DE102020206996A1 - Depth-variable towing sonar and procedures for operating - Google Patents

Abstract

The present invention relates to a watercraft 10 with a towing sonar, the towing sonar having a pull cable area 30 and an antenna area 40, the pulling cable area 30 of the towing sonar being arranged between the watercraft 10 and the antenna area 40 of the towing sonar, with a first immersion body in front of the antenna area 40 20 and / or a second immersion body 20 is arranged behind the antenna area 40, characterized in that the immersion body 20 has at least one depth adjustment device.

Description

The invention relates to a towing sonar which can be towed behind a watercraft to detect sound, at least the area of the towing sonar with the hydrophones being able to be brought into different water depths in an adjustable manner.

Conventional towing sonars usually have a buoyancy-neutral receiving antenna with hydrophones, the running depth (towing depth) of which is set by the length and / or the density of the towing cable deployed and the speed of the tugboat. The running depth is always a compromise between the coverage of the water column and the maximum horizontal detection range.

In general, the location performance depends on the profile of the speed of sound over the water depth. A disturbance of the localization can occur because sound anomalies arise at a so-called thermocline and / or convergence zone (transition of water layers with different temperatures, pressures etc.). Due to the locally high refraction of the sound waves, a thermocline acts like a reflective horizontal partition for sonar location, whereby the water-borne sound is deflected into a series of curves that curve up to the surface of the water and the seabed. With the exception of very tight angles, sonars can only locate on the side of the thermocline on which they are located. Convergence zones are created in particular by the fact that sound beams in the water are bent in such a way that blind zones and zones with compression are created. While the compaction effect enables occasionally higher localization ranges, the blind or shadow zones prevent continuous localization.

On the other hand, a watercraft can travel in waters of different depths. In shallow regions near the coast, for example also in the Baltic Sea, the shallow water depth means that a towed sonar should be towed in a comparatively shallow water depth. In deep water, for example in areas of the North Sea or the Atlantic, it can be advantageous to drag the tow sonar at a shallow or greater depth.

From the DE 10 2016 109 108 A1 a drum for a towing antenna is known

From the DE 10 2015 116 750 A1 a towing sonar with a transducer arrangement with a tenter frame is known.

From the DE 10 2015 115 693 A1 a towed sonar with a first antenna and a second antenna is known. Antennas can be used in different water depths via coupling elements.

From the U.S. 5,532,975 A a device for positioning seismic equipment in a predetermined underwater position is known.

From the WO 2008/043823 A1 the arrangement of a depth-variable device on a tow rope is known.

For reasons of durability and ease of use, it is desirable to be able to reach different water depths in a simple manner and without manual conversion.

The object of the invention is to provide a towing sonar that can be operated easily at different water depths without having to change the length of the towing cable or the towing speed or the diving depth of a towing watercraft.

This object is achieved by the watercraft with the features specified in claim 1 and by the method with the features specified in claim 11. Advantageous further developments emerge from the subclaims, the following description and the drawings.

The watercraft according to the invention has a tow sonar. The drag sonar can be picked up by a drum, for example. In this case, the watercraft can pick up and deploy the towing sonar. In an alternative embodiment, the tow sonar can be connected to the watercraft, that is to say, for example, brought to the place of use with the help of another vehicle and deployed behind the watercraft and connected to it. This embodiment is particularly preferred in the case of small watercraft, very particularly in the case of unmanned watercraft. But there are also submarines which, due to the mission, are connected to a tow sonar that cannot be picked up by the submarine, in particular before the mission in the port. This has the advantage that space and weight can be saved in the submarine. On the other hand, one accepts the disadvantage that the towing sonar is permanently arranged behind the submarine, which must also be taken into account when navigating.

As a watercraft, all watercraft come into consideration, in particular for Combat of submarines are used (Anti Submarine Warfare, ASW). For example and in particular it concerns cruisers, destroyers, frigates, corvettes and submarines as well as unmanned watercraft. But especially in the current times, in which bistatic procedures are gaining in importance, as the locatability of the submarines is being further reduced, the tow sonar can also be pulled by other ships in the formation. For example, an unmanned vehicle can be deployed as a signal transmitter from a ship and the towing sonar can be connected to the ship. In this way, you often get a higher detection probability of submarines in the area without revealing your own position. If the data cannot then be evaluated directly on the watercraft, they can then also be transferred to another further watercraft, in particular to another watercraft with an active sonar.

The towing sonar has a pull cable area and an antenna area. The towing sonar can preferably also have an end cable behind the antenna area. With its flow resistance, the end rope ensures that the towing sonar is as straight as possible. In addition, the towed sonar can have a sonar transmission device. This means that the towing sonar can also be used for active sonar processes. The disadvantage of all active sonar methods, however, is that one's own location is inevitably betrayed by the active emission of sound and thus leads to a hazard for the watercraft. This is therefore particularly preferred when the watercraft is an unmanned watercraft.

The pull cable area of the towing sonar is arranged between the watercraft and the antenna area of the towing sonar. On the one hand, the pull cable area creates a distance between the watercraft and the antenna area. This minimizes the influence of the watercraft's own noise on the antenna area. In addition, the pull cable area is also there to compensate for a difference in height between the watercraft and the antenna area. In this area, the pull cable area usually runs diagonally through the water, since a difference in height has to be compensated for. For the best evaluation of the received data, however, the antenna area should be arranged horizontally and as straight as possible.

According to the invention, a first immersion body is arranged in front of the antenna area and / or a second immersion body is arranged behind the antenna area. In this case, a first immersion body is preferably arranged in front of the antenna area and a second immersion body is arranged behind the antenna area or, very particularly preferably, a first immersion body is arranged in front of the antenna area, particularly preferably a first immersion body is arranged only in front of the antenna area. The immersion body or the immersion body has at least one depth adjustment device. While the depth at which the antenna area is towed is conventionally set via the parameters towing speed of the watercraft, density of the antenna area, density of the pull cable area and length of the pull cable area (often varies over the length delivered by a drum), the immersion body has a Depth setting device, an active setting of the depth is possible at least partially independently of the aforementioned parameters. The immersion body or the immersion body has at least one first environmental sensor.

In particular, the first environment sensor is selected from the group consisting of pressure sensors, salinity sensors, sound velocity sensors, temperature sensors, conductivity sensors, optical sensors, flow sensors, and sonar. In particular, stratifications of water with different temperatures or salinity can represent a barrier to sound due to the change at the stratification boundary. It can therefore be advantageous to directly measure the variable that leads to this effect, for example the temperature or the salt content, in order to stay safely below or above such a stratification, for example below or above a thermocline. In this way, it can be more reliable to control these layers in a targeted manner, since the height of these layers can be changed. The salt content can, for example, be determined either directly, for example using sodium ion-selective sensors, or, for example, indirectly using a conductivity detector. However, a simple depth measurement, for example by means of a pressure sensor, is easier to implement. This sensor could be provided redundantly, that is to say twice. An optical sensor, in particular an upwardly directed optical sensor, could also determine the diving depth through the absorption of sunlight, in particular in conjunction with a second optical sensor on board the watercraft. A sensor that determines the speed of sound would have the advantage that the essential variable is recorded immediately, regardless of whether it changes due to a change in temperature or a change in the salt content. A sonar can be used if it is specifically designed to detect the ground. In this way, a safe distance above the ground can be maintained in shallow water, for example. In this way, damage to the drag sonar can be avoided.

In a further preferred embodiment, the immersion body has at least one second environment sensor, the second environment sensor being different from the first environment sensor and the second environment sensor being selected from the group consisting of pressure sensor, salinity sensor, sound velocity sensor, temperature sensor, conductivity sensor, optical sensor, flow sensor, sonar .

With the watercraft according to the invention, it is possible to use a towing sonar, both in shallow water and in deep water, without this having to be converted, for example, or without significant restrictions on the speed of travel at different depths. It is also possible to use the antenna area of the towing sonar in a targeted manner at a certain water depth, that is to say, for example, optionally above or below a thermocline. The invention thus enables the flexible use of a towing sonar, for example on a frigate, both in deep water, for example in the Atlantic, and in shallow water, for example in the Baltic Sea. The invention can also be used when a submarine is selected as the watercraft, for example, to use the submarine on one side of a thermocline and the antenna area of the towing sonar above or below it on the other side of the thermocline.

In a further embodiment of the invention, the depth adjustment device is selected from the group comprising depth rudder and ballast tank. The immersion body preferably has both a depth rudder and at least one, better still two, ballast tanks. With the help of a depth rudder and / or a ballast tank, the diving body can change the diving depth in a targeted manner. As a result, it pulls the antenna area connected to it to this depth, so that the depth of the antenna area can be selected and set via the immersion body. In this way, the area from which sound can be received can then also be specifically selected. The combination of a down elevator and ballast tank is particularly beneficial, as the down elevator can enable the depth to be changed quickly and in a targeted manner. On the other hand, the diving depth can be kept stable for a long time using a ballast tank. In addition, there is then no need to have to steer continuously with a down rudder, which increases the flow resistance and thus increases the energy consumption of the watercraft and reduces its top speed. The immersion body particularly preferably has only the depth rudder and no ballast tank as a depth adjustment device, since this allows the system to be kept simple and small.

In a further embodiment of the invention, the immersion body additionally has a rudder. With an additional rudder, the antenna area can be shifted laterally parallel to the direction of travel of the watercraft. This has great advantages especially in two application scenarios. In shallow water it is possible to remove the antenna area from the wake of the towing watercraft. On the other hand, in the case of an active sonar, this lateral distance between the line of travel of the watercraft and the towing line of the antenna area can mislead a potential enemy about the position of the towing watercraft, since he would expect the towing watercraft in a straight line in front of the actively transmitting towing sonar. Even if a potential enemy takes this possibility into account, there is a significantly increased uncertainty about the position of the towing watercraft, since, for example, it is unclear whether the towing sonar will be pulled to starboard or port.

In a further embodiment of the invention, the immersion body has a control device. The control device is designed to read out the first environmental sensor and to control the depth adjustment device. The immersion body can therefore automatically control a predetermined depth-correlated variable, which can also be the depth itself, and, if necessary, actively control it.

In a further alternative embodiment of the invention, the watercraft has a control device. The control device is designed to read out the first environmental sensor and to control the depth adjustment device. The advantage is that all information is available directly and immediately in the operations center. In addition, especially in the case of larger depth adjustments, this information is also relevant for the evaluation of the sonar data of the Schlappsonar, since a straight, horizontal arrangement of the hydrophones can no longer be assumed in the case of larger changes.

In a further embodiment of the invention, the immersion body can be connected to the towing sonar in a reversible and detachable manner. Very particularly preferably, the immersion body is unmanned, particularly preferably autonomous, can be brought to the drag sonar and can be connected to the drag sonar. Particularly in the area of application in a submarine, it is not possible to manually couple or uncouple components, for example a transmitter for an active sonar or even a diving body, when the towing sonar is deployed or retrieved. The tow sonar must therefore be able to be wound onto a drum in a simple form. In this form, however, it becomes technically difficult to arrange a diving body in a towing sonar. The immersion body is therefore preferably equipped with a drive system and preferably has the shape of a torpedo. In this way, the immersion body can be deployed from a weapon barrel. The immersion body can then either be guided by wire or brought autonomously to the towing sonar and coupled to it. In the case of wire steering, the wire is then cut so that the barrel can be closed. In addition, the drive system can also be used to change the height of the antenna area even more quickly.

In a further embodiment of the invention, the drag sonar runs through the immersion body. The immersion body is reversibly detachable when winding up and reversibly connectable to the towing sonar when winding down. Examples of such compounds are those skilled in the art, for example WO 2008/043823 A1 known, the disclosure content of which is hereby fully included. This is particularly preferred if the watercraft is a submarine. In this case, the immersion body remains outside of the submarine after the towing sonar has been wound up.

In a further embodiment of the invention, the pull cable area has a data connection between the watercraft and the immersion body, the immersion body being controllable via the data connection. Data lines run in the towing cable area in order to route the sonar data from the antenna area into the watercraft. The integration of a corresponding data connection for the immersion body is therefore very simple. As a result, direct control and thus setting of the immersion depth of the antenna area can also be easily implemented directly from the sonar system. Optionally, a connection for supplying energy to the immersion body can also be provided. Alternatively, the various systems can be connected to the watercraft via separate energy supplies through the pull cable area, so that control only takes place via the energy provided to the individual systems. For example, a pump in the immersion body can be temporarily supplied with energy, which pumps water out of a ballast tank and thus causes a reduction in the diving depth. A servomotor of a down rudder or rudder can also be supplied with energy in order to bring about the resulting change. The information is thus only transmitted through the transmission of energy. The data connection can be established by an electrically conductive cable. This can be a pure data connection. Alternatively, an energy-carrying line can also be used to transport the data over the same line in addition to the energy transfer. The data connection can also be established by a fiber optic cable.

In a further alternative embodiment of the invention, a data connection between the watercraft and the immersion body is established by means of an acoustic modem, the immersion body being controllable via the data connection. This embodiment enables retrofitting for existing systems without having to change the pull cable.

In a further embodiment of the invention, the immersion body has an active sonar. This can be advantageous especially if the towing sonar is pulled on a different side of a thermocline than the watercraft is.

In a further embodiment of the invention, the watercraft has two towing sonars, of which at least one towing sonar has a diving body, preferably both towing sonars are each equipped with at least one diving body. This makes it possible to use a first drag sonar above a thermocline, for example, and the second drag sonar, for example, below a thermocline. This makes it extremely difficult for an enemy submarine to evade location.

In a further embodiment of the invention, the immersion body does not have any gas-filled areas. The first immersion body is preferably completely encapsulated or flushed with water. By dispensing with gas-filled areas, a sudden change in the speed of sound at the boundary between solid and gaseous is avoided, thus reducing the reflectivity for sound waves and thus the signature of the immersion body. This embodiment is particularly preferred for the passive embodiment. In the case of an active sonar on board the immersion body, it reveals its position by emitting the sound waves, so that signature optimization is unnecessary.

In a further embodiment of the invention, the power supply takes place via a power cable in the pull cable area, the power cable having at least four cores and the power cable each having two cores with the same polarity, with cores of opposite polarity being adjacent to one another. In the case of four cores, there are two cores with a high potential (+) and two with a low potential (-). These four wires are arranged at the corners of a square so that wires with the same potential are diagonally opposite one another. This reduces the electromagnetic signature.

1. a) Ausbringen des Schleppsonars,
2. b) Vorgeben einer tiefenkorrelierten Größe,
3. c) Ansteuern der aus der tiefenkorrelierten Größe ergebenden Tiefe durch den Tauchkörper mit Hilfe der Tiefeneinstellvorrichtung,
4. d) Kontinuierliches Messen einer zur tiefenkorrelierten Größe korrelierten Messgröße mit dem ersten Umgebungssensor,
5. e) Auswerten der Messgröße und prüfen, ob eine Tiefenanpassung durchgeführt werden muss und wenn notwendig ansteuern der Tiefeneinstellvorrichtung.

In a further aspect, the invention relates to a method for operating a watercraft according to the invention. The procedure consists of the following steps:

1. a) deployment of the towed sonar,
2. b) specification of a depth-correlated quantity,
3. c) Control of the depth resulting from the depth-correlated variable by the immersion body with the aid of the depth setting device,
4. d) Continuous measurement of a measured variable correlated to the depth-correlated variable with the first environmental sensor,
5. e) Evaluating the measured variable and checking whether a depth adjustment needs to be carried out and, if necessary, actuating the depth adjustment device.

The depth-correlated variable specified in step b) can be, for example, the depth itself, an ambient pressure, an ambient temperature, an ambient conductivity or a salt content. Of course, the depth-correlated variable can be changed at any point in time, for example in order to continue the search with the drag sonar at a different depth and thus, for example, in a different slice. The method then jumps back to step b), followed by the approach to the new depth in step c).

Steps d) and e) represent a control loop to hold the towing sonar in the desired position. The continuous measurement in step d) does not have to be uninterrupted. Rather, this can also happen in intervals, with the interval lengths being able to be adapted. In particular, the length of the interval can be made dependent on the variability of the measured variable. If there are only very slight fluctuations, measurements are taken, for example, in a minute interval; if more pronounced changes occur, the interval is changed to 10 seconds, for example, or even greater changes to 1 second or uninterrupted.

The use of such a control loop makes it possible, in particular, by specifying, for example, a temperature or a salinity, to remain specifically below or above a stratification, regardless of the water depth at which it is located.

In a further embodiment of the invention, the depth profile of the measured variable is determined during step c). The temperature or salinity curves are often only known to a limited extent. It is therefore advantageous to record this profile in the current situation and to be able to use this information to adapt the further mission. The determination of the depth profile can be repeated regularly when the depth changes.

In a further embodiment, a first depth is initially specified and the depth profile of the measured variable is determined during step c). The ideal position for the hydrophones is then determined from this depth profile and then, for example, the temperature or salinity of this position is specified as a depth-correlated variable. For this purpose, a sufficiently deep first depth is selected in the first step in order to be sure that the desired transition in the water is passed through and thus measured.

In a further embodiment of the invention, the watercraft has a first immersion body and a second immersion body, with coordination for the simultaneous change in depth taking place between the first immersion body and the second immersion body.

• 1 Wasserfahrzeug mit Schleppsonar und Tauchkörper
• 2 Tauchkörper
• 3 Unterseeboot mit Schleppsonar und Tauchkörper

The watercraft according to the invention is explained in more detail below with reference to an exemplary embodiment shown in the drawings.

• 1 Watercraft with towing sonar and diving body
• 2 Immersion body
• 3 Submarine with towing sonar and diving body

In 1 a watercraft 10 , for example a frigate, with a tow sonar. The towing sonar has a pull cable area 30th on as well as an antenna area 40 . In addition, the towed sonar has an immersion body 20th on who is in 2 is shown enlarged. The immersion body 20th is detachable with the antenna area 40 and the pull cable area 30th connected. To the towing sonar on a winch on the watercraft 10 to roll up, becomes the immersion body 20th severed. The immersion body 20th has a down elevator 50 and a rudder 70 as well as a ballast tank 60 on. Via a data line in the pull cable area 30th are these components by the watercraft 10 controlled so that the immersion depth of the antenna area 40 can be set in a targeted manner.

In 3 is an example of a submarine 12th shown. In contrast to the in 1 The example shown is the immersion body 20th laterally coupled to the towing sonar. The immersion body 20th is here over the weapon barrel of the submarine 12th Applied separately from the towing sonar and only coupled under water. Of course, a coupling at the water surface is theoretically conceivable when a submarine 12 has surfaced.

List of reference symbols

10

Watercraft

12th

Submarine

20th

Immersion body

30th

Pull cable area

40

Antenna area

50

Down elevator

60

Ballast tank

70

Rudder

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016109108 A1 [0005]
• DE 102015116750 A1 [0006]
• DE 102015115693 A1 [0007]
• US 5532975 A [0008]
• WO 2008/043823 A1 [0009, 0026]

Claims (13)

Watercraft (10) with a towing sonar, the towing sonar having a pull cable area (30) and an antenna area (40), the pulling cable area (30) of the towing sonar being arranged between the watercraft (10) and the antenna area (40) of the towing sonar, with A first immersion body (20) is arranged in front of the antenna area (40) and / or a second immersion body (20) is arranged behind the antenna area (40), the immersion body (20) having at least one depth adjustment device, characterized in that the immersion body (20) has at least one first environment sensor. Watercraft (10) according to Claim 1 , characterized in that the depth adjustment device is a depth rudder (50). Watercraft (10) according to one of the preceding claims, characterized in that the immersion body (20) additionally has a rudder (70). Watercraft (10) according to one of the preceding claims, characterized in that the immersion body (20) has a control device, the control device being designed to read out the first environmental sensor and to control the depth setting device. Watercraft (10) according to one of the Claims 1 until 3 , characterized in that the watercraft has a control device, the control device being designed to read out the first environmental sensor and to control the depth adjustment device. Watercraft (10) according to one of the preceding claims, characterized in that the first environmental sensor is selected from the group pressure sensor, salinity sensor, sound velocity sensor, temperature sensor, conductivity sensor, optical sensor, flow sensor, sonar. Watercraft (10) according to one of the preceding claims, characterized in that the immersion body (20) can be connected to the towing sonar in a reversible and detachable manner. Watercraft (10) according to Claim 5 , characterized in that the towing sonar runs through the plunger (20), the plunger 20 being reversibly releasable when it is wound up and reversibly connectable to the towing sonar when it is winded down. Watercraft (10) according to one of the preceding claims, characterized in that the pull cable area (30) has a data connection between the watercraft (10) and the immersion body (20), the immersion body (20) being controllable via the data connection. Watercraft (10) according to one of the preceding claims, characterized in that the immersion body (20) has an active sonar. Method for operating a watercraft (10) according to one of the preceding claims, the method comprising the following steps: a) deployment of the towed sonar, b) specification of a depth-correlated quantity, c) controlling the depth resulting from the depth-correlated variable by the immersion body (20) with the aid of the depth setting device, d) Continuous measurement of a measured variable correlated to the depth-correlated variable with the first environmental sensor, e) Evaluating the measured variable and checking whether a depth adjustment needs to be carried out and, if necessary, actuating the depth adjustment device. Procedure according to Claim 11 , characterized in that the depth profile of the measured variable is determined during step c). Method according to one of the Claims 11 until 12th , characterized in that the watercraft (10) has a first immersion body (20) and a second immersion body (20), with coordination for the simultaneous change in depth taking place between the first immersion body (20) and the second immersion body (20).

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