Results 171 to 180 of about 1,720 (206)

Synthesis of three‐dimensional ionograms

Radio Science, 1973
A previously reported method of exact calculation of ray‐path parameters for a spherically symmetric ionosphere with its center of curvature displaced from the center of the earth is extended to permit the synthesis of three‐dimensional ionograms, i.e., group path, azimuthal angle of arrival, and elevation angle of arrival versus frequency, for a ...
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The interpretation of topside sounder ionograms

Proceedings of the IEEE, 1969
Most of the phenomena observed on Alouette I and Alouette II ionograms are identified and interpreted. Simple as well as complex ionograms are treated, but emphasis is placed on ionograms exhibiting very low electron density, spread-F and field-aligned propagation.
E.L. Hagg, E.J. Hewens, G.L. Nelms
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The analysis of night-time ionograms

Journal of Atmospheric and Terrestrial Physics, 1975
Abstract The analysis of ionospheric h′(ƒ) records can give appreciable errors at night, when large amounts of ionisation may be present with plasma frequencies less than the minimum recorded frequency ƒ min . The errors depend on both the total amount of low-density ionisation, and on the ionisation gradient near ƒ min .
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Analysis of Stress Ionograms.

1977
Abstract : Anomalous radar returns seen on ionograms following ionospheric barium releases are analyzed to determine their origin and their interpretation. Two types of echoes are identified; one type originates from the barium cloud and the other type from layers formed by the descent of barium ions into the E-region.
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Classification of spread-F ionograms

Journal of Atmospheric and Terrestrial Physics, 1962
Abstract Scaling of original ionograms obtained in the polar regions has lead to a classification scheme for spread-F ionograms. Defined are three types of frequency spreading (spreadish-F, furcated-F and spurred-F) and one type of range spreading. Each type is subdivided into species.
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A note on the analysis of oblique ionograms

Journal of Atmospheric and Terrestrial Physics, 1973
Abstract A previously reported method of analysis of oblique ionograms is reformulated to enable an exact ray-calculation analysis of the oblique ionograms using only the assumptions of spherically symmetric ionosphere concentric with the Earth and neglect of the Earth's magnetic field.
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Image understanding of oblique ionograms: the autoscaling problem

1996 Australian New Zealand Conference on Intelligent Information Systems. Proceedings. ANZIIS 96, 2002
The paper presents an image understanding system for oblique ionograms, which are a two dimensional measurement of the high frequency properties of the ionosphere. The system for image understanding of oblique ionograms (called "autoscaling") presented here involves three stages.
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The stability of ionogram analysis techniques

Journal of Atmospheric and Terrestrial Physics, 1982
Abstract Ionograms commonly contain discontinuities or cusps in the virtual-height trace. These produce spurious oscillations in the calculated real heights, when second or higher order analysis techniques are used. The magnitude of this effect is studied using basic discontinuities and model ionograms.
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ionogram, n.

2023
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Deep-learning for ionogram automatic scaling

Advances in Space Research, 2020
Libo Liu, Jian Wang, Zhuowei Xiao
exaly