Results 171 to 180 of about 5,388 (217)

Comparison of IRI-2016 model-predictions of F2-layer peak density height options with the ionosonde-derived hmF2 at the equatorial station during different phases of solar cycle

Advances in Space Research, 2019
We have investigated the performance of 2016 International Reference Ionosphere (IRI) at equatorial Ouagadougou (12.4°N, 358.5°E; dip latitude: 1.5°N), Burkina Faso station, using 4 years 5 months of hourly monthly median M(3000)F2 values from January to
O. S. Oyekola
semanticscholar   +1 more source

Coincident Airglow, VHF Radar, and Ionosonde Observations of Electrified Medium‐Scale Traveling Ionospheric Disturbances in the Equatorial Latitudes

Geophysical Research Letters, 2019
The occurrence of late night spread F in the low and equatorial latitude regions during solar minimum is not properly understood. Radar observations have revealed occurrence of postmidnight echoes at low and equatorial latitudes during solar minimum ...
V. L. Narayanan, A. Patra, S. Gurubaran, P. Pavan Chaitanya, K. Emperumal   +4 more
semanticscholar   +1 more source

Digital spacecraft ionosondes

Advances in Space Research, 1981
Abstract In cooperation with RCA, Astro-Electronics Division, a digital spacecraft ionosonde has been developed and its prototype built by ULCAR. On-board use of the Direct Discrete Fourier Transform for signal-to-noise enhancement, suppression of unwanted echoes and the identification of echo properties permit several applications.
openaire   +1 more source

Legendre coding for digital ionosondes

Radio Science, 2005
A 1019 bit Legendre code was evaluated for use in digital ionosondes. Experimental testing was done using the Canadian Advanced Digital Ionosonde (CADI). Theoretically, the 1019 Legendre code autocorrelation function of this new sequence has very low peak sidelobe level of −32.6 dB, and the system signal‐to‐noise‐ratio (SNR) will be improved by 30 dB ...
J. Huang, J. W. MacDougall
openaire   +1 more source

A computational tool for ionosonde CADI's ionogram analysis

Computers & Geosciences, 2013
The purpose of this work is to present a new computational tool for ionogram generated with a Canadian Advanced Digital Ionosonde (CADI). This new tool uses the fuzzy relation paradigm to identify the F trace and from this form extract the parameters foF2, h'F, and hpF2. The tool was very extensively tested with ionosondes that operate at low latitudes
Valdir Gil Pillat, Lamartine Nogueira Frutuoso Guimarães, Paulo Roberto Fagundes, José Demísio Simões da Silva   +3 more
openaire   +1 more source

Combination of ionosonde and riomethr data for absorption measurements

Journal of Atmospheric and Terrestrial Physics, 1976
Abstract A method is described for combining ionosonde and riometer data which overcomes limitations in both techniques for the measurement of normal absorption in the lower ionosphere. The usefulness of these techniques is thereby considerably increased.
Kressman, R.I., Piggott, W.R.
openaire   +2 more sources

Virtual ionosonde network in conjugate hemisphere

2011 XXXth URSI General Assembly and Scientific Symposium, 2011
The global ionosonde network distribution is uneven concentrated on land with gaps over the oceans. Figure 1 demonstrates percentage latitudinal distribution of the critical frequency foF2 provided by global ionosonde network with data volume dominating in Zone 1 (50 to 60°N) and Zone 2 (35 to 45°N) of the Northern hemisphere.
T. L. Gulyaeva, F. Arikan, I. Stanislawska   +2 more
openaire   +1 more source

Vertical Sounders — the Ionosonde

1991
One of the first measurements of ionospheric layer height was reported by Appleton and Barnett in 1926, who used a continuous wave transmitter and a receiver located from 65 to 130 km distant from the transmitter. The ground wave and the skywave arrived at the receiver with a relative phase difference.
openaire   +1 more source

Preliminary observations with a directional ionosonde

Planetary and Space Science, 1971
The addition of three spaced aerials and minor instrumentation to a conventional ionosonde permits the measurement of the angle-of-arrival of ionospheric reflections. Such a directional ionosonde (which is essentially a swept-frequency interferometer) is described, together with a derivation of the formulae relating the angles-of-arrival to the ...
openaire   +3 more sources

The ionosphere response to severe geomagnetic storm in March 2015 on the base of the data from Eurasian high-middle latitudes ionosonde chain

Journal of Atmospheric and Solar-Terrestrial Physics, 2017
In the paper we study the ionosphere response to the March 2015 severe geomagnetic storm according to Eurasian high-middle latitude ionosonde chain. On the basis of the ionosonde chain data we have restored the time/longitude dynamics of the high-middle ...
B. Shpynev, N. Zolotukhina, N. Polekh, K. Ratovsky, M. Chernigovskaya, A. Belinskaya, A. E. Stepanov, V. Bychkov, S. Grigorieva, V. Panchenko, N. A. Koren’kova, J. Mielich   +11 more
semanticscholar   +1 more source