Sound transducer for sending and / or receiving underwater sound signals, underwater antenna, trailing antenna, sonar, and watercraft

Abstract

The invention relates to a sound transducer for sending and / or receiving underwater sound signals, wherein the sound transducer comprises at least two sound transducer shells, each comprising a piezoceramic material and each being electrically conductive on an outer surface and an inner surface, the sound transducer shells forming a toroidal shape so that an underwater sound signal can be sent and / or can be received rotationally symmetrically. The invention also relates to an underwater antenna, a trailing antenna, a sonar for sending and / or receiving underwater sound signals, and a watercraft.

Description

[0001] The invention relates to a transducer for transmitting and / or receiving underwater sound signals, wherein the transducer comprises at least two transducer shells, each of which has a piezoceramic material and is electrically conductive on an outer and an inner surface. The invention further relates to an underwater antenna, a towed antenna, a sonar for transmitting and / or receiving underwater sound signals, and a watercraft.

[0002] For underwater use, transducers for receiving and / or transmitting underwater sound signals are typically designed in a spherical shape for omnidirectional directional characteristics. To also enable the transmission and / or reception of underwater sound signals rotationally symmetrical to the antenna axis, spherical hydrophones are arranged in circular paths around a tow cable, for example, for a trailing antenna. Such a spherical hydrophone is known, for example, from DE 10 2016 103944 A1.

[0003] A disadvantage of this design is that each spherical hydrophone must be individually mounted on a support, and a large number of hydrophones are required to provide a sufficient area for receiving and / or transmitting with high sensitivity. Furthermore, there is a risk that the hydrophones, arranged in circular paths around a pull cable, and their associated components may interfere with each other's reception and / or transmission.

[0004] Figures 20 and 21 of US 4876675 show a trailing antenna with a flexible tube 52, inside which several piezoelectric receiver units 50 are arranged along a flexible, elongated core 51. Each receiver unit 50 comprises two cylindrical elements 53L and 53R, polarized in opposite directions and isolated from each other by a disk-shaped plate 54. Each element 53L and 53R has an inner surface with an electrode 55 and an outer surface with an electrode 56. Each disk-shaped element 53L and 53R, as well as the plate 54, has a hole in its center through which the core 51 passes. Two adjacent receiver units 50 are separated from each other by a buffer space 57.

[0005] US 4797863 shows a buoy (sonobuoy 16) which carries a hydrophone 20 via a cable (long tether 22) and on whose upper edge a transmitter 24 is mounted, cf. Fig. 1 Depending on signals from the hydrophone 20, the transmitter 24 generates and transmits signals. The hydrophone 20 comprises a circular membrane (diaphragm 26) whose outer circumferential surface is wound around an annular, resilient, and deformable steel band (annular band 28 of spring steel), cf. Fig. 2 and Fig. 3 A coaxial cable 30 is routed around this steel strip 28. The cable 30 has an electrically conductive core 40, which is surrounded by a flexible piezoelectric material 42, see Fig. 4. A dielectric housing 44 surrounds the piezoelectric material 42. A series of dielectric loops 38 connects the cable 30 to the steel strip 28.

[0006] US 20040017129 A1 shows a sound transducer in the form of a circular helix, see Fig. 26 and Pars.

[0110] and

[0111] .

[0007] The purpose of the invention is to improve the state of the art.

[0008] The problem is solved by a sound transducer for transmitting and / or receiving underwater sound signals according to claim 1, wherein the sound transducer has at least two sound transducer shells, each of which has a piezoceramic material and is electrically conductive on an outer surface and an inner surface, and the sound transducer shells together form a torus-shaped form, so that an underwater sound signal can be transmitted and / or received in a rotationally symmetrical manner.

[0009] This enables rotationally symmetrical transmission and / or reception of underwater sound signals with a single torus-shaped transducer. Due to this geometry and the absence of the otherwise typical higher sensitivity of a hydrophone in a specific direction, nearby ship noises, such as those of a tugboat, are detected less strongly.

[0010] In addition, the transducer area, which is necessary for transmitting and / or receiving an underwater sound signal, is significantly increased, resulting in higher sensitivity.

[0011] A key aspect of the invention is that a rotationally symmetrical directional characteristic is achieved through a torus-shaped single sound transducer.

[0012] Thus, a large number of spherical hydrophones around an axis for a rotationally symmetrical directional characteristic, as well as corresponding contacts, electrical connections, signal conditioning and other associated components, are dispensed with, and these components do not need to be arranged multiple times. The following terms will be explained:

[0013] A "sound transducer" is, in particular, a device for transmitting and / or receiving underwater sound signals. For example, one or more sound transducers are used when employing active and / or passive sonar. Specifically, the sound transducer receives underwater sound signals and converts them into an electrical signal for further processing (receiver) and / or converts an electrical signal into an acoustic signal, which is then transmitted (transmitter). For example, a transmitting transducer can also be towed behind a ship. Underwater, hydrophones can be used as sound transducers to record underwater sound. In this case, a hydrophone converts the underwater sound into an electrical signal corresponding to the sound pressure. When used underwater, a frequency range between approximately 10 Hz and 400 kHz is typically employed.

[0014] A "transducer shell" is, in particular, the shell of a transducer. The transducer shell is specifically a planar supporting structure that is doubly (spatially) curved and can withstand loads both vertically and in a plane. At least two transducer shells form the torus shape of the transducer, whereby, due to the shell structure, the torus is hollow and / or filled with components. The at least two transducer shells can have any number of interfaces to form the torus shape. The transducer shells can be halves of a torus divided vertically or horizontally in the middle. The torus can also consist of several circumferential ring-segment shells.

[0015] The term "piezoceramic" refers specifically to transducer shells made of solid ceramic and / or a composite material. A piezocomposite ceramic, as a composite material, contains piezoelectric ceramic filaments and a filler. The piezoceramic transducer shells function primarily as piezoelectric transducers, generating an electrical voltage when subjected to mechanical pressure or performing a mechanical movement when an electrical voltage is applied. When sound pressure is applied, the piezoceramic transducer shells are deformed, thus generating an electrical voltage across them. In this case, the transducer functions as a sound receiver.By applying pressure to the transducer shells, the transducer shells deform and electrically charged areas form on the outer and / or inner surface of the transducer shells (piezoelectric effect).

[0016] An "outer surface" is, in particular, the outer boundary surface of a sound transducer shell and / or torus-shaped form. The outer surface is specifically the external surface of the sound transducer shell and / or torus-shaped form that can be struck by sound pressure.

[0017] An "inner surface" is, in particular, the inner boundary surface of a transducer shell and / or the torus-shaped form. When the torus-shaped form is created by at least two transducer shells, the inner surface is, in particular, the inner boundary surface of the torus-shaped form adjacent to the cavity of the torus-shaped form.

[0018] "Electrically conductive" means, in particular, that a material has a high density of freely moving charge carriers and thus good electrical conductivity, as well as the lowest possible electrical resistance, making the material suitable for transporting charged particles. Specifically, the transducer shells each have an electrically conductive material on their outer and inner surfaces.

[0019] A "torus-shaped form" is a geometric object that has a bulged surface with a hole. The geometric shape of a transducer shell is created when a curved curve, in particular a semicircle or a semi-ellipse, is rotated along a circle. A torus is created when a closed curved curve, in particular a circle or an ellipse, is rotated along a circle. In particular, a torus can have the shape of a lifebuoy, tire, or donut. A torus is, in particular, a mathematical solid that is created by rotating a perpendicular circle around a vertical axis that lies outside the circle, with the circle and axis lying in the same plane. The torus-shaped form is created by at least two transducer shells and is hollow inside and / or filled with associated components of the transducer.

[0020] "Rotationally symmetric" means in particular that the sound transducer can be rotated around its center point and assumes exactly the same position as in the initial state before the rotation more than once and / or the angular dependence of the strength of the received and / or transmitted underwater sound waves does not change (rotationally symmetric directional characteristic).

[0021] In another embodiment of the sound transducer, two sound transducer shells are designed as shell halves.

[0022] Thus, the torus-shaped form of the sound transducer can be created by two sound transducer shell halves.

[0023] It is particularly advantageous if the shell halves are axially symmetrical to the vertical or horizontal axis of symmetry of the torus-shaped form.

[0024] To fix the transducer shells and / or to provide a support for other associated components, a support plate can be arranged between the transducer shells and / or the shell halves.

[0025] A "carrier plate" is, in particular, a plate made of ceramic and / or plastic. Specifically, a carrier plate consists entirely or partially of ceramic and / or has a thin layer thickness, for example, between 0.5 mm and 2.0 mm, to ensure good decoupling. Besides connecting the transducer shells and / or providing acoustic decoupling, the carrier plate also serves as a circuit board and / or power supply for the transducer and / or other components. In particular, additional components can be arranged on the carrier plate within the inner cavity of its torus-shaped form. A carrier plate can also be a foil.

[0026] In another embodiment of the sound transducer, the piezoceramic material comprises a polarized piezoelectric ceramic and / or ceramic filaments.

[0027] The corresponding shape of the piezoceramic material of the sound transducer shells is imprinted and / or pre-aligned according to the torus-shaped form.

[0028] "Ceramic filaments" are, in particular, thin and / or thread-like ceramic structures. These can take the form of rods, cylinders, tubes, and / or plates. When a sound pressure is applied, the ceramic filaments are elastically deformed, resulting in a change in electrical polarization and thus the generation of an electrical voltage across the ceramic solid, in which case the sound transducer acts as the sound receiver.

[0029] In order to enable the piezoelectric effect and to establish an electrical contact and a secure electrical connection to the outside, the electrically conductive outer surface and / or the electrically conductive inner surface has or have a metal layer and / or an electrode.

[0030] An "electrode" is, in particular, an electrical conductor that interacts with a counter electrode and a medium located between the two electrodes. An electrode consists, in particular, of an electrical conductor, for example, a metal and / or graphite. An electrode can also be designed as an electrically conductive layer on the transducer shells. For example, the electrode can be a copper layer or a silver layer.

[0031] It is particularly advantageous to set the outer electrodes of the transducer shells to zero potential for additional shielding of electronic components within the hollow body of the torus-shaped housing. This ensures that the shielding effect does not interfere with the transducer's performance, as the digitization of the sound signals typically occurs only in subsequent external signal processing stages.

[0032] In another embodiment of the sound transducer, signal processing electronics are arranged inside the torus-shaped form.

[0033] Signal processing electronics are used to convert an electrical signal into an acoustic signal and / or vice versa. These electronics primarily process analog signals. A signal processing electronics unit typically includes an amplifier, an amplifier chain, a circuit for converting and / or digitizing electrical and / or analog signals, and / or a data transmission unit.

[0034] To enable a secure electrical contact, the electrically conductive inner surface is connected to an insulated area for contact with the outer surface via a conductive connection.

[0035] An "electrically conductive connection" establishes, in particular, an electrical contact between the electrically conductive inner surface and the outer surface. A conductive connection can be, in particular, a soldered joint, a welded joint, a press fit, a wound joint, an adhesive joint, and / or a plug connection. The conductive connection can also be achieved via a conductive layer applied over a surface, an adhesive, a contact tongue, and / or a conductor wire.

[0036] An "isolated area" is, in particular, an area and / or section which prevents an electrically conductive connection.

[0037] In another embodiment of the sound transducer, the electrically conductive inner surface and / or the electrically conductive outer surface is / are contacted by means of a support cable and / or a conductor.

[0038] This allows the transducer to be supplied with power externally and / or electronic signals from the transducer to be transmitted to an external evaluation unit.

[0039] A "support cable" is, in particular, a rope or cable that bears the weight of one and / or more transducers and / or the force required to pull all components of a towed antenna, including one or more transducers, in water. The support cable has, in particular, at least one electrical conductor and / or is surrounded by an electrical conductor. The support cable is made of, in particular, plastic and / or metal, or, for example, aramid and / or copper.

[0040] In another aspect of the invention, the problem is solved by an underwater antenna, wherein the underwater antenna has a previously described sound transducer.

[0041] This means that a single transducer according to the invention provides a space-saving underwater antenna with omnidirectional characteristics. Furthermore, several transducers according to the invention can be used in a suitable arrangement within the underwater antenna, and the antenna can also be designed as an active transducer.

[0042] An "underwater antenna" is, in particular, a technical device for transmitting and / or receiving underwater sound signals. For this purpose, an underwater antenna typically includes one or more transducers and / or hydrophones. The underwater antenna is used either independently or as part of a passive and / or active sonar system.

[0043] In an additional aspect of the invention, the problem is solved by a trailing antenna, wherein the trailing antenna has at least two previously described sound transducers, a support cable for holding the sound transducers and a tube for encasing the support cable and the sound transducers, wherein the tube is filled with a sound-conducting medium, and the support cable is guided through a hole which is formed in a center of the torus-shaped form of the sound transducer, or on each sound transducer.

[0044] This provides a trailing antenna in which the torus-shaped transducers can be easily threaded through their respective central holes using the suspension rope and / or a suspension cable and used in a trailing sonar system. Furthermore, the transducers are quickly and easily accessible and / or repairable and replaceable in the event of a defect in the trailing antenna.

[0045] Preferably, the support cable is guided through the central hole of each torus-shaped sound transducer, but alternatively, the support cable can also be guided and / or attached to the outside of the sound transducer.

[0046] A "tube" is in particular an elastic tubular casing of the trailing antenna, which encloses the support cable, the sound transducers, other fittings, electronic components and / or cables and is filled with a sound-conducting medium.

[0047] A towed antenna is, in particular, a long linear antenna that is towed behind a ship by a tow cable (or rope). Specifically, the towed antenna has a flexible, tubular casing in which several transducers and / or hydrophones are arranged. The tubular casing can be filled with gel or liquid. A towed antenna is, in particular, a component of a passive towed sonar and / or the acoustic receiving section of an active towed sonar. The towed antenna is towed at a suitable depth and thus operated away from noise from the towing vessel. Due to the rotationally symmetrical directional characteristic of the transducers, rotation of the towed antenna on the tow cable in the water does not affect the quality of the received signals or the rotationally symmetrical directional characteristic.

[0048] In another embodiment, the trailing antenna has a third transducer, a fourth transducer, a fifth transducer and / or further transducers.

[0049] This allows for further improvements in accuracy, sensitivity, and directional characteristics.

[0050] Consequently, a more precise determination of the position of sound sources in the water is possible, since several and / or different sound transducers are focused on the sound source.

[0051] To fix the sound transducers and specify an exact position for each transducer, a shaped piece is arranged between the sound transducers.

[0052] This allows a more precise method for determining the position of sound sources (beam forming) and thus improves sound source localization.

[0053] A "fitting" is a part with a defined shape. A fitting can, in particular, be a tube-like part. The fitting has a hole, especially in its center, through which it can be threaded onto a support cable. A fitting is, in particular, arranged between two transducers and is preferably equal to or slightly larger than the hole in the torus-shaped form of the transducer, so that the fitting holds the adjacent transducers at a defined distance from each other. A fitting can also be an end piece, which can additionally be arranged at the beginning and / or end of a trailing antenna. A fitting can also be a float.

[0054] In order to provide power to the transducers in the towed antenna and / or the associated components, as well as to enable signal transmission between the towed antenna and a towing vessel, the support cable is designed as a cable or a cable is routed around the support cable.

[0055] A "cable" is defined in particular as a single- or multi-core bundle of conductors (individual wires) sheathed in an insulating material, which serves to transmit energy or information.

[0056] In an additional aspect of the invention, the problem is solved by a sonar for transmitting and / or receiving underwater sound signals, wherein the sonar comprises a previously described sound transducer or several previously described sound transducers and / or a previously described underwater antenna and / or a previously described towed antenna.

[0057] Thus, a sonar is provided which enables very precise localization of objects in space and / or underwater, as the received and / or transmitted underwater sound signals are processed without interference from noise of the towing vessel and with high sensitivity and rotationally symmetrical directional characteristics.

[0058] A sonar is, in particular, a device for locating objects in space and / or underwater using received and / or transmitted sound signals. This includes, in particular, active sonar, which emits its own signal, and passive sonar, which only receives transmitted sound signals. It can also be a bistastatic or multistatic sonar, which can transmit and receive simultaneously from different platforms. A sonar typically includes an underwater antenna and / or a towed antenna.

[0059] In an additional aspect of the invention, the problem is solved by a watercraft, wherein the watercraft has a previously described sound transducer or several previously described sound transducers and / or a previously described underwater antenna and / or a previously described towed antenna and / or a previously described sonar.

[0060] This provides a watercraft that can very quickly and accurately detect and / or track the position of an object underwater.

[0061] A "watercraft" is a vehicle that can move on, in, and / or under water. Examples of watercraft include tugboats and / or submarines.

[0062] The invention will now be explained in more detail using exemplary embodiments. These will show... Figure 1 is a highly schematic representation of a torus hydrophone, Figure 2 is a highly schematic top view of the torus hydrophone. Figure 1 , and Figure 3 is a highly schematic, not to scale, cross-sectional view of a tugboat with a towed antenna and a torus transmitter on the seabed.

[0063] A torus hydrophone 101 has a first torus shell half 103 and a second torus shell half 105, which are firmly bonded at their contact surfaces to form a torus shape.

[0064] The first torus shell half 103 and the second torus shell half 105 each consist of a piezoelectric ceramic 109 and each have a silver layer 107 on their outer surface and their inner surface (not shown). The piezoelectric ceramic 109 of the first torus shell half 103 and the second torus shell half 105 are polarized in the same way.

[0065] Corresponding to its torus shape, the torus hydrophone 101 has a hole 113 in its center. Furthermore, the torus hydrophone 101 has a contact area 111 for corresponding contact between the inner surface and the outer surface of the first torus shell half 103 and the second torus shell half 105.

[0066] A tugboat 331 travels on a water surface 317 and has a winch 333 at its stern. A towing antenna 321 is connected to the winch 333 by means of a towing cable 335 and is towed in the water by the tugboat 331.

[0067] The trailing antenna 321 has an aramid rope 323 which is connected to the trailing cable 335. On the side of the trailing cable 335, the aramid rope 323 is guided through an end piece 329 and connected to another end piece 329 on the opposite side of the trailing antenna 321. Between the two end pieces 329, eight torus hydrophones 101 are threaded onto the aramid rope 323 at regular intervals, each of which is guided through the hole 313 of the torus hydrophones 101. A spacer 327 is arranged between each torus hydrophone 101, ensuring that the torus hydrophones 101 maintain a uniform distance from one another and their respective positions.

[0068] The torus hydrophones 101 are electrically contacted via a line (not shown) which is routed around the aramid rope 323 and is electrically connected to the tow cable 335.

[0069] The end piece 329, the torus hydrophones 101 and the spacers 327 are surrounded on their outer surface by a tube 325 which is filled with a sound-conducting oil.

[0070] An active underwater transmitter 212 is arranged on the seabed 215 and has a torus transmitter 201 and a carrier 223, with one tip of the carrier 223 glued into the hole in the middle of the torus transmitter 201.

[0071] To mark a hazard (not shown), the active underwater transmitter 221 emits an underwater sound signal at regular intervals. For this purpose, an alternating voltage at a suitable frequency is applied to a piezoelectric ceramic element of the torus transmitter 201 by means of electronics (not shown) inside the torus transmitter 201. This causes the piezoelectric ceramic element of the torus transmitter 201 to expand and emit an underwater sound signal of 75 kHz with a rotationally symmetrical directional characteristic into the water.

[0072] The underwater sound signals from the active underwater transmitter 221 are detected by the torus hydrophones 101 of the towed antenna 321. The incident sound pressure deforms the piezoelectric ceramic 109 of the two torus shell halves 103 and 105, thereby changing their electrical polarization and generating an electrical voltage across the silver layers 107 of the two torus shell halves 103 and 105. Inside the torus hydrophones 101, this electrical voltage is converted into an analog signal by means of signal processing electronics (not shown) and transmitted via the line (not shown) around the aramid rope 323 and the tow cable 335 to a signal processing unit (not shown) located externally on the towboat 331.

[0073] Despite rotation of the towed antenna 321 on the tow cable 335 due to a water current, the underwater sound signals of the active underwater transmitter 221 are detected rotationally symmetrically by the torus hydrophones 101 of the towed antenna 321 with high sensitivity, without interference from the ship noise of the tugboat 331. Thus, the position of the active underwater transmitter 221 is precisely located and the hazard is identified. Reference symbol list

[0074] 101 Torus hydrophone 103 First torus shell half 105 Second torus shell half 107 Silver layer 109 Piezoelectric ceramic 111 Contact area 113 Hole 201 Torus transducer 215 Seabed 221 Active underwater transmitter 223 Carrier 317 Water surface 321 Towing antenna 323 Aramid rope 325 Hose 327 Spacer 329 End piece 331 Tugboat 333 Winch 335 Towing cable

Claims

1. Sound transducer (101, 201) for transmitting and / or receiving underwater sound signals, wherein the sound transducer comprises at least two sound transducer shells (103, 105), each of which comprises a piezoceramic material (109) and is electrically conductive on an outer surface and an inner surface, characterized in that the sound transducer shells together form a torus-shaped shape, so that an underwater sound signal can be transmitted and / or received in a rotationally symmetrical manner.

2. Sound transducer according to claim 1, characterized in that two sound transducer shells are designed as shell halves.

3. Sound transducer according to one of the previous claims, characterized in that a carrier plate is arranged between the sound transducer shells and / or the shell halves.

4. Sound transducer according to one of the previous claims, characterized in that the piezoceramic material has a polarized piezoelectric ceramic (109) and / or ceramic filaments.

5. Sound transducer according to one of the previous claims, characterized in that the electrically conductive outer surface and / or the electrically conductive inner surface comprises or comprise a metal layer (107) and / or an electrode.

6. Sound transducer according to one of the previous claims, characterized in that signal processing electronics are arranged inside the torus-shaped form.

7. Sound transducer according to one of the previous claims, characterized in that the electrically conductive inner surface is connected to an insulated area on the outer surface by means of a conductive connection for contacting.

8. Sound transducer according to one of the previous claims, characterized in that the electrically conductive inner surface and / or the electrically conductive outer surface is contacted by means of a support cable (323) and / or a line.

9. Underwater antenna (221), characterized by a sound transducer according to one of claims 1 to 8.

10. Towed antenna (321), wherein the towed antenna comprises at least two transducers according to any one of claims 1 to 8, a support cable (323) for holding the transducers, and a hose (325) for enveloping the support cable and the transducers, wherein the hose is filled with a sound-conducting medium, characterized in that the support cable is guided through a hole (113) formed in the center of the torus-shaped form of the sound transducer or at each sound transducer.

11. Towed antenna according to claim 10, characterized in that the towed antenna comprises a third sound transducer, a fourth sound transducer, a fifth sound transducer, and / or further sound transducers.

12. Towed antenna according to one of claims 10 or 11, characterized in that a molding piece (327) is arranged between the sound transducers.

13. Towed antenna according to one of claims 10 to 12, characterized in that the support cable is designed as a cable or a cable is guided around the support cable.

14. Sonar for transmitting and / or receiving underwater sound signals, characterized in that the sonar has one or more transducers according to one of claims 1 to 8 and / or an underwater antenna according to claim 9 and / or a towed antenna according to one of claims 10 to 13.

15. Watercraft (331), characterized by one or more transducers according to any one of claims 1 to 8 and / or an underwater antenna according to claim 9 and / or a towed antenna according to any one of claims 10 to 13 and / or a sonar according to claim 14.

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