分辨率空间相机。

Overview: How to further improve the lightweight ratio of high-performance meter-level space mirrors is one of the core issues in the field of large aperture optomechanical structure design. In this paper, a primary mirror blank with a clear aperture of Φ1200 mm was developed for a high-resolution space camera, which achieves the goal of designing area density below 40 kg/m². The SiC mirror blank was manufactured by gel injection molding and reaction sintering process, with the classical back three-point support scheme together with the testing state of the optical axis being horizontally adopted to simplify the supporting structure. Novel lightweight measures such as an alternate arrangement of main and auxiliary stiffeners and the addition of lightweight holes to vertical walls were used inside the semi-closed blank, which further improves the lightweight ratio of space mirrors with the sandwich structure. Distributed datums were proposed to replace the traditional datum setting, which reduces the machining area of datums by more than 80% and improves machining efficiency significantly. A robot arm is used for polishing in optical processing, and the local surface deformation is 47 nm in PV value under the typical polishing pressure of 1.77 kPa, with the mirror surface of 4 mm thick and the spacing between stiffener ribs of 81 mm. A parametric model of the mirror blank was built with shell elements, which contains ten variables including stiffener thickness and blank height, and integrated optimization was carried out so as to determine the optimal combination of structural parameters, using the multi-island genetic algorithm. The final design weight of the mirror blank is 46.9 kg, with corresponding area density of 38.8 kg/m². The RMS value of self-weight deformation of the mirror blank is only 2.87 nm with its optical axis being horizontal, and the free fundamental frequency is 602 Hz, indicating that the mirror blank has good dynamic and static characteristics, which satisfies the design requirements of space cameras. After machining, the measured weight of the mirror blank is 51.3 kg, about 9.4% overweight than the design, and the facesheet is about 1 mm thicker, mainly caused by the inhomogeneity of the molding process. During the centroid position test of the primary mirror blank, the deviation between the measured and theoretical centroid position is about 3.7 mm in the axial direction and 2.0 mm in the radial direction, which can be compensated through adjustment of the supporting structure and has limited influence on the optical performance of mirror assembly. At present, the primary mirror blank has already been polished to RMS λ/8 (λ=632.8 nm) of surface shape accuracy, with no obvious print-through effect observed. The lightweight structure scheme and optimization method of the mirror blank proposed in this paper can provide an important reference for the design of similar space mirrors with the characteristics of large aperture and low areal density.

This paper utilizes uniquely decodable codes (UDCs) in an M-to-1 free-space optical (FSO) system. Benefiting from UDCs’ nonorthogonal nature, the sum throughput is improved. We first prove that the uniquely decodable property still holds, even in optical fading channels. It is further discovered that the receiver can extract each source’s data from superimposed symbols with only one processing unit. According to theoretical analysis and simulation results, the throughput gain is up to the normalized UDC’s sum rate in high signal-to-noise ratio cases. An equivalent desktop experiment is also implemented to show the feasibility of the UDC-FSO structure.

大口径长条形反射镜是大型离轴三反相机的核心部件之一，针对“吉林一号”宽幅01C星中通光口径为1250 mm×460 mm的主反射镜，系统论述了1.2 m量级大长宽比反射镜组件的结构设计方法，并对所研制的主镜开展了详细的验证。从材料属性和现有工艺出发，镜体材料选择反应烧结碳化硅，采用半封闭式轻量化形式，通过二目标全局优化确定了镜体结构参数的最佳组合，最终镜体设计质量为41.8 kg，面板厚5 mm、最薄加强筋仅厚3 mm。采用经典背部三点支撑方案，优化柔性支撑中的双轴柔性铰链结构参数以兼顾组件基频和热稳定性，并与镜体质心位置进行匹配。提出了主镜组件的装配流程和相应的消应力措施。测试结果表明：主镜在装调重力工况下全口径面形精度均方根值为0.016λ(λ=632.8 nm)，翻转180°后主镜全口径面形精度均方根值为0.019λ；实测主镜组件一阶基频为127.8 Hz，经大量级随机振动和高低温循环后，主镜面形精度均方根值基本不变。主镜组件具有良好的动、静力学特性，且面形精度高、稳定性良好，能够满足高性能空间光学系统的使用要求。

1.8 m×0.5 m口径的长条形主反射镜是某空间离轴三反光学系统的重要光学元件，其面形精度的好坏是决定光学系统在轨成像质量的关键。为保证主镜组件结构的稳定性、可靠性及反射镜的面形精度，提出一种适用于大尺寸长条形反射镜的双轴柔性支撑结构。首先，基于运动学等效原理提出双轴柔性支撑的初始结构，建立了柔性环节刚度数学模型并研究了其刚度特性。然后，对柔性支撑的安装位置进行了参数化研究并对柔性支撑的关键尺寸进行了优化设计。最后，确定了反射镜组件的最终设计方案。仿真与试验结果表明，反射镜组件一阶固有频率为104 Hz。X/Y两个光轴分别对径向施加1 G重力时面形精度RMS值分别为4.81 nm、6.09 nm，优于λ/50（λ=632.8 nm），均满足设计要求。组件正样动力学环境试验表明，反射镜组件的动力学特性良好，柔性支撑系统稳定可靠，与仿真结果一致。目前反射镜全口径面形精度已加工至λ/30 RMS，并在此精度下进行了自重0°/180°的±1 G面形检测试验，结果显示其稳定性良好。