昼夜过渡区低频一跳天波中不同模式区分及特性分析  

Distinction and Characteristic Analysis of Different Modes of Low-Frequency One-Hop Sky Wave in the Day-Night Transition Area

作　　者：周丽丽[1] 郑悦 穆中林[2] 胡欣悦 朱新月 何立风 ZHOU Li-li;ZHENG Yue;MU Zhong-lin;HU Xin-yue;ZHU Xin-yue;HE Li-feng(School of Electronic Information and Artificial Intelligence,Shaanxi University of Science and Technology,Xi’an,Shaanxi 710021,China;College of Aeronautics and Astronautics Engineering,Air Force Engineering University,Xi’an,Shaanxi 710038,China)

机构地区：[1]陕西科技大学电子信息与人工智能学院,陕西西安710021 [2]空军工程大学航空航天工程学院,陕西西安710038

出　　处：《电子学报》2023年第7期1964-1969,共6页Acta Electronica Sinica

基　　金：国家自然科学基金(No.62171265)。

摘　　要：昼夜混合路径条件下低频天波传播特性的研究对导航授时系统中应用模式拓展及低电离层参数反演均具有重要的研究意义.本文以地—电离层中100 kHz载频罗兰-C信号的时域有限差分(Finite Difference Time Domain,FDTD)仿真为前提,基于传统的过零检测和快速傅里叶变换(Fast Fourier Transform,FFT)/逆快速傅里叶变换(Inverse Fast Fourier Transform,IFFT)频谱相除算法,对昼夜混合信道(传播路径为东西取向)中地面接收的一跳天波进行模式区分及特性分析.给出了在白天至夜晚、夜晚至白天两种突变电离层下罗兰-C一跳天波中不同模式随收发距离的变化规律,同时给出了模式干涉区域优势场量的分布情况.结果表明,对于昼夜混合模型,一跳天波中存在来自不同高度及昼夜突跳边界反射的多种模式,基于传统方法检测的幅度相位存在不稳定干涉效应,模式界定困难,而基于FFT/IFFT频谱相除算法能够将主要模式进行细化区分,从而获得更高精度、更平稳的模式特性.It is of great significance to study the propagation characteristics of low-frequency sky waves under the condition of day-night mixed paths for the application of navigation and time service systems and the inversion of low iono⁃sphere parameters.Based on the finite difference time domain(FDTD)simulation of Loran-C signal(carrier frequency:100 kHz)in the day-night mixed Earth-ionosphere waveguide,this paper uses the traditional zero crossing detection and the fast Fourier transform/inverse fast Fourier transform(FFT/IFFT)spectrum division methods to distinguish the different modes of one-hop sky waves received on the ground in the mixed channel(assuming the propagation path is east-west orien⁃tation),and analyzes the propagation characteristics of the main modes.The propagation characteristics of different modes in one-hop Loran-C sky waves are given under two mixed ionosphere conditions,i.e.from day to night and from night to day.At the same time,the distribution of the dominant field in the mode interference region is given.The results show that for the diurnal mixed path,there are multiple reflection modes from the ionosphere at different heights and its abrupt bound⁃ary.The amplitude and phase detected by the traditional method have unstable interference effect,and it is difficult to dis⁃tinguish the modes.However,the FFT/IFFT spectral division algorithms can refine and distinguish the main modes,so as to obtain more stable and accurate mode features.

关 键 词：一跳天波 波跳理论 FDTD FFT/IFFT 频谱相除算法 昼夜模型 

分 类 号：TN011[电子电信—物理电子学]