地下电磁信号对民航机场导航台站的干扰机理分析与仿真计算

目的研究地下电磁信号对机场导航台站的干扰机理,并进行仿真计算。方法建立导航台天线的电流分布模型,研究外部电磁干扰对导航台天线上电流分布形式的影响。基于导航台的工作原理,研究外部电磁干扰对导航台辐射方向图的影响,并进行仿真计算。计算航线下滑线空间点上的场强值受外部电磁信号干扰的影响。结果地下电磁信号传播至导航台天线所在区域,造成T型天线的左右顶负载的电流不再满足镜像反对称的状态,导致T型天线覆盖区域中的场强值变化,水平面的无方向性方向图产生波瓣分裂,进而导致航线下滑线上空间点接收到的场强值幅度产生波动,仿真结果显示波动值高达32.7%。结论地下电磁信号对无方向性信标台造成干扰,导致原来的无方向性方向图产生波瓣分裂,航线下滑线上的场强值产生波动,影响了飞行安全,需要加以抑制屏蔽。

Interference Mechanism Analysis and Simulation Calculation of Underground Electromagnetic Signal to Civil Airport Navigation Station

Objective To study interference mechanism of underground electromagnetic signal to airport navigation station and carry out simulation calculation. Methods Distributed current model on antenna of navigation station was established. Influences of external electromagnetic interference on distributed current form were analyzed. Based on radiation principle of airport navigation station, influences of external electromagnetic interference on navigation station radiation pattern were studied and simulated, and influence of external electromagnetic interference on E-filed amplitude at route glide line were calculated. Results Underground electromagnetic signal propagated to the area of the airport navigation station antenna and caused that top load currents on both sides of the T-type antenna no longer satisfy the mirror-antisymmetric state. Field intensity in the field covered by T-antenna also changed. Radiation lobe splitting appeared in the non-directional diagram at horizontal plane and field intensity range received at the spatial point of air line glide also fluctuated. The fluctuating value shown in the simulation result reached up to 32.7%. Conclusion Underground electromagnetic signals cause interferences to non-directional beacon, resulting in radiation lobe splitting at horizontal plane and E-filed fluctuations on route glide line. Underground electromagnetic interference affects flight safety and needs to be suppressed by shielding.