有限元方法模拟甚低频/低频波传播特性

Finite element method simulation on propagation characteristics of very low frequency and low frequency waves

  • 摘要: 针对陆基无线电导航授时系统,基于频域有限元方法模拟了甚低频(very low frequency, VLF)/低频波传播,以解决快速预测复杂地-电离层波导中无线电波电磁特性的问题. 引入传递函数法,将有限元方法提取的空间宽带复传递函数映射至时域,完成了瞬态波形重构与附加二次时延的提取. 与文献结果对比验证了有限元方法的准确性,数值计算了无线电波幅值和相位随地形起伏、电离层参数、传播距离和工作频率的变化特点. 相关工作为无线电导航授时技术的评估、系统设计与优化部署、信号幅值和相位快速准确预测提供有力的技术支撑.

     

    Abstract: For land-based radio navigation and timing systems, the propagation of very low frequency (VLF)/low frequency (LF) waves is simulated based on the frequency-domain finite element method, to address the challenge of rapidly predicting electromagnetic properties of radio waves in the complicated Earth-ionosphere waveguide. By introducing the transfer function method, the spatial broadband complex transfer function extracted by the finite element method is mapped to the time domain. Transient waveform reconstruction and the extraction of additional secondary delay are accomplished. The accuracy of the finite element method is validated by comparison with results in the reference. Effects of topographic undulations, ionospheric parameters, propagation distance, and working frequency on the amplitude and phase of radio waves are numerically computed. This work provides powerful technical support for the evaluation, system design and optimization deployment of radio navigation and timing technologies, as well as rapid and accurate prediction of the amplitude and phase of signals.

     

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