SCIPION: a flexible ionospheric digital sounder. Illustration of its capabilities for spatial coherence studies of Es and F regions

Roux, Yann; Ménard, Jacky; Jolivet, J.-P.; Davy, P.; Bourdillon, Alain

doi:10.1049/cp:19970754

Cited by 3 publications

(3 citation statements)

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“…Least‐squares‐filtered minimum‐phase Shinnar‐Le Roux pulses 47‐49 were designed using Vespa 50,51 and used to create both bands of two dual‐band pulses: one optimized for fat‐water imaging at 3 T 45 and one for 7 T 29 . The larger chemical shift difference at 7 T allowed the use of broader and, hence, shorter minimum‐phase SLR RF pulses with a duration of 8.0 ms compared to 11.8 ms at 3 T, allowing a first echo time of about 2.5–4.5 ms at 7 T compared to about 4.5–7.0 ms at 3 T.…”

Section: Methodsmentioning

confidence: 99%

Quantitative susceptibility mapping of the head‐and‐neck using SMURF fat‐water imaging with chemical shift and relaxation rate corrections

Bachratá

Trattnig

Robinson

2021

Magnetic Resonance in Med

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Section: Methodsmentioning

confidence: 99%

Quantitative susceptibility mapping of the head‐and‐neck using SMURF fat‐water imaging with chemical shift and relaxation rate corrections

Bachratá

Trattnig

Robinson

2021

Magnetic Resonance in Med

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“…Low latitude regions, around [20,30] • around both sides of the magnetic Equator, are very influenced by electromagnetic forces that appear because geomagnetic fields run horizontally over the magnetic equator [11]. The electrical conductivity is larger than usual over the Equator, forming a current named electrojet and being subject to electrodynamic lifting and fountain effect, distorting the general form of the ionosphere.…”

Section: The Regions Of the Ionosphere In Terms Of Latitudementioning

confidence: 99%

“…All of them use different kind of waveforms designed to detect the prevailing propagation conditions. Furthermore, several architectures and methodology have been proposed in the literature [28][29][30] to obtain the key parameters of the ionospheric channel, such as the following: (i) Frequency and temporal dispersion by means of the scattering function, (ii) Time of flight, (iii) Signal to noise ratio, (iv) Link power attenuation, (v) Phase stability, (vi) Angle of arrival and (vii) Independent measurements for ordinary and extraordinary rays.…”

Section: Narrowband and Wideband Techniques: Snr Availability And Time And Frequency Dispersionmentioning

confidence: 99%

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Hervás

Bergadà

Alsina-Pagès

2020

Sensors

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High Frequency (HF) communications through ionospheric reflection is a widely used technique specifically for maritime, aeronautical, and emergency services communication with remote areas due to economic and management reasons, and also as backup system. Although long distance radio links can be established beyond line-of-sight, the availability, the usable frequencies and the capacity of the channel depends on the state of the ionosphere. The main factors that affect the ionosphere are day-night, season, sunspot number, polar aurora and earth magnetic field. These effects impair the transmitted wave, which suffers attenuation, time and frequency dispersion. In order to increase the knowledge of this channel, the ionosphere has been sounded by means of narrowband and wideband waveforms by the research community all over the world in several research initiatives. This work intends to be a review of remarkable projects for vertical sounding with a world wide network and for oblique sounding for high latitude, mid latitude, and trans-equatorial latitude.

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Sounding Methods in HF Sky Wave Communications

Orga¹,

Alsina-Pagès²,

Bergadà³

et al. 2022

Wiley Encyclopedia of Electrical and Electronics Engineering

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The existence of the ionosphere as an electrically charged region in the atmosphere was suggested way back in 1839 by Friedrich Gauss. However, it was not until the 1920s that Edward Appleton proved that signals could be received without line of sight anywhere on the planet when emitting in high‐frequency ranges and by means of the ionosphere. The study of the ionosphere has widely attracted the interest of communication researchers due to its complexity regarding time and frequency dispersion. In this chapter, the techniques to characterize the ionospheric HF channel are reviewed. Also, the outcomes of the most relevant research projects working on that issue are provided. This chapter also gives the calculations required to conduct the study of channel availability, signal‐to‐noise ratio, multipath delay spread, and Doppler spread. Finally, the outcomes of these calculations are provided for a real case study involving a 12 760‐km long‐haul link from Antarctica to Europe.

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SCIPION: a flexible ionospheric digital sounder. Illustration of its capabilities for spatial coherence studies of Es and F regions

Cited by 3 publications

References 0 publications

Quantitative susceptibility mapping of the head‐and‐neck using SMURF fat‐water imaging with chemical shift and relaxation rate corrections

Quantitative susceptibility mapping of the head‐and‐neck using SMURF fat‐water imaging with chemical shift and relaxation rate corrections

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Sounding Methods in HF Sky Wave Communications

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