电磁波地形抛物方程解的误差分析

Error analysis of solutions to electromagnetic terrain parabolic equations

为了研究电磁波的传播规律,分析地形起伏变化对近地面大气层中高频电磁波传播损耗的影响,借助地形抛物方程,采用混合分步傅里叶变换(mixed split-step Fourier transform),推导了考虑地形起伏与不考虑地形起伏时的误差。结合地形抛物方程传播模式软件(terrain parabolic equation model software),分别计算了3种不同地形下的电磁波单程传输损耗,并给出相应的损耗图。误差分析结果表明:高频电磁波的传输损耗主要取决于地形高度函数对水平距离的二阶导数相对于大气折射率垂直梯度的大小。

To study the electromagnetic wave propagation rule and the influence of terrain case on the highfrequency propagation in the troposphere, the terrain parabolic equation and the mixed split-step Fourier transform were used to calculate the errors in terrain cases and no-terrain cases. TPEM（terrain parabolic equation model） software was adopted to compute one-way propagation loss under three different terrain cases and the corresponding coverage diagrams were shown. The results of error analysis indicate that the propagation loss of the high-frequency electromagnetic wave was dependent on the comparison between the second derivative of the terrain height function and the horizontal range with vertical gradient of refraction index.