基于可动副面的偏馈天线误差补偿技术及其影响研究

With the development of technology and the deepening of space exploration，requirement of observation equipment for scientists has been improved. For radio telescope, not only large diameter and high precision were required for astronomical observation, but also higher working efficiency was requested. For these, adjustment of movable subreflector is proposed in the study for offset antenna, active compensation of deformation of antenna structure and rapid transformation of feeds which is working in different frequency will be achieved. .The study of compensation technology of errors for offset antenna and its effects will be mainly made in this project. Analysis of theory and simulation for position of subreflector is done with geometrical optics; the deformation of antenna structure is analyzed and simulated in displacement field and electromagnetic field with electromechanical coupling theory, the best position of subreflector is determined so as to achieve compensation in real time. Pointing errors are analyzed which are caused by movable mechanism of subreflector, and pointing error sources will be determined by antenna field measurement and theoretical analysis in order to improve antenna pointing accuracy. The study is to realize active compensation of antenna deformation and rapid beam switching, so as to improve observation effect and work efficiency for radio telescope.

随着科学技术发展和宇宙探索的不断深入，科学家对观测设备的要求也不断提高。对于射电望远镜而言，不但要求其具有大口径、高精度的天文观测，而且要求望远镜具有较高的工作效率。针对射电望远镜的这些需求，拟在本研究中通过副面运动调节，实现天线结构变形的主动补偿和不同频率工作馈源的快速转换。.本项目主要针对基于可动副面的偏馈天线误差补偿技术及其影响进行研究，通过几何光学对不同偏置馈源工作时对应的副面位置进行理论与仿真分析；基于机电耦合理论，对天线结构的变形进行位移场和电磁场的分析与仿真，确定副面在全仰角下的最佳对焦位置，以实现副面的实时补偿；并对副面调整机构引起的指向误差进行误差分析，通过实测和理论分析，确定附加指向误差源，以提高天线的指向精度。通过本研究旨在实现中小型天线结构变形主动补偿和波束快速转换，以提高望远镜的观测效果和工作效率。

针对本项目研究的核心问题副面最佳位置的确定与副面偏差对指向的影响，主要基于机电耦合思想，从结构变形对天线电性能影响角度，围绕反射面天线副面位置主动调整补偿方法的研究，分析了双反射面天线副面位置偏差对电性能的影响机理，分析了副面位置偏差对口径场相位误差及天线增益和指向的影响情况；研究了基于机电耦合思想的副面位置优化调整方法，建立了副面位置调整量与天线远场方向图之间的数学关系模型，采用优化的方法，建立了以电性能为目标的副面优化模型，并进行了算例仿真；研究了天线结构误差对指向的影响机理，基于几何光学原理推导了天线结构误差对指向的影响模型，获得了波束偏移因子计算关系；针对乌鲁木齐南山26米天线，基于天文扫描观测采用副面位置一维搜索的方法进行了多个频段偏焦馈源的副面位置优化，使天线性能得到了改善。本项目的研究过程，撰写论文4篇，申请专利6项，并培养学生3名。