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Abstract

Meteor radio technology /oral 7th Oct at 10 h 10 m /

Svitlana Kolomiyets

Kharkiv National University of Radio Electronics, Kharkiv, Ukraine

Objectives Results

Meteor Radio Technologies initially served geophysics andcommunications. At the same time, well-developed meteor astronomy isrequired to successfully service meteor geophysics and meteorcommunications. A radar meteor echo is the radar scattering signaturefrom the free-electrons in a plasma trail generated by entry ofextraterrestrial particles into the atmosphere. Three categories ofscattering mechanisms exist: specular, nonspecular trails, and head-echoes. Traditional VHF meteor radars (often called all-sky radars)primarily detect the specular reflection of meteor trails travelingperpendicular to the line of sight of the scattering trail, while High Powerand Large Aperture (HPLA) radars efficiently detect meteor head-echoes and, in some cases, non-specular trails.

Specular trail. Measurements of this type are classified as classicalmeteor radio technology starting 1950th till now. They are / were used inSKiYMET radars[3] and the Kharkiv meteor radar system “MARS” [10].

Head-echo. Since the 1990s, head echo observations have beenconducted utilizing most high-power large-aperture (HPLA) radarfacilities around the world, e.g. the 46.5 MHz MU radar [9]. Dualfrequency measurements of common meteor head echoes were carriedout with the VHF radar MAARSY (53.5 MHz) and the UHF EISCAT(930 MHz) radar [4.9]

The enhanced design of the Southern Argentina Agile Meteor Radar(SAAMER) deployed at the Estacion Astronomica Rio Grande (EARG)in Tierra del Fuego, Argentina has the ability to apply differenttechnologies on a single instrument, which adds value to scientificresults. Transmitting frequency32.55MHz; Peak60 kW; PRF 1765 Hz [5];

Forward scattering of VHF radio waves by the meteor ionized trailsincorporates unique characteristics for usage in various applications. Theoblique incidence of radio signals off the meteor trails enables thedetection of faint meteors using low power transmitters. Currently, it iswidely used in amateur observations, including for the organization ofobservation radio networks [17]. It is professionally used in meteorcommunications and in metrology of time and frequency scales. Thereare forecasts for a great future in professional astronomical research too.

Conclusion

References

Contact

Dr. Kolomiyets, Svitlana

E-mail: svitlana.kolomiyets@nure.ua

BL Kashcheyev Radio Astronomy Research Laboratory, SRD,

Kharkiv National University of Radio Electronics, 14 Nauky ave.,

Kharkiv 61166, Ukraine Web: nure.ua

1 . Brown P. et.al. (2005) The velocity distribution of meteoroids at the Earth as measured by the CanadianMeteor Orbit Radar (CMOR). Earth, Moon, and Planets.

2. Ellyett C.D., Davies J.G. (1948)Velocity of meteors measured by diffraction of radio waves from trailsduring formation. Nature, 161, 596-7

3 Hocking W.K. , Kolomiyets S.V. (2020) Radio meteor physics – a comparison between techniques from 1945to the mid-1970's. Radiotekhnika, 2(201), 78–90.

4. Janches D. et al. (2020) Characteristics of very faint (+16) meteors detected with the Middle AtmosphereALOMAR Radar System (MAARSY). Icarus, 340, p. 113444. Elsevier

5. Janches D. et al. (2013) Interferometric Meteor Head Echo Observations using the Southern Argentina AgileMeteor Radar (SAAMER). NASA Technical Reports Server (NTRS)

6 .Jones, J., Webster, A. R., Hocking W. K. (1998) An improved interferometer design for use with meteorradars. Radio Science, Vol. 33, 1, 55-65.

7.Kahscheyev B.L. et al.(1996) Meteors today.-K.:Technika,195. In Russian

8. Kashcheyev B.L (1960) Radar observations of meteors according to the program of the InternationalGeophysical Year . Research of the ionosphere and meteors. Digest of articles. Section V of the IGY program(Ionosphere and Meteors) Moscow: Publishing House of the USSR Academy of Sciences, 2, 40–53.

9 Kero J., Szasz C., and Nakamura T (2013) MU head echo observations of the 2010 Geminids: radiant, orbit,and meteor flux observing Ann. Geophys., 31, 439–449.

10. Kolomiyets S.V. (2012) Kharkiv automated meteor radio system “MARS”: Its historical significance inradio astronomy. 22nd International Crimean Conference "Microwave & Telecommunication Technology“ ,46-47.

11. Kolomiyets S.V. (2018) Meteor sky in Time-Domain Astronomy, Proceedings of theInternational Astronomical Union 14 (S339), 318-321

12. Lovell B. (1954) Meteor astronomy, Oxford At Claredon press, 48

13.McKay-Bukowski D. et. al. (2015) KAIRA: The Kilpisjärvi AtmosphericImaging Receiver Array—SystemOverview and First Results. IEEE Transactions on geoscience and remote sensing, 53, 3, March 2015

14. Villard O.G., Peterson A.M. (1953) Meteor Scatter.A Newly-Discovered Means for Extended-Range Communication in the 15- and 20-Meter Bands. April 1953QST 11-15,124,126.

15 Webster A.R. et al.( 2004) The Canadian Meteor Orbit Radar (CMOR), Atmos. Chem. Phys. Disc 4, 1181-1201.

Web recourses

16. https://www.imo.net/resources/faq/

17. http://www.rmob.org/index.php

18. https://openarchive.nure.ua/handle/document/39

19. https://kashcheyevseminar.org.ua/en/list-of-participants/

Meteor radars continuously send radio pulses into the sky and look for returned signalswith the characteristics of a meteor trail. Meteor radio technology can also use externalsources of radiation. Both the first and second statements mean that there is a partialpollution of the frequency range (25-30MHz et.al.). In the same time, due to the fact thatthe use of radio frequencies is a strictly controlled process, meteor radar, if usedcorrectly, has the right to exist and perform its important research functions. There aremany advanced modern instruments, e.g. SAAMER (32.5 MHZ), CMOR (29.85 MHz),MAARSY (53.5 MHZ). Also used such as MU radar (46.5 MHz), EISCAT (930 MHz).

Meteor observation with the forward scatter method (2; 20-75; 40-50; 150; 500 MHz)provides an alternative inspiration for low-cost study of meteors (careful application).

An important advantage of meteor radio technology is that it works day and night,even when the sky is covered with clouds or when the meteors are very weak (orartificial illumination of the sky is significant). The informational content of the radarmethod is certainly the maximum in comparison with other methods.

Meteor skies in the Earth atmosphere have at the altitudes 70-130, km, where meteortrails arise. Meteor trails are unpredictable and “random”. Radio meteor information ismore dependent on various factors of selectivity and methods of accounting for theeffect of this selectivity on statistical data are very complex.

The international GLOBMET project was a comprehensive meteor research programof the 1980s.This and other geophysical projects contributed to the development ofmeteor radio technologies.

Ukrainian radar research of meteors in Kharkiv started as part of the InternationalGeophysical Year 1957 project. Now these studies are associated with the KharkivNational University of Radio Electronics, its B.L. Kashcheyev research laboratory ofRadio Astronomy, BSRP out-of-town observer for the study of meteors as Property ofUkraine and some other units. Past radar “MARS” was connected with frequencies 36.9;22; 31.1 MHz. There is an experience of an equatorial expedition with using 36.9 MHz.

The purpose of the report is to present the features of meteor radiotechnologies in meteor science, astronomy, radio astronomy and someother areas. As well as discussion of the possible impact of meteor radiotechnologies on dark and quiet skies for science and society. The objectof research of meteor radio technologies is the meteoroid, the meteortrail and radio waves. Subject of research - scattered or reflected signaland its characteristics

It is known that the enchanting phenomenon of shooting stars in the dark

sky is associated with the formation of ionized trails that appears after the

invading from space meteoroids. In the visible range, we fix the light with

the eye (or an optical device) and astronomers need a dark sky to study

the meteor phenomenon in the visible range. Radio technologies make it

possible to study meteors day and night, even when the sky is covered

with clouds or when the meteors are very weak (or artificial illumination

of the sky is significant). In this case, as a rule, not the radio emission of

the meteor itself is recorded (the meteor's own radio emission is very

weak), but the reflected radiation of an external source from the trail.

Meteor radio technologies include semi-active and active radiolocation.

The report will pay attention to the problem of meteor radiolocation from

the point of view of pollution of certain wave ranges. At the same time,

meteor radiolocation is an important modern toolkit. The existing

contradiction will be discussed.

Fig. 6 Example of the Radio Sky at the junction of possibilities KAIRA

(Kilpisjärvi Atmospheric Imaging Receiver Array / LBA system operates

from approximately 20 to 80 MHz, since 2012 ) & others. CREDIT [13]

Fig.8 Illustrating backward and forward reflection (or "scattering") from a

meteor trail [14], which may be under-dense, over-dense, intermediate

Background

Multiwavelength astronomy allows researchers to see and hear the sky

above our head. But this is only part of our perception of the cosmos. The

hot handshake of the Universe in the form of meteor substance burning in

the atmosphere of the Earth, sometimes with the precipitation of

meteorites threatening the ecology, occurs every seconds. We are talking

about the enchanting phenomena of ‘shooting stars’, which have a

scientific name – ‘meteors’. Meteors are usually observed in the optical

range, with a range of visual vision (380 ÷750 nm). Meteors occur as a

result of the invasion of the Earth's atmosphere by meteoroids from space.

A meteoroid is a rock or particle with a limiting size of 30 mn to one

meter in diameter. The meteoroid's own radio emission is very small and

will not be considered in this report. When the meteors appears, the

density of electrons in atmosphere increase and the radio wave of high

frequency reflects. The total range of radio waves have frequencies f as

high as 300 GHz to as low as 30 Hz ( λ :10 mm÷10,000 km, f=c/ λ ).

Radio meteor technologies use a small fraction of the frequencies of this

common range. At the same time, an active source of radio emission is

required to carry out meteor measurements.

Radio meteor ground-based sounding (Fig. 1) of

the atmosphere at frequencies of 20-75 MHz is

associated with the state and dynamics of the

Earth's atmosphere at altitudes of 70 - 130 km,

the influx of meteor substance into the Earth's

atmosphere and its distribution in the

interplanetary space of the Solar System.

Information is obtained using electromagnetic

waves emitted by the transmitter and recorded

by the receiver by reflecting radio echoes from

meteor trails. In the radar method of

observing meteors, information messages are

formed as a result of the interaction of a

meteor body with the Earth's atmosphere and

the reflection of radio waves from the

resulting meteor trail (Fig.2-3). The rapid

development of meteor radio technology began

after the World War II and the International

Geophysical Year 1957 program. Theory and

practice are here [18], note Lovell [12],

Kashcheyev [8, 18-19].

Fig.1 Radio sounding

Fig. 2 [18] Radio meteor :

MARS radar data in 1967

Fig. 3 [1,18]: a) b) c) [2]

Fig.4 "Life history”: Meteoroid entering and the life phases of the

meteor trail (left). Meteor echo and its characteristics (right) [14].

Fig.5 Tasks that are solved using meteor technologies&meteor astronomy [11]

Fig.7 All-Sky Interferometric Meteor Radars (SKiYMET) are scientific

instruments used for observing meteors etc. Production till

2021: Genesis Software Pty Ltd., North Adelaide, South Australia,

Australia& MARDOC Inc., Canada (W.K. Hocking [3])

Table Parameters of Ukrainian meteor radar “MARS” et al.