基于全局透射边界条件的宽角抛物方程电波预测模型

Radio propagation prediction model based on wide-angle parabolic equation with non-local boundary condition

提出了一种新型的基于全局透射边界条件(non-local boundary condition,NLBC)的Greene近似宽角抛物方程(wide-angle parabolic equation,WAPE)电波预测模型,用于求解对流层远距离复杂环境中的电磁波传播特性.采用有限差分法(finite difference method,FDM)求解WAPE得到了三对角线性方程组,可以快速地求解整个空间的电场分布,也可以对不规则的地表环境进行精确建模.本文提出的WAPE模型解决了传统的PE离轴传播角度偏小的问题,将电波的最大传播仰角提升至约50°,同时大大减小了计算区域中上边界吸收层的设置尺寸,从而提高了PE的计算效率.实验证明,当伪微分算子的相位误差不超过0.002时,Tappert、Claerbout和Greene近似形式得到的最大传播角分别为20°、35°和45°.最后,通过与经典的光学双射线模型进行对比,证明本文提出的基于NLBC的Greene近似WAPE模型的可计算传播仰角更大,对上边界处反射电磁波有良好的吸收效果.因此,本文的模型适用于对流层远距离复杂环境中电磁波传播特性的精确预测.

This paper present a new Greene approximation wide-angle parabolic equation(WAPE)radio prediction model based non-local boundary condition(NLBC).This model can be used to calculate radio propagation characteristics in complicated environment.Tridiagonal linear equations are achieved by the finite difference method(FDM),which not only quickly solve field distribution in the whole domain but also accurately model irregular terrain.The Greene approximation WAPE model is proposed to resolve a limited propagation angle problem,which increased propagation angle up to about 50°.This model greatly reduces the sizes of absorbing layer,which improve the computational efficiency of the PE method.In this paper,it is found that for an arbitrary phase error limit of 0.002,the Tappert,Claerbout and Greene approximations have acceptable propagation angle limits of approximately 20°,35°and 45°respectively.The PE results are compared with the classical optical dual-ray model.The results show that the Greene approximation PE model has greater radio propagation angle and higher prediction accuracy,and get good absorbing effect of electromagnetic wave on upper boundary condition reflection.The Greene WAPE models can accurately predict radio propagation characteristics in complicated atmospheric environment.