RU2755751C1 - Mobile acoustic reflector - Google Patents

Abstract

FIELD: marine technology.SUBSTANCE: invention relates to the field of marine technology and is intended for navigation equipment of marine areas and ensuring the safety of navigation and determining the coordinates of surface ships, vessels, underwater objects at sea. The mobile acoustic reflector is an autonomous uninhabited underwater vehicle. It contains an on-board control system and a navigation system, a sonar, a current source, a power plant with an energy source and an engine, a propulsor, steering machine drives and an external tail with rudders, an antenna and a receiver of a GLONASS-type satellite navigation system connected to the on-board control system, a computing device and hydrostatic and hydrodynamic pressure sensors. The underwater vehicle has a compartment that houses an acoustic reflector and devices for bringing it into working position, including an inflatable buoy, a gas generator, a coil with aт electromechanical cable and a drive, as well as a ballast compartment with a pyrotechnic valve.EFFECT: navigation safety increases.1 cl, 5 dwg

Description

The invention relates to the field of marine technology and is intended for navigation equipment of sea areas and ensuring the safety of navigation and determining the coordinates at sea of surface ships, ships, underwater objects.

The navigation equipment of the sea area is a system of special coastal and floating structures, structures and devices designed to ensure the safety of navigation (navigation) and is used to determine the coordinates of ships and vessels at sea, their correct orientation while sailing in coastal and shallow areas. The means of navigation equipment are coastal and floating beacons, luminous and non-luminous signs, navigation lights, floating warning signs (buoys and milestones), radio, radar and hydroacoustic beacons, ground stations of radio navigation systems and other means [1].

The most difficult thing is to ensure the safety of navigation and accurate orientation underwater of underwater craft, since most of the aids to navigation is installed on the surface of the water or on the shore. Therefore, to provide underwater craft with navigation data, hydroacoustic or acoustic reflectors (AR) and beacons are used.

Known acoustic reflector, taken as an analogue of the invention. It has a core and a sheath. When the reflector is irradiated with an acoustic wave, it generates a counter more powerful acoustic echo signal. For this, one large hole is made in the reflector shell and a number of small holes are made in a circle from it, through which the reflector is filled with water when immersed. The holes represent the windows for the transmission of acoustic energy: small for the input signal, and the large central one for the output. The thickness of the shell and the dimensions of the core depend on the operating frequencies of the reflector. Acoustic waves incident on the reflector shell are transmitted through small windows to the core and the rear wall of the shell, where they are focused and reflected towards the exit central window. At the same time, powerful elastic waves in the same phase are generated in the shell wall. As a result of the addition of sound waves reflected from the back wall of the shell and focused into the output window with elastic waves propagating in its wall, a more powerful back acoustic echo signal is formed [2].

Depending on the materials used, the size and shape of the acoustic reflector, when irradiated by a sonar with known characteristics, it can suppress an acoustic wave reflected from the rear surface by its front surface of the shell, or, conversely, make it "audible", ensuring the identification of this acoustic reflector [2], [3].

The use of several separate acoustic windows in the wall of the acoustic reflector shell allows, as a result of the constructive combination of the corresponding reflected output acoustic signals, to form an amplified output acoustic signal at one or more predetermined frequencies [4, p. 7]. The reflector can be tuned to a given frequency by appropriately choosing the main diameter and thickness of the shell and the properties of the corresponding materials of each component, which provide the required acoustic wave propagation speed inside the core material and the possibility of constructive interference between two focused echoes passing through acoustic channels of different lengths.

To create a feature or features with high recognizability in the amplified reflected output acoustic signal, the concept of combining the waves transmitted through the reflector shell with the waves obtained due to internal focusing, as a result of which, the output signal acquires a specific temporal characteristic or a specific spectral composition is used. In this case, the corresponding phasing of two echo signals from the shell as a result of geometric focusing, as well as from the outer shell due to elastic waves, provides a specific frequency resonance that "colors" the echo signal.

The specified properties of the acoustic reflector make it possible to recognize it against the background of other underwater objects in the environment, including those with a high level of interference, which determines the following areas of its application [4]:

- marking of points of the geographical location of various underwater objects: pipelines, power and telephone cables, objects of navigation equipment, hazardous bottom objects, sections of subsea oil or gas platforms, etc.;

- marking or demarcation of zones of economic or commercial interest;

- identification of valuable containers lost as a result of accidents or falling overboard, as well as determination of the location of aircraft black boxes;

- control of geophysical structures and others.

The size of the acoustic reflector is selected depending on the size of the underwater object it designates. For example, for marking divers or sea animals, acoustic reflectors with a size of 50 to 100 mm are usually used [4].

Acoustic reflectors have other advantages, for example, they do not require current sources to emit signals and do not produce their own noise.

As a disadvantage, it is noted that for the navigation equipment of sea areas, it is required to involve surface vessels and other carriers and means with appropriate navigation equipment. This attracts the attention of unwanted observers to the area and increases the cost and time of work. This disadvantage is due to the inability of the acoustic reflector to move independently in the water.

Known mobile sonar buoy beacon (GBM), taken as a prototype of the invention, having a current source, control equipment, a floating float with an antenna and a receiver of a satellite navigation system of the GLONASS type and equipment for receiving and emitting hydroacoustic signals [5], [6]. GBM is located in a separate module of an autonomous unmanned underwater vehicle (AUV), which has an onboard control system, communication and navigation devices, a power plant with an energy source and an engine, a propeller, steering gear drives and an external tail with rudders. In addition, the module is equipped with a device for separating the pop-up float from the AUV and returning it back with a drive and a reel with a cable connecting the receiver of the satellite navigation system located in the float with the buoy control equipment, as well as a device for recognizing signals for requesting their forces to allow the transfer of information requested by them. an encoder that converts information to prevent its recovery in the event of interception by foreign objects and a decoder that converts information inversely, a computing device and hydrostatic and hydrodynamic pressure sensors that are used to calculate the drift speed of a mobile sonar beacon when it is laid on the ground, the direction and magnitude of the horizontal drift of the float relative to the set point.

The disadvantages of the mobile GBM are the relatively short duration of operation due to the use of a power source for transmitting information to navigation objects, which is gradually discharged and becomes unusable. Its other disadvantage is its own emission of signals, which unmasks its work.

The aim of the invention is to develop a mobile acoustic reflector based on an AUV, which has the ability to independently arrive at a designated area, occupy a point with the required coordinates or find a given underwater object and install an acoustic reflector in a previously unequipped position as a navigational reference.

To achieve the objective of the invention, a mobile acoustic reflector is proposed, which is an autonomous uninhabited underwater vehicle having an on-board control system and an on-board navigation system, a sonar, a current source, a power plant with an energy source and an engine, a propulsion device, steering gear drives and an external tail with rudders, an antenna and a receiver for a satellite navigation system of the GLONASS type, connected to the on-board control system, a computing device, and hydrostatic and hydrodynamic pressure sensors.

The underwater vehicle has a compartment that houses an acoustic reflector and devices for bringing it to its operating position, including an inflatable buoy, a gas generator, a reel with a cable-rope and a drive, as well as a ballast compartment with a pyrotechnic valve.

The device of the mobile acoustic reflector and its operation are shown in Fig. 1-5.

FIG. 1 shows a mobile acoustic reflector (AWP) and its device, where: 1 - mobile acoustic reflector, 2 - onboard navigation system, 3 - onboard control system, 4 - hydrostatic pressure sensor, 5 - current source, 6 - computing device, 7 - sonar, 8 - hydrodynamic pressure sensor, 9 - power plant with an energy source, 10 - engine, 11 - steering gear drives, 12 - rudders, 13 - propeller, 14 - ballast compartment, 15 - inflatable buoy with receiving antenna of satellite navigation system, 16 - gas generator, 17 - pyrotechnic valve, 18 - drive coil, 19 - acoustic reflector.

The on-board navigation system AWP (2) ensures its movement along a given route with a given accuracy, the on-board control system (3) controls the operation of all devices and mechanisms of the AWP, the hydrostatic pressure sensor (4) serves to determine the depth of the place, and the hydrodynamic pressure sensor (8 ) - to estimate the speed of movement. The sonar (7) is intended for orientation in the water space and for the detection of obstacles when the AWP moves along the route, as well as for the detection of objects specified in the route assignment as landmarks. The current source (5) provides the necessary energy control equipment. The ballast compartment (14) is required to install the AWP in the designated place on the anchor, for which, after the pyrotechnic valve (17) is triggered, it is filled with water, and the AWP sinks to the bottom. The inflatable buoy (15) is used to ascend to the surface and receive the updated coordinates of the AWS from the satellite navigation system at the designated point, and after accepting the water ballast and placing the AWP at anchor - to hold the acoustic reflector (19) at a given depression. A gas generator (16) is used to inflate the buoy (15) with gas. The reel with a drive (18) is designed to unwind the cable-rope (22) to a predetermined length and to ascend the inflatable buoy (15) to the surface for communication with the satellite, as well as to hold the acoustic reflector (19) at a given recess after the AWP is anchored.

FIG. 2 and 3 illustrate the work of the AWP after arriving at the designated point.

FIG. 2 shows how the AWP (1), having the current course and speed (20), arrives at the designated point and ascends (21) to a given depth, after which it inflates an inflatable buoy (15) with gas and raises it to the water surface (24). With the help of the antenna (23) of the satellite navigation system located on the inflatable buoy (15), the AWP receives (26) from the spacecraft (25) its current geographic coordinates and refines its path to the dive point in the onboard navigation system.

FIG. 3 shows the moment when the pyrotechnic valve (17) is triggered at the design point at the command of the onboard control system (3), the ballast compartment (14) is filled with water and the AWP (1) is immersed (27) to the bottom (28). As a result, the acoustic reflector (19) is installed at a given point, at a given depth and is ready for operation.

The device and principle of operation of a typical acoustic reflector [3] is shown in Fig. 4. Here, numbers indicate: 19 - acoustic reflector, 30 - front of acoustic waves directed by the source to the reflector and reflected back by it, 31 - direction of the acoustic wave beam from the source to the reflector, 32 - hole in the peripheral acoustic window, 33 - reflector core, 34 - the shell of the acoustic reflector, 35 - the path of the acoustic wave entering the acoustic reflector and moving in its shell (transverse wave), 36 - the path of the acoustic wave entering the acoustic reflector through the peripheral acoustic window and moving in the core (elastic wave), 37 - focal point (focus), 38 - the path of the acoustic wave entering the acoustic reflector through the central acoustic window and moving in the core after its entrance (elastic wave), as well as the path of a more powerful counter acoustic wave directed to the source and resulting from the addition of the in one phase of the counterpropagating elastic waves of the core reflected from the focal point (36) and transverse x acoustic waves of the shell of the acoustic reflector (35), 39 is the central acoustic window, 40 is the direction of the beam of the reflected acoustic wave amplified by the acoustic reflector to its source.

FIG. 5 shows the operation of the AWP as a navigational reference when the underwater object (41) enters the zone of the acoustic reflector (19), produces an acoustic transmission in its direction (42) and receives a response signal that allows the underwater object to clarify its location.

The technical result of the invention is a mobile acoustic reflector, which is able to independently follow in a submerged position to a designated area to a point with the required coordinates or to a given stationary underwater object, anchor there and be used in the future by its floating craft as a long-term and invisible navigational landmark.

Sources of information used in the development of the invention:

1. Naval Dictionary / Ch. ed. V.N. Chernavin. M .: Voenizdat, 1989 .-- 511 p. P. 265.

2. Acoustic reflectors. Invention patent RU 2562919 / SABSI ASSET LOCATION TECHNOLOGIES LIMITED (GB). M .: FIPS, 2015. Bul. No. 25.

3. Acoustic reflectors. Invention patent RU 2566388 / SABSI ASSET LOCATION TECHNOLOGIES LIMITED (GB). M .: FIPS, 2015. Bul. No. 30.

4. Adjustable acoustic reflector. Invention patent RU 2495501 / Secretary of State for Defense (GB). M .: FIPS, 2013. Bul. No. 28.

5. Patent for invention RU 2709058. Mobile sonar beacon and method of navigation equipment for the sea area / A.V. Ivanov, A.V. Novikov. Moscow: FIPS, 2019.Bul. No. 35].

6. Patent for invention RU 2710831. Self-propelled hydroacoustic buoy-beacon and method of navigation equipment of the sea area / A.V. Ivanov, A.V. Novikov. M: FIPS, 2020. Bul. No. 2.

Claims (1)

Mobile acoustic reflector, which is an autonomous uninhabited underwater vehicle with an on-board control system and navigation system, sonar, power source, power plant with an energy source and an engine, a propulsion device, steering gear drives and an external tail with rudders, an antenna and a receiver for a satellite navigation system of the type GLONASS, connected with the on-board control system, a computing device and sensors of hydrostatic and hydrodynamic pressure, characterized in that the underwater vehicle has a compartment in which an acoustic reflector is located and devices for bringing it into working position, including an inflatable buoy, a gas generator, a reel with a cable-rope and a drive, as well as a ballast compartment with a pyrotechnic valve.

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