面向精度保持性的网状天线反射面自适应设计方法

The antenna reflector accuracy during the service has a direct impact on its in-orbit electrical performance, and further concerns the satellite communication. Mesh reflector antennas work in harsh space environment and cannot be adjusted in-orbit. So, the space thermal environment may lead to the fluctuation and degrade of the surface accuracy. However, the present form finding method and ground test cannot ensure the surface accuracy on service. This proposal aims at improving the on-orbit reflector accuracy through the following research. The antenna on-orbit temperature field is analyzed and the integrated model of the truss and cable nets considering the inhomogeneous temperature distribution is established to study the effects of the thermal environment on the reflector accuracy. Based on this, the optimization design for the on-orbit surface accuracy is conducted. Then, some tension ties are replaced by SMA wires to obtain the adaptive reflector by utilizing the periodically varied on-orbit temperature field of the antenna. The SMA wire’s amount, locations and design parameters are determined thorough modeling and optimization. The above research is to enrich and develop the design methodology for mesh reflector antennas, and form the novel form finding method aiming at on-orbit surface accuracy. Technically, this proposal explores the application of SMA to satellite antennas and provides solutions for the on-orbit adjustment problem of mesh reflector antennas.

星载网状天线服役时的反射面精度直接影响其在轨电性能，进而关系到整个卫星通信。网状天线服役于恶劣空间环境且不具备在轨调整功能，大范围交变温差和极端高低温会引起反射面精度的波动及劣化，而目前的索网找形方法和地面调整试验无法兼顾其在轨精度。本项目以提高天线服役精度为目标，拟通过天线在轨温度场分析、计及非均匀温度分布的桁架-索网耦合建模，探索服役热环境对网面成形精度的影响机理，开展以服役精度为目标的一次找形设计；在此基础上进行反射面在轨二次主动调整，采用形状记忆合金（SMA）丝代替部分纵向索实现对天线非均匀热变形的自补偿，通过建模和优化确定SMA索的设计参数、布置数量和高效分布位置，主动利用天线在轨温度场周期性变化这一“不利”因素实现反射面自适应调整。以期在理论上丰富和发展网状天线设计方法，形成天线在轨精度保障方法；在技术手段上，探索智能材料在星载天线上的应用，突破网状天线难以在轨调整的技术瓶颈。

星载天线是移动通信、电子侦察、地球观测、陆地遥感和深空探测等航天及国防领域必不可少的关键设备，而网状反射面天线是目前应用范围最广的一类星载天线。网状天线服役时的反射面精度直接影响其在轨电性能，进而关系到整个卫星通信。本项目面向星载网状天线大口径、高精度的发展趋势，针对目前索网找形方法和地面调整试验无法兼顾其在轨精度的研究现状和网状天线无法在轨调整的技术瓶颈，围绕网状天线在轨精度保持性问题开展了系统研究，主要研究内容如下：①天线在轨温度场分布研究；②计及非均匀温度分布的环形桁架-柔性索网耦合建模；③天线服役精度优化；④反射面自适应设计。. 基于上述研究内容，通过相关理论研究和实验测试，分析并计算了天线服役期间不同轨道位置处的温度场分布，建立了桁架-索网热结构耦合模型，为准确分析和预测空间环境对天线反射面精度的影响提供了理论基础和技术手段。摒弃了传统常温设计的思路，创造性地提出了面向服役精度的网状天线在轨性能集成设计方法，解决了天线在轨期间的精度保持性问题。针对现有技术条件下天线无法在轨调整的问题，提出“变废为宝”的设计思路。主动利用结构服役期间温度场周期性变化这一“不利”条件，采用形状记忆合金（SMA）丝代替部分纵向索进行在轨主动调整，通过本构模型融合和迭代优化实现反射面在轨自适应设计。