We briefly describe the multifrequency multiple‐path radio system and illustrate its observationa... more We briefly describe the multifrequency multiple‐path radio system and illustrate its observational capabilities by performing, as an example, the study of dynamic processes that occurred in the ionosphere over China during the partial solar eclipse on August 11 2018. This system, based on the software‐defined radio technology and capable of operating in the 10‐kHz to 30‐MHz band, has been developed jointly by Harbin Engineering University, the People's Republic of China, where it is located, and V. N. Karazin National University, Ukraine. The principle of the system operation is based on measurements of a Doppler shift of frequency. The implementation of Marple's algorithm for autoregression spectrum analysis has permitted an increase in a Doppler resolution down to 0.02 Hz and in a temporal resolution down to 7.5 s. The number of radio propagation paths and their orientation depend on the specifics of problems being solved. The interpretation of the eclipse effects is complicated by processes launched by the dusk terminator. The eclipse was associated with an increase in the number of rays, the generation of oscillation processes in the atmospheric gravity wave range of periods, and with a negative Doppler shift of frequency at first and a positive shift of smaller magnitude subsequently. The solar eclipse launched ~9–14% amplitude quasiperiodic oscillations in the electron density, while a maximum decrease of order 26% was observed over the Hailar–Harbin path in the ionospheric E region. The latter value does not virtually differ from theoretical estimates.
. The paper deals with the effects that accompanied the Super Typhoon Kong-Rey action in the iono... more . The paper deals with the effects that accompanied the Super Typhoon Kong-Rey action in the ionosphere over the People’s Republic of China (PRC). The observations were made using the Harbin Engineering University, PRC, multifrequency multiple path coherent software defined radio system. The typhoon began on September 29, 2018 and ceased to exist on October 6, 2018. The ionospheric response to the super typhoon action was clearly observed to occur both on October 1–2, 2018 (when the typhoon was 2,800–3,300 km from the propagation path midpoints and its energy gained a maximum value) and on October 5–6, 2018 when the typhoon was 1,000–1,500 km from the midpoints and its energy decreased by a factor of about 4. The ionospheric effects are more pronounced along the nearest propagation paths, whereas no effect was detected along the propagation path at the farthest distance from the typhoon. The super typhoon action on the ionosphere was accompanied by the generation or amplification of quasi-periodic variations in the Doppler shift by a factor of 2–3, as well as by noticeable variations in the signal amplitude. The Doppler spectra were observed to broaden in a number of cases. The period of wave perturbations exhibited variability in the ~20 min to ~120 min range, which suggests that the perturbations in the ionospheric electron density were caused by atmospheric gravity waves (AGWs) generated by the typhoon; in addition, the greater the AGW period, the greater the Doppler shift. As the period increased from 20 min to 120 min, the Doppler shift amplitudes increased from ~0.1 Hz to 0.5–1 Hz, whereas the amplitude of quasi-periodic variations in the electron density increased from a few to several tens of per cent within the same range of the AGW periods. The Doppler measurements have shown that the dusk terminator and super typhoon acted synergistically to amplify the ionospheric response to these sources of energy.
. The paper deals with the variations in the Doppler spectra and in the relative amplitudes of th... more . The paper deals with the variations in the Doppler spectra and in the relative amplitudes of the signals observed at oblique incidence over the People’s Republic of China (PRC) during the partial solar eclipse of 5–6 January 2019 and on reference days. The observations were made using the multifrequency multiple path radio system for sounding the ionosphere at oblique incidence. The receiver system is located at the Harbin Engineering University campus, PRC, and 14 HF broadcasting station transmitters are used for taking measurements along the Lintong/Pucheng to Harbin, Hwaseong to Harbin, Chiba/Nagara to Harbin, Hailar/Nanmen to Harbin, Beijing to Harbin (three paths), Goyang to Harbin, Ulaanbaatar/Khonkhor to Harbin, Yakutsk to Harbin (two paths), Shijiazhuang to Harbin, Hohhot to Harbin, and Yamata to Harbin radio wave propagation paths. The specific feature of this partial solar eclipse was that it occurred during local time morning with a geomagnetic disturbance (Kp = 3–) in the background. The response of the ionosphere to the solar eclipse have been inferred from temporal variations in the Doppler spectra, the Doppler shift, and in the signal relative amplitude. The partial solar eclipse was found to be associated by Doppler spectrum broadening, up to ±1.5 Hz, alternating sign Doppler shift variations, up to ±0.5 Hz, in the main ray, and by quasi-periodic Doppler shift changes. The relative amplitude of electron density disturbances in the 15 min period atmospheric gravity wave field and in the 4–5 min period infrasound wave field is estimated to be 1.6–2.4 % and 0.2–0.3 %, respectively. The estimates of a maximum decrease in the electron density are in agreement with the observations.
2019 IEEE 2nd Ukraine Conference on Electrical and Computer Engineering (UKRCON), 2019
The data retrieved from the International Monitoring System (IMS) set up by the Comprehensive Nuc... more The data retrieved from the International Monitoring System (IMS) set up by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) are used to determine approximate relations for the basic characteristics of the infrasound signals generated by the passage and airburst of the Chelyabinsk celestial body on February 15, 2013.
2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS), 2018
Numerical simulations of disturbances in the electron temperature and density arising from the ac... more Numerical simulations of disturbances in the electron temperature and density arising from the action of ultra-short super-powerful radio pulses with different durations and powers on the Earth's atmosphere and ionosphere are presented. It is demonstrated that the electron density in the 30–60 km altitude range can be increased by 12 orders of magnitude, while the electron temperature shows an increase of the order of 10 to 100 times. The pulse durations and powers needed to create artificial ionized layers have been estimated.
2021 IEEE 3rd Ukraine Conference on Electrical and Computer Engineering (UKRCON), 2021
The aim of this study is to observe the changes in the characteristics of HF radio waves travelin... more The aim of this study is to observe the changes in the characteristics of HF radio waves traveling through the ionosphere perturbed by the super typhoon Hagibis during October 6–13, 2019 period. The measurements have been taken with the Harbin Engineering University (the People's Republic of China) multi-frequency multiple path software defined radio system. The super typhoon acted to enhance wave activity in the atmosphere and to generate wave processes with 10 to 120-min periods. The atmospheric gravity waves have been confirmed to conduct coupling within the atmosphere-upper-atmosphere-ionosphere system. The impact on the ionosphere was the largest when the super typhoon energy was a maximum, i.e., on October 8, 10, and particularly 9, 2019, and when the typhoon was at distances of ~2,500 km to ~3,000 km from the midpoints of the propagation paths. The wave processes acted to excite oscillations in the reflection level height from 30–50 km to 60–90 km. In the $F$ region, the ~20-min period harmonic in electron density changes were seen with amplitude of 10-12%, while the ~60-120-min period harmonics with amplitudes of 30-60%.
We briefly describe the multifrequency multiple‐path radio system and illustrate its observationa... more We briefly describe the multifrequency multiple‐path radio system and illustrate its observational capabilities by performing, as an example, the study of dynamic processes that occurred in the ionosphere over China during the partial solar eclipse on August 11 2018. This system, based on the software‐defined radio technology and capable of operating in the 10‐kHz to 30‐MHz band, has been developed jointly by Harbin Engineering University, the People's Republic of China, where it is located, and V. N. Karazin National University, Ukraine. The principle of the system operation is based on measurements of a Doppler shift of frequency. The implementation of Marple's algorithm for autoregression spectrum analysis has permitted an increase in a Doppler resolution down to 0.02 Hz and in a temporal resolution down to 7.5 s. The number of radio propagation paths and their orientation depend on the specifics of problems being solved. The interpretation of the eclipse effects is complicated by processes launched by the dusk terminator. The eclipse was associated with an increase in the number of rays, the generation of oscillation processes in the atmospheric gravity wave range of periods, and with a negative Doppler shift of frequency at first and a positive shift of smaller magnitude subsequently. The solar eclipse launched ~9–14% amplitude quasiperiodic oscillations in the electron density, while a maximum decrease of order 26% was observed over the Hailar–Harbin path in the ionospheric E region. The latter value does not virtually differ from theoretical estimates.
. The paper deals with the effects that accompanied the Super Typhoon Kong-Rey action in the iono... more . The paper deals with the effects that accompanied the Super Typhoon Kong-Rey action in the ionosphere over the People’s Republic of China (PRC). The observations were made using the Harbin Engineering University, PRC, multifrequency multiple path coherent software defined radio system. The typhoon began on September 29, 2018 and ceased to exist on October 6, 2018. The ionospheric response to the super typhoon action was clearly observed to occur both on October 1–2, 2018 (when the typhoon was 2,800–3,300 km from the propagation path midpoints and its energy gained a maximum value) and on October 5–6, 2018 when the typhoon was 1,000–1,500 km from the midpoints and its energy decreased by a factor of about 4. The ionospheric effects are more pronounced along the nearest propagation paths, whereas no effect was detected along the propagation path at the farthest distance from the typhoon. The super typhoon action on the ionosphere was accompanied by the generation or amplification of quasi-periodic variations in the Doppler shift by a factor of 2–3, as well as by noticeable variations in the signal amplitude. The Doppler spectra were observed to broaden in a number of cases. The period of wave perturbations exhibited variability in the ~20 min to ~120 min range, which suggests that the perturbations in the ionospheric electron density were caused by atmospheric gravity waves (AGWs) generated by the typhoon; in addition, the greater the AGW period, the greater the Doppler shift. As the period increased from 20 min to 120 min, the Doppler shift amplitudes increased from ~0.1 Hz to 0.5–1 Hz, whereas the amplitude of quasi-periodic variations in the electron density increased from a few to several tens of per cent within the same range of the AGW periods. The Doppler measurements have shown that the dusk terminator and super typhoon acted synergistically to amplify the ionospheric response to these sources of energy.
. The paper deals with the variations in the Doppler spectra and in the relative amplitudes of th... more . The paper deals with the variations in the Doppler spectra and in the relative amplitudes of the signals observed at oblique incidence over the People’s Republic of China (PRC) during the partial solar eclipse of 5–6 January 2019 and on reference days. The observations were made using the multifrequency multiple path radio system for sounding the ionosphere at oblique incidence. The receiver system is located at the Harbin Engineering University campus, PRC, and 14 HF broadcasting station transmitters are used for taking measurements along the Lintong/Pucheng to Harbin, Hwaseong to Harbin, Chiba/Nagara to Harbin, Hailar/Nanmen to Harbin, Beijing to Harbin (three paths), Goyang to Harbin, Ulaanbaatar/Khonkhor to Harbin, Yakutsk to Harbin (two paths), Shijiazhuang to Harbin, Hohhot to Harbin, and Yamata to Harbin radio wave propagation paths. The specific feature of this partial solar eclipse was that it occurred during local time morning with a geomagnetic disturbance (Kp = 3–) in the background. The response of the ionosphere to the solar eclipse have been inferred from temporal variations in the Doppler spectra, the Doppler shift, and in the signal relative amplitude. The partial solar eclipse was found to be associated by Doppler spectrum broadening, up to ±1.5 Hz, alternating sign Doppler shift variations, up to ±0.5 Hz, in the main ray, and by quasi-periodic Doppler shift changes. The relative amplitude of electron density disturbances in the 15 min period atmospheric gravity wave field and in the 4–5 min period infrasound wave field is estimated to be 1.6–2.4 % and 0.2–0.3 %, respectively. The estimates of a maximum decrease in the electron density are in agreement with the observations.
2019 IEEE 2nd Ukraine Conference on Electrical and Computer Engineering (UKRCON), 2019
The data retrieved from the International Monitoring System (IMS) set up by the Comprehensive Nuc... more The data retrieved from the International Monitoring System (IMS) set up by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) are used to determine approximate relations for the basic characteristics of the infrasound signals generated by the passage and airburst of the Chelyabinsk celestial body on February 15, 2013.
2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS), 2018
Numerical simulations of disturbances in the electron temperature and density arising from the ac... more Numerical simulations of disturbances in the electron temperature and density arising from the action of ultra-short super-powerful radio pulses with different durations and powers on the Earth's atmosphere and ionosphere are presented. It is demonstrated that the electron density in the 30–60 km altitude range can be increased by 12 orders of magnitude, while the electron temperature shows an increase of the order of 10 to 100 times. The pulse durations and powers needed to create artificial ionized layers have been estimated.
2021 IEEE 3rd Ukraine Conference on Electrical and Computer Engineering (UKRCON), 2021
The aim of this study is to observe the changes in the characteristics of HF radio waves travelin... more The aim of this study is to observe the changes in the characteristics of HF radio waves traveling through the ionosphere perturbed by the super typhoon Hagibis during October 6–13, 2019 period. The measurements have been taken with the Harbin Engineering University (the People's Republic of China) multi-frequency multiple path software defined radio system. The super typhoon acted to enhance wave activity in the atmosphere and to generate wave processes with 10 to 120-min periods. The atmospheric gravity waves have been confirmed to conduct coupling within the atmosphere-upper-atmosphere-ionosphere system. The impact on the ionosphere was the largest when the super typhoon energy was a maximum, i.e., on October 8, 10, and particularly 9, 2019, and when the typhoon was at distances of ~2,500 km to ~3,000 km from the midpoints of the propagation paths. The wave processes acted to excite oscillations in the reflection level height from 30–50 km to 60–90 km. In the $F$ region, the ~20-min period harmonic in electron density changes were seen with amplitude of 10-12%, while the ~60-120-min period harmonics with amplitudes of 30-60%.
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