共享铁塔与航空无线电导航台站防护间距的计算

Calculation of protective distance between shared tower and aeronautical radio navigation station

为得到航空无线电导航台站的防护间距,建立基站天线激励条件下的共享铁塔电磁散射求解模型,采用矩量法和物理光学法对电场积分进行混合求解,并针对兆赫兹频段带来的阻抗矩阵求解资源量过大的问题,提出引用多层快速多极子算法(multi level fast multipole method,MLFMM)以降低计算复杂度,实现测距台站处的干扰场强求解。以共享铁塔的安装方式、铁塔塔型、铁塔基数为变量,分别求解了3种因子条件下干扰场强的变化规律,并以干扰防护率为阈值,建议航空无线电导航台站信号覆盖范围内的共享铁塔与航空无线电导航台站测距信标台之间的防护间距为11.1 km。

In order to obtain the protection distance of the aeronautical radio navigation station,this paper established a shared tower electromagnetic scattering solution model under the excitation condition of the base station antenna.The moment method and the physical optics method were used to mix and solve the electric field integration.The impedance matrix was used to solve the problem of excessive resources,and multi level fast multipole method(MLFMM)was proposed to reduce the computational complexity and solve the interference field strength at the ranging station.Using the installation method of the shared tower,the tower type,and the number of tower base stations as variables,the variation law of the interference field strength under the conditions of three factors were solved respectively.With the interference protection rate as the threshold,it is recommended that within the signal coverage of the aeronautical radio navigation station,the protection distance between the shared tower and the aeronautical radio navigation station ranging beacon station is 11.1 km.