Far-near-field coupling calculation method for a 110 m radio telescope based on the parabolic equation and time domain near-field physical optics
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维普
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正在新疆奇台建设的110m全向可动射电望远镜是一个可以接受微弱射电信号的天文设备,台址周围较大范围内存在着数量众多的干扰源会影响其观测精度与效率.本文提出了一种基于抛物方程和时域物理光学法(Parabolic Equation and Time Domain Physical Optics,PE-TDPO)的混合计算方法,以 110 m全向可动射电望远镜为研究对象,对台址附近大区域内干扰源信号的传播过程进行建模.在较大地理尺度上对干扰信号从台址远场至近场的电磁耦合特性进行了综合评估,为大型射电望远镜电磁干扰问题处理提供理论依据.本文以通信基站作为典型干扰源,基于数字地图建立射电望远镜台址周围的高精度地形模型,采用抛物方程对干扰信号的远场电波传播进行分析,得到从干扰源处至射电望远镜处的信号传播的路径损耗和传播因子;其次将PE方法计算得出的远场电场值代入TDPO的积分中,得到干扰信号在射电望远镜焦点处的近场耦合特性;最后讨论了远场干扰源特性对射电望远镜的远-近场耦合的影响.
Recently,the electromagnetic environment surrounding large radio telescopes has become increasingly complex,with several interference sources in close proximity to radio observatories.These sources considerably influence the accuracy and efficiency of radio observations.In this work,a calculation method based on the parabolic equation and time domain physical optics was proposed to solve this issue.The research object of this investigation is an omnidirectional,movable radio telescope with a 110-m diameter in the Xinjiang Province,and the focus of this paper is to model the propagation of interference signals produced from the surrounding interference sources.This study aims to comprehensively estimate and analyze the electromagnetic coupling characteristics of these interference signals,spanning from the far field to the near field and provide a reliable foundation for effectively addressing the issueof electromagnetic interference encountered by actual large radio telescopes.First,the communication base station is taken as a representative interference source,and a high-precision terrain model is constructed based on the digital map of the surroundings of the radio telescope site.The parabolic equation is utilized to analyze the far-field radio wave propagation of the interference signal,enabling the determination of path loss and propagation factors from the interference source to the radio telescope.Second,the far field electric field calculated from the radio wave propagation is incorporated into the integration expression of the time domain physical optics method,facilitating the evaluation of the near-field coupling characteristics of the interference signal at the focus of the radio telescope.Finally,the influence of far-field interference source characteristics on the far-near-field coupling characteristics of the radio telescope is discussed.
radio telescopeparabolic equationtime domain physical opticsfar-near-field coupling
维普
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