RADIO PHYSICS AND RADIO ASTRONOMY
type: channel
description: The Journal “Radio Physics and Radio Astronomy” (RPRA) is a peer-reviewed quarterly scientific journal of the National Academy of Sciences of Ukraine. RPRA was established in 1995. State Registration Certificate for printing mass media is КВ №1231, 02.02.1995; re-registration: КВ 25208-15148 ПР from 20.07.2022 ISSN 2415-7007 (Online) ISSN 1027-9636 (Print) Abbreviated key title: Radio phys. radio astron. DOI: https://doi.org/10.15407/rpra URL: http://rpra-journal.org.uа Language of publishing: Ukrainian, English Founders: The National Academy of Sciences of Ukraine Institute of Radio Astronomy of the National Academy of Sciences of Ukraine O. Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine Publisher: The NAS-Ukraine Academperiodyka Publishing House The NAS-Ukraine Academperiodyka Publishing House replicates the RPRA within the NAS-Ukraine Journal Support Program. RPRA publishes papers, brief information and letters to the editors relating to the modern problems of radio physics, radio astronomy and astrophysics, containing the results of fundamental and applied researches, description of research methods, hardware implementation and practical application, as well as current information such as comments, events, men of science. The RPRA is included into the List of scientific professional editions of Ukraine, approved by the Decree No. 582 of 24.04.2024 of the Ministry of Education and Science of Ukraine, in which the results of Ph.D. and Doctoral theses (in physics and mathematics) are recommended to be published. Current Issue Volume 31, No.1 (2026) CONTENT
publisher: Видавничий дім «Академперіодика»
language: en-US
publication name: RADIO PHYSICS AND RADIO ASTRONOMY
issn: 1027-9636
copyright: Since April 2018, all papers in RPRA are published under the terms of the Creative Commons Attribution 4.0 International (CC-BY) License with the authors retaining a copyright to their papers. This license permits anyone to copy, distribute, spread, and adapt the paper content, without obtaining permission from the author(s) or the Journal, provided the proper acknowledgement of the work used authorship and initial publication in this journal. Please see the full license terms and requirements at https://creativecommons.org/licenses/by/4.0/ The authors of the papers published prior to December 2018, have granted the Journal the right of the first publication and retain the copyright as the owners of the manuscript.
items: WAYS TO IMPROVE MEASUREMENT ACCURACY OF ATMOSPHERIC TRACE GAS PARAMETERS: HARDWARE AND DATA PROCESSING
items: GEOMAGNETIC NEAR FIELD DISTURBANCES AS GENERATED BY THE JANUARY 15, 2022 UNIQUE EXPLOSION OF THE TONGA VOLCANO
items: DATA ACQUISITION AND MULTITHREAD PROCESSING IN STEPPED-FREQUENCY NOISE GROUND-BASED SAR FOR 2D REAL-TIME IMAGING
items: TERRESTRIAL INVESTIGATION OF THE LOW-FREQUENCY SENSITIVITY OF A RADIO ASTRONOMICAL ANTENNA PROPOSED FOR LUNAR FAR-SIDE OBSERVATIONS OF COSMIC RADIO EMISSIONS
items: AN OPEN RESONATOR WITH INTERNAL INHOMOGENEITIES
items: In memory of Oleg I. Sukharevsky

WAYS TO IMPROVE MEASUREMENT ACCURACY OF ATMOSPHERIC TRACE GAS PARAMETERS: HARDWARE AND DATA PROCESSING
type: item
description: Subject and Purpose. Analysis of ways to increase the accuracy of determining the parameters of the Earth’s atmosphere through the improvement of the ground-based spectral radiometric complex designed for monitoring carbon monoxide (CO) by millimeter radio wave radiation control, which was developed at the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine The purpose is achieved by reducing the measurement errors of the emission amplitude of the observed tracer gas through the operational determination of the absorption of radio waves in the troposphere. By performing a rapid calibration of the troposphere opacity and promptly accounting for changes in radio signal absorption, we increase the accuracy and reliability of measurements of atmospheric CO radio emission intensity. This method is suitable for any systems of this type. By studying the frequency stability of local oscillators of all stages of frequency conversion in the receiving system, the maximum error in measuring stratospheric wind speeds at altitudes from 20 to 80 kilometers was determined. Methods and Methodology. The improved CO-monitoring setup measures radiometric atmospheric profiles, from which a new data processing method introduced in the paper quickly derives the antenna scattering coefficient. Then, the tropospheric absorption of the radio signal is evaluated immediately during monitoring in near-real time. Results. The CO-monitoring spectroradiometric complex has been upgraded and improved, enabling the measurement of radiometric atmospheric profiles and providing a prompt, near-real-time determination of the antenna scattering coefficient (previously unavailable). It has been demonstrated that monitoring the antenna scattering coefficient enhances the determination accuracy of the CO emission line amplitude, thereby increasing the reliability and validity of the obtained results. The studies related to the modernization of the monitoring instrument helped us evalu…
creator: A. M. Korolev
creator: V. V. Myshenko
creator: D. L. Chechotkin
creator: D. V. Shulga
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1
starting page: 3
doi: 10.15407/rpra31.01.003

GEOMAGNETIC NEAR FIELD DISTURBANCES AS GENERATED BY THE JANUARY 15, 2022 UNIQUE EXPLOSION OF THE TONGA VOLCANO
type: item
description: Subject and Purpose. The January 15, 2022 explosion of the Tonga volcano, unique in its power, led to significant disturbances of the Earth’s subsystems, including the lithosphere and the World Ocean — atmosphere — ionosphere — magnetosphere system, plus the geophysical fields like the baric, the electric and the magnetic. A task of great importance is a detailed study of disturbances in all the subsystems and of the fields involved, in particular, a further study of geomagnetic field component variations (and such of their derivatives) that appear to be generated in the near-field zone by the unique explosion of January 15, 2022. Methods and Methodology. To analyze temporal variations of the geomagnetic field, data records of its three spatial components have been used, specifically of the X, Y, and Z, and of their time derivatives Ẋ, Ẏ, and Ż , as recorded at geomagnetic observatories (stations) of the INTERMAGNET network during the explosion. The measurement error never exceeded 0.1 nT. The time resolution was 1 min. The records obtained on the quieter days of January 13, 2022 and January 17, 2022 have been chosen as reference data. Results. Some specific features have been identified of the near-field geomagnetic effects that accompanied the powerful explosion of the Tonga volcano. The activity led to generation of an aperiodic "bay-shaped" disturbance and a number of quasi-periodic magnetic disturbances. The "bay-shaped" synchronous disturbances in the field components X-, Y- and Z- measured at the West Samoa API station as 15 nT, 28 nT, and –13 nT, respectively, and lasted for 120 to 146 min. Their generation mechanism is associated with the formation of an ionospheric "hole" under the action of a blast wave. The time delay of the "bay-shaped" disturbances was close to 16 min. Among the quasiperiodic disturbances, the earlier ones observed at the API station demonstrated a 6 min delay time, being caused by an acoustic resonance of a 4.4 min period and a 2 nT a…
creator: L. F. Chernogor
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1
starting page: 11
doi: 10.15407/rpra31.01.011

DATA ACQUISITION AND MULTITHREAD PROCESSING IN STEPPED-FREQUENCY NOISE GROUND-BASED SAR FOR 2D REAL-TIME IMAGING
type: item
description: Subject and Purpose. In the paper, the real-time operation of the data acquisition (DAQ) system for stepped-frequency noise ground-based Synthetic Aperture Radar (SAR) is described with an emphasis on DAQ system characteristics and software in an effort to elaborate a real-time operation algorithm on this basis. Methods and Methodology. The real-time operation algorithm outlined in the paper uses Fourier analysis to process input signals acquired with the SAR receiver. The algorithm utilizes multithreading technology to achieve the required real-time performance. The validity of the proposed algorithm is evaluated against conventional signal processing algorithms and techniques using MATLAB packages for numerical analysis and graphic visualization. The experimental investigation of the proposed real-time operation algorithm as part of the software for the developed stepped-frequency noise ground-based SAR was conducted indoors via preliminary laboratory tests. Results. An algorithm for real-time data acquisition and radar imaging has been developed. Its implementation in the software for stepped-frequency noise ground-based SAR enhances the performance of the data acquisition and processing system. A comparative analysis has been performed, showing that the results obtained in the context of the proposed real-time signal-processing program align with reconstructions by standard signal-processing simulation techniques. Measurements performed with the DAQ system as part of the developed stepped-frequency noise ground-based SAR validate our approach and its particular implementation. The observations suggest good target visibility. The target resolution in range and azimuth provided by a 32-element antenna array exceeds that of the 16-antenna configuration. The multithreading approach essentially reduces software runtime. As a result, making a single radar image takes about 10 milliseconds. Conclusions. It has been shown that the developed data acquisition and processi…
creator: K. Lukin
creator: D. Tatyanko
creator: O. Zemlyaniy
creator: V. Palamarchuck
creator: M. Zaets
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1
starting page: 26
doi: 10.15407/rpra31.01.026

TERRESTRIAL INVESTIGATION OF THE LOW-FREQUENCY SENSITIVITY OF A RADIO ASTRONOMICAL ANTENNA PROPOSED FOR LUNAR FAR-SIDE OBSERVATIONS OF COSMIC RADIO EMISSIONS
type: item
description: Subject and Purpose. Theoretical and experimental studies of an active antenna element, seen as a part of the future low-frequency radio telescope for an observatory on the lunar far-side. The project is focused on design simplification. The objective of the research is to provide for a high fl uctuational sensitivity of the telescope while minimizing antenna’s mass and dimensions, thereby facilitating its delivery and deployment on the lunar surface. Methods and Methodology. To develop an antenna element up-scaled from the GURT prototype for 4...40 MHz, it was proposed to exclude the three-meter vertical support, using the arms of the crossed dipoles as load-bearing elements. Effectiveness was evaluated through estimating the antenna’s sensitivity, specifi cally by applying the criterion which proceeds from estimates of excess of the external over the internal noise temperature. Terrestrial experiments used short-wave radio noise as a virtual "free generator", which allowed determining characteristics of the antenna over a wide frequency range. This method enabled evaluating the antenna’s operation under actual interference conditions governed by the state of ionospheric layers D and F2. Results. Numerical analysis and measurements showed that the proposed design, devoid of the support rack, does not significantly degrade the antenna’s sensitivity, allowing efficient reception in the 7...40 MHz range. Experiments also demonstrated possibility of operation below 7 MHz, although terrestrial effectiveness is limited by local radio interference. Under lunar conditions, where such interference is absent, additional prospects for efficient observations are open. The data confirm the antenna’s ability to follow the impact of geophysical phenomena on ionospheric parameters. Conclusions. The results confirm effectiveness of the simplified active antenna design and suitability for lunar missions. The antenna can be employed for monitoring solar radiation and studying space r…
creator: I. M. Bubnov
creator: O. O. Stanislavsky
creator: S. M. Yerin
creator: P. L. Tokarsky
creator: O. O. Konovalenko
creator: L. O. Stanislavsky
creator: O. S. Belov
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1
starting page: 35
doi: 10.15407/rpra31.01.035

AN OPEN RESONATOR WITH INTERNAL INHOMOGENEITIES
type: item
description: Subject and Purpose. Investigations on axially symmetric oscillations excited in a hemispherical open resonator (OR) are presented with a specific focus on the effects exerted by internal inhomogeneities in the OR structure. In this context, a waveguide section is inserted in the center of one of the OR mirrors, and the field distributions of axially symmetric oscillations and the OR oscillation spectrum selection are examined. The motivation behind this study is to minimize the geometric size of the inserted waveguide while still accommodating a small-diameter dielectric sample, thereby ensuring that the measurement results are as little affected by diffraction loss as possible. Methods and Methodology. The electric-field distribution of OR eigenoscillations is studied in the framework of quasi-optic methods of probe perturbations. The OR resonance characteristics and the physical phenomena occurring within the OR are examined using established and validated techniques to measure transmission coefficients along the EHF path. Results.It has been established that in a circular waveguide with radius ɑ = 0.6042w0 (w0 is the TEM00q mode field spot radius), the TE11 mode is excited with an efficiency of 0.8993 by the central spot of the TEM10q mode. The oscillation amplitude distribution was measured at a frequency of 74.98 GHz. The axial symmetry of the OR structure is broken, but axially symmetric oscillations are still excited due to the flat insert. The circular waveguide section provides angular selection of the oscillation spectrum. The loss introduced by this waveguide to the OR does not exceed −2 dB. Conclusions. A hemispherical open resonator incorporating specific inhomogeneities that facilitate axially symmetric OR oscillations has shown potential for measuring the electrophysical parameters of materials. For this, a disk-shaped sample is placed at the bottom of a circular waveguide section inserted into the OR flat mirror in its center. Keywords: extremely hi…
creator: I. K. Kuzmychov
creator: O. S. Lukash
creator: O. A. Voitovych
creator: Yu. V. Prokopenko
creator: G. I. Churyumov
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1
starting page: 64
doi: 10.15407/rpra31.01.051

In memory of Oleg I. Sukharevsky
type: item
description: In memory of Oleg I. Sukharevsky
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-03-24
publication date: 2026-03-24
volume: 31
number: 1