Multiple phase screen calculation of wide bandwidth propagation
Multiple phase screen calculation of wide bandwidth propagation
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DOI：
10.1029/2008rs004054
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发表时间：
2009-02
期刊：
影响因子：
1.6
通讯作者：
D. Knepp;L. Nickisch
中科院分区：
文献类型：
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作者：
D. Knepp;L. Nickisch
本文介绍了二维多相屏（MPS）计算的结果，该计算计算了穿过电离层传播后电场的数值实现或样本函数。 MPS 代码求解抛物线波动方程并允许直接计算接收信号的实现。电离由一系列随机相位屏幕表示，这些屏幕表征了电子密度波动的严重程度和频谱。对于宽带宽信号，MPS 代码在传播信号带宽上的许多频率上执行；傅里叶变换技术用于获得时域中的传播信号。 MPS 模拟非常通用，可以应用于涉及以空间变化的电子密度功率谱为特征的大量、分离的电离层的问题。 MPS 技术可以处理所有级别的电离层扰动，从最不严重的（仅发生很小的相位波动）到最严重的频率选择性闪烁的情况。提出了几个传播信号的例子，同时显示了电离层传递函数和脉冲响应函数的发展。重复计算，并对实现进行平均，得到双频双位互相干函数（MCF）、 Γ(x, f) 及其傅里叶变换 S(q,τ)，即广义功率谱。宽带宽 MPS 结果与相位屏衍射方法中使用的强散射理论获得的结果非常匹配。
This paper presents results from a two‐dimensional multiple phase screen (MPS) calculation that computes numerical realizations or sample functions of the electric field after propagation through the ionosphere. The MPS code solves the parabolic wave equation and allows for direct computation of realizations of the received signal. The ionization is represented by a series of random phase screens that characterize the severity and spectrum of the electron density fluctuations. For wide bandwidth signals, the MPS code is exercised for many frequencies over the bandwidth of the propagating signal; Fourier transform techniques are used to obtain the propagating signal in the time domain. The MPS simulation is quite general and may be applied to problems involving numerous, separated, layers of ionization characterized by spatially varying electron density power spectra. MPS techniques can handle all levels of ionospheric disturbances from the least severe, where only small phase fluctuations occur, to the most severe case of frequency selective scintillation. Several examples of propagating signals are presented that simultaneously show the development of the ionospheric transfer function and the impulse response function. The calculations are repeated, and the realizations are averaged to obtain the two‐frequency, two‐position mutual coherence function (MCF), Γ(x, f) and its Fourier transform S(q,τ), the generalized power spectrum. The wide bandwidth MPS results closely match results obtained from strong scatter theory as utilized in the phase screen diffraction method.