Abstract
The article discusses the features of interference in sonar channels. Sonar or interference associated with the noise of the marine environment, or noisy media sonar channel communications equipment. Under noisy environments understand the noise of the sea itself (dynamic noise), ice, biological, seismic and technical noise. Noise protection act as a natural field interference, unmanageable and determines the limit of technical feasibility of reducing the intrinsic noise of the sonar channel communications equipment. Noises sonar equipment carrier communication channel due to the radiation of acoustic energy into the water over a wide frequency band due to operation of the propeller of the machines, auxiliary machinery and the hull interaction with the oncoming flow of water. By the nature of the interaction with the interference signal is classified as additive and multiplicative. Contribution of selected sources in the total field of noise depends on several factors, such as the ship's speed, placement and cowling design and so on. A quantitative assessment of the impact of interference to the reception of sonar signals characterized by the use of correlation functions or power spectra (intensity), knowing that estimated noise perceived by receiving acoustic antenna. In terms of receiving signals multiplicative noise equivalent power increase interference. They lead to a decrease in signal / noise ratio at the receiver input. However, their characteristic is that their impact, in contrast to the additive noise, cannot be compensated by increasing transmission power. Therefore, to assess the real noise immunity of signal reception and evaluation of the capacity of hydro-acoustic communication system is necessary to know the laws of the distribution of instantaneous values of the level and phase of the signal at the receiver input. A specific kind of interference is the interference associated with the manifestation of the Doppler effect. The sonar system due Doppler effect caused by relative movement between the emitting and receiving antennas. As a result of research obtained: evaluation of a one-dimensional function of the noise densityW(U), estimate of the expectationand variance of the noise .
Keywords: sonar channel, additive noise, multiplicative noise, Doppler effect, the signal amplitude and noise, and phase of the signal interference, signal / noise ratio, noise immunity, the expectation and variance of the noise
References
1. Urick R.J. Principles of underwater sound. New York, McGraw-Hill, 1975 (Russ. ed.: Uric R.D. Osnovi gidroakustiki. Leningrad, Sudostroenie Publ., 1978. 448 p.).
2. Mit'ko V.B., Evtyutov A.P., Gushchin S.E. Gidroakusticheskie sredstva svyazi i nablyudeniya [Hydroacoustic means of communication and control]. Leningrad, Sudostroenie Publ., 1982. 200 p.
3. Evtyutov A.P., Mit'ko V.B. Primery inzhenernykh raschetov v gidroakustike [Examples of engineering calculations in hydroacoustics]. Leningrad, Sudostroenie Publ., 1981. 256 p.
4. Chvertkin E.I. Gidroakusticheskaya telemetriya v okeanologii [Hydroacoustic telemetry in oceanology]. Leningrad, LGU Publ., 1978. 148 p.
5. Makarov A.A., Chinenkov L.A., sci. dir. Razrabotka printsipov i ustroistv peredachi geofizicheskoi informatsii po gidroakusticheskomu kanalu svyazi: otchet [Development of the principles and devices for geophysical data transmission on hydroacoustic communi-cation channel]. Novosibirskii elektrotekhnicheskii institut sviazi imeni N.D. Psurtseva. No. 81019632, 1982. 76 p. (In Russian, unpublished)
6. Matvienko V.N., Tarasyuk Yu.F. Dal'nost' deistviya gidroakusticheskikh sredstv [Range of hydroacoustic devices]. Leningrad, Sudostroenie Publ., 1981.
7. Evtyutov A.P., Kolesnikov A.E., Lyalikov A.P. et al. Spravochnik po gidroakustike [Reference on hydroacoustics]. Leningrad, Sudostroenie Publ., 1982. 344 p.
8. Brekhovskikh L.M., ed. Akustika okeana [Ocean acoustics]. Moscow, Nauka Publ., 1974.
9. Chernov L.A. Korrelyatsiya amplitudy i fazy pri rasprostranenii voln v srede so sluchainymi neodnorodnostyami [Correlation of the amplitude and phase of wave distribution in the medium with casual obstacles]. Akusticheskii zhurnal – Acoustical Physics, 1955, vol. 1, iss. 1, pp. 89–95. (In Russian)
10. Kovyazin V.I., Krivolapov G.I., Makarov A.A., Chernetskii G.A. Statisticheskie kharakteristiki gidroakusticheskikh kanalov dlya ADS [Statistical characteristics of hydroacoustic channels for autonomous bottom stations]. Morskaya seismologiya i seismometriya [Marine seismology and seismometry]. Moscow, Institut okeanologii AN SSSR Publ., 1989, pp. 74–80.
11. Krivolapov G.I., Poteryaeva L.A., Chernetskii G.A. Rezul'taty ispytaniya apparatury dvustoronnei gidroakusticheskoi svyazi dlya avtonomnykh donnykh stantsii [The results of the tests of the apparatus of bidirectional hydroacoustic coupling for autonomous bottom stations]. Metodika i tekhnika seismoakusticheskikh i vibroseismicheskikh issledovanii na akvatoriyakh [The methodology and technology, and vibroseis seismic-acoustic research on waters]. Ed. by V.I. Dobrinskii. Novosibirsk, VTs SO AN SSSR Publ., 1988, pp. 10–16.
12. Filippov B.I., Chernetskiy G.A. Analiz statisticheskikh kharakteristik signalov i pomekh v gidroakusticheskikh kanalakh svyazi [Analysis of statistical characteristics of signals and noises in hydroacoustic communication channels]. Vestnik Astrakhanskogo gosudarstvennogo tekhnicheskogo universiteta. Seriya: Upravlenie, vychislitel'naya tekhnika i informatika – Vestnik of Astrakhan State Technical University. Series: Management, Computer Science and Informatics, 2015, no. 3, pp. 78–84.
13. Filippov B.I. Algoritm funktsionirovaniya sistemy izmereniya distantsii s ispol'zovaniem gidroakusticheskogo kanala svyazi [Algorithm of functioning of the system of distance measurement using hydroacoustic channel of communication]. Vestnik Astrakhanskogo gosudarstvennogo tekhnicheskogo universiteta. Seriya: Upravlenie, vychislitel'naya tekhnika i informatika – Vestnik of Astrakhan State Technical University. Series: Management, Computer Science and Informatics, 2016, no. 4, pp. 87–98.
14. Filippov B.I. Energeticheskii raschet gidroakusticheskikh linii svyazi [Energy calculation of hydroacoustic communication lines]. Vestnik Astrakhanskogo gosudarstvennogo tekhnicheskogo universiteta. Seriya: Upravlenie, vychislitel'naya tekhnika i informatika – Vestnik of Astrakhan State Technical University. Series: Management, Computer Science and Informatics, 2016, no. 3, pp. 67–77.
15. Filippov B.I. Opredelenie naklonnoi dal'nosti mezhdu sudnom i donnoi stantsiei [Determination of slant range between a ship and a bottom station]. Vestnik Ryazanskogo gosudarstvennogo radiotekhnicheskogo universiteta – Vestnik of Ryazan State Radio Engineering University, 2016, no. 55, pp. 33–40.
16. Filippov B.I., Chernetsky G.A. Increase of reliability of transfer of blocks the digital information on the hydroacoustic communication channel. Journal of Siberian Federal University. Engineering & Technologies, 2016, vol. 9, iss. 4, pp. 489–499.