Results 21 to 30 of about 950 (162)

Performance Analysis of a Portable Low-Cost SDR-Based Ionosonde

Atmosphere, 2023
This work presents a software-defined radio ionosonde (ISDR) developed at the Abdus Salam International Centre for Theoretical Physics (Italy) and the Institute of Radio Astronomy (Ukraine) and installed at the Ukrainian Antarctic Station in 2017.
Oleksandr Koloskov, Anton Kashcheyev, Oleksandr Bogomaz, Andriy Sopin, Bogdan Gavrylyuk, Andriy Zalizovski   +5 more
doaj   +1 more source

New Chung-Li Ionosonde in Taiwan: System Description and Preliminary Results

Remote Sensing, 2022
In spite of being interrupted several times in its long history of operation since 1950, the routine observation of the ionosphere with various ionosondes installed at the Chung-Li ionosphere station in Taiwan has been achieved successively for more than
Kai-Jun Ke, Ching-Lun Su, Ruey-Ming Kuong, Hsyang-Chan Chen, Hung-Shi Lin, Po-Hsun Chiu, Ching-Yuan Ko, Yen-Hsyang Chu   +7 more
doaj   +1 more source

Global response of Magnetic field and Ionosonde observations to intense solar flares on 6 and 10 September 2017

E3S Web of Conferences, 2018
Intense X-ray fluxes during solar flares are known to cause enhanced ionization in the Earth’s ionospheric D, E and F region. This sudden change of ionospheric electron density profile is serious problem to radio wave communication and navigation system.
Fujimoto Akiko, Yoshikawa Akimasa, Ikeda Akihiro   +2 more
doaj   +1 more source

Algorithm for high quality ionograms [PDF]

Electronics Letters, 2000
A new ionogram algorithm, which is highly successful in generating robust and sharp digital ionograms free of artefacts and processing noise, is presented. An important feature of the algorithm is the distortionless zooming capability, which allows the user to concentrate only on the desired magnetoionic components of the ionogram.
Arikan F., Salous, S., Arikan, O.
openaire   +2 more sources

A study of O/X wave data assimilation and inversion for ionospheric vertical electron density profiles

Frontiers in Astronomy and Space Sciences
Vertical sounding of the ionosphere yields ionograms that reflects the relationship between virtual height and frequency, and electron density profiles can be obtained by inversion of the ionogram.
Longlong Niu, Chen Zhou, Na Wei, Zhong-Xin Deng, Yun Ning, Rong Chen, Wen Liu   +6 more
doaj   +1 more source

Manual Scaling of Ionograms Measured at Jeju (33.4°N, 126.3°E)

Journal of Astronomy and Space Sciences, 2018
The ionosphere has been monitored by ionosondes for over five decades since the 1960s in Korea. An ionosonde typically produces an ionogram that displays radio echoes in the frequency-range plane.
Yong Ha Kim, Ki-nam Kim
doaj   +1 more source

Variability of Weddell Sea ionospheric anomaly as deduced from observations at the Akademik Vernadsky station

Український антарктичний журнал, 2021
Ionospheric Weddell Sea anomaly is an inversion of diurnal variation of the electron density in the ionosphere over Antarctic Peninsula, Weddell Sea, and neighbor territories observed during Antarctic summer.
A. Zalizovski, I. Stanislawska, V. Lisachenko, O. Charkina   +3 more
doaj   +1 more source

Image processing of digital chest ionograms

The British Journal of Radiology, 1988
Abstract A number of image-processing techniques have been applied to a digital ionographic chest image in order to evaluate their possible effects on this type of image. In order to quantify any effect, a simulated lesion was superimposed on the image at a variety of locations representing different types of structural detail ...
J R, Yarwood, B M, Moores
openaire   +2 more sources

Fast Ionogram Observations of Ascending Thin Layers Locally Transported from the E to F Region at Equatorial and Low Latitudes

Remote Sensing, 2022
By using fast ionogram observations, we report the first simultaneous observations of ascending ion layers at equatorial and low latitudes. The ionosonde measurements at Sanya (18.3°N, 109.6°E; dip lat. 12.2°N) and Chumphon (10.7°N, 99.4°E; dip lat.
Lianhuan Hu, Guozhu Li, Zonghua Ding, Wenjie Sun, Xiukuan Zhao, Haiyong Xie, Zhengping Zhu, Tatsuhiro Yokoyama, Jiaping Lan, Zhaoguo Huang, Baiqi Ning   +10 more
doaj   +1 more source

Frequency Window With Homogeneous Time of Flight (ToF) for Near Vertical Incidence Skywave (NVIS) Propagation Determined Based on Ionograms

IEEE Access
The Multi-Carrier Modulation (MCM) technique in the Near Vertical Incidence Skywave (NVIS) propagation mode poses a challenge due to the ionosphere’s dynamic behavior.
Varuliantor Dear, Faruk Afero, Rezy Pradipta, Prayitno Abadi, Mohammad Sigit Arifianto, Iskandar   +5 more
doaj   +1 more source