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DEPLOYMENT OF A MODERN STANDARD IONOSPHERIC STATION

 

V. A. Shapstev, L. S. Terekhov

Russian Academy of Science, Institute for Informatics Technologies and Applied Mathematics, 28 Andrianov str., 644077, Omsk, RUSSIA

Introduction

Nowadays the world community is moving from an armaments race to the solution of ecological problems. Some technological processes are accompanied with negative and even dangerous effects (eg. radioactive precipitation, ozone holes etc.) which have global effects. Strategic solutions to these problems are required for the future of humanity. In particular, fundamental ecological ways of thinking, such as being ecological professionals by means of international information exchange, national and international ecology education networks and international financial support for ecology projects via the NATO and European Community. A worldwide system of ecological monitoring is being created [1].

In this connection, a project for an optimised global ionospheric monitoring network is very important [2,3]. Often the ionosphere - the upper part of the Earth's envelope - is very sensitive to processes occurring on the Earth and in its atmosphere.

In addition to a global network [2], new arguments are suggested for the deployment of a model ionospheric sounding station in Omsk (55 N, 73 W) Russia as part of a global ionosonde network.

Unique geographical location of the city of Omsk

The geographical latitude of Omsk is 55 north, ie. the city is situated nearly in the middle of the latitude region 30 -70 north, where the D layer winter anomaly is observed. The phenomenon of the winter anomaly at this latitude is expected to manifest itself especially clearly. Omsk is situated at the bottom of a land plain, which is the greatest on our planet, far from sea and mountain discontinuities. If we start from the modern hypothesis that middle atmospheric processes form the ionospheric winter anomaly, then this phenomenon can be investigated in the Omsk region free from terrain discontinuity effects that can create distortions in the regular transfer of atmospheric mass.

The background electro-magnetic noise level is relatively low at Omsk because it is situated far from powerful sources of atmospheric noise (eg. the Indian Ocean lightning centre) and far from radio transmission centres which are usually located at sea ports.

Scientific Potential of the City of Omsk

Ionospheric monitoring data are useful for both fundamentally scientific and practical applications. Geophysicists who specialise in predicting global environmental change carry out fundamental investigations of ionospheric behaviour. The practical applications of monitoring data are in the control of rising noise levels, seismic activity electromagnetic precursor detection [4] and ozone hole observation networks etc. Modern HF communication systems urgently need more detailed and timely information on ionospheric structure and dynamics.

Omsk is a large scientific Center in the field of radio investigations, with many scientific personnel in radio physics and radio engineering. There are several research and development enterprises and educational institutions in Omsk, eg. State Engineering University, Omsk State University and Institutions of the Russian Science Academy which need ionospheric sounding data while being themselves able to carry on the development and manufacture of ionosondes. Much high level ionospheric research has previously been carried out demonstrating the competence of Omsk engineers and scientists. For example, a theoretical analysis of ionospheric sounding was carried out and a systematic error was revealed in virtual height h' measurements. Apparently, this error is a characteristic feature of all modern methods of radiowave sounding in a non-uniform plasma layer. This error is especially large in the vicinity of the layer critical frequency. But in the vicinity of the ionospheric F2 layer, the value of the virtual height h' itself is bigger and masks the h' measurement error. This diverted the attention of the researchers from this kind of error. Taking this into account, a procedure was suggested for ionospheric plasma sounding that provides the possibility of reducing the h' measurement errors in the vicinity of foF2 by an order of magnitude [5]. This theoretical research needs experimental confirmation using a research ionosonde.

Earlier (in one of the first Russian ionospheric laboratories in the city of Tomsk) a procedure for a more precise determination of critical frequency of a non-stationary foF2 layer was developed. This procedure was based on the Doppler effect and also needs confirmation by means of a research ionosonde [6].

The precise determination of both virtual height and foF2 will provide the basis for quick ionospheric prediction, including recognition within seconds if sudden ionospheric disturbances occur caused by solar flares. Secondly, it would be possible to determine the fine structure of an HF ionospheric communication channel which in turn will increase its carrying capacity.

Some investigations were carried out in Omsk to study the multi-ray structure of decametric wave propagation. For this purpose, the sounding of an Omsk-Moscow radio route with wide-band (40 kHz) signals was used [7]. As a result, a dynamic multi-ray propagation map was obtained over a typical latitude route about 3000 km long [8].

Substantial experience was accumulated concerning radiometer complex construction for the continuous measurement of interference and of propagation for decametric radio waves. The construction was also used for the mixed-level simulation of communication conditions to assist the computer-aided testing of radio receiving devices [9].

The continuous monitoring of the ionospheric D layer is performed to register electromagnetic precursors of earthquakes [4].

For a long time, radio channel and network simulation has been carried out in Omsk. A subsystem for signal parameter calculation, based on sounding data, is a part of a programmed system for the hierarchal simulation of radio network information [10, 11]. There are several radio industry enterprises in the city HF-VHF communication systems, such as point-to-point radio receiver devices, frequency synthesisers and crystal oscillators.

Station Hardware

The functional circuit of an ionosonde which is supposed to decrease virtual height h' measurement errors by an order of magnitude cannot be published just now because it is the subject of a Patent Application which is now under consideration by the Russian Federation Inventions Committee.

The Omsk Ionospheric State (OIS) functional tasks and hardware structural composition are a matter for special design work. Our opinion is that the station should have the following component parts:

a modern research ionosonde similar to the Dynasonde with programmed functions;

a means for accumulating a data bank accessible at least in the Western Siberian Region;

a computer work station intended for the simulation of ionospheric dynamics,

ionospheric sounding procedure algorithms for adapting communications to ionospheric conditions;

computer simulators or trainers for schoolchildren and students.

Conclusion

The Omsk community is interested in work associated with ionospheric parameter measurements. The following topics are investigated:

HF radio communication systems simulation;

experimental investigations of seismotectonic phenomena affecting the lower ionosphere and thus MF and LF propagation in order to develop earthquake prediction methods;

new designs for prospective HF radio communication systems intended for underpopulated regions.

Obviously the deployment of a new but not very modern ionospheric station or the dislocation of an old one (eg. from Tomsk or Novosibirsk) is pointless. Those stations are at the end of their natural life and are obsolete.

Starting from zero makes it easier to create an effective work program for future years. That is why we are in favour of the creation of a new Center of fundamental geophysical investigation in Omsk, a place that is quiet in seismic terms.

The problem of obtaining personnel for a future Omsk Ionospheric Station is also worth a mention. We should begin the training of staff right now. For this purpose, it is expedient to begin a joint program of Dynasonde software development. In the course of program development, our research workers will master the new equipment. New creative and business relations will help to develop network operations using modern ionosondes.

References

1. XXI Century Agenda. An Environmental and Development Conference, Rio-de-Janeiro, 3-14 July 1992.

2. J. W. Wright and A. K. Paul. Toward Global Monitoring of the Ionosphere in Real Time by a Modern Ionosonde Network. NOAA ERL SEL, US. Dept. of Commerce, NOAA/ERL (Boulder, Colorado 80303), July 1981, 61p.

3. INAG Bulletin 48, August 1986.

4. I. L. Guffeld, V. F. Marenko, E. A. Ponomarev and V. S. Yampolskyi, Issledovaniya D-oblasti ionosferi metodom naklonnogo zondirovaniya na sverchdlinnikh volnakh Poisk elektromagnitnikh predvestnikov zemletryasenii - Moskow: Institute for Earth Physics, AS of USSR, 1988 - P.150-168.

5. L. S. Terekhov, V. E. Zelenkov and V. A. Shaptsev. Russian Federation Investion Claim N92004925/09. Data of priority - November 5, 1992.

6. L. S. Terekhov, B. B. Borisov, S. L. Sokolnikov and Y. E. Tarashchuk, USSR Invention Certificate N 1493938. Date of priority - July 7, 1987.

7. E. S. Poberezgskii, Optimalnaya filtraciya signalov zondirovaniya v nebelom shume Radiotechnics 1977, No. 5 - P.91-93.

8. E. S. Poberexgskii, Optimalnaya tipitschnikh korotkovolnovikh trass Technika Sredstv svyazi, Technika radiosvyazi, 1979, No. 8-P.86-92.

9. V. A. Shapstev. Ob odnoi funkcii raspredeleniya ogibayuschei summarnikh radiopomekh Problemi kibernetiki - Tomsk: University, 1963, No. 64 - P.166-173.

10. V. B. Shulman, V. A. Shaptsev, V. A. Filimonov, Y. P. Tokarev, T. S. Kolobanova and A. V. Elciov-Stelkov, Sovremennoe sostoyanie i napravleniya razvitiya modelioovaniya radiokanalov Tecknika sredstv svyazi, Sistemi svyazi, 1990, No. 6 - P.46-53.

11. Panov S. A., Y. P. Tokarev and V. A.Shapstev, Multi Level Modelling of Communication Networks Using Radio Channels Proceedings of the Int. Conf. on Functionability Problems of Comm. Networks, 2-6 Sept. 1991 - Novosibirsk, 1991 - P. 150-157.

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