Open AccessIonospheric processes observed with the passive oblique-incidence HF Doppler radar
Author(s) -
Qiang Guo,
Yu Zheng,
Л. Ф. Черногор,
К. П. Гармаш,
V. T. Rozumenko
Publication year - 2019
Publication title -
vìsnik harkìvsʹkogo nacìonalʹnogo unìversitetu ìmenì v.n. karazìna. serìâ radìofìzika ta elektronìka
Language(s) - English
Resource type - Journals
ISSN - 2311-0872
DOI - 10.26565/2311-0872-2019-30-01
Subject(s) - ionosphere , doppler effect , high frequency , radio wave , radar , computer science , radio propagation , software defined radio , remote sensing , doppler radar , radio frequency , radio science , geology , physics , geophysics , telecommunications , astronomy
Urgency. The urgency is caused by the need to continuously monitor with radio instrumentation dynamic processes acting in the ionosphere, which arise due to variations in space weather, the impact of high-energy sources of natural and anthropogenic origin. To meet this challenge, V. N. Karazin National University and Harbin Engineering University specialists has developed a coherent multi-frequency multi-path radio system for obliquely probing the ionosphere. Purpose of Work. The paper illustrates the instrument capability for the study of dynamic processes arising in the ionosphere during a solar terminator, a moderate earthquake, a strong ionospheric storm, and in the cource of a partial solar eclipse.Techniques and Methodology. The system design is base on the software-defined radio (SDR) technology. The system is capable of receiving radio waves in the 10 kHz – 30 MHz band. The versatile computer software permits us to adjust the system for solving various problems. The number of the radio propagation paths and their orientation depends on the problem being solved. The premise upon which this radio system operation is based is measurements of the Doppler shift of the frequency. The autoregressive algorithm provides a 0.02 Hz root-mean-square Doppler line error and 7.5-s time resolution. Having the Doppler spectrum time dependencies for various radio paths archived, time series corresponding to various radio-wave modes undergo further processing.Results. As an example of successful instrument performance, dynamic processes operating in the course of a dusk terminator, the moderate (magnitude 5.9) earthquake on July 7, 2018, the strong ionospheric storm on August 26, 2018, and the partial (0.74 magnitude) solar eclipse over China on August 11, 2018 have been investigated. The ionospheric response to the impact of energy sources of various nature has been detected and investigated; it was accompanied by an increase in the number of rays, Doppler spectrum broadening, aperiodic and quasi-periodic variations in the Doppler shift of the frequency, generation of alternating sign variations in the electron density and wave disturbances having atmospheric gravity wave and infrasound parameters.Conclusions. The radio system located at the Harbin Engineering University campus successfully performs continuous radio monitoring of dynamic processes caused by various energy source in the ionosphere.