大型障碍物影响下航向信标敏感区的划设

国际民航组织给出了仪表着陆系统航向信标(localizer, LOC)敏感区划设建议,但没有考虑大型障碍物的影响,也没有提供相应理论说明。中国民航正在提升仪表着陆系统的运行等级,必须评估大型建筑物对该敏感区的影响。聚焦机载LOC接收信号的调制度差(difference in depth of modulation, DDM),分析研究大型障碍物产生的LOC反射信号、边缘绕射信号及尖顶绕射信号对DDM的影响,基于双频20单元LOC阵列天线建立DDM计算模型,仿真分析了铁质和水泥材质大型障碍物在不同位置时对DDM的影响,获得了大型障碍物影响下LOC敏感区,并为国内某条实施III类运行跑道附近的机库改造提供相应建议。

Setting the sensitive area of localizer under the influence of large obstacles

The suggestions on the sensitive area of the localizer (LOC) of the instrument landing system are given by the International Civil Aviation Organization, but the influence of large obstacles is not considered, and the corresponding theoretical explanation is not provided. The operation level of the instrument landing system is being upgraded by the Civil Aviation Administration of China, so it is necessary to assess the influence of large buildings on this sensitive area. Focusing on the difference in depth of modulation (DDM) of the signal received by airborne LOC, the influence of LOC reflection signals, edge diffraction signals, and tip diffraction signals generated by large obstacles on DDM is analyzed and studied, DDM calculation model is established based on 20 elements double-frequency LOC array antenna, and the influence of large obstacles made of iron and cement on DDM at different positions is simulated and analyzed. The LOC sensitive area under the influence of large obstacles is obtained. The corresponding suggestions are provided for the modification of a hangar near a category Ⅲ runway in China.