Field-Strength Variations of LF One-Hop Sky Waves Propagation in the Earth–Ionosphere Waveguide at Short Ranges

Zhou, Lili; Yan, Jingjing; Mu, Zhonglin; Pu, Yurong; He, Lifeng

doi:10.1109/lawp.2019.2929780

Cited by 9 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since 2011, we have studied the propagation characteristics of different mode waves in complex Earth-ionosphere waveguide based on the 2-D cylindrical-coordinate FDTD and parabolic equation methods. However, our study did not take into account the effects of the anisotropic ionosphere influenced by the natural magnetic field, and it was limited to the nearillumination region of one-hop sky waves [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Long-distance Propagation Characteristics of LF Multi-hop Sky Waves

Zhou,

Zhu,

et al. 2023

PIER Letters

Self Cite

View full text Add to dashboard Cite

This paper focuses on the decomposition of different modes of Loran-C resultant waves, including ground waves and onehop/two-hop sky waves, propagating in the Earth-ionosphere waveguide obtained from direct finite-difference time-domain (FDTD) modeling in the presence of the natural magnetic field. After providing the FDTD iterative formulas for the ionosphere affected by the natural magnetic field, the Loran-C resultant waves propagating in the anisotropic Earth-ionosphere waveguide are estimated using the FDTD algorithm. In both the daytime and nighttime ionosphere models, different orientations of the natural magnetic field are taken into account. The arrival times of the different propagation modes for the resultant waves were then determined using a multipath time-delay estimation method. With the above delays, the amplitudes of the different modes are acquired by solving overdetermined equations. Finally, the decomposition results are compared with those obtained in the absence of the natural magnetic field. The numerical experimental results indicate that, with a radiation power of 1 kW and a natural magnetic field of 0.5 Gs, the influence of the direction of the natural magnetic field on the field strength of one-hop sky waves is significant when the propagation distance of LF radio waves is less than 1000 km. Radio waves have multipath effects such as convergence, divergence, and diffraction due to the curvature of the Earth and the ionosphere. This results in significant interference phenomena when the propagation distance of two-hop sky waves is greater than 500 km.

show abstract

Section: Introductionmentioning

confidence: 99%

Analysis of Long-distance Propagation Characteristics of LF Multi-hop Sky Waves

Zhou,

Zhu,

et al. 2023

PIER Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Normally, the signal simulator is required to model the signals within the channel to accurately characterise eLoran pulsed signal groups. The signal model accuracy mainly depends on the time of arrivals (TOAs) of ground-wave and sky-wave [5,[11][12][13][14]. The TOA of the ground-wave is affected by weather factors and has different degrees of additional time delay [2,13,15,16].…”

Section: Introductionmentioning

confidence: 99%

High‐precision simulation technology for enhanced Loran signal simulators based on Lagrange farrow structure filter

Yuan

et al. 2022

IET Radar Sonar & Navi

Self Cite

View full text Add to dashboard Cite

In this study, a real‐time high accuracy signal simulation technique for an enhanced Loran (eLoran) signal simulator is proposed, which can be used to verify the performance of the eLoran receiver. The proposed method is based on a maximumly flat design of the low‐pass filter, and high simulation accuracy can be obtained in the low‐frequency band. The simulator structure is based on the variable fractional delay Farrow structure, which can regenerate eLoran signals with high‐precision time of arrival (TOA) in real‐time based on discrete samples on a hardware platform. By comparison of existing methods and the true TOA data validation, the proposed method has high performance for low‐frequency narrow‐band eLoran signals and the proposed technology can apply to arbitrary TOA real‐time simulations.

show abstract