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Proceedings ArticleDOI

Analysis of VLF Radio Wave Propagation Characteristics and Its Influence on Underwater Platform Communication

TL;DR: The characteristics of VLF wave propagation in earth-ionosphere waveguide are analyzed and the influence of ground electrical characteristics, ionospheric electrical characteristics and wave characteristic parameters on the communication of underwater platforms is pointed out.
Abstract: VLF communication is one of the most effective means to command underwater platform at present. However, the reliability of VLF communication will be degraded due to various factors in the process of VLF signal propagation. In this paper, the characteristics of VLF wave propagation in earth-ionosphere waveguide are analyzed. The influence of ground electrical characteristics, ionospheric electrical characteristics and wave characteristic parameters on the communication of underwater platforms is pointed out. By studying these laws and making use of the good predictability of the VLF band, the attenuation and disturbance in the propagation process can be predicted. So we can achieve the best communication effect and improve the reliability of the underwater platform VLF communication.
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01 Jan 1967

176 citations

Journal ArticleDOI
TL;DR: In this article, the modal interference distance (DMS) and the nighttime D region VLF reflection height (hN) of very low frequency (VLF) signals from navigational transmitters propagate through the Earth-ionosphere waveguide formed by the Earth and the lower conducting ionosphere and show the pronounced minima during solar terminator transition between transmitter and receiver.
Abstract: Very low frequency (VLF) signals from navigational transmitters propagate through the Earth-ionosphere waveguide formed by the Earth and the lower conducting ionosphere and show the pronounced minima during solar terminator transition between transmitter and receiver. Pronounced amplitude minima observed on 19.8 kHz (NWC transmitter) and 24.8 kHz (NLK transmitter) signals recorded at Suva (18.149°S, 178.446°E), Fiji, during 2013–2014, have been used to estimate the VLF modal interference distance (DMS) and nighttime D region VLF reflection height (hN). The NWC transmitter signal propagates mostly in west-east direction, and the NLK transmitter follows a transequatorial path propagating significantly in the east-west direction. The values of DMS calculated using midpath terminator speed are 2103 ± 172 km and 2507 ± 373 km for these paths having west-east and east-west components of VLF subionospheric propagation, respectively, which agree with previously published results and within 10% with theoretical values. We have also compared the DMS estimated using a terminator time method with that calculated using terminator speed for a particular day and found both the values to be consistent. The hN values were found to be maximum during winter of Southern Hemisphere for NWC signal and winter of Northern Hemisphere for NLK signal VLF propagation paths to Suva. The hN also shows significant day-to-day and seasonal variabilities with a maximum of about 10 km and 23 km for NWC and NLK signal propagation paths, respectively, which could be due to the atmospheric gravity waves associated with solar terminator transition, as well as meteorological factors such as strong lightnings.

8 citations

Journal ArticleDOI
TL;DR: In this article, the authors have studied the dynamics of the nighttime lower ionosphere height through continuous monitoring of the VLF modal interference distance (so-called distance D), which is related to the nighttime propagation modes within the Earth-Ionosphere waveguide.

6 citations


"Analysis of VLF Radio Wave Propagat..." refers background in this paper

  • ...[7] [8] The value of β and h can be expressed by the following empirical formula....

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Proceedings ArticleDOI
01 Aug 2016
TL;DR: In this article, the modal interference distance (DMS) for west-east propagation path (NWC-Suva) has been estimated using Terminator Time method which is based on the measure and analysis of the occurrence times of amplitude minima.
Abstract: Pronounced amplitude minima are observed on 19.8 kHz signal recorded at Suva (18.149°S, 178.446°E), Fiji, from a VLF navigational transmitter located in North West Cape (NWC), Australia. The propagation path is mixed over land and sea having Transmitter-Receiver Great Circle Path distance 6.7 Mm. In this paper the modal interference distance (D MS ) for west-east propagation path (NWC-Suva) has been estimated using Terminator Time method which is based on the measure and analysis of the occurrence times of amplitude minima. The experimental values of D MS were found to be consistent with the theoretical values calculated using the mode theory of VLF wave propagation in the Earth-ionosphere waveguide.

5 citations


"Analysis of VLF Radio Wave Propagat..." refers background in this paper

  • ...According to the polarization characteristics of the field, the waveguide mode has transverse magnetic (TM) wave mode, transverse electric (TE)wave mode, transverse electromagnetic (TEM) wave mode and so on [9][10]....

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