归心测量中轮轨式VLBI天线的水平钢轨形变建模

Modeling Azimuthal Steel-Track Deformation to Determine the Reference Point of Wheel-Track VLBI Antenna

  • 摘要: 为在本地测量中更精确地测定VLBI(very long baseline interferometry)天线参考点(reference point,RP)点位,分析了水平钢轨残余形变对四轮座架式天线的影响,首次提出并推导了用以改正归心解算靶标点(target point,TP)坐标的水平钢轨残余形变模型,结合实测靶标坐标与钢轨水准数据,解释了TP坐标残差中的系统性效应,精化了TP理论坐标,显著提高了参考点测定精度。结果表明,采用水平钢轨残余形变改正模型与估算模型可分别使靶标坐标归心拟后残差中误差提高50%和65%,归心精度均可提高约30%。此外,本钢轨残余形变估算模型还可有效用于该类天线钢轨形变的监测。

     

    Abstract: To determine a more precise reference point (RP) coordinate of Very Long Baseline Interfero-metry (VLBI) antenna in a local surveying, the effects of azimuthal track deformations in four-wheels and pedestal-based radio telescopes are analyzed, and an azimuthal steel-track residual deformation correction model is firstly proposed and derived to correct the coordinates of target points (TPs), which are used to determine the RP position. Using the real measurements of TPs and the leveling data of the steel track, systematic effects in residual of TP coordinates are explained and theoretical TP coordinates are corrected so that the corresponding RP precision is significantly improved. The results show that applying azimuthal steel-track residual deformation correction and estimation models can improve the standard error of post-fit TP residuals by 50% and 65%, respectively. The RP precision can improve about 30%. Moreover, the proposed steel-track residual deformation estimation model can be well applied to monitor the azimuth steel-track deformation of four-wheels and pedestal-based antenna.

     

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