| 引用本文： |
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张 驰,芮国胜,王 瑞,等.计算电离层VLF波传输特性的时域有限差分算法[J].电讯技术，2016，56（11）： - . [点击复制]
- ZHANG Chi,RUI Guosheng,WANG Rui,et al.A finite difference time domain algorithm for calculating VLF wave transmission characteristics in ionosphere[J].，2016，56（11）： - . [点击复制]
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| 摘要: |
| 在星载甚低频（VLF）通信技术中，研究甚低频信号在电离层中的传输特性具有重要意义。现有的利用时域有限差分（FDTD）算法研究电离层传输特性大多基于高频脉冲信号，且传播模型相对粗略，计算存在一定误差。为此，建立了更为精确的电离层各向异性传播模型，对常规的FDTD算法引入变步长因子，并用该算法对VLF波在电离层中的场强衰减进行了数值计算，研究了昼夜变化及频率对其传输特性的影响。仿真结果与卫星实测数据对比表明：与常规的FDTD算法以及全波分析方法相比，引入变步长因子的FDTD算法精度更高；在VLF频段，降低频率有利于电磁波穿透电离层，且白天的衰减明显大于夜间；VLF波在射入电离层并穿透D层时衰减严重（30~40 dB），约为F1层中衰减的3倍。 |
| 关键词: 甚低频通信 甚低频波 电离层传输特性 时域有限差分算法 变步长因子 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（41476089） |
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| A finite difference time domain algorithm for calculating VLF wave transmission characteristics in ionosphere |
| ZHANG Chi,RUI Guosheng,WANG Rui,XUE Peng |
| () |
| Abstract: |
| Research on very low frequency(VLF) signal transmission characteristics in the ionosphere is vital for satellite VLF communications. Existing finite difference time domain(FDTD) algorithms on the study of ionospheric propagation properties are mostly based on high-frequency pulse signal and propagation model is relatively coarse，and there is a certain calculation error. Therefore，a more precise anisotropic ionospheric propagation model is established，and variable step size factor is introduced to conventional FDTD method .With the algorithm,VLF wave field in the ionosphere strong attenuation is calculated to study the frequency changes and effect on the transmission characteristics of day and night. Comparison between simulation results and satellite data shows that compared with the conventional FDTD algorithm and full-wave analysis method，FDTD method introducing variable step factor has a higher calculation accuracy;at VLF band，reducing the frequency is helpful for electromagnetic waves to penetrate the ionosphere and the attenuation during the day is significantly greater than that at night;VLF waves attenuate greatly in entering the ionosphere and penetrating the D layer (30~40 dB)，which is about 3 times in F1 layer. |
| Key words: very low frequency(VLF) communication VLF wave ionosphere transmission characteristics finite difference time domain(FDTD) algorithm variational step factor |
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