Hydroacoustic system for imaging underwater space

FIELD: physics.

SUBSTANCE: hydroacoustic system for imaging underwater space has antenna units for the portside and the starboard 1 and 1', receiving amplifiers 2 and 2', analogue-to-digital converters 3 and 3', power amplifiers 4 and 4', a multi-beam echo sounder antenna 5, receiving amplifier units 6, analogue-to-digital converter units 7, a power amplifier unit 8, a roll measuring device 9, a depth measuring device 10, a module for generating, receiving and packing signals 11, an interface unit 12, a navigation system 13 and an on-board computer 14. The invention provides a continuous band for scanning the bottom owing to that the invisibility band of the antennae of the portside and the starboard overlaps with the multi-beam echo sounder; formation of the bottom relief in real time, higher accuracy and reliability of imaging the relief due to high accuracy and reliability of eliminating ambiguity when calculating phase shift on antennae.

EFFECT: providing a continuous band for scanning the bottom and formation of the bottom relief in real time.

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The invention relates to the field of sonar technology and can be used in equipment that provides playback of bottom topography in real time.

A device hydroacoustic system for visualization of the underwater environment on the basis of multi-technological complex for investigation of the shelf containing the module side-scan sonar (SSS), the acoustic module profilograph, module, sonar, navigation system, processing unit and the registration unit operational control information, the block synchronous display and reception, switch modes, and HBO contains towed on a cable-cable gondola, which is equipped hydroacoustic antennas, analog-to-digital Converter, the host computer with the monitor and graphic blocks and magnetic Desk. (A utility model certificate of the Russian Federation No. 16406, IPC G01V 1/38, 05D G 27/00, publ. 27.12.2000,)

The disadvantage of this device is the inability to play with it, the bottom topography and the presence of invisible area in the center of the swath.

A device hydroacoustic system for visualization of the underwater environment on the basis of marine geo-acoustic complex "MAC", containing the on-Board unit of the carrier vessel, connected cable cable with beech the dummy hardware module, includes serially connected unit of data collection and unit registration and processing of information with outboard towed module includes a side-scan sonar (SSS) long range, HBO high-resolution acoustic profilograph, depth sounder, sonar navigation system, synthesizer sounding signals, interface control signals, sensors spatial position of the towed unit, unit of digital sensors, the unit pressure sensor and analog sensors, interface, analog sensors, cable interface, digital transceiver, single-Board computer and the power supply of the towing module, connected through a system data bus and control, and the synthesizer outputs the excitation signal is connected to the first inputs of sonar review long range, side-scan sonar, high resolution, acoustic profilograph, sounder and beacon-defendant, input-output interface control signals connected to the second input blocks of side-scan sonar long range, side-scan sonar, high resolution, acoustic profilograph, sounder and beacon the Respondent, the outputs are connected to inputs of the cable interface, the input-output of which is connected a digital transceiver. (Testimony on polezno the model of the Russian Federation No. 38233, IPC G01V 1/38, G05D 27/00, publ. 27.05.2004,)

The disadvantage of this device is the inability to play the bottom topography and the presence of invisible zones.

The closest in technical essence and the achieved result of the present invention (the prototype) is known hydroacoustic system for visualization of the underwater space containing blocks of antennas of the left and right sides, the outputs of which are connected with the corresponding cascaded receiver amplifiers and analog-to-digital converters, and inputs connected to the outputs of amplifiers, the meter roll, module formation, receiving, and packaging signals to the inputs of which are connected analog-to-digital converters, amplifiers and measuring roll, a block interface, navigation system and trip computer, and to the input of the on-Board computer is connected to the output of the navigation system and through the interface unit output module formation, receiving, and packaging signals and blocks the receiving antenna of the profilograph and the first and second antennas pump profilograph. (Matvienko J.V., Voronin V., Tarasov SP., Skara AV, Tutynin E.V. Ways to improve hydroacoustic technologies seabed surveys using Autonomous unmanned underwater vehicles / Underwater exploration and robotics is ahnika. 2009. №2(8) p.4-15).

Through the use of interferometric side-scan sonars (IGBO) prototype allows you to play the bottom topography. However, in the band of his review is still invisible area. In addition, the construction of exact relief is possible only in the process of secondary processing using data obtained on different tacks.

The technical result of the invention is the provision of a continuous swath of the seabed and the formation of bottom topography in real time.

The technical result is achieved due to the fact that the hydroacoustic system for visualization of the underwater space containing blocks of antennas of the left and right sides, the outputs of which are connected with the corresponding cascaded receiver amplifiers and analog-to-digital converters, and inputs connected to the outputs of amplifiers, the meter roll, module formation, receiving, and packaging signals, connected to the outputs of the analog-to-digital converters and the meter roll, the inputs of amplifiers and an interface unit, a navigation system and trip computer, and to the input of the on-Board computer is connected to the output of the navigation system and through the power interface output module formation, reception and packaging signals, equipped with a multibeam antenna, Ahola is a, series-connected blocks of the receiving amplifiers and blocks analog-to-digital Converter connected between the output of the antenna multibeam echosounder and module formation, receiving, and packaging signals, the block power amplifiers connected between the input of the antenna multibeam echo sounder and the output module of the formation, receiving, and packaging signals, and connected to the input of this block meter depth.

The invention is illustrated by drawings. Figure 1 presents the block diagram of the proposed device, and figure 2 - block diagram of computer signal processing.

Hydroacoustic system for visualization of the underwater space contains blocks antennas of the left and right sides 1 and 1', the outputs of which are connected with the corresponding cascaded receiver amplifiers 2 and 2' and the analog-to-digital converters 3 and 3', and inputs connected to the outputs of the amplifiers 4 and 4', the antenna multibeam sonar 5, the receiving elements which are connected with the inputs of the blocks receiving amplifiers 6 and blocks analog-to-digital converters 7, block power amplifier 8 connected to the radiating elements of the antenna multibeam echosounder 5 meter roll 9, the depth measuring device 10, the module the formation, receiving, and packaging signals 11, the interface unit 12, the navigation system is it 13 and the on-Board computer 14, thus to the inputs of the module formation, receiving, and packaging signals 11 are connected analog-to-digital converters 3, 3' and the block 7, the power amplifiers 4, 4' and 8 blocks, measuring roll 9 and 10 meter depth, and to the inputs on-Board computer 14 is connected to the navigation system 13 through the interface unit 12 output module formation, receiving, and packaging signals.

Block diagram of computer system signal processing block contains reading and decompressing signals 15, sequentially connected to the output of the block forming the directivity characteristics 16, the evaluation unit time delay of the echo signals 17 and sequentially connected to the output unit 15, respectively, the units of measurement of the phase and amplitude of 18 and 18', the blocks initial assessment phase 19 and 19', the blocks estimation of angles of incidence of beams 20 and 20', and also blocks calculate the coordinates of the intersection points of rays with the bottom surface 21, 21' and 21", the block coordinate reference intersection with the bottom of the geographical map 22 and the block graphic display 23. The device operates as follows.

The emitted signals are formed in the block 11 and sequentially connected to the power amplifiers 4, 4' and 8 and radiating antennas 1, 1' and 5. Structurally, the antenna is designed so that the beam width of each antenna is quite narrow along the movement direction and wide in the transverse direction is AI, moreover, the sector antenna 5 falls in the middle swath of the seabed and sector review of the antennas of the left and right sides 1 and 1' are located to the left and to the right of the media and cross sector review of the multibeam echosounder. Receiving antenna multibeam echosounder 5 consists of a series of elements arranged along a line (or arc), face down and lying in the plane perpendicular to the direction of movement. Blocks of antennas of each of the boards 1 and 1' are composed of two directional receivers with narrow directivity in the longitudinal direction and broad in the vertical plane. The output signal of the elements of the receiving antennas 1, 1' and 5 are amplified in blocks 2, 2' and 6, are digitized in blocks 3, 3' and 7 and enter in block 11, in which the packing of the received signals for further transmission through the interface unit 12 to the vehicle 14. The signals from the receiving antennas 1, 1' and 5 in block 11 mixed with the output signal of the measuring roll 9 and 10 meter depth, to the onboard computer 14 is additionally connected navigation system 13 that provide the necessary information support to bind playing topography map. Signal processing in the on-Board computer 14 is as follows. The signals from the interface unit 12 accepts a block read and R is spakovsky signals 15 and divided into three streams, the corresponding signals from the units receiving antennas multibeam sonar 5 and blocks antennas 1 and 1' of the left and right sides. Collectively, the signals from elements of the receiving antenna multibeam echosounder in the block 16 is formed of a fan of the directivity characteristics, the axes of which are evenly distributed across the width of the sector survey multibeam echosounder. For each beam formed in the block 17 is calculated correlation function of the received signal with the emitted and the position of the maximum of the correlation function is estimated delay time of the echo signal coming from the point of intersection of the beam with the bottom. Thus, the output of block 17 is formed by a set of delay times τ(α_iand maxima of the correlation function A(α_ifor each beam, characterized by the angle α_i.

The output signal of the pairs of receiving antennas of the left and right sides in blocks 18 and 18', respectively, are the current estimates of the amplitude of the echo signal and the phase shift between the signals at the outputs of the pair of antennas. The amplitude of the signal is determined by summing the squares of the real and imaginary parts of the output of each antenna:

where Re₁, Im₁That Re₂and Im₂the real and imaginary components of the signals at the output of the first and second antennas, respectively.

The phase shift is determined by the known ability is BOM:

Due to the periodicity of the functions of the arc tangent of the assessment phase shift is accurate up to a constant multiple of π.

The phase shift corresponds to the angle α:

where β is the slope of the line connecting the linear antenna HBO;

d is the distance between the linear antennas HBO;

λ is the wavelength of the radiation in the water.

The ambiguity of the evaluation phase shift leads to the ambiguity of the definition of the angle of incidence of the beam. The device prototype to disambiguate the playback of the bottom relief is secondary processing by using data obtained at several tacks. In the proposed device the ambiguity determination of the phase shift is eliminated in the blocks 19 and 19' directly in the processing of the current data. This is achieved by the fact that to identify the correspondence between the phase shift and the angle of incidence of the beam data is used multibeam sonar. On the received set of delays τ(α_ieach time t can be put into correspondence with the angle α, for which the delay time is equal to t. Selecting a reference time t₀you can determine the appropriate initial angle α₀and in accordance with the formula (2) to provide the initial f is zu Δφ ₀.

where γ₀- the value of the roll media on the time t₀.

In blocks 20 and 20' calculates the current angle of incidence of the beam. The equation to calculate this angle is obtained by subtracting (3) from (2):

Due to the fact that the conversion formula is used the difference of phase shifts in the initial and the current time, the uncertainty in the calculation of the phase at the initial moment of time becomes irrelevant. However, when calculating the phase shift in the current time it is necessary to consider the phase increment multiples of 2π. For this purpose it is necessary to carry out the counting of interference fringes, and with the advent of each new bands to add 2π to the current assessment phase, executed by the formula (1).

Thus, the output units 20 and 20' for each point in time are generated estimates of the angles of incidence of the beam on the bottom surface. In blocks 21, 21' and 21" estimated dependence of the angle α, for the current time t_ithe computation of the coordinates of intersection with the bottom. Assuming the speed of sound with depth remains unchanged, X_α,iand Z_α,ithe point of intersection of the beam with the bottom relative to the center of the antenna are determined analytically:

For the distribution of the coordinates of the point of intersection of the beam with the bottom in terms of the known distribution of the velocity of sound in depth can be used radiation program, which for a given angle of incidence of the beam builds the path of propagation of the beam and calculates the propagation time along the trajectory. The trajectory of the beam is built up until the time of sound propagation by the beam is not bodø is half the current time. The totality of all the constructed trajectories determines the coordinates of the points X_α,i, Z_α,ion the terrain surface in the coordinate system of the corresponding antenna. In block 22 is the conversion of these points in a geographic map according to the following formula:

X_i=X_N+(X_α+X_α,i)cosK+(Y_α-L_G)sin K

Y_i=Y_H+(Y_α-L_G)cos K+(X_α+X_α,i)sin

Z_i=H_PM+Z_α+Z_i

where X_Nand Y_Hgeographical coordinates media sonar defined navigation system media;

L_G- the horizontal distance between the basis of the coordinates of the carrier and submarine sonar module.

K - heading angle of movement of the carrier;

X_α, Y_α, Z_αcoordinates of the phase center of the antenna relative to the center of the underwater sonar module.

H_PMthe depth of the underwater module.

All received information is displayed in graphical form on the display unit of the received information 23.

The invention in contrast to the prototype provide the rest:

- continuous swath of the seabed due to the fact that the band stealth antennas right and left sides covered by multibeam echosounder;

- the formation of bottom topography in real time by eliminating each sending probing signals ambiguity angles of arrival of the reflected bottom signals into blocks of antennas of the right and left sides through the use of data multibeam sonar in overlapping sectors of the review.

1

1, 1' - blocks of antennas of the left and right sides

2, 2' - reception amplifiers

3, 3' - analog-to-digital converters

4, 4' - amplifiers

5 - antenna multi-beam echo sounder (MBE)

6 is a block receiving amplifiers

7 - analog-to-digital converters

8 - block power amplifiers

9 - chronometer

10 - meter depth

11 is a block formation, receiving, and packaging signals (control unit?)

12 - unit interface

13 - navigation system

14 - computer

2

15 - Block read and decompress signals

16 is a block forming directivity (HN)

17 - evaluation unit time delay of the echo signals

18, 18' - units of measurement of phase and amplitude

19, 19' - block assessment the initial phase

20, 20' - block estimates of angles of incidence of rays

21,21', 21" - blocks calculate the coordinates of the intersection points of rays with the surface of the bottom

the 22 - block binding coordinates of intersection with the bottom of the map

23 is a block graphic display

Hydroacoustic system for visualization of the underwater space containing blocks of antennas of the left and right sides, the outputs of which are connected with the corresponding cascaded receiver amplifiers and analog-to-digital converters, and inputs connected to the outputs of amplifiers, the meter roll, module formation, receiving, and packaging signals to the inputs of which are connected analog-to-digital converters, amplifiers and measuring roll, a block interface, navigation system and trip computer, and to the input of the on-Board computer is connected to the output of the navigation system and through the power interface output module formation, receiving, and packaging signals, characterized in that it equipped with antenna multibeam echosounder, series-connected unit of the receiving amplifiers and analog-to-digital Converter connected between the output of the antenna multibeam echosounder and module formation, receiving, and packaging signals, the block power amplifiers connected between the input of the antenna multibeam echo sounder and the output module of the formation, receiving, and packaging signals, and connected to the input of this block is a meter depth.