System comprising a towed body and a signal processing unit
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2026-04-08
AI Technical Summary
Current towed bodies for sonar antennas lack agile depth control, relying on fixed depressors and limited winch speed, resulting in sluggish depth adjustments and reduced operational flexibility, especially at high speeds or with short traction devices.
Incorporating a pair of depressors with variable angles, controlled independently by a signal processing unit, allowing for active stabilization and depth adjustment, and optionally a second pair of depressors for enhanced lift and control, along with a rudder for comprehensive stabilization.
Enables precise and dynamic depth control, improved sonar performance, reduced turbulence, increased diving depths, and reduced traction device footprint, allowing for stable operation at varying speeds and in shallow waters, with enhanced maneuverability and collision avoidance capabilities.
Smart Images
Figure EP2024063697_28112024_PF_FP_ABST
Abstract
Description
[0001] System with a towed body and a signal processing unit
[0002] Description
[0003] The invention relates to a towing body for towing behind a watercraft, in particular a military watercraft.
[0004] The use of towed tows for sonar antennas, especially for military use, is well known. Typically, towed tows are used for sonar antennas operated by surface vessels. The tow can then be positioned in the water between the surface vessel and the towed tow antenna (single tow) or operated independently, without a tethered tow antenna (dual tow / stand-alone operation).
[0005] The towed body has its own buoyancy / downforce. By means of the buoyancy or downforce of the towed body, the towing depth of the towed antenna can be adjusted depending on the towing speed and the length of the traction device between the surface vehicle and the towed body by knowing the buoyancy or downforce of a towed antenna arranged on the towed body. The towed body can have depressors (also known as vanes) to adjust its own buoyancy (especially horizontal ones). These are usually fixed, however, so that the buoyancy or the passive running depth is set once during manufacture of the towed body. The towing depth can then only be changed by changing the length of the traction device or changing the travel speed of the surface vehicle. The travel speed, however, is, among other things,due to maneuvers, cannot be varied at will, so that in practice often only the change in the length of the towing device remains. The deployed cable length and thus the effective mass in the water depends on the speed with which the winch of the surface vehicle can retrieve the towing device and deploy it in a controlled manner. However, this speed is limited due to ship construction constraints (forces, energy, etc.). The system is therefore very sluggish in terms of its towing depth. Some towed bodies have two dependently movable depressors (also known as rudders) with which a variable towing depth of the towed antenna can be generated in certain depth ranges. However, these depressors cannot be controlled independently of one another, but are rather controlled synchronously in order to keep the tethered towed antenna (single tow) or the towed body alone (dual tow / stand-alone) at a predetermined depth.
[0006] DE 22 23 798 A discloses a depth control system for submarine seismic cable systems, with which a towed seismic cable is held at a predetermined depth. The depth control system comprises a plurality of non-rotatably mounted "otters" arranged at regular intervals with the seismic cable to hold the seismic cable at a selected depth. The figures clearly show that two pairs of rudders are used for depth control, i.e., two elevators 30X-1 and 30X-2 and two ailerons 30Y-1 and 30Y-2. However, it is clear from Fig. 8 and Fig. 15 in particular that the ailerons and elevators are only controlled in pairs, and independent control of the individual rudders is not possible.
[0007] The object of the present invention is therefore to create an improved concept for towed bodies and, if applicable, sonar towed antennas attached thereto.
[0008] 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.
[0009] Embodiments show a system with a towed body for towing behind a watercraft, in particular a surface vessel, for example a ship. This means that the towed body can be connected to the watercraft by means of a traction device and pulled through the water by the latter. A towed antenna can in turn be attached to the towed body. Typically, the towed antenna has waterborne sound transducers for receiving waterborne sound, in particular waterborne sound receivers. Towed antennas are therefore suitable for passive sonar. Waterborne sound transducers for transmitting waterborne sound, in particular waterborne sound transmitters, can be arranged in the towed body. Thus, an active sonar system can also be formed with the waterborne sound transducers of the towed body and the towed antenna. Furthermore, it is possible, in addition to or alternatively to the towed antenna, to position other sensors or, if appropriate, effectors over the towed body in a depth-variable manner.A traction cable, a traction rope or a traction belt can be used as a traction device.
[0010] The towed body has a (first) pair of depressors, each of which has a variable inclination angle to enable depth control of the towed body. Depressors with variable inclination angles are also referred to as rudders. The two depressors preferably form an angle of 180°. This means that the two depressors are preferably located in a common plane.
[0011] The system further comprises a signal processing unit configured to control the depressors of the (first) pair of depressors, i.e., their inclination angle, independently of one another. This means that each depressor can be controlled independently. The signal processing unit can be arranged, for example, in the towed body or the watercraft. Due to the ability to control the depressors individually and independently of the other depressor, the depressors can perform both the function of an aileron and the function of a rudder.
[0012] The idea is to make the towed body more agile by using several independently controllable, variable depressors. This means that increased, active depth variability is possible. This has several advantages. Firstly, the towed body can be actively stabilized in the water with two independently controllable depressors around both the roll and pitch axes. This allows the towed antenna, or rather the towed body itself, to move evenly in the water and have better reception and transmission characteristics. For example, this can be used to optimize the use of the towed antenna for a synthetic aperture sonar (SAS). However, for conventional use as an active or passive sonar, a smooth movement of the towed antenna in the water is advantageous. For example, this also reduces turbulence on the towed antenna, which can negatively affect the signal-to-noise ratio.
[0013] Furthermore, it is possible to achieve greater diving depths of the towed body and thus of the towed antenna even at high speeds and with a short towing device. Both the high speed and the short towing device otherwise lead to the towed body experiencing greater buoyancy. However, using the variable depressors, the diving depth can be increased even with a short towing device. The footprint of the towing device, i.e. the maximum required volume and thus weight for storing the towing device on board the vessel, can thus be reduced, as the towing device can be dimensioned shorter to carry out the same missions. The variable depressors also enable the trimming (of the buoyancy / downforce) of the towed body depending on changed masses within the towed body, for example through replaceable elements such as sensors, or changes, e.g., in the mass, buoyancy, drag, etc. of the towed elements, e.g.by exchanging them.
[0014] In addition, towed antennas are designed for a specific speed range. This range can be extended by using the towed body, as the towed antenna can remain stable in the water, especially at low speeds.
[0015] In further embodiments, the towed body has a second pair of depressors, wherein the depressors of the second pair of depressors also each have variable angles of inclination. In particular, the signal processing unit is designed to adjust the angles of inclination of the depressors of the (first) pair and the second pair of depressors independently of the angle of inclination of one of the other depressors. This means that each depressor can be controlled independently. The term "control" refers to both control (without feedback of the current setting angle) and regulation (with feedback of the current setting angle). Preferably, the depressors of the first pair of depressors enclose an angle of 180°. More preferably, the depressors of the second pair of depressors enclose an angle of 180°. This meansThe depressors of the first pair of depressors and the second pair of depressors each lie in a common plane. It is also possible for the depressors of the first pair of depressors and the depressors of the second pair of depressors to lie in a common plane. In particular, one depressor of the first pair of depressors and one depressor of the second pair of depressors each point in the same direction from the towed body.
[0016] A further advantage is that the four depressors can generate a very rapid change in buoyancy / downforce. This enables, among other things, effective collision avoidance. The towed body can also enable the use of towed antennas in shallow waters or near coastal areas, where towed antennas are currently not used for safety reasons. In addition, towed antennas are designed for a specified speed range. This can be extended by using the towed body, as the towed antenna can be kept stable in the water, especially at low speeds. In addition, active control of buoyancy / downforce and the roll and pitch angle enables an expansion of the possible ship maneuvers with the towed body deployed.
[0017] A pair of depressors is understood to mean, in particular, two depressors arranged symmetrically to an axially extending plane, in particular lying in the plane. This means that the plane extends from the tip (bow) to the end (stern) of the towed body. Advantageously, under ideal conditions, a normal to the plane runs parallel or perpendicular to the seabed or water surface.
[0018] In exemplary embodiments, the two depressors of the first pair of depressors are arranged in a front half, in particular in a front third, of the towed body. Additionally or alternatively, the two depressors of the second pair of depressors are arranged in a rear half, in particular a rear third, of the towed body. The depressors in the rear part of the towed body can be arranged on a tail unit of the towed body. Thus, the leverage of the variable depressors is optimized, allowing the lift (or downforce) and the horizontal attitude, e.g., via the tail unit, to be optimized.
[0019] Advantageously, the towed body also features a rudder. The additional rudder, in combination with the four variable depressors, allows the towed body to be stabilized simultaneously in all spatial axes. When used with two depressors (a pair of depressors), it is also possible to stabilize the towed body in all spatial axes. However, stabilization in the roll and pitch axes cannot occur simultaneously.
[0020] In further embodiments, the system comprises a winch and a traction device, wherein the traction device connects the towed body to the winch and wherein the winch is designed to wind and unwind the traction device. A traction cable, a traction rope or a traction belt can be used as the traction device, for example. The signal processing unit is preferably designed to control the winch in order to adjust a distance between the winch and the towed body. Thus, the towing depth of the towed body can be adjusted not only by the depressors but also by the length of the traction device. In combination, this results in the towed body's greatest agility. For example, by retrieving the traction device and simultaneously controlling all existing depressors (e.g.two or four depressors) in such a way that they generate maximum lift, the towed body gains height as quickly as possible and can thus, for example, effectively avoid an obstacle on the waterbed.
[0021] In exemplary embodiments, the signal processing unit is configured to control the depressors of the first pair of depressors (and optionally the second pair of depressors) in one operating mode such that the towed body operates alternately above and below a predetermined water depth. This makes it possible, for example, to operate the towed body and thus the towed sonar above and below a boundary layer in the water. Boundary layers in the water form, for example, due to temperature differences.
[0022] Boundary layers have the effect of diffracting or refracting sound, so that either no measurement is possible on the other side of the boundary layer, or a potential target is detected at a different location than its actual location. If measurements are performed on both sides of the boundary layer, this effect can be neglected, meaning the determined position information of objects such as targets becomes more accurate. This operating mode can be referred to as boundary-layer operation.
[0023] Additionally or alternatively, the signal processing unit can control the winch in the operating mode (boundary layer operation) in such a way that the towed body operates alternately above and below the predetermined water depth.
[0024] In further embodiments, the signal processing unit is designed, in a further operating mode, in particular to avoid collisions, to control the winch such that it retrieves the traction device at at least 80%, preferably at least 90%, more preferably at least 95% of its maximum permissible retrieval speed and, in addition, to control the depressors such that the depressors generate at least 80%, preferably at least 90%, more preferably at least 95% of their maximum buoyancy. This operating mode can be referred to as anti-collision operation. By previously setting a safety distance between the towed body and the seabed, for example in the signal processing unit, a seabed collision can be avoided within the system boundaries. Such a system can be of decisive advantage, particularly for shallow water operations, and can make operations there safer.
[0025] In a further embodiment, a towed antenna is arranged on the towed body. In one operating mode, the signal processing unit is preferably configured to control the depressors such that the towed antenna is aligned linearly with an average deviation of a maximum of 15%, preferably a maximum of 10%, more preferably a maximum of 5%. This operating mode can also be referred to as towed operation. Additionally or alternatively, in this operating mode, the signal processing unit can control the depressors such that the towed antenna is arranged horizontally with an average deviation of a maximum of 15%, preferably a maximum of 10%, more preferably a maximum of 5%.
[0026] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. It shows:
[0027] Fig. 1 : a schematic partial perspective view of a towed body with two pairs of variable depressors.
[0028] 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.
[0029] Fig. 1 shows a towing body 20 for towing behind a watercraft 50. The towing body 20 is shown in perspective. Furthermore, Fig. 1 shows a side view of a watercraft 50. The connection to the watercraft 50 is established by means of a traction device 22, which can be wound onto a winch 52 on the watercraft 50. For reasons of clarity, the watercraft 50 is shown in a schematic side view. The rotation of the winch is represented by the movement arrow 30d.
[0030] The towed body 20 has a first pair of depressors 24 and a second pair of depressors 26. In the view, one of the two depressors is visible at a time, while the other depressor is arranged mirror-symmetrically on a shell 28 of the towed body 20. Plane 29, which is shown in a section, can serve as the plane of symmetry. The depressors 24, 26 each have variable angles of inclination to enable depth control of the towed body 20. The mobility is illustrated by the movement arrows 30a, 30b. Optionally, the depressors can be moved as a whole or they can have flaps to move part of the depressors.
[0031] Optionally, the towed body 20 has a (tail) fin 32. A rudder 34 can be arranged in the fin 32. A movement arrow 30c indicates the direction of movement of the rudder 34. Optionally, the depressors 26 of the second pair of depressors can also be arranged on the fin 32.
[0032] Furthermore, a towed antenna 36 can be attached to the towed body, in particular to its rear.
[0033] Further optionally, the towed body 20 has at least a plurality of waterborne sound transducers 38a, 38b or other "payloads," such as sensors. Points 38c indicate that the towed body 20 can have any number of waterborne sound transducers 38. The waterborne sound transducers can be arranged inside the hull or outside the hull, for example, in a belly 40.
[0034] A signal processing unit 54 is also shown. The signal processing unit 54 can control the depressors 24, 26 and / or the winch 52. The signal processing unit 54 can be arranged, for example, in the watercraft 50 or in the towed body 20. Communication between the signal processing unit and the winch or depressors can take place via the traction device 22.
[0035] Depending on the embodiment, the combination of towed body 20 and signal processing unit 54, additionally or alternatively optional traction means 22, additionally or alternatively optional winch 52, additionally or alternatively optional towed antenna 36, additionally or alternatively optional watercraft 50, can be referred to as system 18. .
[0036] 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 have 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). Hydrophones, for example, can be used as water sound transducers. The sound transducers are preferably not suitable for medical applications and are not used for medical applications.
[0037] 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.
[0038] 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. List of Reference Symbols:
[0039] 18 systems
[0040] 20 Towing body 22 Traction device
[0041] 24 first pair of depressors
[0042] 26 second pair of depressors
[0043] 28 Cover
[0044] 30 movement arrows 32 fin
[0045] 34 rudder
[0046] 36 towed antenna
[0047] 38 waterborne sound transducers
[0048] 40 Belly 50 Watercraft
[0049] 52 winds
[0050] 54 Signal processing unit
Claims
Patent claims 1 . System (18) with the following features: - towing body (20) for towing behind a watercraft (50), the towing body (20) having a pair of depressors (24), the depressors (24) each having variable angles of inclination to enable depth control of the towing body; - a signal processing unit (54) which is designed to control the depressors of the pair of depressors (24) independently of one another.
2. System (18) according to claim 1, comprising a winch (52) and a traction means (22), wherein the traction means (22) connects the towed body (20) to the winch (52) and wherein the winch (52) is designed to wind up and unwind the traction means (22).
3. System (18) according to claim 2, wherein the signal processing unit (54) is designed to control the winch (52) in order to adjust a distance between the winch (52) and the towed body (20).
4. System (18) according to one of the preceding claims, wherein the signal processing unit (54) is designed to control the depressors (24) of the pair of depressors in an operating mode such that the towed body (20) operates alternately above and below a predetermined water depth.
5. System (18) according to claim 3 and 4, wherein the signal processing unit (54) is designed to control the winch (52) in the operating mode such that the towed body (20) operates alternately above and below the predetermined water depth.
6. System (18) according to one of claims 3, 5 or 4 in its reference back to claim 3, wherein the signal processing unit (54) is designed, in a further operating mode, in particular for collision avoidance, to control the winch (52) in such a way that it is driven at least 80% of its maximum permissible retrieval speed, the traction means (22) is retrieved and the depressors (24) are controlled in such a way that the depressors (24) generate at least 80% of their maximum buoyancy.
7. System (18) according to one of the preceding claims, - with a towed antenna arranged on the towed body (20), - wherein the signal processing unit (54) is designed in an operating mode to control the depressors (24) such that the trailing antenna (36) is linearly aligned with an average deviation of a maximum of 5%.
8. System (18) according to one of the preceding claims, - with a towed antenna arranged on the towed body (20), - wherein the signal processing unit (54) is designed in an operating mode to control the depressors (24) such that the trailing antenna (36) is arranged horizontally with an average deviation of a maximum of 5%.
9. System (18) according to one of the preceding claims, wherein the towed body (20) has a second pair of depressors (26), wherein the depressors (26) of the second pair of depressors each have variable angles of inclination.
10. System (18) according to claim 9, wherein the signal processing unit (54) is configured to control the depressors (24, 26) of the pair of depressors and the second pair of depressors such that their inclination angles are set independently of the inclination angle of one of the other depressors (24, 26).
11. System (18) according to one of claims 9 or 10, wherein the two depressors (26) of the second pair of depressors are arranged in a rear half, in particular rear third, of the towed body.
12. System (18) according to one of claims 9 to 11, wherein the two depressors (26) of the second pair of depressors are arranged symmetrically to an axially extending plane.
13. System (18) according to one of the preceding claims, wherein the two depressors (24) of the pair of depressors are arranged in a front half, in particular front third, of the towed body (20).
14. System (18) according to one of the claims, wherein the two depressors (24) of the pair of depressors are arranged symmetrically to an axially extending plane.
15. System (18) according to one of the preceding claims, wherein the towed body (20) has a rudder (34).