基于干涉全息法测量射电望远镜主面重力变形和副面位姿

Main reflector gravity deformation and sub-reflector position measurement for radio telescope based on interferometer

本文围绕天马65 m (TM65 m)射电望远镜主面重力变形和副面位姿展开实测研究.论文先概述了主面测量的方法,主要讨论了基于微波全息法的测量方法和天线扫描方法,然后论述了采用Very Long Baseline Interferometer (VLBI)测量65 m主面各俯仰角的重力变形,对测量误差进行了评估,进而构建了重力模型,并与仿真结果进行了比较,两者变化趋势一致.同时,推导并仿真了主焦馈源、副面位姿偏移和口径面相位的解析关系,然后基于该解析关系和VLBI测量得到的口径面相位数据,并采用最小二乘法解算得了实际TM65 m副面位姿随俯仰的变化情况,该测量结果在三维方向上与传统基于主动副面的幅度扫描法结果一致性强,该方法为测量副面位姿提供了不同于传统法的可行途径.

This paper focuses on the measurement of the main reflector gravity deformation and sub-reflector position change on Tianma 65 m(TM65 m)radio telescope.Firstly the paper summarizes the methods of principal measurement.Microwave holography and cross scan pattern are disscussed.Then the gravity deformation of the main reflector over the entire elevation measured by VLBI method is discribed.The measurement accuracy is also estimated.At last,the gravity model is constructed and compared with the simulation.They agree with each other.The formulas along with the simulation give a description between the offsets of feed,sub-reflector and the aperture phase.The sub-reflector position of TM65 m is obtained by the least square method that applied on the aperutre phase and the formulas.The sub-reflector positions measured are consistent with that of the traditional amplitude method in X,Y and Z directions.This method provides a different way to measure the position model of the sub-reflector.