Automatic fitting of quasi-parabolic segments to ionospheric profiles with application to ground range estimation for single-station location

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

doi:10.1016/0021-9169(90)90095-5

Cited by 20 publications

(14 citation statements)

References 10 publications

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“…(4-6), and in part used to build foF2 mapping using the NN model. Thus, the foF2 at the middle of each transmitter and receiver is obtained by using an automatic ionospheric oblique sounding inversion algorithm based on ionospheric quasi parabolic (QP) model and ray tracing (Dyson and Bennett, 1988;Chen et al, 1990;Chen et al, 2012). Furthermore, it is well known that the foF2 measurements at the mid-point of the radio links are used to calibrate the model and method.…”

Section: Models Results and Discussionmentioning

confidence: 99%

Comparison of the Kriging and neural network methods for modeling foF2 maps over North China region

Jiang

Zhou

Liu

et al. 2015

Advances in Space Research

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Section: Models Results and Discussionmentioning

confidence: 99%

Comparison of the Kriging and neural network methods for modeling foF2 maps over North China region

Jiang

Zhou

Liu

et al. 2015

Advances in Space Research

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“…Second, the electron density profile at the midpoint is fitted with a quasi-parabolic segment (QPS) model [Chen et al, 1990]. Analytic ray tracing is performed from the transmitter location to the midpoint and back to the receiver using this QPS profile.…”

Section: 1mentioning

confidence: 99%

An evaluation of a new two‐dimensional analytic ionospheric ray‐tracing technique: Segmented method for analytic ray tracing (SMART)

Norman¹,

Cannon²

1999

Radio Science

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Abstract. Analytic ray tracing is considerably less time consuming than numerical ray tracing. However, despite the advantage of speed, analytic ray tracing has a major limitation: the difficulty of including the effects on the ray path of horizontal gradients in electron density. In the past this difficulty has been addressed using ionospheric models whereby an effective tilt is introduced by displacing the center of the ionosphere from the center of the Earth. In this paper, ray equations for the ground range, phase path, group path, and divergent power loss are developed for a new two-dimensional analytic ray tracing technique, known as the segmented method for analytic ray tracing (SMART), which is able to deal with horizontal gradients in electron density. Ray tracing using two tilting methods are compared with ray tracing using SMART. Further, these results are compared with a numerical ray tracing program known as homing-in ray tracing (HIRT). IntroductionThe operation of high-frequency (HF) sky wave, communication, and radar systems can be enhanced by the application of accurate and fast ray tracing coupled with realistic and near real-time ionospheric specification models. For ray tracing, there are three candidate approaches: numeric, analytic, and approximations based on reflections from an equivalent mirror. The latter will not be addressed further in this paper. Of the two former techniques the analytic techniques are faster than the numeric, and consequently they are particularly advantageous in HF applications where it is necessary to trace a vast number of rays. Analytic ray tracing uses explicit equations to define the ionosphere and to determine ray parameters such as ground range, reflection height, phase path, group path, and divergent power loss [1997] showed that computer run times using SMART are approximately an order of magnitude faster than those of numerical ray tracing packages, and errors in ground range calculations were typically less than 2.5%.In this paper the assessment of SMART is extended to ground range, phase path, group path, and divergent power loss by the development of the appropriate equations. Results from SMART are compared with the results obtained from two tilted ionosphere analytic approaches and also with the 489

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“…The electron density profile at the location where the ray enters the ionosphere is fitted with a multiquasi-parabolic segment (QPS) model [Chen et al, 1990]. A multiquasi-cubic segment (QCS) model [Norman et al, 1996] would work just as well.…”

Section: Qps Model and Formulismmentioning

confidence: 99%

A two‐dimensional analytic ray tracing technique accommodating horizontal gradients

Norman¹,

Cannon²

1997

Radio Science

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Abstract. A new two-dimensional analytic ray tracing method, known as segmented method for analytic ray tracing (SMART), which automatically segments the ionosphere along the ray path is described. Unlike other techniques, SMART is able to accurately ray trace through horizontal gradients which vary with altitude along and in the direction of the ray path. Computer run times are approximately 10 times faster than those of numerical ray tracing packages, and ground range errors are typically less than 2.5%. IntroductionRay tracing is a powerful and useful tool in a number of modern applications where a detailed knowledge of radio wave propagation through the ionosphere is required. Examples are over-the-horizon radar systems, single station location, and HF direction finding systems. The management of these beyond line-of-sight systems depends critically on realistic ionospheric modeling along with accurate and fast ray tracing through these models.Accurate ray tracing is normally carried out using numerical techniques. These usually require Haselgrove's equations, [Haselgrove, 1955;Haselgrove and Haselgrove, 1960], where the parameters of both the position and ray direction need to be integrated simultaneously at each point along the ray path. This means that although numerical ray tracing is very accurate, the required computational time is high. Furthermore, in many applications it is necessary to trace a vast number of separate rays. Thus, when dealing with near real-time applications, which is increasingly the case, it is far more desirable, if not essential, to make use of analytic ray tracing techniques. Analytic ray tracing techniques are much faster than numerical approaches, but they are more restricted in the ionospheric models to which they can be applied.As its name suggests, analytic ray tracing uses explicit equations to define the ionosphere and to determine ray parameters such as ground range, reflection height, phase path, group path, and divergent power loss. Consequently, analytic ray tracing is considerably less time consuming than numerical ray Published in 1997 by the American Geophysical Union.Paper number 96RS03200.tracing. Despite the advantage of speed, analytic ray tracing does, however, have two main limitations. The first of these is the absence of explicit equations which include the effects of the Earth's magnetic field on the ray path. However, a first-order correction, using a frequency-scaling technique, has been developed by Chen [1989] and Bennett et al. [1991]. The second limitation is the difficulty of including horizontal gradients. In the past only ionospheric models with very simple horizontal gradients have been approximated. Bennett and Dyson [1989], for example, used a method whereby an effective tilt was introduced by displacing the center of the ionosphere from the center of the Earth. In many cases the horizontal gradients in the ionosphere increase with altitude such that the gradients are much smaller in the E region than in the F region. Norman et al. [1995] de...

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Automatic fitting of quasi-parabolic segments to ionospheric profiles with application to ground range estimation for single-station location

Cited by 20 publications

References 10 publications

Comparison of the Kriging and neural network methods for modeling foF2 maps over North China region

Comparison of the Kriging and neural network methods for modeling foF2 maps over North China region

An evaluation of a new two‐dimensional analytic ionospheric ray‐tracing technique: Segmented method for analytic ray tracing (SMART)

A two‐dimensional analytic ray tracing technique accommodating horizontal gradients

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