RU2799974C1 - Correlation method for measuring the parameters of the aquatic environment fine structure - Google Patents

Abstract

FIELD: hydroacoustics and oceanography.

SUBSTANCE: invention relates to correlation methods for measuring the speed of movement, allowing to determine the speed of the vessel both relative to the bottom and diffusor relatively passively carried by the currents and located in the layers of the fine structure of the ocean's aquatic environment, and is also accompanied by measuring the depths of the water area along the route with the required accuracy. The invention can be used to acoustically measure the space-time pattern of the current field, which is considered as anisotropic and inhomogeneous. The current velocity is a random function of the geographical coordinates of the measurement site, horizon depth and time. In particular, when crossing the field in a horizontal plane, the time correlation intervals of the current velocity are estimated in units of hours, and the spatial correlation interval is estimated up to about thousands of meters. The operability of the method is based on the fact that information is obtained by ultrasonic sounding of sets of scatterers in 1.2,… , i, .., k layers of an inhomogeneous aquatic environment, which are separated by boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, sound speed, for example, the vertical velocity gradient at the boundaries between layers can exceed 5-10 cm/s per meter of depth), moreover, sets of scatterers are randomly and statistically nonuniformly distributed in the water volumes of the layers (from 1 to k ). Scatterers (bubbles, suspended particles, plankton, various inhomogeneities, etc.) in the layers have neutral buoyancy, are passively transferred by water masses with different linear current velocities v _ilay relative to the bottom, moreover, the magnitude of their acoustic impedance (рс) _1lay, (рс) _{2 lay}, …., (рс) _ilay randomly fluctuate with respect to the value of acoustic impedance (p _av c _av ) of aquatic environment, i.e. in the general case, a set of scatterers can be both acoustically soft and acoustically hard relative to the water environment. From an acoustic point of view, plankton is a collection of scatterers in the aquatic environment, the density and compressibility of which differs from those of the surrounding liquid, and the efficiency of ultrasound scattering depends on how much the density and compressibility of the scatterers differ from the corresponding properties of the environment and on the ratio the dimensions of the scatterers and the ultrasonic wavelength are found. Registration of the acoustic resistance of the surface of a set of scatterers, which characterizes its dynamic response to the impact of an elastic wave, resulting in phase shifts either for sound pressure (“acoustically soft” boundary) or for the oscillatory velocity of particles of the environment (“acoustically hard” boundary) in the reflected wave , can make it possible to use this value as an additional classification feature for studying the anisotropic and inhomogeneous spatiotemporal pattern of the current field.

EFFECT: increasing the reliability of obtaining information about the parameters of flows in the layers of the fine structure of a statistically heterogeneous aquatic environment with randomly distributed volumes of scatterers, obtaining a new volume of primary data about the underwater environment and expanding the operational capabilities of the method.

2 cl, 3 dwg

Description

The invention relates to the field of hydroacoustics and oceanography, in particular to correlation methods for measuring the speed of movement, which makes it possible to determine the speed of the vessel both relative to the bottom and relative to passively carried by the currents scatterers located in the layers of the fine structure of the ocean's aquatic environment, and is also accompanied by measuring the depths of the water area along the route with the required accuracy.

The invention can be used to acoustically measure the space-time pattern of the current field, which is considered as anisotropic and inhomogeneous. The current velocity is a random function of the geographic coordinates of the measurement site, horizon depth, and time. In particular, when crossing the field in a horizontal plane, the time correlation intervals of the current velocity are estimated in units of hours, and the spatial correlation interval - up to about thousands of meters. The operability of the method is based on the fact that information is obtained by ultrasonic sounding of sets of scatterers in 1,2, ..., , .., layers of an inhomogeneous aquatic environment, which are separated by boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, sound speed, for example, the vertical velocity gradient at the boundaries between layers can exceed 5–10 cm/s per meter of depth), and the sets of scatterers are randomly and statistically inhomogeneously distributed in the water volumes of the layers (from 1 to k ). Scatterers (bubbles, suspended particles, plankton, various inhomogeneities, etc.) in the layers have neutral buoyancy, are passively transferred by water masses with different linear current velocities relative to the bottom, and the values of their acoustic impedances , , …., randomly fluctuate with respect to the value of acoustic impedance aquatic environment, i.e. in the general case, a set of scatterers can be both acoustically soft and acoustically hard relative to the water environment. From an acoustic point of view, plankton is a collection of scatterers in the aquatic environment, the density and compressibility of which differs from similar characteristics of the surrounding liquid, and the efficiency of ultrasound scattering depends on how much the density and compressibility of the scatterers differ from the corresponding properties of the environment and on the ratio of the dimensions of the scatterers and the ultrasonic wavelength. Registration of the acoustic resistance of the surface of a set of scatterers, which characterizes its dynamic response to the action of an elastic wave, resulting in phase shifts either for the sound pressure (“acoustically soft” boundary) or for the vibrational velocity of the particles of the medium (“acoustically hard” boundary) in the reflected wave, can make it possible to use this value as an additional classification feature for studying the anisotropic and inhomogeneous space-time pattern of the flow field.

Known autocorrelation method for measuring the speed of the vessel, in which to determine its absolute speed is used its unambiguous dependence on the value of the coefficient autocorrelation of the low-frequency envelope of the echo signal from the seabed (see Bukaty V.M., Dmitriev V.I. Hydroacoustic logs. M.: Food industry, 1980, p. 119-121).

This method is implemented as follows:

1) is placed on the bottom of the ship IPIA, consisting of the required number of electro-acoustic transducers (EAP), each of which is equipped with a piezoelectric element, shielding units, hydro-, electrical and noise insulation;

2) ensure the operability of the emission / reception modes of each EAP through the use of reverse / direct piezoelectric effects for a piezoelectric element of a simple geometric shape (rod, plate, disk) with a given resonant frequency ;

3) regulate the spatial arrangement of the acoustic axis of the RPIA until it coincides with the normal relative to the bottom, which ensures irradiation from top to bottom with ultrasonic energy of the section of the "water - bottom" interface with a random distribution of bottom irregularities through sets of scatterers of the aquatic environment, in 1,2, ..., , .., layers of which they are randomly and statistically non-uniformly distributed, diffusers have neutral buoyancy and acoustic resistance , which differs from a similar parameter of the aquatic environment, are passively transferred by water masses with different linear current velocities relative to the bottom;

4) generate electrical oscillations in the radiating path of the equipment, which are converted into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ;

5) using the inverse piezoelectric effect, electrical signals are converted using the piezoelectric elements of the EAP IPIA into periodic sendings of ultrasonic waves with the required duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency , which forms an ultrasonic beam due to interference in the aquatic environment;

6) carry out ultrasonic irradiation and establish acoustic contacts with the surfaces of the sections:

- the boundaries of the section "water - bottom" with a random distribution of bottom irregularities,

- sets of diffusers of the aquatic environment, in 1, 2, ...,, .., layers of which they are randomly and statistically non-uniformly distributed, scatterers have neutral buoyancy,

for example, on-volume depth horizon - their number is, each set of those in-th layer has its own linear size, reflectivity and acoustic impedance, and the set can be both acoustically rigid>), and acoustically soft<) - relative to the aquatic environment, passively transferred by water masses with a linear flow velocity relative to the bottom;

7) provide, due to the movement of the vessel-carrier of the equipment, a continuous change in the position of the IPIA relative to

as sets of diffusers of the aquatic environment, in 1,2,…, , .., layers of which they are randomly and statistically inhomogeneously distributed, and are also passively transferred by water masses with different linear current velocities relative to the bottom

and many randomly distributed bottom irregularities,

which will cause the formation of a volumetric reverberation process and a delayed echo signal, the square of the envelope of which will contain the frequency spectrum, and their envelope will fluctuate in a chaotic manner;

8) using the direct piezoelectric effect of the piezoelectric elements of the EAP IPIA, the echo signal fluctuating in amplitude from the moving area of the uneven seabed is converted into the corresponding electrical signal supplied to the input of the receiving path of the equipment;

9) determine in the receiving path of the equipment the value of the autocorrelation coefficient of the envelope of the echo signal, which allows you to calculate the speed of the vessel ;

10) display, record and document the results of measurements in the equipment.

The autocorrelation method for measuring velocity requires the use of a single IPIA, errors associated with the orientation of the antenna relative to the direction of motion are excluded, but it has the following disadvantages:

1) the stationarity of the received echo signal and, accordingly, the repeatability of the shape of the autocorrelation functions for each value of the speed of movement is required, which is difficult to implement in practice, since in real conditions the shape of the autocorrelation function will be different for the same speed of the ship in different areas of the ocean floor. Under specific operating conditions (maneuvering both on the roads and in the port, providing locking and mooring), the performance of this method due to the use of the above processing of only the amplitude characteristics of echo signals can be impaired, since in the waters of "man-made" waterways (navigable channels of the internal transport system of rivers, lakes, reservoirs, etc., artificial channels and fairways of harbors), there are practically no uneven bottom surface topography due to dredging works.

2) the accuracy of velocity measurement is limited by the lack of the ability to adjust the sharpness of the directional action of the PSIA and the single-frequency mode of operation. As follows from the ratio maximum fluctuation frequency the envelope of the echo signal from the region of the uneven seabed moving due to the movement of the vessel (see Bukaty V.M., Dmitriev V.I. Hydroacoustic logs. M .: Food industry, 1980, p. 109) depends on both the speed of the vessel υ and the angular width of the main lobe XH of the receiving antenna, and the wavelength λ probing signal, which ultimately determines the significance of the methodological and instrumental errors of the autocorrelation method.

3) the method does not provide for the possibility of measuring the depth under the keel of a moving vessel, the relative speed of its movement, as well as measuring the parameters of currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment. Thus, to solve the above problem in the receiving tract of the device, only the amplitude features of the echo signals present in the hydroacoustic channel are processed, while in order to obtain a more complete amount of primary data on the parameters of the flows in the layers of the fine structure of a statistically inhomogeneous aquatic medium with scatterers randomly distributed in their volumes, it is necessary to additionally use the phase features of the echo signals.

A known cross-correlation method for measuring the speed of a ship-carrier of the equipment, in which its unambiguous dependence on the value of the cross-correlation coefficient of fluctuations of envelope echo signals from the bottom, received by spatially separated interference receiving antennas (IPA) is used to calculate the speed (see Loginov K.V. Electrical navigation and fish-searching devices. - M .: Easy and food industry, 1983, p. 203-204 ).

This method is implemented as follows:

1) three antennas are placed on the bottom of the vessel in its diametrical plane - interference emitting (hereinafter - RIA) and two receiving (hereinafter - RIA), consisting of the required number of EAP, each of which is equipped with a piezoelectric element, shielding units, hydro-, electrical and noise insulation, and the acoustic axes of all antennas coincide with the normals relative to the bottom, the IAP are separated by a known distance L from each other and are located in the aft and bow parts of the vessel, and the RIA - is in the middle between them;

2) ensure the operability of the emission / reception modes of each EAP through the use of reverse / direct piezoelectric effects for a piezoelectric element of a simple geometric shape (rod, plate, disk) with a given resonant frequency ;

3) generate electrical oscillations in the radiating path of the equipment and convert them into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ;

4) using the inverse piezoelectric effect of the EAP IIA piezoelectric elements, the amplitude-pulse modulated oscillations are converted into periodic bursts of ultrasonic waves with the required duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency , which generates ultrasonic pulsed radiation due to interference in the aquatic environment;

5) is carried out by conducting a cycle of echo sounding with the first pair of antennas - IIA and nasal IPA - the first acoustic contacts with surface areas

- sets of diffusers of the aquatic environment, in 1, 2, ...,,.., layers of which they are randomly and statistically non-uniformly distributed, the scatterers have neutral buoyancy, for example, on-volume depth horizon - their number is, each set of those in-th layer has its own linear size, reflectivity and acoustic impedance, and the set can be both acoustically rigid>), and acoustically soft<) - relative to the aquatic environment, passively transferred by water masses with a linear flow velocity relative to the bottom

and the boundaries of the section "water - bottom" with a random distribution of bottom irregularities,

which ensures the formation of the first information signals - a volumetric reverberation process and a delayed echo signal, the square of the envelopes of which will contain the frequency spectrum, and their envelope will fluctuate in a chaotic manner;

6) using the direct piezoelectric effect of the piezoelectric elements of the EAP nasal IPA, the first information signals, in particular, the echo signal fluctuating in amplitude from the surface area of the "water-bottom" interface with a random distribution of bottom irregularities, are converted into the corresponding electrical signal entering the input of the receiving path of the equipment;

7) move with speed the vessel carrying the equipment along the course of movement so that the second pair of antennas - IAM and aft IPA - is located above the same section of the surface of the "water - bottom" interface with a random distribution of bottom irregularities,

but already in other areas of the surfaces of the sets of diffusers of the aquatic environment, in 1, 2, ...,, .., layers of which they are differently, but also randomly and statistically non-uniformly distributed, for example, on-volume depth horizon - their number will be already, each set of those in-that layer can have other -linear size, reflectivity and acoustic impedance, and the set can be both acoustically rigid>), and acoustically soft<) - relative to the aquatic environment, and they were in the area of ultrasonic irradiation due to the transfer by water masses with a linear velocity of currents relative to the bottom;

8) by conducting a cycle of echo sounding by the second pair of antennas - IIA and stern IPA, acoustic contacts with surface areas

- other sets of diffusers of the aquatic environment, in 1, 2, ...,,.., layers of which they are also randomly and statistically inhomogeneously distributed, and they ended up in the area of ultrasonic irradiation due to the transfer by water masses with different linear current velocities relative to the bottom, for example, on-volume depth horizon with linear current velocity relative to the bottom - the amount will be with linear dimensions, reflectivity and acoustic impedance, and each set can be both acoustically rigid>), and acoustically soft<) - relative to the aquatic environment,

and the same "water - bottom" interface with the same random distribution of bottom irregularities,

which ensures the formation of time-shifted second information signals - a volumetric reverberation process and a delayed echo signal, the square of the envelopes of which will contain the frequency spectrum, and their envelope will fluctuate in a chaotic manner;

9) using the direct piezoelectric effect of the piezoelectric elements of the EAP of the stern IPA, time-shifted second information signals are converted, in particular, an echo signal fluctuating in amplitude from the same section of the surface of the “water-bottom” interface, which has a random distribution of bottom irregularities, into the corresponding electrical signal input to the input of the receiving path of the equipment;

10) determine in the receiving path of the equipment the value of the cross-correlation coefficient for the envelopes of the first and second electrical signals fluctuating in a chaotic manner in time, corresponding to the same section of the surface of the “water-bottom” interface, which has a random distribution of bottom irregularities, which makes it possible to calculate the speed of the vessel ;

11) display, record and document the results of measurements in the equipment.

However, this cross-correlation method for measuring the speed of the ship-carrier of the equipment has the following disadvantages:

1) the ground speed measurement accuracy is limited by the lack of the ability to adjust the sharpness of the directional action of RIA and PIA and the single-frequency mode of their operation. So, for example, the relative fluctuation error in measuring the ground speed (methodical measurement error due to the probabilistic nature of fluctuations in the envelope of echo signals from the bottom) is determined by the relation

where coefficient (0.3 - 0.4) is determined by the scattering properties of the seabed, longitudinal spacing (base) IPA, data averaging time (see Bukaty V.M., Dmitriev V.I. Hydroacoustic lags. M.: Food industry, 1980, pp. 143-157). From (1) it follows that the relative fluctuation error of ground speed measurement is determined by the technical parameters of the system and to the greatest extent depends on the values of the measured speed, the wavelength of the probing signal, the sharpness of the directional action of the transmitting and emitting antenna, and to reduce the error, it is proposed to increase the longitudinal separation of the antennas and the averaging time, increase the operating frequency and increase the angular width of the main lobe of the XH (for interference antennas with a constant aperture, with an increase in the operating frequency, the sharpness of the directional action increases, i.e. the angular width of the main lobe of the XH decreases).

2) the method does not provide for the possibility of changing the accuracy of measuring the depth under the keel of the vessel. So, the masking of the real topography of the seabed along the route of the vessel is due to the sphericity of the wave front of the ultrasonic sounding signals, as a result of which there is an uncertainty in the assessment of the actual depth (see Kudryavtsev V.I. Commercial hydroacoustics and fish location. M .: Food industry, 1978, p. 255-258;

3) the hydrophysical fields of the ocean are characterized by the presence of a fine structure of a stepped nature, i.e. Layers of sufficiently uniform properties with thicknesses from tens of meters to units of centimeters, which are separated from each other by boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, density, speed of sound). To obtain information about the presence of this layered stratification of the aquatic environment, it is necessary to process the amplitude and phase features of the volumetric reverberation signals, the performance of the proposed method can be based on the establishment of echo contacts with scatterers that are randomly and statistically inhomogeneously distributed in the water volumes of the layers and are passively transferred by water masses with different linear current velocities. relative to the bottom.

4) in order to obtain a more complete amount of primary data on the parameters of currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment, it is important to measure a set of values - size, reflectivity and acoustic resistance, and the value of the latter fluctuates arbitrarily relative to the value of acoustic resistance aquatic environment. However, this method does not provide for the possibility of registering such an informative parameter of scatterer sets in any of the layers as acoustic impedance.

The listed shortcomings of cross-correlation methods for measuring ground speed limit their applicability and make it more promising to develop similar methods, the operation of which is based on establishing a statistical relationship between random processes that have the same correlation functions - two continuously recorded real-time functions of the distribution of water body depths along the ship's route.

As a prototype, a correlation hydroacoustic method was chosen that allows you to determine the ground speed of the vessel, in which, to determine the absolute value of the ground speed, its unambiguous dependence on the value of the cross-correlation coefficient of two continuously recorded voltages at the outputs of the IPIA as a function of the distribution of the depths of the reservoir (bottom profile) along the route of the vessel (see Handbook of hydroacoustics. A.P. Evtyutov, A.E. Kolesnikov et al. - L .: Shipbuilding, 198) 2, pp. 28-29).

This method is implemented as follows:

1) placed at a distance in the diametrical plane of the vessel, in particular, in the fore and aft parts of the bottom, the RTSI of echo sounding systems, which consist of the required number of electroacoustic transducers (EAP), each of which is equipped with a piezoelectric element, shielding units, hydro-, electrical and noise insulation, moreover, the RTIA are oriented vertically down with acoustic axes, have the same wave sizes, and the bottom areas irradiated by ultrasound under the bow and stern of the vessel do not overlap;

2) ensure the operability of the emission / reception modes of each EAP through the use of reverse / direct piezoelectric effects for a piezoelectric element of a simple geometric shape (rod, plate, disk) with a given resonant frequency ;

3) generate electrical oscillations in the radiating path of the equipment and convert them into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ;

4) using the inverse piezoelectric effect of the piezoelectric elements of the EAP, bow and stern IPIA of amplitude-pulse modulated oscillations are converted into periodic bursts of ultrasonic waves with the required duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency and forming due to interference in the aquatic environment under the bow and stern parts of the hull moving at speed ships ultrasonic irradiating beams;

5) carry out acoustic contacts with surface areas:

- sets of diffusers of the aquatic environment, in 1, 2, ...,, .., layers of which they are randomly and statistically inhomogeneously distributed, each set of scatterers in any of layers has a "unique" set of characteristics, in particular, on-the depth horizon -number of structural elements, their linear size, reflectivity and acoustic impedance, which differs from the similar parameter of the aquatic environment, and neutral buoyancy, as a result of which sets of scatterers are passively transferred by water masses with different linear current velocities relative to the bottom

- the water-bottom interface with a random distribution of bottom irregularities, and these surfaces of the sections are at a given time under the bow (H) and stern (K) parts of a vehicle moving at a speed ship, which ensures the simultaneous formation of two space-time dependencies of information signals - volumetric reverberation processes and delayed echo signals, the squares of the envelopes of which will contain the frequency spectrum, and their envelopes will fluctuate in a chaotic manner;

6) using the direct piezoelectric effect of the piezoelectric elements of the EAP, the forward and stern IPIA moving at a speed ship two spatio-temporal dependences of information signals, in particular, the amplitudes of echo signals from both irradiated sections of the "water - bottom" interface with random and different distributions of bottom irregularities, into the corresponding electrical signals entering the input of the receiving path of the equipment;

7) determine as the vessel moves along a given course, two amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, which are proportional to the distribution of the depths of the water area under the bow and stern parts of the hull moving at speed ship, and these functions are identical to each other, but shifted in time by an amount ;

8) determine the value of the cross-correlation coefficient for two amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the “water-bottom” interface and proportional to the distribution of the depths of the water area under the bow and stern of the hull along the course of the vessel, which allows you to calculate the speed of the vessel ;

9) display, record and document the results of measurements in the equipment.

However, this correlation hydroacoustic prototype method has the following disadvantages:

1) the accuracy of measuring the ground speed is limited by the lack of the ability to adjust the sharpness of the directional action of narrow-band EAP IPIA and their single-frequency mode of operation. So, for example, for the prototype under consideration, the relative fluctuation error in measuring the ground speed , determined by relation (1), is also relevant for the analog discussed above - the method of cross-correlation measurement of ground speed (see Loginov K.V. Electrical navigation and fish-searching devices. - M .: Easy and food industry, 1983, p. 203-204). From (1) it follows that, despite the decrease in the relative fluctuation error of the ground speed measurement due to the increase in the longitudinal spacing (base) IPIA, in the method there is no possibility of increasing the accuracy characteristics by adjusting the value of an important parameter - - the width of the peak of the cross-correlation function, which may be necessary when maneuvering the vessel at low speeds in narrow places, in the waters of the harbor, etc. In the prototype, changing the peak width of the cross-correlation function is hampered by the fact that this value is determined by interrelated parameters - the wavelength of the probing signal and the severity of the directional action of the IPIA. So, with a constant aperture, due to a decrease in the wavelength of the probing signal, the sharpness of the directional action increases, which follows from the relationship (see A.P. Evtyutov, V.B. Mitko Engineering calculations in hydroacoustics. - 2nd ed., revised and added. - L .: Shipbuilding, 1988. p. 17-27). The speed measurement accuracy deteriorates significantly in the presence of amplitude and phase fluctuations that are not correlated with the movement of the vessel - with a wide main lobe of the XH antenna and a corresponding level of its lateral radiation, surface reverberation signals can become the cause of such fluctuations;

2) the method does not provide for the possibility of changing the accuracy of measuring the depth under the keel. The proposed monostatic echo sounding scheme to improve the accuracy of the depth profile of the reservoir and detailed detailing of the bottom topography may involve selection of the optimal spatial characteristics of the ultrasonic fields generated by the IPIA, which is not carried out in the prototype;

3) the hydrophysical fields of the ocean are characterized by the presence of a fine structure of a stepped nature, i.e. Layers of sufficiently uniform properties with thicknesses from tens of meters to units of centimeters, which are separated from each other by boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, density, speed of sound). To obtain information about the presence of this layered stratification of the aquatic environment, the processing of volumetric reverberation signals is optimal, however, in this analogue method, these measurements are not carried out, although scatterers (bubbles, suspended particles, plankton, various heterogeneities, etc.) in the layers have neutral buoyancy and are passively transferred by water masses with different linear current velocities relative to the bottom;

4) in specific operating conditions (maneuvering both on the roads and in the port, providing locking and mooring), the performance of the correlation method - prototype using the above-described processing of only the amplitude characteristics of echo signals may be impaired. The fact is that in the water areas of “man-made” waterways (navigable channels of the internal transport system of rivers, lakes, reservoirs, etc., artificial channels and fairways of harbors) there are practically no uneven topography of the bottom surface due to dredging, while the difference in acoustic resistance of the bottom surface with outcrops of both dense bedrock (“acoustically rigid”) and gas-saturated sediments - sediment (“acus tically soft") is retained. Under these operating conditions, the method should provide for the possibility of registering a change in such an informative parameter of the irradiated areas of the bottom surface on the route as the acoustic impedance of the water-soil interface. Thus, the expansion of the operational capabilities of the correlation method - a prototype that allows you to determine the depths of water areas and the speed of the vessel-carrier of the equipment relative to the bottom when moving on natural and artificial transport waterways, can be achieved by appropriate processing of the phase characteristics of echo signals.

General features coinciding with the claimed invention:

1) place on the bottom of the ship two ISIA, consisting of the required number of EAP, each of which is equipped with a piezoelectric element, screening units, hydro-, electrical and sound insulation;

2) ensure the operability of the emission / reception modes of each EAP through the use of reverse / direct piezoelectric effects for a piezoelectric element of a simple geometric shape (rod, plate, disk) with a given resonant frequency ;

3) regulate the spatial arrangement of the acoustic axis of both RPIAs until they coincide with the normal relative to the bottom, which ensures irradiation from top to bottom with ultrasonic energy of the section of the "water - bottom" interface with a random distribution of bottom irregularities through sets of scatterers of the aquatic environment, in layers of which they are randomly and statistically inhomogeneously distributed, having acoustic resistance, which differs from the similar parameter of the aquatic environment, and neutral buoyancy, as a result of which sets of scatterers are passively transferred by water masses with different linear current velocities relative to the bottom;

4) generate electrical oscillations in the radiating path of the equipment and convert them into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ;

5) convert electrical signals using the direct piezoelectric effect of the piezoelectric elements of the EAP IIA of amplitude-pulse modulated oscillations into periodic sendings of ultrasonic waves with the required duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency , which forms an ultrasonic beam due to interference in the aquatic environment;

6) carry out acoustic contacts with surface areas of sets of diffusers of the aquatic environment, in layers of which they are randomly and statistically inhomogeneously distributed, having acoustic resistance , which differs from the similar parameter of the aquatic environment, and neutral buoyancy, as a result of which sets of scatterers are passively transferred by water masses with different linear current velocities relative to the bottom, and the “water-bottom” interface with a random distribution of bottom irregularities, and these surface areas are at a given time under the bow (H) and stern (K) parts of a vehicle moving at a speed vessel, which ensures the formation of information signals - volumetric reverberation processes and delayed echo signals, the squares of the envelopes of which will contain the frequency spectrum, and their envelopes will fluctuate in a chaotic manner;

7) using the direct piezoelectric effect of the EAP piezoelectric elements, the bow and stern IPIA information signals are converted, in particular, echo signals fluctuating in amplitude from the surfaces of different sections of the “water-bottom” interface with random and differing from each other distributions of bottom irregularities, moreover, these surface sections are at a given time under the bow (H) and stern (K) parts of the vehicle moving at speed ship, into the corresponding electrical signals entering the input of the receiving path of the equipment;

8) determine in the receiving path of the equipment as the vessel moves along a given course, two slowly changing functions of the distribution of the depths of the reservoir, i.e. non-coinciding at a given moment in time dependencies of electrical signals And , proportional to the distribution of depths of the water area under the bow and stern of the hull, and these functions are identical to each other, but shifted in time by ;

9) determine the value of the cross-correlation coefficient for the dependencies of electrical signals that do not match at a given time And , proportional to the distribution of the depths of the water area under the bow and stern of the hull on the way of the ship, which allows you to calculate the speed of the ship ;

10) display, record and document the results of measurements in the equipment.

The problems caused by the general deficiencies of the prototype and the above analogues include insufficient compliance with the operational requirements, in particular, low angular resolution and noise immunity during vertical probe of both the bottom of water bodies and the water thickness in the conditions of shallow water, while only the amplitude features of the echosilles of the main frequency are processed, while to obtain a more complete volume Vino data on the subtle structure of layers of a heterogeneous aquatic environment with randomly distributed volumes of diffusers must additionally use phase features.

The aquatic propagation medium has a nonlinearity of its elastic properties, which leads to the appearance of various nonlinear effects during the propagation of an intense ultrasonic wave (see Hydroacoustic Encyclopedia. Under the general editorship of V.I. Timoshenko. - Taganrog, Publishing house TRTU. 2000. p. 438 - 441). Nonlinear effects in an acoustic field can be considered as a result of a change in the properties of the medium in the propagation region of a powerful probing pump signal with a frequency , which leads to a distortion of the shape of the profile of a wave of finite amplitude as it propagates towards the scattering bottom surface, i.e. generation of higher harmonic components with frequencies , Where - serial number of the harmonic. Acoustic fields of higher harmonic signals have specific spatial characteristics: on the acoustic axis of the PSIA, a change in the properties of the medium under the action of a powerful pump wave with a frequency occurs to the greatest extent, in connection with which the angular width of the main lobe of the XH for each subsequent harmonic is less, and in the directions of the additional XN maxima at the fundamental frequency the change in the properties of the medium occurs to a much lesser extent, which leads to a decrease in the efficiency of harmonic generation in these directions, i.e. the level of the lateral field HH for each subsequent harmonic is less than that of the previous one (see T. J. Muir. Nonlinear acoustics and its role in the geophysics of marine sediments // Acoustics of marine sediments / Ed. Yu. Yu. Zhitkovsky. - M .: Mir, 1977. - p. 245 - 250). Analyzing the information presented in this source on the angular distributions of the sound pressure amplitude of phase-coupled signals of multiple frequencies we can conclude that with their use it is advisable to develop a multi-frequency correlation method for measuring the speed of movement, using which it is possible to refine the data:

- a detailed structure of the distribution of the depths of the reservoir in real time on the move of the vessel-carrier of the equipment,

- absolute (relative) speed of the carrier vessel,

- flow parameters in the fine structure layers of a statistically inhomogeneous aquatic environment.

Thus, a technical problem for the acoustic methods known in the prior art for measuring the parameters of flows of a statistically inhomogeneous aquatic environment is the impossibility of obtaining reliable information about the parameters of flows in the fine structure layers of a statistically inhomogeneous aquatic environment with randomly distributed volumes of scatterers.

The objective of this invention is to create a method that allows you to expand the operational capabilities of the correlation method for measuring the speed of currents.

The technical result of the invention is to increase the reliability of obtaining information about the parameters of the currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment with randomly distributed volumes of scatterers, which makes it possible to obtain a new amount of primary data on the underwater situation and to expand the operational capabilities of the method.

The claimed result is achieved by the fact that in the well-known correlation hydroacoustic method for measuring the speed of currents, in which:

- placed at a distance in the diametrical plane of the vessel, in the fore and aft parts of the bottom, two RTMS of echo sounding systems, which consist of the required number of EAPs, each of which is equipped with a piezoelectric element, screening units, hydro-, electrical and noise insulation, and both RTIAs are oriented vertically down with acoustic axes, have the same wave sizes, and the bottom areas irradiated by ultrasound under the bow and stern of the vessel do not overlap;

- ensure the operability of the emission / reception modes of each EAP through the use of reverse / direct piezoelectric effects for a piezoelectric element of a simple geometric shape (rod, plate, disk) with a given resonant frequency ;

- generate electrical oscillations in the radiating path of the equipment, which are converted into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ;

- using the direct piezoelectric effect of the EAP piezoelectric elements, the bow and stern IPIA are converted amplitude-pulse modulated oscillations into periodic bursts of ultrasonic waves with a given duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency and forming due to interference in the aquatic environment under the bow and stern parts of the hull moving at a speed ships ultrasonic irradiating beams;

- carry out acoustic contacts with areas of surfaces - sets of diffusers of the aquatic environment, in 1, 2, ..., , .., layers of which they are randomly and statistically inhomogeneously distributed, while each set of scatterers in any of layers has a "unique" set of characteristics, in particular, on -the depth horizon - the number of structural elements , their linear size , reflectivity and acoustic impedance , which differs from the similar parameter of the aquatic environment, as well as neutral buoyancy, as a result of which the sets of scatterers are passively transferred by water masses with different linear current velocities relative to the bottom

- “water-bottom” interface with a random distribution of bottom irregularities, and these surfaces of the sections are at a given time under the bow and stern IPIA of the echo sounding systems, i.e. bow (H) and stern (K) parts of a moving vessel with a speed relative to the bottom, which ensures the simultaneous formation of two space-time dependences of information signals - volumetric reverberation processes and delayed echo signals, the squares of the envelopes of which will contain the frequency spectrum, and their envelopes will fluctuate in a chaotic manner;

- convert using the direct piezoelectric effect of the piezoelectric elements of the EAP bow and stern IPIA moving at a speed ship two spatio-temporal dependences of information signals, the amplitude of echo signals from both irradiated sections of the "water - bottom" interface with random and different distributions of bottom irregularities, into the corresponding electrical signals entering the input of the receiving path of the equipment;

- determine as the vessel moves along a given course, two amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, which are proportional to the distribution of the depths of the water area under the bow and stern parts of the hull moving at speed ship, and these functions are identical to each other, but shifted in time by an amount ;

- determine the value of the cross-correlation coefficient for the dependencies of electrical signals that do not match at a given time And , proportional to the distribution of depths of the water area under the bow and stern parts of the hull along the course of the vessel, which makes it possible to calculate the speed of the vessel ;

- display, record and document the results of measurements in the equipment

additionally introduced the following operations

- set for both IPIA echo sounding systems the criterion of compliance of their wave sizes with the range of values

Where - antenna diameter, - ultrasonic wavelength with frequency , propagating at a speed in water, - the amplitude of the sound pressure in Pascals near the surface of the IPIA in the radiation mode;

- generate with the help of the radiating path of the equipment electrical oscillations with a frequency , coming to two IRDA echo sounding systems in the radiation mode;

- using the direct piezoelectric effect of the piezoelectric elements of the EAP of two EPIA echo sounding systems, amplitude-pulse modulated oscillations are converted into periodic bursts of powerful ultrasonic waves with a given duration, ensuring the transfer of acoustic energy to the particles of the aquatic environment, sufficient to manifest the nonlinear elastic properties of the aquatic environment under the bow and stern parts of the hull moving at speed vessel, which forms two parametric radiating antennas (PRA) in the aquatic environment, in the volumes of which nonlinear sources of the generated spectral components are distributed (self-action);

- generate two polyharmonic beams of ultrasonic phase-coupled signals with multiple frequencies by means of both PIAs in the aquatic environment , Where - the serial number of the harmonic, the acoustic fields of the harmonics are coaxial, their wave vectors are oriented vertically downwards, and with an increase in the number of the harmonic, the beams have decreasing cross sections;

- installed on ultrasonic phase-coupled signals with multiple frequencies acoustic contacts with surface areas:

- sets of diffusers of the aquatic environment, in 1, 2, ...,, ..., layers of which they are randomly and statistically inhomogeneously distributed, each set of scatterers in any of layers has a "unique" set of characteristics, in particular, on-the depth horizon - the number of structural elements, their linear size, reflectivity and acoustic impedance,

- the boundaries of the section "water - bottom" with a random distribution of bottom irregularities,

moreover, these surfaces of the sections are at a given moment of time under the bow and stern IPIA of the echo sounding systems, i.e. bow (H) and stern (K) parts of a moving ship with a speed ( ) relatively layer, which ensures the formation bow and stern information signals that carry both amplitude and phase information about surface areas, making it possible to judge their reflectivity and acoustic resistance, as well as their depth;

15) convert using the direct piezoelectric effect of the piezoelectric elements of the EAP bow and stern IPIA bow and stern information signals from

sections of surfaces of sets of scatterers of the aquatic environment that move at different speeds currents on 1, 2,…, , .., depth horizons and are currently under the bow (H) and stern (K) parts of the moving with speed ( ) vessel relative to th layer,

- and the boundaries of the section "water - bottom" with a random distribution of bottom irregularities,

into the corresponding electrical signals entering the input of the receiving path of the equipment;

- carry out vertical spatial stratification of sets of scatterers of the aquatic environment into 1, 2, ..., , .., depth horizons, producing in the receiving paths of echo sounding systems on phase-coupled signals of multiple frequencies strobe of the corresponding electrical signals by setting the same values - the width of the strobe , their initial location relative to the bottom, speed and sequence of movement of the strobe;

- are generated in the receiving path of the equipment on each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, which are proportional to the distribution of the depths of the water area under the bow and stern parts of the hull moving at speed vessel;

- measure for pairs identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals And , quantities transport delay values , which allows us to calculate vessel speed values relative to the bottom;

- are generated in the receiving path of the equipment on each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals visualizing acoustic contacts with sets of scatterers located in separate 1, 2,…, , .., layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons, for example, for th depth horizon And , proportional to the random distribution of sets of scatterers in - that layer under the bow and stern parts of the hull moving at a speed vessel regarding -th layer (horizon);

- measure for pairs of identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals, for example, for th depth horizon And , quantities transport delay values , having measured which, they calculate vessel speed values = relatively -th layer (horizon);

- calculate speed values currents in -th layer (depth horizon) as the difference between the values ship's speed relative to -th layer (depth horizon) and velocities vessel relative to the bottom, where the “+” sign corresponds to the passing, the “-” sign - to the opposite direction of the current in -th layer (depth horizon) of the reservoir, respectively, relative to the velocity vector of the vessel;

- are generated in the receiving path of the equipment on two phase-coupled signals of multiple frequencies two amplitude-time dependences of electrical signals visualizing acoustic contacts and resistances of scatterer sets located in separate 1, 2, ...,, .., layers when dividing the aquatic environment into 1, 2, ...,, .., depth horizons, for example, forth depth horizon And, proportional to the random distribution of the acoustic resistance value (soft or hard relative to the aquatic environment) of sets of scatterers in- that layer under the bow and stern parts of the hull moving at a speed vessel regarding-th layer (horizon);

- they are measured for two identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals that visualize acoustic contacts, and the resistance of scatterer sets, for example, for th depth horizon And , the value of the transport delay , by measuring which, calculate the value of the ship's speed = relatively -th layer (horizon);

- determine the values of the arithmetic mean values of speeds:

1) the absolute movement of the ship, i.e. relative to the bottom

2) the relative motion of the vessel, i.e. with respect to 1, 2,…, , .., layers,

3) passive transfer of sets of scatterers located in separate 1, 2, ..., , .., layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons;

- carry out display, registration and documentation of measurement results in the equipment:

1) a detailed structure of the distribution of the depths of the reservoir in real time on the move of the vessel-carrier of the equipment,

2) the absolute (relative) speed of the carrier ship,

3) the parameters of currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment, which is presented as a vertical profile of the current velocity in k layers of a stratified water volume, which is projected onto the diametrical plane of the ship.

The proposed method is illustrated by the following drawings.

Figure 1 shows a block diagram of a device that implements the claimed invention;

figure 2 - schematically shows the dependence of the values of electrical voltages , produced by the receiving paths of the bow and stern echo sounding systems, from the current time on probing signals of multiple frequencies: -, , ….. , i.e. functions of the sea depth (bottom profiles on the spectral components of the polyharmonic sounding signal);

in Fig.3. schematically shown:

a) a layer of the water volume containing sets of scatterers - “acoustically soft” (on the left, plankton saturated with gas bubbles, < ), “acoustically hard” (on the right, the volume saturated with suspended particles, > ); b) dependencies of video-pulse information electrical signals And on time t, which are proportional to the distribution of acoustic resistance of sets of scatterers in this layer.

Implementing the proposed method, the multi-frequency correlation hydroacoustic log (figure 1) functionally combines two (bow and stern) echo sounding systems (radiation, reception, display and registration of information), supplemented by common paths: correlation processing of information, measuring the speed of the vessel, phase processing and control. Echo sounding systems have a common radiation path: generator 1 is connected through serially connected timer-modulator 2, power amplifier 3 and switches 4 and 5 in the "Transmission" mode with IPIA 6 and 7 (stern and bow, respectively). Bow 7 and stern 6 IPIA are placed in the diametrical plane along the ship's hull at a distance (base), are oriented with their acoustic axes vertically down to the seabed surface. Ultrasonic echo contacts with different, but belonging to the same route, sections of the bottom surface are carried out through the aquatic environment. The aquatic environment has an inhomogeneous fine structure with boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, sound speed) for layers of sets of scatterers that are randomly and statistically inhomogeneously distributed in the water volumes of the layers (from 1 tok), having different acoustic impedance and neutral buoyancy, are passively carried by water masses with different linear current velocities relative to the bottom. Echo sounding systems have separate receiving paths. IPIA 6 through switch 4 (stern) in the "Receive" mode is connected through parallel-connected chains of series-connected band-pass filters 8, 9, ...., 10 (frequencies), gated amplifiers 14, 15, ..., 16, amplitude detectors 20, 21, ..., 22 s-input analog key 26, and IPIA 7 through the switch 5 (nose) in the "Receive" mode is connected through parallel-connected chains of series-connected band-pass filters 11, 12, ...., 13 (frequencies), gated amplifiers 17, 18, ..., 19, amplitude detectors 23, 24, ..., 25 s- input analog key 27. In both echo sounding systems, paths for displaying and recording information are provided, for which the outputs- input analog keys are connected to the inputs of indicators and recorders: in the stern echo sounding system -- input analog key 26 - with indicator 33 and recorder 34, and in the bow echo sounder system -- input analog key 27 - with indicator 35 and recorder 36. Receiving paths of echo sounding systems are connected to a common path for correlation processing of information and measuring the ground speed of the ship: outputs- input analog switches 26 and 27 are connected to two inputs of the multiplying device 29, and the analog switch 26 (stern) is connected through the adjustable time delay unit 28, the control input of which is connected through the extreme controller 32 to the output of the integrator 30 and the input of the measuring device 31. The input of the integrator 30 is connected to the output of the multiplying device 29. Operated amplifiers 14, 15, ..., 16 and 17, 18, ..., 19, analog switches 26 and 27, indicators 33 and 35, recorders 34 and 36, and the chronizer-modulator 2 are connected to the corresponding outputs of the control unit 37. Phase processing is carried out in the receiving paths of both echo sounding systems. So, in the receiving path of the nasal (N) echo sounding system (figure 1) after filtering (bandpass filter 11, frequency and bandpass filter 12, frequency) and amplification (amplifier 17, frequency and amplifier 18, frequency) stand out - electrical signal with frequency, which after frequency doubler 40 () is fed to the first input of the phase detector 44, as well as an electrical signal with frequency through the phase shifter 42 is fed to the second input of the phase detector 44, the output of which is connected to an additional input- input analog key 27. Exit-input analog switch 27 is connected both to the indicator 35 and to the recorder 36, and also through the adjustable time delay unit 28 with the first input of the multiplier 29. The control input of the phase shifter 42 is supplied with an electrical signal from the corresponding output of the control voltage generation unit 38, which is triggered by a sync pulse from the additional output of the control unit 37. Characteristics of a bipolar electrical signal, formed at the output of the phase detector 44 and fed through the adjustable time delay unit 28 to the first input of the multiplier 29, are proportional to the change in such an informative parameter of the irradiated areas of the scatterer sets located in the selected layer at a given depth horizon under the bow echo sounder system on the ship’s route, as the acoustic resistance of the scatterer sets, and when locating “acoustically soft” a (plankton saturated with gas bubbles, <) the signal will have a negative polarity, and for "acoustically hard" (volume saturated with suspended particles, >) is positive, and for areas with intermediate values of acoustic impedance, the electrical signal will have a fluctuating amplitude and polarity. Phase processing in the receiving path of the stern (K) echo sounding system is carried out in a similar way: - after filtering (bandpass filter 8, frequency and bandpass filter 9, frequency) and amplification (amplifier 14, frequency and amplifier 15, frequency) stand out - electrical signal with frequency, which after frequency doubler 39 () is fed to the first input of the phase detector 43, as well as an electrical signal with frequency through the phase shifter 41 is fed to the second input of the phase detector 43, the output of which is connected to an additional input- input analog key 26. Output- input analog switch 26 is connected to the indicator 33 and to the registrar 34, as well as to the second input of the multiplier 29. The second input of the multiplier 29 receives a bipolar electrical signal, formed at the output of the phase detector 43, which is proportional to the change in such an informative parameter of the irradiated areas of the sets of scatterers located under the stern echo sounding system on the ship's route, as acoustic resistance. Note that the electrical signal, formed at the output of the phase detector 44 by the stern echo sounding system on the ship's route,will be delayed by a period of time relative to electrical signal, already formed at the output of the phase detector 43 by the bow echo sounding system on the ship's route. Thus, as the vessel moves along a given course, two amplitude-time dependences of electrical signals are continuously determined And, visualizing the acoustic contacts and resistances of diffuser sets located in separate 1, 2,…,, .., layers when dividing the aquatic environment into 1, 2, ...,, .., depth horizons, for example, forth depth horizon And, proportional to the random distribution of the value of acoustic resistance (soft or hard relative to the water environment) of sets of scatterers in- that layer under the bow and stern parts of the hull moving at a speed vessel with regard toth layer (horizon).

The inventive method using a multi-frequency correlation hydroacoustic lag that implements the proposed method occurs as follows.

Generator 1 of the radiating path of echo sounding systems generates an electrical signal with frequency , supplied to the input of the chronizer-modulator 2, which is put into operation by the operator on command from the control unit 37, as a result of which a radio pulse is obtained at the output of the chronizer-modulator 2 with harmonic content. After power amplifier 3 radio pulse enters through the switches 5 and 4 in the “Transmission” mode to the IPIA 7 and 6 (bow and stern, respectively), emitting powerful (in accordance with relation (2)) probing ultrasonic signals into the aquatic environment, which has a nonlinearity of its elastic properties. Bow 7 and stern 6 IRIA echo sounding systems are placed in the diametrical plane along the ship's hull at a distance and oriented acoustic axes vertically downwards (figure 1), and their XN must have such a sharpness of the directional action that the irradiated areas of the bottom do not overlap.

Note that the bow 7 and stern 6 IRIA echo sounding systems provide the formation and reception of wave processes in the aquatic environment, because It is ultrasound that is effective for transmitting and receiving information in the aquatic environment, and the design of this multi-frequency correlation method for measuring the parameters of the aquatic environment causes a significant increase in the power of the emitted waves. Under these conditions, the role of the hydroacoustic channel as a sound-conducting medium begins to change - from "linear" acoustics, within which the change in water density still linearly depends on the change in the sound pressure of the propagating wave process, which determines the implementation of the superposition principle to "nonlinear" acoustics, where the nonlinearity of its elastic properties begins to manifest itself, causing both self-action and interaction of propagating waves of finite amplitude, leading to the generation of new spectral components of combination frequencies. It should be taken into account that all processes leading to a decrease in the acoustic energy flux density - dissipative, diffractive, etc. weaken non-linear phenomena, which makes it important to clarify the range of values of the non-linear regime both for the EAP bow 7 and stern 6 IPIA echo sounding systems, and emitted powerful waves. Below we will discuss the criterion for the correspondence (6) of the wave sizes for the EAP of both 6, 7 IPIA echo sounding systems to the range of values 10 < < , which ensures the operability of the multi-frequency correlation hydroacoustic lag, in which the proposed method is implemented.

In nonlinear acoustics, it is customary to evaluate the relative influence of dissipative, diffractive, and nonlinear effects on powerful radiated waves by calculating dimensionless quantities: the Khokhlov parameter , the Reynolds number or parameter (see Novikov B.K., Rudenko O.V., Timoshenko V.I. Nonlinear hydroacoustics. - L .: Shipbuilding, 1981. - 264 p., pp. 13-14, 100 -102, Zarembo L.K., Krasilnikov V.A. Introduction to nonlinear acoustics. - M .: Publishing house "Nauka", 1966. - 520 pp., pp. 98 -110) for a specific EAP using the ratios:

- distance of a plane wave break with a frequency (rad/s) and sound pressure amplitude (Pa) at the EAP surface, m;

is the length of the Fresnel diffraction region for a pump wave with a frequency (rad/s), m;

- acoustic wave attenuation distance, m. Attenuation coefficient (Np/m) acoustic signal with frequency in sea water, calculate according to the ratios of Sheehy and Helly, as well as Lieberman (see Novikov B.K., Rudenko O.V., Timoshenko V.I. Nonlinear hydroacoustics. - L .: Shipbuilding, 1981. - 264 p., pp. 23-26). For fresh water attenuation factor (Np/m) related to frequency (1/s) by the following equation: (see Yakovlev A.N., Kablov G.P. Short-range sonars. - L .: Shipbuilding, 1983.-200s., pp. 7-9)

amplitude of the sound pressure of the pump signal near the EAP surface, Pa. Here:

the amplitude of the sound pressure of the pump signal, reduced to a distance of 1 meter from the EAP, taking into account attenuation.

Approximately estimate the limiting values of the pumping sound pressure amplitudes at which nonlinear effects begin to appear, it was proposed (see Novikov B.K., Rudenko O.V., Timoshenko V.I. Nonlinear hydroacoustics. - L .: Shipbuilding, 1981. - 264 p., pp. 248-252) as follows. The formation of discontinuities for plane waves is characterized by the value of the parameter hence the corresponding amplitude of the sound pressure near the EAP surface is equal to

Where - dissipative coefficient of the medium. But since diffraction phenomena significantly weaken nonlinear effects, for limited pump beams at these values breakup may or may not occur. Then, neglecting the nonlinear damping of the pump wave and assuming , the limiting levels of sound pressure amplitudes are calculated by the formula

Thus, the amplitude of the sound pressure near the surface of the EAP for each of the pump signals, the FIA lies within the limits determined in accordance with (8) and (9). Relation (9) taking into account the fact that the diameter of the IPIA , and frequency , can be transformed and presented in the form

which limits the value of the EAP wave size from above for IPIA 7 and 6 (bow and stern, respectively) echo sounding systems, and the lower boundary ( ) can be established from the results of experiments (see Novikov B.K., Rudenko O.V., Timoshenko V.I. Nonlinear hydroacoustics. - L .: Shipbuilding, 1981. - 264 p., pp. 161-165, 171-179, 182-188).

Let us analyze the typical results of experimental measurements of the spatial characteristics of acoustic signals of multiple frequencies obtained by implementing the "linear" and "nonlinear" modes of radiation of a powerful single-frequency pump signal, for example, for the EAP of the IPIA fish-searching equipment of the Taimen-M sonar in the self-action mode (see Voloshchenko V.Yu., Voloshchenko A.P. Parametric hydroacoustic means of short-range underwater observation. Southern Federal University. - Rostov-on- Don, Taganrog: Publishing house of Southern Federal University, 2018.-176 p., pp. 29-42). So, for IPIA RPA "Taimen-M" several angular distributions of sound pressure amplitudes for acoustic signals of multiple frequencies are presented, obtained in two modes:

1) ( ) - "linear", corresponding to the direct excitation of the EAP of the antenna at frequencies =50 kHz ( ), =100 kHz ( ), =150 kHz ( );

2) ( ) - "non-linear", corresponding to the standard mode of excitation of the EAP of the RPA antenna at the frequency =50 kHz ( ), which leads to the generation of higher harmonics in the aquatic environment ( ).

So, the IPIA of the Taimen-M sonar has: in the "nonlinear" mode - at a frequency \u003d 50 kHz angular width of the main lobe XH at a level of 0.7 \u003d 14.4 ° and the level of lateral radiation =(-19 dB); at frequency = 100 kHz - =10.8° and = (- 23 dB); at frequency = 150 kHz - =8.1° and = (-23 dB);

in the "linear" mode of direct excitation - at a frequency\u003d 50 kHz angular width of the main lobe XH at a level of 0.7 = 14.4° and the level of lateral radiation = (-19 dB); at frequency= 100 kHz -= 7.2° and= (-19 dB); at frequency= 150 kHz -= 4.8° and= (-18 dB).

It can be seen from the presented data that in the “linear” case at all US frequencies, the level of the side field of the XH practically does not change (-18 dB), and the angular width of the main lobe of the XN decreases in accordance with the known patterns - (14.4 °, 7.2 °, 4.8 °) - (see A.P. Evtyutov, V.B. Mitko Engineering calculations in hydroacoustics. - 2nd ed., Rev. and add. - L. : Shipbuilding, 1988. pp. 17-27), in the "nonlinear" mode, a powerful acoustic signal most noticeably changes the elastic properties of the aquatic environment precisely on the antenna axis, which leads to a significant weakening of the side field - from (-18 dB) to (-23 dB) - and a gradual sharpening of the main lobe - (14.4 °, 10.8 °, 8.1 °), and the use of the "non-linear mode" significantly expands the operating range of the device, realizing the proposed method.

Analyzing the above information about location signals of multiple frequencies , we can conclude that it is advisable to use the bow 7 and stern 6 IRIA echo sounding systems in a complex - "nonlinear mode" - the formation of wave processes in the aquatic environment, - "linear mode" - the reception of reflected signals, which will expand the operational capabilities of the known correlation method, providing, in particular, obtaining reliable information about the parameters of the currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment with randomly distributed volumes of scatterers.

The aquatic environment has an inhomogeneous fine structure with boundary layers with sharp changes in thermodynamic characteristics (temperature, salinity, sound speed) forilayers of scatterers, which are randomly and statistically non-uniformly distributed in the water volumes of the layers (from 1 tok), having different acoustic impedanceand neutral buoyancy, and are passively carried by water masses with different linear current velocities relative to the bottom (see Michael S. Gregg. Ocean Microstructure // Ocean Science / Edited by O. I. Mamaev. - M .: Progress Publishing House, 1983. - p. 219-243). Polyharmonic probing ultrasonic signal containing spectral components with frequencies, propagates in the ranging medium, which has acoustic resistance (), Where- medium density,- the speed of sound in it reaches the moving ones located in the medium (layers of diffusers with acoustic resistance, forming a volumetric reverberation signal) and objects at rest (bottom) relative to it with acoustic resistance ()≠() and reflected from them. The amplitudes of the reflected ultrasonic waves that carry information about objects are determined by their scattering (reflecting) properties, which are determined by the shape of the objects, the exposure angle, and wave sizes. The reflected spectral components of the polyharmonic ultrasonic signal, due to the smallness of the disturbance amplitudes during backpropagation, obey the laws of "linear" acoustics, reach the IPIA 7 and 6 (bow and stern, respectively) echo sounding systems, convert their EAP into the corresponding electrical, and polyharmonic electrical signals carry certain amplitude information about the interfaces, make it possible to judge their reflectivity in a wide frequency band (), as well as about their removal from IPIA 7 and 6. Thus, when the vessel moves at a speed using both echosounder systems on different spectral components of the reflected polyharmonic signal can be fixed with different resolution details of the detailed profiles of the irradiated areas of the surfaces of the sets of scatterers of the aquatic environment, in layers of which they are randomly and statistically non-uniformly distributed. It should be noted that each set of scatterers in any of layers has a "unique" set of characteristics, in particular, on-volume depth horizon - the number of structural elements, their linear size, reflectivity and acoustic impedance. As can be seen from figure 1, these-you are e areas of surfaces of sets of scatterers in layers of the aquatic environment are at a given time under the bow (Н) and stern (К) parts of the moving at a speed () vessel relative tolayer, which ensures the formation bow and stern information signals, in particular, volumetric reverberation processes, the envelopes of which fluctuate chaotically, as well as-th sections of the seabed surface located on a common route.

For this purpose, the corresponding signal processing is carried out in the receiving paths of the bow and stern echo sounding systems of a moving vessel. at the command of the operator through the control unit 37. As a result, at the output of the receiving path of the nasal echo sounding system after filtering (bandpass filters 11 ( ), 12 ( ),…13 ( )), gating and amplification (gated amplifiers 17, 18, ...19), detection (detectors 23, 24, ...25) and the corresponding switching -input analog key 27 emits a video-pulse electrical signal , corresponding to the echo signal of any one selected by the operator as a working spectral component from a set of frequencies , , …., from the irradiated surfaces of the layers of scatterers, as well as the seabed located under the bow of the ship's hull. Video impulse electrical signal is supplied to the path for displaying and recording information - to the inputs of the indicator 35 and the recorder 36, triggered by the supply of a clock pulse from the output of the control unit 37. Similarly, at the output of the receiving path of the aft echo sounder system after filtering (bandpass filters 8 ( ), 9 ( ),…10 ( )), gating and amplification (gated amplifiers 14, 15, ...16), detection (detectors 20, 21, ...22) and the corresponding switching -input analog key 26 emits a video-pulse electrical signal , corresponding to the echo signal of any one selected by the operator as a working spectral component from a set of frequencies , , …., from the irradiated surfaces of the layers of scatterers, as well as the seabed, located under the aft part of the ship's hull. Video impulse electrical signal is fed into the path for displaying and recording information - to the inputs of the indicator 33 and the registrar 34, triggered by the supply of a clock pulse from the output of the control unit 37. Figure 2 schematically shows the dependence of the magnitudes of electrical voltages , produced by the receiving paths of the bow and stern echo sounding systems, from the current time on probing signals of multiple frequencies: -, , ….. , i.e. functions of the depth of the sea corresponding to its relief, as can be seen from the comparison of figure 1 and figure 2 (bottom echograms on the route of the vessel, registered on the spectral components of the polyharmonic sounding signal),

As an example, let us consider the influence of the angular width of the main CI lobe and the level of lateral radiation of the IRIA of the echo sounding system on the nature of the recording of the seabed relief, in particular, in our case, the resulting sharpness of the directional action transmitting antenna, where . So, the obtained image of the bottom relief on the echogram basically corresponds to the actual relief, however, the bottom irregularities (depressions and elevations) are smoothed out. When the bow of the vessel passes over the depression (figure 1), its slopes are irradiated by a polyharmonic probing ultrasonic signal containing spectral components formed in a nonlinear aquatic environment with frequencies , on which IPIA 7 in the radiation mode has a different severity of directional action (nonlinear mode). It should be noted that the sharpness of the directional action of the same IPIA 7 in the mode of receiving a higher frequency component also increases: (linear mode). Thus, the formation of the resulting HH of the IPIA antenna 7 for each spectral component has its own characteristics, due to the multiplication of its HH by pressure in both modes: the attenuation of the level of side radiation, a slower decrease in the angular width of the main lobe of the HH, and . As follows from figure 1, the signals of different spectral components are reflected from different areas of the surface of the cavity, as a result of which they return to the IPIA 7 non-simultaneously, which leads to an elongation of the echo signals, as well as registration on the echogram of the first reflected signals that came from the points of the cavity surface closest to the receiver. Thus, the image of the relief of the depression (hill) on the echogram is the locus of points on the horizontal projection of the irradiated area of the deepening (hill) of the seabed, located at the shortest distance from IPIA 7 at different positions of the bow of the vessel relative to the depression (see Loginov K.V. Electrical navigation and fish-searching devices. - M .: Easy and food industry, 1983, p. 292-29 6). As can be seen from the graphical constructions, the degree of distortion of the profile of depressions and elevations of the bottom on the echogram decreases for higher frequency spectral components (figure 2). The masking of the real relief of the seabed along the route of the ship is due to the sphericity of the wave front of the ultrasound signals, as a result of which there is an uncertainty in the assessment of the actual depth and irregularities on the received echogram are shown as smoothed. In the event that the depth measurement is carried out in water areas with large bottom slopes, the indicator and the echo sounder recorder will record depths less than the actual one, since their operation is due to the arrival of the first echo signal corresponding to the shortest distance between the TSSI and the bottom, which determines the presence of appropriate corrections in measurement practice. In particular, if α - the angle of the bottom slope is greater than the angular width of the main lobe ХН at a level of 0.7, then the first to arrive at the antenna is an echo signal propagating in a direction perpendicular to the inclined section of the bottom, and the correction for the bottom slope is determined by the formula

moreover, in this direction, the section of the inclined bottom can “acoustically illuminate” the additional lobe of the XH, which indicates the relevance of reducing the level of lateral radiation of the ISIA echo sounders. From relation (11) it can be seen that an increase in the sharpness of the directional action of the echo sounder PIIA (i.e., a decrease ) leads to a decrease . When the vessel passes through water areas with a strongly dissected bottom, the depth measurement error will also depend on the bottom profile: when the vessel moves, a band of the bottom surface with a width of , within which the nearest bottom areas are recorded, which masks the irregularities in the immediate vicinity, in connection with which an increase in the sharpness of the directional action of the PSIA will lead to a more accurate display of the complex bottom profile on the recorder.

Thus, as the vessel moves at a speed at a given rate are continuously generated in the receiving path of the equipment at each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, which are proportional to the distribution of the depths of the water area under the bow and stern parts of its hull. These functions are identical to each other and can be registered by the operator on any of the operating frequencies. depending on the specific conditions of navigation, but shifted in time by the values - transport delays - . To determine the values of time intervals video pulse electrical signals And , corresponding to the echo signals of any one selected by the operator as a working spectral component from a set of frequencies , , …., echo sounding systems are fed to two inputs of the multiplying device 29, and the signal from the stern IPIA is through the adjustable time delay unit 28. From the integrator 30, the signal is proportional to the coefficient cross-correlation of signals And , is supplied to the extreme controller 32 and to the measuring device 31. The control signal from the extreme controller 32 acts on the adjustable delay block 28, which sets such a delay so that the maximum signal is maintained on the measuring device 31, i.e. coefficient maximum correlations. The value of the entered delay determines the speed of the ship, measured at several frequencies

For a multi-frequency correlation hydroacoustic lag, it is possible to increase the accuracy characteristics and select the optimal value of the relative fluctuation error of ground speed measurement determined by relation (1), by adjusting the value of an important parameter - - the width of the peak of the cross-correlation function, which may be necessary when maneuvering the vessel at low speeds in narrow places, in the waters of the harbor, etc. It should be noted that the use of the reversible interference antenna of the RPA "Taimen" as a multi-frequency correlation hydroacoustic lag IPIA can provide a reduction in the relative fluctuation error of the ground speed measurement. due to the fact that, due to the laws described above, it is possible to adjust the value of the parameter - - peak width of the cross-correlation function for the corresponding spectral component of the polyharmonic signal (when using a higher frequency signal, the numerator decreases faster than the denominator , which causes a decrease in the ratio itself ) , where is the wavelength of the ultrasonic signal used (varies with once), is the angular width of the resulting main lobe of the HN IPIA (radiation - "nonlinear" mode, reception - "linear" mode).

Let's consider one more example. The relative error in measuring the ground speed due to the vertical movements of the vessel on the roll with amplitude detection is described by the relation

Where - the average value of the range of vertical movements of the vessel, - the period of vertical oscillations of the vessel. It can be seen from (13) that, with amplitude detection, the relative error in measuring the ground speed due to the vertical movements of the ship on the roll increases with an increase in the range of vertical movements and with a decrease in the ground speed of the ship and the roll period, but decreases with a narrower main lobe of the SI SIAA.

The mode of operation of the correlation hydroacoustic log for measuring the absolute ground speed of the vessel is described above, i.e. relative to the bottom of the sea, and at great depths the device can operate in a relative mode, the information carrier in which is volumetric reverberation. To this end, the operator sets the vertical stratification of the sets of scatterers placed in the aquatic environment by 1, 2, ...,, .., depth horizons, carried out in the receiving paths of echo sounding systems (strobe amplifiers 17, 18, ... 19 and 14, 15, ... 16), on phase-coupled signals of multiple frequencies strobe of the corresponding electrical signals by setting the same values - the width of the strobe, their initial location relative to the bottom, the speed and sequence of the gate movement. As a result, are produced in the receiving path of the equipment at each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals visualizing acoustic contacts with sets of scatterers located in separate 1, 2, ...,, .., layers when dividing the aquatic environment into 1, 2, ...,, .., depth horizons, for example, forth depth horizon And, proportional to the random distribution of sets of scatterers in- that layer under the bow and stern parts of the hull moving at a speed vessel regardingth layer (horizon). For them, similar operations are carried out using the blocks and links described above, i.e. measure for pairs of identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals, for example, forth depth horizon And, quantities transport delay values, having measured which, they calculate vessel speed values= relativelyth layer (horizon). This makes it possible to calculate speed values currents in-that layer (depth horizon) as the difference between the values ship's speed relative to-th layer (depth horizon) and velocities vessel relative to the bottom, where the sign "+" corresponds to the passing, the sign "-" - to the opposite direction of the current in-th layer (depth horizon) of the reservoir, respectively, relative to the velocity vector of the vessel.

However, in specific operating conditions (maneuvering both in the roadstead and in the port, providing locking and mooring), the operability of the device that implements the proposed method, due to the use of only the above-described processing of only the amplitude characteristics of echo signals of multiple frequencies may be broken. The fact is that in the water areas of “man-made” waterways (navigable channels of the internal transport system of rivers, lakes, reservoirs, etc., artificial channels and fairways of harbors), there are practically no uneven topography of the bottom surface due to dredging, and volumetric reverberation signals also do not provide a clear separation of the fine structure of the aquatic environment into layers due to amplitude features, while the difference in acoustic impedance of scatterer sets is preserved. Under these operating conditions, the device provides for the possibility of registering a change in such an informative parameter of the irradiated areas of the surfaces of the sets of diffusers in the layers of the aquatic environment on the route of the ship as their acoustic impedance. Thus, the expansion of the operational capabilities of the proposed method, which makes it possible to determine the depths of water areas and the speed of the vessel (absolute and relative) when moving on natural and artificial transport waterways, can be achieved by appropriate processing of the phase characteristics of echo signals of multiple frequencies.

Let us consider the basics of the operability of the phase receiving path of a device that implements the proposed method, based on the use of the following method for obtaining a phase-frequency characteristic (PFC) of the interface, implemented using two coherent harmonic acoustic signals And multiple frequencies And , differing in frequency by an integer number of times or , with the help of which the echo sounding system irradiates the surface (see Voloshchenko V.Yu., Timoshenko V.I. Parametric hydroacoustic means of short-range underwater observation. (Part 1). - Taganrog: Publishing House of TTI SFU, 2009.-294 p., pp. 204 - 206). Let two acoustic signals

Where And - initial phases and cyclic frequencies for the corresponding acoustic signals. If the reflective surface is far away , then in time to the receiving antenna (without attenuation and expansion of the wave front) echo signals will arrive:

Where And - wave numbers for the corresponding signals with frequencies And ; - speed of sound in water; And - magnitudes of the moduli of the reflection coefficients and the acquired phase shift for the sound pressure of acoustic signals upon reflection from the irradiated surface. After processing in the receiving paths of the location device of phase-coupled echo signals And (filtering, amplification, reduction to one frequency, phase detection) it is possible to obtain information about the phase characteristic of the reflective surface of the target by determining the phase of one of the echo signals by comparison with another echo signal used as a reference. So, for example, the phase difference reduced to the same frequency of phase-coupled signals ( ) multiples of frequencies And , will be equal to:

those. the phase difference of the phase shifts acquired during reflection does not depend on time propagation of signals, nor from distance to the reflecting object, but is determined only by the ratio of the acoustic impedance of the surface of the object and the location environment. When irradiating acoustically "hard" objects (outcrop of dense bedrock, rocky bottom in the sea), acoustic resistance which is greater than the acoustic resistance of the propagation medium , reflection of acoustic signals And multiple frequencies occurs without a phase shift by radian, i.e. And . In the case of reflection from acoustically “soft” objects (the upper layer of river soil saturated with gas bubbles), the acoustic resistance which is less than the acoustic resistance of the propagation medium , reflection of acoustic signals And multiple frequencies occurs with a phase shift of radian, i.e. And .

In the device that implements the proposed method, both in the bow (N) and stern (S) echo sounding systems, as phase-coupled signals of multiple frequencies, a pump signal with a frequency and the second harmonic formed in a nonlinear water medium with a frequency . Consider the operation of the phase receiving path of the device that implements the proposed method, for example, in the receiving path of the nasal (H) echo sounding system (figure 1) after filtering (bandpass filter 11, frequency and bandpass filter 12, frequency ) and amplification ( amplifier 17, frequency and amplifier 18, frequency ) stand out - electrical signal with frequency , which after frequency doubler 40 ( ) is fed to the first input of the phase detector 44, as well as an electrical signal with frequency through the phase shifter 42 is fed to the second input of the phase detector 44, the output of which is connected to an additional input - input analog key 27. Exit -input analog switch 27 is connected both to the indicator 35 and to the recorder 36, and also through the adjustable time delay unit 28 with the first input of the multiplier 29. The control input of the phase shifter 42 is supplied with an electrical signal from the corresponding output of the control voltage generation unit 38, which is triggered by a sync pulse from the additional output of the control unit 37. Characteristics of a bipolar electrical signal , formed at the output of the phase detector 44 and fed through the adjustable time delay unit 28 to the first input of the multiplier 29, are proportional to the change in such an informative parameter of the irradiated areas of the scatterer sets located in the selected layer at a given depth horizon under the bow echo sounder system on the ship’s route, as the acoustic resistance of the scatterer sets, and when scanning “acoustically soft”, a (plankton saturated with gas bubbles, < ) the signal will have a negative polarity, and for "acoustically hard" (volume saturated with suspended particles, > ) is positive, and for regions with intermediate values of acoustic impedance, the electrical signal will have fluctuating both amplitude and polarity.

The operation of the phase receiving path of the multifrequency correlation lag in the receiving path of the stern (K) echo sounding system is carried out in a similar way: - after filtering (bandpass filter 8, frequency and bandpass filter 9, frequency ) and amplification (amplifier 14, frequency and amplifier 15, frequency ) stand out - electrical signal with frequency , which after frequency doubler 39 ( ) is fed to the first input of the phase detector 43, as well as an electrical signal with frequency through the phase shifter 41 is fed to the second input of the phase detector 43, the output of which is connected to an additional input - input analog key 26. Output - input analog switch 26 is connected both to the indicator 33 and to the recorder 34, as well as to the second input of the multiplier 29. A bipolar electrical signal is supplied to the second input of the multiplier 29 , formed at the output of the phase detector 43, which is proportional to the change in such an informative parameter of the irradiated areas of the sets of scatterers located under the stern echo sounding system on the ship's route, as acoustic resistance. Note that the electrical signal , formed at the output of the phase detector 44 by the stern echo sounding system on the route of the vessel , will be delayed by a period of time relative to electrical signal , already formed at the output of the phase detector 43 by the bow echo sounding system on the ship's route. Thus, as the vessel moves along a given course, two amplitude-time dependences of electrical signals are continuously determined And , visualizing acoustic contacts and resistances of diffuser sets located in separate 1, 2, ..., , …, layers when dividing the aquatic environment into 1, 2, ..., , …, depth horizons, for example, for th depth horizon And , proportional to the random distribution of the value of acoustic resistance (soft or hard relative to the water environment) of sets of scatterers in - that layer under the bow and stern parts of the hull moving at a speed vessel with regard to th layer (horizon).

Figure 3 in the upper part does not show a moving vessel carrier of hydroacoustic equipment, as well as multi-frequency beams from its echo sounding systems, but it is assumed to move from left to right, as in figure 1. Let us clarify that in figure 1 in the aquatic environment its stratified structure is schematically depicted, in the layers of which there are sets of scatterers passively carried by currents. More details in Fig.3. schematically depicted: a) a fixed separate layer of the water volume (marked with horizontal strokes), containing sets of scatterers - “acoustically soft” (on the left, an area filled with dots, plankton saturated with gas bubbles, < ), “acoustically hard” (on the right, the area filled with shading, volume saturated with suspended particles, > ). The results of processing phase-related signals of multiple frequencies - the first and second harmonics - in the phase receiving path of a vessel moving from left to right are shown in Fig.3 b) in the form of two dependencies of video-pulse information electrical signals And on time t, which are proportional to the distribution of acoustic resistance of sets of scatterers in this layer. The bow echo sounding system of the ship-carrier first irradiates both "acoustically soft" (negative video pulse) and "acoustically hard" (positive video pulse) sets of scatterers spatially separated in the layer. Then the stern echo sounding system also irradiates the same sets of scatterers, as a result of which we get the same sequence of video pulses, but shifted along the time axis to the right, due to the delay of the stern echo sounding system of the moving vessel.

In the future, the operator measures for two identical to each other, but shifted in pairs in time, the amplitude-time dependences of electrical signals And , visualizing acoustic contacts, and the resistance of diffuser sets, for example, for th depth horizon And , the value of the transport delay , having determined which, the value of the speed of the ship is calculated = relatively th layer (horizon).

To determine the value of the time interval video pulse electrical signals And , is fed to two inputs of the multiplying device 29, and the signal from the nasal FIA is through the adjustable time delay unit 28. From the integrator 30, a signal proportional to the coefficient cross-correlation of these signals, is fed to the extreme controller 32 and to the measuring device 31. The control signal from the extreme controller 32 acts on the adjustable delay block 28, which sets such a delay so that the maximum signal is maintained on the measuring device 31, i.e. coefficient maximum correlations. The magnitude of the introduced delay determines the absolute speed of the ship, measured on phase-coupled acoustic signals of multiple frequencies

Similarly, measurements can be made, for example, for th depth horizon And, the value of the transport delay, by measuring which, calculate the value of the ship's speed= relativelyth layer (horizon).

Thus, the device that implements the proposed method allows the operator to calculate the values of the arithmetic mean values of speeds: 1) the absolute movement of the vessel, i.e. relative to the bottom, 2) the relative movement of the vessel, i.e. with respect to 1, 2, …, , …, layers, 3) passive transfer of sets of scatterers located in separate 1, 2, ..., , …, layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons.

In addition, the display, registration and documentation of the results of measurements of the detailed structure of the distribution of the depths of the reservoir in real time on the move of the ship carrying the equipment, as well as the parameters of the currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment in the form of a vertical profile of the current velocity in k layers of a stratified water volume projected onto the diametrical plane of the vessel.

Claims (32)

1. Correlation method for measuring the parameters of the fine structure of the aquatic environment, which consists in the fact that - placed at a distance in the diametrical plane of the ship, in particular in the fore and aft parts of the bottom, two measuring parametric radiating antennas of the RTSI of echo sounding systems, including a given number of electroacoustic transducers of the EAP, with both RTIAs oriented vertically down with acoustic axes, have the same wave sizes, and the areas of the bottom under the bow and stern of the vessel irradiated by ultrasonic waves do not overlap; - provide operability in the modes of emission / reception of each EAP through the use of reverse / direct piezoelectric effects with a given resonant frequency ; - generate electrical oscillations in the radiating path of the equipment, which are converted into short-term amplitude-pulse modulated oscillations, the envelope of which repeats the shape of rectangular pulses, and the package contains a carrier frequency ; - using the direct piezoelectric effect of the EAP piezoelectric elements, the bow and stern IPIA are converted into amplitude-pulse modulated oscillations into periodic bursts of ultrasonic waves with a given duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment due to the propagation of oscillations with a cyclic frequency and forming due to interference in the aquatic environment under the bow and stern parts of the hull moving at speed ships ultrasonic irradiating beams; - carry out acoustic contacts with surface areas: sets of diffusers of the aquatic environment, in 1, 2, ..., , .., layers of which they are randomly and statistically inhomogeneously distributed, while each set of scatterers in any of layers has its own set of characteristics on the i -th depth horizon, which include the number of structural elements , their linear size , reflectivity and acoustic impedance , which differs from the similar parameter of the aquatic environment, as well as by neutral buoyancy, as a result of which sets of scatterers are passively transferred by water masses with different linear current velocities relative to the bottom the “water-bottom” interface with a random distribution of bottom irregularities, and these surfaces of the sections are at a given time under the bow and stern IPIA of the echo sounding systems, i.e. bow (H) and stern (K) parts of a moving vessel with a speed relative to the bottom, which ensures the simultaneous formation of two space-time dependences of information signals - volumetric reverberation processes and delayed echo signals, the squares of the envelopes of which will contain the frequency spectrum, and their envelopes will fluctuate in a chaotic manner; - convert using the direct piezoelectric effect of the piezoelectric elements of the EAP bow and stern IPIA moving at a speed ship two spatio-temporal dependences of information signals, in particular the amplitudes of echo signals from both irradiated sections of the "water - bottom" interface with random and different distributions of bottom irregularities, into the corresponding electrical signals entering the input of the receiving path of the equipment; - determine as the vessel moves along a given course, two amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, proportional to the distribution of the depths of the water area under the bow and stern parts of the hull moving at speed ship, and these functions are identical to each other, but shifted in time by an amount ; - determine the value of the cross-correlation coefficient for the dependencies of electrical signals that do not match at a given time And , proportional to the distribution of depths of the water area under the bow and stern parts of the hull along the course of the vessel, which makes it possible to calculate the speed of the vessel ; characterized in that - set for both IPIA echo sounding systems the criterion of compliance of their wave sizes with the range of values Where - antenna diameter, - ultrasonic wavelength with frequency , propagating at a speed in water, - the amplitude of the sound pressure in Pascals near the surface of the IPIA in the radiation mode; - generate with the help of the radiating path of the equipment electrical oscillations with a frequency , coming to two IRDA echo sounding systems in the radiation mode; - using the direct piezoelectric effect of the piezoelectric elements of the EAP of two EPIA echo sounding systems, amplitude-pulse modulated oscillations are converted into periodic bursts of powerful ultrasonic waves with the required duration, ensuring the transmission of acoustic energy to the particles of the aquatic environment, sufficient to manifest the nonlinear elastic properties of the aquatic environment under the bow and stern parts of the hull moving at speed vessel, which forms in the aquatic environment two parametric radiating PIA antennas, in the volumes of which the nonlinear sources of the generated spectral components are distributed; - generate two polyharmonic beams of ultrasonic phase-coupled signals with multiple frequencies by means of both PIAs in the aquatic environment , Where - the serial number of the harmonic, and the acoustic fields of the harmonics are coaxial, their wave vectors are oriented vertically downwards, and as the harmonic number increases, the beams have decreasing cross sections; - set on ultrasonic phase-coupled signals with multiple frequencies acoustic contacts with surface areas: sets of diffusers of the aquatic environment, in 1, 2, ...,,.., layers of which they are randomly and statistically inhomogeneously distributed, each set of scatterers in any of layers has a "unique" set of characteristics, in particular, oni-volume depth horizon - the number of structural elements, their linear size, reflectivity and acoustic impedance, the “water-bottom” interface with a random distribution of bottom irregularities, and these surfaces of the sections are at a given time under the bow and stern IPIA of the echo sounding systems, i.e. bow (H) and stern (K) parts of a moving ship with a speed ( ) relatively layer, which ensures the formation bow and stern information signals that carry both amplitude and phase information about surface areas, making it possible to judge their reflectivity and acoustic resistance, as well as their depth; - convert using the direct piezoelectric effect of the piezoelectric elements of the EAP bow and stern IPIA bow and stern information signals from surface areas of sets of scatterers of the aquatic environment that move at different speeds currents on 1, 2,…, , .., depth horizons and are currently under the bow (H) and stern (K) parts of the moving with speed ( ) vessel relative to the i -th layer, and the "water - bottom" interface with a random distribution of bottom irregularities into the corresponding electrical signals arriving at the input of the receiving path of the equipment; - carry out vertical spatial stratification of sets of scatterers of the aquatic environment into 1, 2, ..., , .., depth horizons, producing in the receiving paths of echo sounding systems on phase-coupled signals of multiple frequencies strobe of the corresponding electrical signals by setting the same values - the width of the strobe , their initial location relative to the bottom, the speed and sequence of the gate movement; - are generated in the receiving path of the equipment on each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals And , visualizing acoustic contacts with irregularities of the "water - bottom" interface, which are proportional to the distribution of the depths of the water area under the bow and stern parts of the hull moving at speed vessel; - measure for pairs of amplitude-time dependences of electrical signals that are identical to each other, but shifted in pairs in time And , quantities transport delay values for determining vessel speed values relative to the bottom; - are generated in the receiving path of the equipment on each of the phase-coupled signals of multiple frequencies By pairs of amplitude-time dependences of electrical signals, visualizing acoustic contacts with sets of scatterers located in separate 1, 2, ..., , .., layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons, for example, for the i -th depth horizon And , proportional to the random distribution of sets of scatterers in the i -th layer under the bow and stern parts of the hull moving at speed vessel relative to the i -th layer; - measure for pairs of identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals, for example, for the i -th depth horizon And , quantities transport delay values , for determining vessel speed values = relative to the i -th layer; - calculate speed values flow in the i -th layer as the difference between the values ship speeds relative to the i -th layer and speeds vessel relative to the bottom, where the sign "+" corresponds to the passing, the sign "-" - the opposite direction of the current in the i -th layer of the reservoir, respectively, relative to the speed vector of the vessel; - are generated in the receiving path of the equipment on two phase-coupled signals of multiple frequencies two amplitude-time dependences of electrical signals visualizing acoustic contacts and resistances of scatterer sets located in separate 1, 2, ..., , .., layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons, for example, for the i -th depth horizon And , proportional to the random distribution of the value of the acoustic resistance of the sets of scatterers in the i -th layer under the bow and stern parts of the hull moving at speed vessel relative to the i -th layer; - measured for two identical to each other, but shifted in pairs in time, amplitude-time dependences of electrical signals, visualizing acoustic contacts and resistance of sets of scatterers, for example, for the i -th depth horizon And , the value of the transport delay , to determine the speed of the vessel = relative to the i -th layer; - calculate the values of the arithmetic mean values of the velocities of the absolute movement of the vessel relative to the bottom, the relative movement of the vessel relative to 1, 2, ..., , .., layers, passive transfer of sets of scatterers located in separate 1, 2, ..., , .., layers when dividing the aquatic environment into 1, 2, ..., , .., depth horizons; - display, register and document the results of measurements of the detailed structure of the distribution of the depths of the reservoir in real time on the course of the ship-carrier of the equipment, the absolute speed of the ship-carrier, the parameters of the currents in the layers of the fine structure of a statistically inhomogeneous aquatic environment, which is presented in the form of a vertical profile of the flow velocity in k layers of a stratified water volume projected onto the diametrical plane of the vessel. 2. Correlation method according to claim 1, characterized in that EAP is used, each of which is equipped with a piezoelectric element simple geometric shape,screening units, hydro-, electrical and sound insulation.