卫星光通信终端光学天线温度特性研究

发布时间：2018-05-04 23:20

本文选题：空间光通信 + 温度场　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：卫星在空间运行的过程中受到空间环境的影响很大。空间环境直接作用于光学天线上，导致光学天线温度分布不均，从而导致光学系统形变。光学系统作为卫星激光通信系统中的核心部件，其形变将影响传输光束的质量，，进而可能严重地影响通信质量。所以研究温度场的变化对于卫星激光通信的影响具有很重要的作用，这对于优化卫星激光通信系统的性能、提高其通信质量等具有重要的意义。本文基于反射式卡塞格伦系统的设计，首先对其光学系统的机械支撑结构进行了设计，并建立光学天线的有限元分析模型；在光学镜面为不同材料，以及不同几何形状的加热片加热下，主要研究光学系统的温度特性。对其温度特性的研究包括了热载荷下主次镜的温度场分布情况，形变量情况，最后通过Zernike多项式拟合得到主次镜镜面的形变量，利用CODE V分析得到系统成像的波前畸变、光斑能量分布、MTF等，同时对相同条件下两种材料系统的光束质量进行了对比分析。围绕上述内容，具体工作内容如下：（1）设计光学系统的支撑结构。光学系统的支撑结构包括主镜底座和次镜支架。采用三点支撑的方式连接主次镜，支架和次镜底座采用同一材料经过切割而制成。主镜底座采用周边支撑方式，主镜底座和次镜支架的材料分别为钛合金和殷钢。通过对支撑结构进行设计，将光学系统实体化。（2）建立光学天线有限元分析模型，对光学系统的温度特性进行仿真研究。对于光学元件材料分别为微晶玻璃和K9的光学系统，其主镜背面，分别采用了三种不同的加热方式加热。通过分析得到三种加热片下光学系统的温度场和形变场的数值随温度的升高呈线性递增。（3）研究了形变对光学系统性能的影响。利用Zernike多项式拟合，得到相应形变后的光学系统，通过CODE V光学分析软件得到相应的光束质量变化情况。其RMS值、P-V值随温度升高呈线性递增。（4）对比分析得到径向加热片对光学系统光束质量的影响小，周向等积加热片次之，周向等径加热片最大。对两种材料而言，在热源温度相同时，微晶材料系统的影响小于K9材料的系统。综上，光学天线的温度稳定性是空间光通信系统的重要指标之一，本文的研究内容为反射式卡塞格林系统的热控设计提供了帮助，主要是加热片几何形状的选取提供了重要的依据。
[Abstract]:Satellites are greatly affected by the space environment in the course of space operation. The space environment acts directly on the optical antenna, which leads to the uneven temperature distribution of the optical antenna, resulting in the deformation of the optical system. As the core component of satellite laser communication system, the deformation of optical system will affect the quality of propagation beam and may seriously affect the quality of communication. Therefore, it is very important to study the change of temperature field for the influence of satellite laser communication, which is of great significance to optimize the performance of satellite laser communication system and improve its communication quality. In this paper, based on the design of reflective Cassegrain system, the mechanical support structure of the optical system is designed, and the finite element analysis model of the optical antenna is established. The temperature characteristics of optical system are studied under the heating of different geometry. The study of the temperature characteristics includes the distribution of the temperature field and the shape variables of the primary and secondary mirror under the thermal load. Finally, the shape variables of the primary and secondary mirror surface are obtained by Zernike polynomial fitting, and the wavefront distortion of the system imaging is obtained by CODE V analysis. At the same time, the beam quality of two kinds of material systems under the same conditions is compared and analyzed. The specific contents of the work are as follows: Design the supporting structure of optical system. The supporting structure of the optical system includes the primary mirror base and the secondary mirror support. Three-point support is used to connect the primary and secondary mirror, the support and the secondary mirror base are cut from the same material. The primary mirror base adopts peripheral support, and the primary mirror base and secondary mirror support are made of titanium alloy and Yin steel respectively. By designing the supporting structure, the optical system is materialized. The finite element analysis model of optical antenna is established to simulate the temperature characteristics of optical system. For the optical systems which are glass-ceramics and K9 respectively, three different heating methods are used in the back of the primary mirror. By analyzing the temperature field and deformation field of three kinds of optical system under heating sheet, the values of temperature field and deformation field increase linearly with the increase of temperature. The effect of deformation on the properties of optical system is studied. The corresponding deformed optical system is obtained by Zernike polynomial fitting, and the change of beam quality is obtained by CODE V optical analysis software. The RMS value and P-V value increased linearly with the increase of temperature. The comparative analysis shows that the radial heating plate has little effect on the beam quality of optical system, the circumferential iso-product heating sheet is the second, and the circumferential equal-diameter heating sheet is the largest. For both materials, the effect of microcrystalline system is smaller than that of K9 system at the same heat source temperature. In summary, the temperature stability of optical antenna is one of the important indexes of space optical communication system. The research content of this paper provides help for the thermal control design of reflective Cassegrain system. It mainly provides important basis for the selection of the geometric shape of the heating plate.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.13

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