RU2593673C2 - Radio-hydroacoustic system for parametric reception of waves of sources and phenomena of atmosphere, ocean and earth's crust in marine environment - Google Patents

Abstract

FIELD: hydrophysics.

SUBSTANCE: invention relates to hydrophysics, geophysics and radio physics and can be used when generating spatially developed pervious radio hydroacoustic monitoring systems of acoustic and hydrodynamic and electromagnetic fields generated by artificial and natural sources, hazardous effects of atmosphere, ocean and Earth's crust in frequency band covering hundreds-tens-units-fraction of Herz, including extremely low frequency vibrations of moving objects and irregularities of marine environment. Summary: radio-hydroacoustic system for parametric reception of waves of sources and effects of atmosphere, ocean and Earth's crust in marine environment includes: installed on opposite boundaries of controlled medium radiating and at least three receiving acoustic transducers connected to radiating and receiving paths, respectively, formed between them three zones of nonlinear interaction pervious and information waves. Proposed radio-hydroacoustic system differs by fact that working zone of nonlinear interaction and parametric conversion pervious and information waves formed in vertical plane medium as multi-beam spatially developed transmissive parametric antenna. For this purpose there are three omnidirectional radiating transducers, vertically arranged in centre of water area and installed on axis, below and above axis of underwater audio channel (UAC). Receiving transducers are integrated into three identical units arranged in vertical plane along isosceles triangles, which are arranged relative to axis UAC similarly radiating units and are arranged in circle and (or) perimeter on opposite boundary of water area. At that, output of receiving channel through transmitting radio unit is connected to information-analytical centre, which output via radio channel is connected to radiating channel signal generation system. Multichannel scanning parametric system is formed as complex vertical multi-beam parametric antennas, arranged in circle or perimeter of water area through 45° and directed radially from radiating center to periphery. Distance between acoustic transducers receiving units in vertical plane is set in accordance with correlation characteristics of structure of transmissive acoustic field. Transmissive radio-hydroacoustic system can be scaled (increased) by combination of measured information with similar subsystems, formed on adjacent water areas, in information-analytical centre using radio communication channels. Frequency band of received waves of different physical nature is hundreds-tens-units-fraction of Herz, including extremely low frequency vibrations of moving objects as whole.

EFFECT: technical outcome is far parametric reception in marine environment waves of different physical nature (acoustic, electromagnetic, hydrodynamic) generated by natural and artificial sources, phenomena and processes of atmosphere, ocean and Earth's crust.

4 cl, 15 dwg

Description

The invention relates to hydrophysics, geophysics and radiophysics. It is intended for the formation of spatially-developed translucent radio-acoustic systems for monitoring acoustic, hydrodynamic and electromagnetic fields generated by artificial and natural sources, as well as dangerous phenomena of the atmosphere, ocean and earth's crust. The frequency range of the measured fields is hundreds, tens, units, or fractions of hertz, including ultra-low-frequency (ELF) waves formed by vibrations of moving objects and inhomogeneities of the marine environment as a whole.

The development of sonar systems for monitoring the fields of objects and the environment based on receiving parametric antennas (PAP) in Russia, as well as in foreign countries (mainly in the USA and Japan), was intensively carried out as far back as the last century. In Russia, parametric antennas were developed and successfully implemented by acoustics of the Taganrog Polytechnic Institute, which has been widely published in publications of various levels and set out in monographs (Novikov B.K., Timoshenko V.I. Parametric antennas in sonar. - L .: Sudostroenie, 1990. S. 17-40, 203-225). Parametric antennas and their radio engineering systems are based on the use of the natural nonlinear properties of the marine environment. In extended PAP towed by sea vessels, in addition to the nonlinear properties of the marine environment, nonlinear properties of the wake area of the carrier vessel are used. In all these cases, only high-frequency acoustic pumping of the medium was used, the frequency of which was tens, usually hundreds of kHz. Parametric antennas have expanded the ability to receive information waves in the low-frequency region, as well as increased the sensitivity of reception of such waves. At the same time, the wave reception range in systems with high-frequency parametric antennas remained insignificant and amounted to hundreds of meters and, in some cases, more than one kilometer. The main disadvantages of parametric systems with high-frequency receiving antennas are the limited range of reception of information fields and the limited ability to measure their spatio-temporal characteristics.

We formulate the fundamental disadvantages of high-frequency parametric antennas, which must be eliminated in the present invention.

1. The small volume of the working zone of the nonlinear interaction of the pumping medium waves and the measured information waves, which especially limits the possibility of efficient reception of waves of the infra-low and fractional frequency ranges that are formed by phenomena in the atmosphere, ocean and the earth's crust.

2. The small length of the parametric antenna and the formation of its volume only near the receiving units, which also limits the possibility of distant reception of information signals as waves of "small amplitudes".

3. The laws of multipath propagation of medium pumping waves and information waves along extended paths are not used, which, in turn, does not provide efficient parametric reception of information waves generated in the air and sea environment, as well as in the bottom soil due to their interaction with translucent waves on long routes of their distribution.

4. There is no controlled relationship between the operation of the emitting and receiving paths of the monitoring system, preferably via radio channels. This excludes the possibility of promptly adjusting the operating modes of the system to the changing environmental conditions of the propagation of translucent waves, as well as to the manifold manifestation of the measured information waves.

The elimination of these shortcomings and the achievement of new positive effects in the present invention can be achieved on the basis of scientific and technical developments of nonlinear translucent hydroacoustics due to the formation of a low-frequency translucent monitoring system as a spatially developed multipath parametric antenna, commensurate with the volume and length of the monitored water area, which is presented in the following statement of application materials.

Known sonar system that implements a method of parametric reception of waves of various physical nature in the marine environment (patent No. 2474794 RU, IPC G01H 3/00, G10K 11/00, dated 06/15/2011). The hydroacoustic system for parametric reception of waves of various physical nature in the marine environment includes emitting and receiving acoustic transducers spaced apart on opposite boundaries of the controlled environment, a working zone of nonlinear interaction and parametric conversion of translucent acoustic and information waves of various physical nature, connected to the transducers, respectively radiating path, which includes series-connected blocks of formiro a receiver of stabilized frequency luminescent signals, a power amplifier and an acoustic transducer (emitter) of medium illumination signals, as well as a path for receiving nonlinearly transformed luminal waves, which includes series-connected blocks of a two-channel amplifier of luminous signals in a parametric conversion band, a phase difference meter, a frequency converter - time scale to the high-frequency region, narrow-band spectrum analyzer, information signal recorder (recorder EPA). Identification of the allocated information signals is carried out taking into account their time-frequency and parametric transformations in the receiving path and the marine environment.

The closest in technical essence to the claimed invention is a hydroacoustic luminaire system that implements a method for parametric reception of waves of various physical nature in the marine environment (RU patent No. 2474793, IPC G01H 3/00, G10K 11/00, dated 06/15/2011). The hydroacoustic system for parametric reception of waves of various physical nature in the marine environment includes emitting and three receiving acoustic transducers located at opposite boundaries of the controlled marine environment, three zones of nonlinear interaction of the luminal and information waves (luminous parametric antennas) connected to the emitting and receiving converters, respectively, as well as the radiating path of the system, which includes series-connected blocks of pho signal stabilizer of the stabilized sound frequency, power amplifier and acoustic transducer (emitter) of the medium illumination signals, as well as a path for receiving nonlinearly transformed luminous waves, which includes series-connected blocks: a three-channel amplifier of luminous signals in the parametric conversion band, a frequency-time converter in the high-frequency region , a narrow-band spectrum analyzer and a registrar (recorder) functionally associated with it; the outputs of the receiving converters are also connected to the inputs of the unit for measuring the functions of correlation of signals between the middle and extreme receivers, then to the unit of the function of their mutual correlation and the registrar. The identification of the information waves generated during the analysis is carried out taking into account the time-frequency and parametric transformations of the luminal waves in the receiving path of the system and in the working area of the medium. Considered hydroacoustic system is selected as a prototype, but has drawbacks that will be eliminated in the claimed invention. Based on this, we consider their essence.

The disadvantages of the prototype system and the above hydroacoustic system are the limited capabilities of the parametric reception of waves generated in the atmosphere, ocean environment and the earth's crust, including those formed outside the zone of placement of the parametric lumen system. This is also expressed in the insufficient sensitivity of reception and, as a result, in the range of reception, but it is especially characteristic when receiving waves entering the marine environment from the atmosphere and the earth's crust (sea soil). The problem of adjusting the operating modes of the emitting and receiving paths of the monitoring system to the changing environmental conditions of the propagation of translucent waves and to the manifold manifestation of sources of information waves is also not being solved. The main reason for these shortcomings is that the luminal monitoring system is not considered as a spatially developed in terms of volume and extent of the medium multi-beam parametric antenna, which uses the laws of multipath wave propagation along long sea routes in the observed sectors of the controlled area.

The problem to which the claimed invention is directed is to increase the range of the parametric reception of information waves generated by natural and artificial sources, as well as processes and phenomena of the atmosphere, ocean and the earth's crust in the sound, infrasound, fractional and ultra-low-frequency (ELF) ranges. The adjustment of the agreed mode of operation of the emitting and receiving paths of the monitoring system to changing environmental conditions of the propagation of luminous waves and to the manifestations of information waves is solved by introducing into the monitoring system an information-analytical center (IAC) that provides operational analysis of multichannel received multifunctional information. In addition to managing the monitoring system, the IAC also provides an operational exchange of measurable information on the fields of the atmosphere, ocean and the earth's crust. This is especially necessary when creating a monitoring system as large-scale within adjacent water areas, for example, the waters of the Sea of Okhotsk and the Kuril Islands. It was in these water areas that the materials used in the application for marine studies of the models of experimental monitoring systems were obtained.

The technical result of the invention is expressed in the development and implementation of a radio-acoustic acoustic monitoring system as a multi-beam parametric antenna, commensurate with the length of the space of the controlled environment. The system provides long-range parametric reception in the marine environment of waves of various physical nature (acoustic, electromagnetic, hydrodynamic) generated by natural and artificial sources, phenomena and processes of the atmosphere, ocean and the earth's crust. The frequency range of the received waves is hundreds, tens, units, or fractions of hertz, including the VLF oscillations of moving objects as a whole. The system also provides the ability to quickly adjust its operating modes to changes in the conditions of the propagation medium of luminal waves, as well as to the manifestation of signs of sources of information waves.

To solve the problem, a radio-acoustic system for the parametric reception of waves, sources and phenomena of the atmosphere, ocean and the earth's crust in the marine environment includes emitting radiation and at least three receiving acoustic transducers installed at the opposite boundaries of the controlled environment, three zones of nonlinear interaction between the transmission and information waves as translucent parametric antennas, as well as those connected with radiating and receiving transducers respectively radiating a path that includes serially connected blocks of a stabilized frequency signal generator in the frequency range of tens to hundreds of hertz, a signal power amplifier and an acoustic transducer as an emitter of medium illumination signals, and a path for receiving nonlinearly transformed translucent waves, which includes serially connected blocks: a three-channel band amplifier of translucent signals, a converter of the time-frequency scale to the high-frequency region, a narrow-band analyzer pektrov, measuring correlation functions of signals between the middle and extreme receiving transducers selection unit further function of their cross-correlation signal and registrar. The proposed radio-acoustic system is fundamentally different in that the working area of nonlinear interaction and parametric transformation of the luminous and information waves is formed in the vertical plane of the medium as a multi-beam spatially developed luminous parametric antenna, for which three omnidirectional radiating transducers are used, vertically located in the center of the water area and mounted on the axis, below and above the axis of the underwater sound channel (PZK), and the receiving transducers are combined They are in three identical blocks located in a vertical plane along isosceles triangles, which are installed relative to the SLC axis similarly to radiating blocks and are placed in a circle and (or) perimeter at the opposite boundary of the water area. In this case, the receiving path of the measuring system is formed as a multi-channel one and includes one channel (line) of spectral analysis for extracting information signals, containing series-connected blocks of a strip amplifier, a converter of the time scale of the received signals in the high-frequency region, a narrow-band spectrum analyzer, and a functionally associated recorder (recorder) ) In this case, the single hydrophones of each receiving unit are connected via cables through the channel switching unit to three lines of correlation and cross-correlation analysis of the measuring system, and the outputs of the channels (lines) of the spectral and correlation analysis of the received transparency signals are connected to the input of the analysis unit of the extracted complex information, the output of which through a radio block connected to the information and analytical center of the monitoring system. The information-analytical center contains serially connected: a receiving radio block, a system analysis block and a transmitting radio block, the output of which is connected via a radio channel to the signal conditioning unit of the transmitting path of the monitoring system. In addition, the multichannel lumen parametric system is formed as a complex of vertical multipath parametric antennas located around the controlled area around the circle or perimeter through 45 ° and oriented radially from the emitting center to the periphery, which ensures the formation of a common spatially developed parametric monitoring system. In addition, the distance between the acoustic transducers of the receiving units placed in a vertical plane is set in accordance with the correlation characteristics of the vertical structure of the translucent acoustic field. In addition, a large-scale translucent radio-acoustic system can be scaled (scaled up) by combining measured information from similar monitoring subsystems formed in adjacent water areas in an information-analytical center using radio communication channels.

A comparative analysis of the features of the claimed invention and known technical solutions indicates its compliance with the criterion of "novelty."

The features of the characterizing part of the claims solve the following functional tasks.

A sign indicating that "the working area of nonlinear interaction and parametric transformation of the luminal and information waves is formed in the vertical plane of the medium as a multi-beam spatially developed luminal parametric antenna", provides the opportunity to solve all the following distinguishing features, and together they solve the generalized problem of the invention. The multipath propagation of translucent waves in an extended marine environment is most effectively realized when receiving waves of artificial and natural sources coming from the atmosphere or from the seabed. It should also be noted that the location of the emitting and receiving acoustic transducers in a vertical plane is based on the laws of multipath wave propagation in an extended sonar channel. In a shallow-water medium of propagation of acoustic waves with a transition to the deep-water zone, the location of the transducers will be determined in accordance with the indicated distinctive properties of the wave propagation channel (L. M. Brekhovskikh. Waves in layered media. - M .: Nauka, 1973. - 340 p.) .

A sign indicating that “for which three omnidirectional radiating transducers are used, vertically located in the center of the water area and installed: on the axis below and above the axis of the underwater sound channel (PPC), and the receiving transducers are combined into three identical blocks located in the vertical planes along isosceles triangles, which are installed relative to the PZZ axis in the same way as radiating blocks and are arranged in a circle and (or) perimeter on the opposite border of the water area, ”provides placement technology I transmitting and receiving units for the implementation of the work of the created enlightened monitoring system.

A sign indicating that the "receiving path of the measuring system is formed as a multichannel one and includes one channel (line) of spectral analysis for extracting information signals, containing series-connected blocks of a strip amplifier, a converter of the time scale of the received signals in the high-frequency region, a narrow-band spectrum analyzer and functionally the associated recorder (recorder) ”, provides a technology for extracting information waves from the received translucent signals in a range zone pass hundreds to tens of unit-share of Hertz, including ELF vibrations of moving objects.

A sign indicating that “single hydrophones of each receiving unit are connected via cables through a channel switching unit to three lines of correlation and cross-correlation analysis of the measurement system”, provides the possibility of receiving information waves of the atmosphere, ocean and the earth's crust based on correlation and mutual correlation analysis for separation of the rays of the transparent signals “above and below”, received by the blocks of the system located above the axis, on the axis and below the SLC axis.

A sign indicating that "the outputs of the channels (lines) of the spectral and correlation analysis of the received translucent signals are connected to the input of the analysis unit of the extracted complex information", provides a synthesis and preliminary analysis of complex information, as well as its preparation for transmission over communication channels in information analytical center.

A sign indicating that “the output of the complex information analysis unit through the radio block is connected to the information and analytical center of the monitoring system containing the receiver radio block in series, the system analysis block and the transmitting radio block, the output of which via radio channel is connected to the signal conditioning unit of the transmitting path of the monitoring system ", Provides a generalized technical result of the created spatially developed enlightened system for monitoring fields of various physical nature atm sphere, and ocean crust over a wide frequency range. This consists in the fact that the system analysis unit of multichannel measured multifunctional information completes the analysis and identification of the sources of formation of waves of the atmosphere, ocean and the earth's crust with the subsequent development of control (correcting) commands (signals) and their transmission via communication channels to the transmitting path of the monitoring system.

An additional sign indicating that “a multichannel luminous parametric system is formed as a complex of vertical multipath parametric antennas located around a circle or perimeter of a controlled water area at 45 ° and oriented radially from the emitting center to the periphery”, makes it possible to form a monitoring system as spatially developed throughout the space of the controlled water area.

An additional feature indicating that “the distance between the acoustic transducers of the receiving units located in the vertical plane is set in accordance with the correlation characteristics of the vertical structure of the luminous acoustic field”, provides noise-resistant separation of information signals and the reliability of the monitoring system in multipath propagation of luminous acoustic waves on long tracks.

An additional feature indicating that the “translucent radio-acoustic system can be scaled (scaled up) by combining the measured information from similar monitoring subsystems formed in adjacent water areas in an information-analytical center using radio communication channels,” makes it possible to build it up in neighboring water areas .

The claimed invention is illustrated by drawings.

In FIG. 1 is a structural diagram of a large-scale radio-acoustic monitoring system.

In FIG. Figure 2 shows the spatial arrangement of the emitting and receiving paths (blocks) of the monitoring system in a controlled area.

In FIG. 3-5 show spectra and spectrograms of hydrophysical fields of sources of the marine environment (sources of ocean fields). Moreover, in FIG. 3 is a spectrogram of the elastic resonant and hydrodynamic fields of a moving marine vessel, measured in a parametric manner. The frequency of illumination of the medium was 400 Hz, the length of the surveyed water area was 30 km. FIG. 4 - spectrum of electromagnetic radiation of a marine vessel. The measurements were carried out by the parametric translucent method, the backlight frequency was 390 Hz. The length of the surveyed water area is 45 km. FIG. 5 - spectrum and spectrogram of noise radiation of a marine vessel (shaft-lobe scale). The drawing shows the result of the "triple" nonlinear interaction of waves of various physical nature in the marine environment. Acoustic waves at a frequency of illumination of 386 Hz, electromagnetic waves at a frequency of 400 Hz and acoustic waves of a vane-blade scale of a marine vessel are observed on a 30-km long path.

FIG. 6, 7 - recording of the earthquake precursor signal (amplitude-time characteristic) and spectrum in 3D format (fields of the sources of the earth's crust). The measurements correspond to the formation of seismic disturbances in the areas of the Kuril island chain and their reception on the measuring field o. Sakhalin, the length of the route is about 200 km.

In FIG. 8, 9 show the spectrum and two spectrograms of the noise radiation of an atmospheric source (aircraft).

In FIG. 10 is a spectrogram of signals of synoptic disturbances of the marine environment for the full period of passage of the cyclone, the length of the luminal line is 345 km (disturbances of the marine environment by the atmospheric field). The measurements were performed on an acoustic translucent field equipped in the transition zone of the Sea of Okhotsk and the Sea of Japan.

In FIG. 11 - spectrum and spectrogram of seismic emissions of coastal engineering sources on the island. Sakhalin is the coastline of Primorye (metro Sosunova), the length of the luminal route was 310 km.

In FIG. 12 presents atmospheric radar measurements of sea surface waves in the presence and absence of a moving underwater object. The measurements were carried out by radar stations spaced in the atmosphere.

In FIG. 13 is a spectrogram of transmission signals (400 Hz) modulated by hydrodynamic waves and VLF oscillations of a moving sea vessel along a 345 km long path.

FIG. 14 - volumetric structure of Fresnel zones between the points of emission and reception of acoustic waves.

FIG. 15 - beam structure of the translucent acoustic field in the hydro-acoustic wave propagation channel.

Radio-acoustic system of parametric reception of waves of various physical nature of sources and phenomena of the atmosphere, ocean and the earth's crust in the marine environment over long sea areas that implements the invention is shown in figure 1, where:

1 - radiating path;

2 - stabilized frequency generator;

3 - power amplifier;

4 - three-channel matching unit;

5-7 - emitting blocks;

8-10 - receiving blocks;

11 - receiving path;

12 - block switching and switching lines of analysis of received signals;

13-16 - lines of correlation and spectral analysis;

13-1, 14-1, 15-1, 16-1 - broadband signal amplifiers;

13-2, 13-3, 14-2, 14-3, 15-2, 15-3 - blocks for measuring the correlation functions between the middle and extreme single receivers;

13-4, 14-4, 15-4 - blocks for measuring the cross-correlation function;

16-2 - a converter of the time scale of the signals in the high-frequency region;

16-3 - narrowband spectrum analyzer;

17 - block registration of measured functions;

18 - registrar allocated information signals;

19 - block analysis of complex information;

20, 24 - transmitting radio units;

21 - information and analytical center;

22 - block system analysis of the measured information;

23, 25 - receiving radio blocks;

26 - radiation source of hydrophysical information waves;

27 - waves of atmospheric sources;

28 - a source of radiation of geophysical information waves;

29 - the seabed;

30 - surface of the sea;

31 - medium multipath wave propagation;

32 - radiation from coastal sources;

33 - working area of nonlinear interaction and parametric transformation of the lumen and information waves.

As shown in FIG. 1, the radiating path 1 of the hydro-acoustic system is an electronic circuit comprising a stabilized frequency generator 2, a power amplifier 3, and a three-channel block matching 4 outputs of the power amplifier with submarine cables and further with radiating blocks 5-7 in series. The measuring system also includes a multi-channel receiving path for separating and recording information waves 11, the inputs of which are connected to receiving blocks 8-10, formed from three transducers located in a vertical plane along the triangles. The receiving path of the system 11 is a multi-channel electronic circuit, including a switching and switching unit for analyzing the received signals 12, connected to four lines of correlation and spectral analysis 13-16, each channel of the spectral analysis includes serially connected broadband amplifiers 13-1, 14-1, 15-1, further with the blocks for measuring the correlation functions between the middle and extreme single receivers blocks 13-2, 13-3, 14-2, 14-3, 15-2, 15-3, then the outputs of the blocks for measuring the functions of the correlation of signals are connected to block by measuring the cross-correlation function 13-4, 14-4, 15-4, and their outputs are connected to the recording unit of the measured functions 17, as well as to the inputs of the complex information analysis unit 19 and further to the radio unit for transmitting the measured information 20 to IAC 21. When This line of spectral analysis 16 includes a serially connected broadband signal amplifier 16-1, the input of which through the channel switching unit 12 is connected to the acoustic transducers of the receiving blocks 8-10, and the output of the broadband amplifier is connected to a time-domain converter the headquarters of the signals to the high-frequency region 16-2, then with a narrow-band spectrum analyzer 16-3 and a functionally associated recorder (recorder) of the extracted information signals 18, as well as with the inputs of the complex information analysis unit 19. Information Analytical Center (IAC) 21 of the monitoring system includes a system analysis unit of the measured information 22 connected to the output of the receiving radio block 23 and the input of the transmitting radio block 24, the output of which is connected via a radio channel through the receiving radio block 25 to the radiating path of the system monitoring 1.

In addition, in FIG. 1 shows: the surveyed water area (multi-path wave propagation medium) 31; radiation sources of hydrophysical and geophysical information waves 26 and 28; sources of atmospheric and coastal waves 27 and 32, the seabed 29, the surface of the sea 30, the working area of nonlinear interaction and parametric transformation of translucent and information waves 33.

The operation of the translucent radio-acoustic system for lighting the situation and monitoring the fields of the atmosphere, ocean and the earth's crust is as follows. The medium backlight emitters 5-7 and receiving units 8-10 are distributed along the controlled water area to the required distance (tens to hundreds of kilometers) and placed (deepened and installed) on the S-axis, as well as below and above the S-axis, which ensures the spatial formation in it developed multipath parametric antenna 33. Measurement of the signs of the manifestation of information waves of the atmosphere, bottom sea, and also coastal sources is carried out simultaneously and simultaneously, and their identification is carried out by the characteristic signs of the spectra and spatial-temporal dynamics, received and analyzed in the complex information analysis unit 19 and finally in IAC 21. For geophysical waves, for example, waves of earthquake precursors, special signal processing can also be carried out using multispectral analysis, which provides the dynamics of the spatio-temporal characteristics of spectral components as characteristic information features the origin and passage of seismic disturbances of the earth's crust (Bochkov G.N., Gorokhov K.V. Multispectral analysis and signal synthesis. - Nizhny Novgorod, 2007 .-- 113 p.).

The created radio-acoustic system can be included in the general regional marine lighting system by combining complex information in the IAC 21. This, in turn, provides the opportunity to adjust the luminous signals generated in the emitting path 1 taking into account the state of the propagation medium of the luminous waves. In addition, this provides the opportunity to fine-tune the operating modes of the monitoring system as widespread to the changing environmental conditions of the propagation of translucent signals, as well as to the variety of manifestations of sources of information waves.

The main laws of nonlinear translucent hydroacoustics that were used in the development of the invention are: a parametric model of translucent hydroacoustics, the principles of formation of translucent parametric antennas in an extended acoustic wave propagation channel, and non-linear interaction of waves of various physical nature in the marine environment. Based on this, we will analyze them.

A parametric model of the low-frequency translucent sonar method in an extended ocean waveguide

The formed spatially developed parametric system is a transparent multibeam parametric (incorporeal) antenna. To justify the luminaire active-passive sonar system as a parametric one with low-frequency illumination of the controlled medium or boundary, we consider the pattern of formation of the luminal line when acoustic energy propagates from the radiation point to the receiving point.

In FIG. Figure 16 shows a qualitative picture of the spatial structure of Fresnel zones between the points of emission and reception of translucent signals. Each of the zones (1 ... h _n ) in space forms ellipsoids of revolution. The first zone forms a region of space, which basically determines the transfer of energy of the translucent acoustic waves from the radiation point A to the receiving point B. The signal energy from the radiation point A to the receiving point B propagates within the space region, the boundaries of which are determined based on the Huygens principle and the construction of the zones Fresnel.

The effect of all other zones as a result of their pairwise neutralization (due to a phase difference of 180 °) is equivalent to the action of about half of the first zone. That is, in order to receive the signal of the same magnitude as in free space at the point of energy reception, it is necessary that the first zone along the entire wave propagation path remains “clean” from screening by obstacles or conversion by scattering inhomogeneities. The radius h of zone n is determined by the Fresnel formula

,

,

where R ₁ , R ₂ - distances that determine the position of the object on the line of radiation - reception; λ is the length of the translucent acoustic wave; n is the number of Fresnel zones (it is enough to take an odd number of zones, for example, three or five).

If the emitting object with the accompanying nonlinear inhomogeneity of the medium is located within the space of the first Fresnel zone, not only screening of the transmitted waves will occur, but also their intensive parametric transformation on this inhomogeneity. In this case, the first Fresnel zone functions as a spatial parametric luminous antenna of a traveling pump wave. A feature of the implementation of the translucent sonar method as a parametric one in the oceanic waveguide is that the hydroacoustic medium control system in this case is a multi-beam receiving-emitting antenna, as shown in FIG. 17, the justification of the benefits of which is the subject of consideration.

The formation of luminous spatially developed parametric antennas in the conditions of multipath propagation of acoustic waves in the marine environment

Using the laws of multipath signal propagation along the paths of a controlled marine area provides a new effect, namely the long-range parametric reception of information waves of various physical nature formed in the air and sea environment, as well as in the bottom soil.

The formation of a set of luminal lines along the paths of a controlled water area is performed relative to a stationary radiating center in a circle or around the perimeter of the water area. This is what ensures the obtaining of a spatially developed luminal parametric antenna commensurate with the spatial volume and extent of the water area. In the luminal monitoring system for the formation of a multi-beam spatially developed antenna, three omnidirectional emitters (transducers) are used, which are located on the axis of the underwater sound channel (CCD), above and below the CCD axis. The receiving units, consisting of three non-directional converters, are placed in a vertical plane along a triangle. In each receiving unit, the correlation functions of the received translucent signals between the middle and extreme (upper and lower) transducers are measured, then the functions of their mutual correlation are measured, which then determine the directions of the reception of information waves by the translucent rays from above and below with increased accuracy. Determination of the angles of arrival of the luminal rays from above and below by three receiving units provides observation and control of all horizons of the route, except those horizons that fall into the shadow zone, where the lumen field is formed by weak rays reflected from the bottom and sea surface (Andreeva IB sound in the ocean .-- L .: Gidrometeoizdat, 1975). At the same time, gentle rays propagating along the SLC axis provide continuous illumination of the space on the horizon of the channel axis. The formation of light zones along the propagation path of the translucent waves is ensured by a special arrangement of the emitting transducers of the monitoring system. The exact placement of the emitting blocks in depth is determined by calculating the radiation structure of the lumen field using the developed programs (Vasilenko AM, Malinovsky V.E., Alyushin D.A. , military unit 90720, 2003; Karachun L.E., Mironenko M.V., Vasilenko AM, Taboyakov A.A. Amplitude-phase structure of the acoustic field in an extended ocean waveguide with variable characteristics of the medium "Amplitude-phase front." Yuzhno-Sakhalinsk, SKB SA MI FEB RAS. St. on the official registration of a computer program, No. 2004611325 of March 29, 2004). The large spatial volume of the luminaire parametric antennas, as well as their length over a controlled area (tens to hundreds of kilometers), provides the possibility of long-range parametric reception of waves of various physical nature in the frequency range of hundreds-tens-units-fractions of hertz.

Interaction of waves of various physical nature in the marine environment

In contrast to the classical parametric devices for emitting and receiving signals, the translucent marine monitoring system, based on the implementation of the laws of nonlinear acoustics, is a multichannel large-scale parametric antenna with low-frequency illumination (pumping) of the medium. The parametric interaction of the luminal and information signals, as well as their conversion by the fields (or special emissions) of objects occurs along the entire propagation path in the aquatic environment. In this case, the most effective parametric interaction is carried out in the nonlinear region that accompanies moving objects, which has sufficiently large values (for example, in the case of a perturbation of the medium by the wake trace, it can be units of cubic kilometers). Turning to the substantiation of nonlinear interaction and the transformation of translucent waves with elastic information waves, we note that the classical expressions of wave interaction as applied to the low-frequency translucent method cannot be used directly. In this case, the interaction can occur at large distances from the receiver (tens to hundreds of kilometers). Based on this, in the classical expressions of the interaction of translucent waves with object waves, one should take into account:

- attenuation of the translucent wave P _n , due to its divergence during propagation in the waveguide in accordance with known principles, which is inversely proportional to the square of the distance P _n / R ² ;

- the interaction of waves in the volume of a nonlinearly perturbed medium V;

- an increased degree of nonlinearity of the medium in the interaction volume γ;

- a small difference between the frequencies of the translucent waves ω _n and the useful signal ω _s , which in this case is within the same order and ensures their more intense interaction.

With these corrections, the analytical dependences for the amplitudes of the Raman waves and the phase modulation index can be represented as follows:

;

,

;

,

where V is the volume of the medium of nonlinear interaction and parametric wave transformation; R is the distance from the radiation point to the location point of the location volume; γ is the coefficient of nonlinearity of the marine environment.

As can be seen from the expressions, the pressure of the Raman waves and the phase modulation index are similar to the classical dependence, but in this case the useful phase modulation of the luminal signals with measured low-frequency signals will increase, which is due to the increased interaction of waves in the medium with increased nonlinearity.

The directivity characteristic of a luminous parametric antenna is similar to a spatial traveling wave antenna and, in this regard, has a high directivity and noise immunity.

It can be represented as

.

.

Thus, the width of the directivity characteristics of the luminous parametric antenna is limited by the limits of the first Fresnel zones, which, in turn, are determined by the wavelength of the luminal signals and the length of the luminal path between the emitting and receiving converters. From this it follows that the directivity and noise immunity of the receiving luminal antenna in some cases can significantly exceed the classical ones. The notion of the width of the directivity characteristic at half power for such an antenna practically disappears, which also provides its advantage.

Let us pass to the substantiation of nonlinear interaction and the transformation of luminal waves by information waves of various physical nature. It is known that the characteristics of the hydrophysical fields of the marine environment in which the hydroacoustic wave propagates affect its parameters. This is due to the fact that the influence of hydrophysical fields is carried out through a change in the density and coefficient of elasticity of the medium. According to its physical nature, the claimed system provides for a change in the density and (or) temperature of a controlled aquatic environment. The distribution of these values in the extended working area of parametric reception (wave interaction) is a consequence of the impact on the marine environment of the measured information fields generated by a complex of signals propagating in the surveyed water area. Obviously, the infra-low-frequency waves generated by special marine sources or natural disasters will manifest themselves in a similar way.

Mathematically, the process of propagation of an electromagnetic wave is described by the well-known diffusion equation, which is derived on the basis of the theory of the interaction of an electromagnetic wave in a conducting fluid, which approximately describes the marine environment. The theoretical basis of the pattern under consideration is that the electric currents generated by the electromagnetic wave pass into Joule heat. Dissipative losses on the conduction current in the marine environment are converted into heat losses, which in turn change the mechanical characteristics of the conductive fluid (density, temperature, heat capacity, etc.). When an acoustic pump wave is transmitted through such a nonlinear medium modulated in space, its parameters will be modulated by changing the phase velocity of the wave along the propagation path. The spectrum of the elastic pump wave changes due to nonlinear conversion; high-frequency and low-frequency parametric components are formed in it. The parametric reception of information waves in the system under consideration is manifested as amplitude-phase modulation of the acoustic pump wave, which propagates with it to the receiving point and then is allocated in the signal processing path. The parametric reception of information waves by the translucent hydroacoustic system can be explained by the hydrodynamic equations developed for a viscous fluid when superimposed on the equation of state of the corresponding changes in the phase velocity of sound in time and space (V. Voronin, I. A. Kirichenko. Study of a parametric antenna in a stratified medium with a changing field of sound velocity. Izvestiya VUZov Journal, Electromechanics, No. 4, -1995; Shostak SV., Mironenko MV, Surgaev IN Amplitude-phase modulation of luminous acoustics waves during their interaction with electromagnetic waves in the marine environment // Sat. - Vladivostok: TOVMI. - Issue 22, 2001, pp. 82-88; Mironenko M.V., Korochentsev V.I. Laws of interaction of elastic and electromagnetic waves in sea water // International Symposium "Underwater Technologies - 2000". Japan, Tokyo. May 2000. - P. 105-109).

Qualitatively, any changes in density and pressure in the marine environment at a constant temperature lead to a change in the phase velocity of sound over time in the zone of interaction of an electromagnetic wave with an elastic wave through a marine medium that conducts electric current. That is, in contrast to the classical equations of hydrodynamics for an ideal fluid, which are used in the theory of nonlinear parametric emitters, the phase velocity of an elastic wave changes in time and space according to the law of change of the electromagnetic wave. Thus, if an electromagnetic wave of a harmonic frequency Ω _em propagates in the working zone of the lumen parametric system, then the phase velocity of the elastic (lumen acoustic) wave will change with the same frequency Ω _sv = Ω _em . Quantitative characteristics of the modulation depth can be obtained using specific engineering models for implementing the method.

Theoretical and marine experimental studies substantiate the regularity and effectiveness of the so-called “triple” interaction of acoustic translucent waves with acoustic and electromagnetic fields of marine sources. It is shown that marine sources, for example, seismic disturbances of the seabed, can be detected by signs of their transformation by elastic and electromagnetic fields of transparent acoustic waves propagating in the medium. The analytical form of such a transformation is as follows:

,

,

where P ^∗ (t), P (t) is the resulting (modulated) and instantaneous values of the translucent acoustic wave; 2ω is the frequency of a nonlinearly generated wave; Ω is the low-frequency acoustic wave from the object; t is the current time; J _n - n-th order Bessel functions; A is the amplitude of the modulated wave; m _p is the modulation coefficient.

An analysis of this expression shows that the vibrational spectrum of interacting waves consists of an infinite number of components located symmetrically with respect to twice the center frequency 2ω, equal to the sum of the frequencies of the interacting waves whose frequency values differ from 2ω by nΩ, where n is any integer. The amplitudes of the n-th side components will be determined by the expression

J _n (2A / P) · 0.5P ² .

It follows from this that the contribution of various side components to the total power of the modulated oscillation is determined by the value 2A / P. Moreover, for small values of the modulation coefficient m _p, the vibrational spectrum consists approximately of harmonics of the center frequency 2ω (total) and two side frequencies: the upper (2ω + Ω) and lower (2ω-Ω).

So, the joint propagation of a translucent sound wave in a nonlinear marine environment with information waves, including with waves of "small amplitudes", is accompanied by their interaction and parametric transformation. It should be noted that the transformation of translucent acoustic waves can be carried out by radiation (waves) of various physical nature (acoustic, electromagnetic, hydrodynamic). The result of the parametric transformation of the interacting waves is their mutual amplitude-phase modulation. The parametric components of the total and difference frequencies formed as a result of the transformation of the luminal waves are effectively distinguished in spectral analysis as signs of phase modulation, which is justified by mathematical dependences and confirmed by the results of marine experiments. The luminal parametric system of the invention, based on the low-frequency illumination of the controlled medium, is formed for each individual acoustic beam, and each lumen of the luminal system is an extended parametric antenna that provides an effective solution to the problem of long-range parametric reception of waves of various physical nature in a wide frequency range. The totality of the “ray tubes” formed in the medium in the vertical plane provides the formation of a multi-beam parametric antenna spatially developed in length and space of the controlled area. The location of the system’s radiating transducers relative to the CCD at horizons above, below and on its axis ensures the formation of illuminance zones near the sea surface and the bottom, as well as along the axis of the CCP channel. The sectorial arrangement of vertical luminal antennas in a circle or perimeter of a controlled water area with a stationary emitter in the center provides the formation of a spatially developed parametric antenna commensurate with the volume and extent of the space of the controlled medium. In addition, it is advisable to install the horizontal horizontal spacing of vertical multipath parametric antennas through 45 degrees, i.e. in the amount of not less than 8 pieces, which corresponds to the implementation of the correlation properties of antennas receiving transmissive signals of a stabilized frequency, and provides suppression of environmental noise with a low correlation as random signals. The advantage of developing a large-scale radio-acoustic luminaire parametric system is the simplicity of its creation and operation. The radiating and receiving paths of the system can be formed from existing radio equipment. PZM-400 type underwater sound beacons can be used as low-frequency emitting transducers. Receiving units as directional correlation systems can be formed from extended multi-element discrete antennas developed by the Special Design Bureau of Marine Research Automation FEB RAS.

The claimed invention is of significant interest for solving the practical problems of marine science, defense and national economic systems, as it can be used in radio-acoustic systems for parametric reception of waves of various physical nature sources and phenomena of the atmosphere, ocean and Earth's crust in the marine environment.

The system is industrially applicable, since it is used for the creation of common components and products of the radio industry and computer technology.

The inventive radio-acoustic system does not adversely affect the ecological state of the marine environment and atmosphere.

Claims (4)

1. A radio-acoustic system for the parametric reception of waves of sources and phenomena of the atmosphere, ocean and the earth's crust in the marine environment, which includes emitting radiation and at least three receiving acoustic transducers installed at the opposite boundaries of the controlled environment, the three zones of nonlinear interaction of the transmission and information waves formed between them as translucent parametric antennas, as well as connected to the radiating and receiving transducers, respectively, the radiating path, which includes I have connected in series blocks of a stabilized frequency signal generator in the frequency range of tens to hundreds of hertz, a signal power amplifier and an acoustic transducer as an emitter of medium illumination signals, and also a path for receiving nonlinearly transformed luminous waves, which includes series-connected blocks of a three-channel strip amplifier of luminous signals, a time-frequency converter in the high-frequency region, a narrow-band spectrum analyzer, a function meter signal correlation between the middle and outer receiving converters, then the block for separating the functions of their mutual correlation and the signal recorder, characterized in that the working area of nonlinear interaction and parametric conversion of the luminal and information waves is formed in the vertical plane of the medium as a multi-beam spatially developed luminous parametric antenna, which uses three omnidirectional radiating transducers, vertically located in the center of the water area and installed x on the axis, below and above the axis of the underwater sound channel (CCD), and the receiving transducers are combined into three identical blocks located in a vertical plane along isosceles triangles, which are installed relative to the CCD axis, similar to radiating blocks and placed around and (or) the perimeter on the opposite border of the water area; the receiving path of the measuring system is formed as a multi-channel and includes one channel (line) of spectral analysis for extracting information signals, containing series-connected blocks of a strip amplifier, a converter of the time scale of the received signals in the high-frequency region, a narrow-band spectrum analyzer and a functionally connected recorder (recorder ); in this case, the single hydrophones of each receiving unit via cables through the channel switching unit are connected to three lines of the correlation and mutual measuring system, and the outputs of the channels (lines) of the spectral and correlation analysis of the analysis of the received transparent signals are connected to the input of the analysis unit of the extracted complex information, the output of which is through the radio block connected to the information and analytical center of the monitoring system, containing a series-connected receiving radio unit, a system analysis unit and a transmitting radio unit, the output of which is connected via a radio channel to the signal conditioning unit of the transmitting path of the monitoring system. 2. The radio-acoustic system according to claim 1, characterized in that the multichannel luminous parametric system is formed as a complex of vertical multipath parametric antennas located at a circle or perimeter of a controlled area through 45 ° and oriented radially from the emitting center to the periphery, which ensures the formation of a common spatial developed parametric monitoring system. 3. The radio-acoustic system according to claim 1, characterized in that the distance between the acoustic transducers of the receiving units located in a vertical plane is set in accordance with the correlation characteristics of the vertical structure of the translucent acoustic field. 4. Radio-acoustic system according to claim 1, characterized in that the large-scale translucent radio-acoustic system can be scaled (scaled up) by combining the measured information from similar monitoring subsystems formed in adjacent water areas in an information-analytical center using radio communication channels.

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