Antenna for receiving waterborne sound

Abstract

The invention relates to an antenna (20) for receiving waterborne sound. The antenna has a casing (22), which surrounds a hollow space, wherein the casing (22) has a tessellation at least in one section, such that the casing (22) can be folded together at least in said section in order to reduce the hollow space.

Description

[0001] Antenna for receiving waterborne sound

[0002] Description

[0003] The invention relates to an antenna for receiving waterborne sound.

[0004] Currently, antennas for receiving underwater sound used in sonar applications always have to consider whether the system should be small and portable or whether high acoustic resolution, i.e., the reception of very long-wave acoustic signals, is desired. Neither is currently possible. For example, towed antennas with high acoustic resolution can be several hundred meters long. However, these systems are not portable. Portable systems have a shorter antenna, which limits the frequencies that can be received with the antenna.

[0005] The object of the present invention is therefore to create an improved concept for antennas for receiving waterborne sound.

[0006] This problem is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

[0007] Embodiments show a foldable antenna for receiving water-borne sound. The antenna has a casing that encloses a hollow space. The casing can therefore be tubular, i.e. hollow cylindrical, for example. The antenna can therefore be used as a towed antenna, for example. However, any other hollow shape is also conceivable, for example with a square, round or elliptical cross-section. In one example, the casing can also be spherical and form a hollow sphere. In a further example, the casing can have a polyhedral geometry. These shapes refer to the completely unfolded casing. If the casing is not completely unfolded, the casing will typically have the shape of a polygon in cross-section due to the edges of the tiles.

[0008] At least in one section, the jacket has a tiling so that the jacket can be folded together, at least in that section, in order to reduce the hollow space of the jacket and thus the volume of the antenna. The tiling (also referred to as tiling) comprises a plurality of tiles. These tiles preferably have common edge points at most at their edges. Furthermore, in the section, each point of the jacket preferably lies within at least one tile (where the edge of the tile belongs to the tile). A tile is considered to be a polygon in the plane, for example a triangle or any other closed shape. The jacket can be folded at the edges of the tiles so that the jacket can be folded together in that area with a suitable arrangement of the tiles. In this respect, the edge is also referred to as a crease edge or fold line. The sum of the crease edges can form the tiling.

[0009] One idea is to use a foldable antenna for receiving waterborne sound. If the antenna has a large folding area, a towed antenna design is conceivable, which does not need to be wound onto a winch but can be stored folded. For example, the antenna in its folded state can have a maximum volume of 50%, preferably 20%, and particularly preferably 10% of the volume of the antenna in its unfolded state. This makes the antenna not only more manageable but typically also lighter, without sacrificing acoustic properties.

[0010] Further areas of application include use with a buoy. Currently, only rings (toroids) or circular disks that are no larger than the buoy can be lowered from a buoy as antennas. With the foldable antenna, it is possible to deploy antennas from the buoy that are larger than the buoy itself, thereby improving the acoustic properties of the antenna. This affects both the radius of the antenna and the height. Using a hollow sphere as an antenna, for example, can achieve improved three-dimensional acoustic resolution compared to a circular disk or toroid. This can improve beamforming.

[0011] To receive the waterborne sound, the antenna has a plurality of waterborne sound transducers. In exemplary embodiments, one of the plurality of waterborne sound transducers is attached to the casing such that the waterborne sound transducer is arranged within the dimensions of a tile. Thus, the waterborne sound transducer is not bent when the casing is folded.

[0012] For example, the water sound transducer, in particular the water sound transducers of the plurality of water sound transducers, of the antenna is plate-shaped or rod-shaped. Preferably, the plate or the rod(s) is flexible. Preferably, a maximum of one water sound transducer is arranged per tile. This means that it is also possible and usual for tiles not to have a water sound transducer. The density of the water sound transducers in the antenna, i.e. the number of free tiles, is determined by the application scenario of the trailing antenna. Many occupied tiles make it possible to cover a broad spectrum of reception frequencies. Few occupied tiles make it possible to provide an inexpensive antenna. The water sound transducer can comprise, for example, rectangular, piezoceramic rods that are embedded between layers of adhesive, a plurality of electrodes and optionally a cover plate or film, e.g. a polyimide film.

[0013] The waterborne sound transducer can be applied as a thin, particularly surface-conformal, film to various types of sheathing materials (typically glued) or embedded in a composite structure. The electrodes of the plurality of electrodes can run transversely to the rods and make electrical contact with them. A main contact strand for the electrodes can run parallel to the rods on either side in order to tap into a voltage from the electrodes or to apply a voltage to them. The electrodes can be alternately connected to one of the two main strands so that the electrodes are arranged in an interlocking manner. This arrangement enables the polarity of the rods in the plane. When a voltage is applied, the waterborne sound transducer acts as a sound transmitter. If no voltage is applied, the waterborne sound transducer acts as a sound receiver. Such a waterborne sound transducer can be based on MFC (Macro Fibre Composite) technology.

[0014] It is, of course, also possible to apply one or more piezo rods directly to the casing or to embed them in the casing. The voltage can also be applied or tapped using electrodes.

[0015] In exemplary embodiments, electronics for processing sensor data from the waterborne sound transducers, for example, for collecting and forwarding sensor data from various waterborne sound transducers, can be arranged on flexible circuit boards, which also have a maximum size of one tile and are arranged within the dimensions of a tile. For example, a circuit board can be attached to a tile on or in which no waterborne sound transducer is arranged.

[0016] A cable for contacting a water-borne sound transducer, more precisely an electrode of the water-borne sound transducer, or the circuit board can be routed (preferably completely) along the bent edges of the tiling. This prevents the cable from being kinked and breaking. For example, the cable can be arranged so that it is routed helically around the sheath. Additionally or alternatively, it is possible to use a cable designed for bends and kinks. Such a cable can be a so-called stranded wire. A stranded wire is a flexible cable made up of a large number of wires that are, in particular, twisted together. Furthermore, it is possible to design the cable, for example, as a flexible ribbon cable. Ribbon cables typically have a plurality of electrical conductors, for example stranded wires, arranged next to one another.If the ribbon cable is designed accordingly, it is also possible, for example, to electrically connect multiple waterborne sound transducers. For this purpose, the electrical conductors can be branched off individually from the ribbon cable to establish contact with one of the waterborne sound transducers. The waterborne sound transducers can, for example, convert a bend perpendicular to a main dimension of the plate or rod(s) into a corresponding waterborne sound signal.

[0017] In exemplary embodiments, the casing is cylindrical in this section, and the tiling comprises adjacent triangles. Such a configuration allows the casing to be folded together in this section.

[0018] Further embodiments show the jacket with an opening which is designed to allow a fluid, in particular a liquid, for example water, to penetrate into the jacket in order to unfold the jacket by filling the cavity with the fluid. The jacket is preferably flooded with the water surrounding the antenna. In principle, however, it is possible to fill the jacket with any desired fluid, for example air or oil, as has been used previously in antennas, in order to unfold the jacket and thus the antenna. However, water has the advantage that the use of an oil-resistant material for the jacket is no longer necessary. This represents a problem, for example, with many polymers. The jacket can therefore comprise or consist of any desired saltwater-resistant material, in particular a polymer.Furthermore, water has the advantage over gas in that it is incompressible and can better withstand the high water pressure, even at shallow depths. Furthermore, water does not need to be carried separately, as the antenna is deployed in the water, allowing the water to flow into the mantle or be pumped into it.

[0019] For example, the antenna can comprise a pump to pump the fluid, preferably water, for example through the opening, into the cavity of the casing, so that the casing unfolds as the cavity is filled. In other embodiments, however, the casing can also fill without a pump, for example, if the antenna is a towed antenna and is towed behind a watercraft. Optionally, the casing further comprises a pressure relief valve designed to allow the fluid, and thus also the water, to escape from the casing if the pressure in the casing becomes too great. This can prevent the casing from being destroyed by excessive internal pressure.

[0020] Furthermore, this pump or another pump can pump the fluid, preferably water, out of the hollow space of the casing, so that the casing is collapsible, at least in that section. If the casing is filled to capacity with water, the water pressure prevents the antenna from collapsing.

[0021] In further embodiments, the antenna is a trailing antenna, so that the length of the trailing antenna is reduced by reducing the cavity of the casing.

[0022] Furthermore, an analogous method for manufacturing an antenna for receiving waterborne sound is disclosed, comprising the following steps: forming a tiling in at least a portion of a cladding material such that the cladding material is foldable along the edges of the tiling; joining ends of the cladding material such that the cladding material forms a cladding enclosing a cavity.

[0023] Furthermore, a method for operating the described antenna for receiving underwater sound is disclosed, comprising the following steps: deploying the antenna from a platform (for example, a watercraft, a buoy, etc.) into a body of water, in particular a lake or a sea, in its folded state; flooding the casing to unfold the antenna; transmitting or receiving underwater sound using the unfolded antenna. After the underwater sound has been completely received, the water can be pumped out of the casing and the antenna folded and retrieved. The transition between the folded state and the unfolded state is smooth, with the antenna

[0024] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. In the drawings: Fig. 1: a schematic side view of a foldable antenna, wherein Fig. 1a shows a casing in an almost completely folded state and Fig. 1b shows the casing in a slightly unfolded state;

[0025] Fig. 2: a schematic representation of a folding pattern for folding the casing material to produce the casing with its tiles according to Fig. 1;

[0026] Fig. 3: a schematic block diagram of an antenna according to embodiments.

[0027] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0028] Fig. 1a and Fig. 1b show a schematic side view of a foldable antenna 20 in two different folded states. The antenna 20 comprises a casing 22 which has a tiling with a plurality of tiles 24. The tiling 24 is shown triangular here, but can also have any other appearance. The casing 22 can be folded along edges 26 which form the tiling in order to reduce the cavity enclosed by the casing 22. Thus, it can be clearly seen from Fig. 1b that the cavity within the casing is larger than the cavity in Fig. 1a. The tiling is shown running over the entire casing; however, depending on the application, it may also be sufficient if the tiling is provided in only one section of the casing 22. Waterborne sound transducers for receiving the waterborne sound are not shown in the figures.These are located inside the casing or integrated into the casing, advantageously within the dimensions of a tile 24. This means that the waterborne sound transducers should preferably not cross any edge 26 of the tiling. Fig. 2 shows the pattern in which the folded edges 26 are arranged to obtain the casing 22 shown in Fig. 1.

[0029] Fig. 3 shows a block diagram of the antenna 20 according to exemplary embodiments. Optionally, the antenna has a pump 28. The pump can pump a fluid, in particular water, out of the antenna 20. Pumping reduces the pressure in the casing 22, allowing the casing to be folded. The fluid can be pumped into the casing 22 through a fluid channel 30, for example, a hose.

[0030] Furthermore, Fig. 3 shows an optional valve 32. Excess fluid can escape from the jacket 22 through the valve 32. This prevents excess pressure from building up in the jacket 22, which could potentially damage the jacket.

[0031] The arrow 34 also shown indicates the direction of movement of the end of the sheath when it is folded or unfolded.

[0032] The disclosed (water) sound transducers are designed for use underwater, particularly in the sea. The sound transducers can convert water sound into an electrical signal (e.g., voltage or current) corresponding to the sound pressure, the water sound signal. Furthermore, it is possible for the sound transducers to convert an applied electrical voltage into water sound. The sound transducers can therefore be used as water sound receivers and / or as water sound transmitters. The sound transducers can comprise a piezoelectric material, such as a piezoceramic, as the sensor material. The sound transducers can be used for (active and / or passive) sonar (sound navigation and ranging, dl: sound navigation and ranging). The sound transducers are preferably not suitable for medical applications and are not used for medical applications.

[0033] Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0034] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

[0035] List of reference symbols:

[0036] 20 antenna

[0037] 22 Coat 24 Tile

[0038] 26 edge

[0039] 28 Pump

[0040] 30 fluid channel

[0041] 32 Valve 34 Arrow

Claims

Patent claims 1. Antenna (20) for receiving underwater sound with the following features: a sheath (22) enclosing a cavity, wherein the sheath (22) has a tiling at least in one section, such that the sheath (22) is foldable at least in that section to reduce the cavity.

2. Antenna (20) according to claim 1, comprising a plurality of water transducers, wherein one water transducer of the plurality of water transducers is attached to or in the sheath (22) such that the water transducer is arranged within the dimension of a tile (24).

3. Antenna (20) according to one of the preceding claims, wherein the water transducers of the antenna (20) are plate-shaped or rod-shaped.

4. Antenna (20) according to claim 3, wherein the underwater sound transducers are configured to convert a bend perpendicular to a main extent of the plate or the rod(s) into a corresponding underwater sound signal.

5. Antenna (20) according to any one of the preceding claims, wherein the mantel (22) is unfolded in the section cylindrical and the tiling has adjacent triangles.

6. Antenna (20) according to one of the preceding claims, wherein the sheath (22) has a plurality of fold edges to form the tiling.

7. Antenna (20) according to claim 6, wherein a conductor for contacting a waterborne sound transducer of the antenna is guided along the bending edges of the tiling.

8. Antenna (20) according to one of the preceding claims, wherein the sheath (22) has an opening configured to allow a fluid to enter the sheath (22) in order to unfold the sheath (22) by filling the cavity with the fluid.

9. Antenna (20) according to one of the preceding claims, comprising a pump configured to pump a fluid, in particular water, out of the cavity of the sheath (22) so that the sheath (22) is foldable at least in that section.

10. Antenna (20) according to one of the preceding claims, comprising a pump configured to pump a fluid, in particular water, into the cavity of the jacket, such that the jacket (22) unfolds as the cavity is filled. Antenna (20) according to any one of the preceding claims, wherein the antenna, in its folded state, has a maximum volume of at most 50%, preferably at most 20%, and particularly preferably at most 10% of the volume of the antenna in its unfolded state. Antenna (20) according to any one of the preceding claims, wherein the antenna is a trailing antenna, such that the length of the trailing antenna is reduced by the reduction of the cavity of the jacket. Antenna (20) according to any one of the preceding claims, wherein the antenna comprises a printed circuit board, in particular a flexible one, wherein the printed circuit board is arranged within the dimensions of a tile (24) and comprises electronics for processing sensor data from the underwater transducers.Method for manufacturing an antenna for receiving underwater sound, comprising the following steps: Forms of tiling at least in one section of a sheath material, such that the sheath material is foldable along the edges of the tiling; Joining the ends of the sheath material so that the sheath material forms a sheath (22) that encloses a cavity.

15. Method for operating an antenna for receiving underwater sound according to any one of claims 1 to 13 comprising the following steps: Deployment of the antenna from a platform into a body of water, in particular a lake or a sea, in its folded state; Floods of the mantle unfold around the antenna; Sending or receiving underwater sound using the unfolded antenna.

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