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在传统中心差分离散混合傅里叶变换(DMFT)抛物方程模型基础上,针对传统算法计算动态阻抗边界条件时的数值振荡及忽略后向传播与散射造成计算误差增大的问题,提出基于前-后向混合差分方法的递归双向DMFT(TW-DMFT)模型,以一阶前-后向差分方程代替传统的中心差分方程拟合阻抗边界条件,以递归双向传播模型改进传统单向预测模型。仿真分析了双向DMFT模型计算不同边界及媒介条件下单刃峰和实际地形的电波传播分布特性,与传统算法及几何绕射理论(GTD)进行比较,新算法提高稳定性及精度的同时弥补了传统算法的不足,更具有普适性。
Based on the traditional Discrete Mixed Fourier Transform (DMFT) parabolic equation model, aiming at the problem of numerical oscillation when the traditional algorithm is used to calculate the dynamic impedance boundary conditions and the calculation error increase due to omission of back propagation and scattering, Recursive Bidirectional DMFT (TW-DMFT) model of backward-mixing difference method is proposed. The first-order forward-backward difference equation is used instead of the traditional central difference equation to fit the impedance boundary condition, and the recursive bidirectional propagation model is used to improve the traditional unidirectional prediction model. Simulation and analysis of the two-way DMFT model to calculate the propagation characteristics of single-wave peak and the actual terrain under different boundary conditions and media conditions, compared with the traditional algorithm and the theory of geometric diffraction (GTD), the new algorithm to improve the stability and accuracy while making up The lack of traditional algorithms, more universal.