Analytic calculation of the ordinary (O) and extraordinary (X) mode nose frequencies on oblique ionograms

Bennett, J. A.; Chen, J.; Dyson, P. L.

doi:10.1016/0021-9169(94)90103-1

Cited by 6 publications

(12 citation statements)

References 2 publications

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“…In order to investigate sensitivity to the length and direction of propagation, calculations were performed for different path configurations with a central receiver at Xi'an. The (1) The separation on east-west path is susceptible on ionospheric variability, which is inconsistent with previous analysis that the separation does not depend strongly on the ionospheric plasma distribution (Bennett et al 1994), while the separation on north-south path does not show significant correlation with local time and season variations.…”

Section: Dependences On Length and Direction Of Propagationcontrasting

confidence: 80%

“…Davies (1990) presented the relationship between the JFs of the O-and X-wave (referred as 𝑓 𝑂 and 𝑓 𝑋 separately) reflected for the cases of trans-equatorial and magnetic east-west propagation, which were 𝑓 𝑋 − 𝑓 𝑂 ≈ 𝑓 𝐻 2 /2𝑓 𝑂 and 𝑓 𝑋 − 𝑓 𝑂 ≈ 𝑓 𝐻 𝑐𝑜𝑠𝐼 (𝐼 is the magnetic dip, 𝑓 𝐻 is the electron gyrofrequency) respectively. An explicit formula about the separation in JFs between O-and X-wave (abbreviated as 𝑓 𝑋 − 𝑓 𝑂 ) as a function of local magnetic dip and azimuth of propagation was obtained by Bennett and Dyson (1994) for long paths, and they also showed how to use analytic ray tracing to determine the separation for shorter paths. Lundborg et al (1995) found that the separation varied with propagation distance and maximum observed frequency (MOF), changing between 0.7MHz when MOF was low (about 5MHz) and 0.4MHz when MOF was high (about 15MHz) for propagation over the path Kiruna to Uppsala.…”

Section: Main Text 1 Introductionmentioning

confidence: 99%

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Statistical and simulation study on the separation in Junction Frequencies between ordinary (O) and extraordinary(X) wave in oblique ionograms

Sun

Wan²,

Zhang³

et al. 2022

Preprint

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The most important aim in interpreting an oblique ionogram is to obtain the accurate Junction Frequencies (JFs) of the ordinary (O) and extraordinary(X) mode. This requires the correct identification of O- and X-mode traces, so it is very helpful and worthy to grasp the relative position between the two modes. In this paper, a statistical and simulation study of the separation in JFs between O- and X-wave is carried out based on observed oblique ionograms over three mid-latitude paths within China and a 3-D ray tracing program. The dependences on local time, season, geomagnetic activity, solar activity, direction and length of propagation, O-wave JF and group path are investigated. The main conclusions are as follows : (a) the separation on east-west path is susceptible on ionospheric variability, while the separation on north-south path does not show a significant correlation with local time and season;(b) a general diurnal tendency and a summer anomaly on east-west propagation are first proposed and discussed, the latter may be related to the effect of the lower layers; (c)the separation varies approximately as the cosine function of the propagation direction owning two maximums at north-south direction and two minimums at east-west direction in mid-latitude region of China; (d) the variation patterns of the separation with the propagation length are obviously not the same in different directions. For the east-west propagation path, the separation decreases to a minimum near ground range of 2000km and then increases very slowly with increasing ground range, while it monotonically increases for north-south propagation path.

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Section: Dependences On Length and Direction Of Propagationcontrasting

confidence: 80%

Section: Main Text 1 Introductionmentioning

confidence: 99%

Statistical and simulation study on the separation in Junction Frequencies between ordinary (O) and extraordinary(X) wave in oblique ionograms

Sun

Wan²,

Zhang³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…As Bennett et al [1994] has pointed out, the X‐ray can be seen to a first approximation to have the same properties as the O‐ray displaced in frequency by the O‐X separation. The Doppler shift on the X mode is then approximately that of the corresponding component of the O mode, as was shown from the Doppler ionograms presented by Lynn [2007].…”

Section: Discussionmentioning

confidence: 99%

A technique for calculating ionospheric Doppler shifts from standard ionograms suitable for scientific, HF communication, and OTH radar applications

Lynn

2009

Radio Science

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[1] High-resolution Doppler ionograms taken at 5 min intervals were obtained from a KEL IPS 71 ionosonde operating over a full ionosonde sweep range. The ionograms were converted into true height profiles using the program POLAN. POLAN also produced an equivalent parabolic layer model of best fit to the true height profile. A parabolic layer model of the ionosphere is defined by three parameters, namely, peak height, maximum electron density/critical frequency, and parabolic thickness. Equations for calculating Doppler shift from a time-varying parabolic layer model have long been known but have seen remarkably little use in the absence of suitable input data and a means of verifying the results. This paper shows that these equations can provide an accurate means of calculating ionospheric Doppler shift based on standard ionospheric ionograms taken at a 5 min rate over a 24 h period when compared with actual Doppler measurements. Apart from its scientific interest, the demonstrated technique will prove particularly valuable in deriving Doppler shift and associated signal fading for the real-time control of over-the-horizon radar and HF communication links.

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“…The ray tracing to determine the propagation paths for each interference source is calculated using the PHaRLAP ray tracing software [ Cervera and Harris , ]. Two‐dimensional numerical ray tracing (2‐D NRT) is used, including an empirical correction for magneto‐ionic splitting [ Bennett et al , ]. For applications requiring greater precision, the full three‐dimensional ray tracing can be used, which is more computationally intensive but allows for the effects of ionospheric tilts and more accurate calculation of magneto‐ionic splitting.…”

Section: Propagation Modelmentioning

confidence: 99%

Modeling the interference environment in the HF band

Pederick

Cervera

2016

Radio Science

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The performance of systems using high frequency (HF) radio waves, such as over-the-horizon radars (OTHR), can be strongly affected by external interferers at great distances (thousands of kilometers) from the systems receiver. However, the propagation of interference has complex behavior and is known to vary with location, time, season, sunspot number, and radio frequency. Understanding how the level of interference varies with all of these factors is important for the design of new systems such as next generation OTHR. By combining databases of known transmitters, ray-tracing propagation, and a model ionosphere, a model of the behavior of interference at HF has been developed.

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Analytic calculation of the ordinary (O) and extraordinary (X) mode nose frequencies on oblique ionograms

Cited by 6 publications

References 2 publications

Statistical and simulation study on the separation in Junction Frequencies between ordinary (O) and extraordinary(X) wave in oblique ionograms

Statistical and simulation study on the separation in Junction Frequencies between ordinary (O) and extraordinary(X) wave in oblique ionograms

A technique for calculating ionospheric Doppler shifts from standard ionograms suitable for scientific, HF communication, and OTH radar applications

Modeling the interference environment in the HF band

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