WO2023011925A1

WO2023011925A1 - Underwater vehicle and method for improving the positional image of an underwater vehicle

Info

Publication number: WO2023011925A1
Application number: PCT/EP2022/070387
Authority: WO
Inventors: Till Wiegand; Florian Schulz; Ivor Nissen
Original assignee: Atlas Elektronik Gmbh; Thyssenkrupp Ag
Priority date: 2021-08-05
Filing date: 2022-07-20
Publication date: 2023-02-09
Also published as: DE102021208506A1; EP4381309A1

Abstract

The invention relates to an underwater vehicle (20) comprising a plurality of sensors (24, 24'), a guide system (27) and a signal processing unit (28). The sensors are designed to determine measurement values (26) in order to generate self-acquired information, wherein one sensor (24') of the plurality of sensors is designed to receive a digital message (40) in order to obtain external information. The guide system (27) is designed to generate a positional image (46) of the underwater vehicle (20) on the basis of the self-acquired information. The signal processing unit (28) is designed to process the digital message (40) and, on the basis of the digital message (40), adapt the positional image (46) or output tactical information.

Description

Underwater vehicle and method for improving the situation picture of an underwater vehicle

Description

The invention relates to underwater communication with an underwater vehicle.

In the role of a stand-alone platform operating on its own, an underwater vehicle, in particular a submarine, traditionally acts independently and has not yet benefited from the possible knowledge of other units. The information required to create a tactical situation and operate the sonar system (target situation, environmental conditions) is compiled and managed by the crew of the underwater vehicle itself or by algorithms in autonomous vehicles. However, this information is limited to what the submersible can gather on its own. The information that the underwater vehicle can develop itself, i.e. independently, is referred to below as intrinsic knowledge.

The object of the present invention is therefore to create an improved concept for underwater vehicles.

The object is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

Exemplary embodiments show an underwater vehicle with a plurality of sensors. The sensors are designed to determine measured values in order to generate their own knowledge. Measured values can include any selection of the following variables, for example: sound pressure, the hydrostatic pressure, a speed of the underwater vehicle, etc. At least one sensor of the plurality of sensors is also designed to receive a digital message in order to obtain external knowledge. Such information is referred to as foreign knowledge that is not the underwater vehicle can or should be determined. Information that should not be determined by the underwater vehicle is, for example, information that increases the probability of the underwater vehicle being discovered. For example, there is a high risk of being discovered if the underwater vehicle climbs to periscope depth or operates an active sonar. Information that cannot be determined by the underwater vehicle relates to information that is out of range of the underwater vehicle, for example sound velocity profiles at a greater distance from the underwater vehicle.

The underwater vehicle also includes a guidance system that is designed to generate a situational image of the underwater vehicle based on its own knowledge. The underwater vehicle also includes a signal processing unit which is designed to process the digital message and to adapt the situational image based on the digital message or to output tactical information. Adjusting the situational picture can also be referred to as adjusting the situational picture.

The message can be sent to the underwater vehicle by means of acoustic underwater communication from another platform in or on the water, e.g. a ship, a buoy, an offshore wind turbine, an unmanned underwater vehicle, a submarine or a diver. Acoustic underwater communication enables a submerged underwater vehicle to be connected to external platforms over tactically and strategically relevant distances of more than 100 km. However, the data transmission rates that can be achieved are limited by the physical properties of the hydrostatic channel, but are sufficient for operational applications. The message can be sent using suitable modulation methods.

The picture of the situation includes, for example, information about objects in or on the water. These are, for example, watercraft such as ships or underwater vehicles such as submarines or unmanned underwater vehicles. This information can be any of the position, direction, Velocity, type, classification features, etc. that objects have. The situation picture is also referred to as the surrounding situation picture.

The idea is to send the underwater vehicle further information from external platforms (foreign knowledge) that it cannot or should not obtain itself, in addition to the information that it can obtain itself (own knowledge). This external information can include data from objects, in particular possible contacts (in particular watercraft), e.g. position, speed, course, classification features, type, etc. of the possible contact, which the underwater vehicle has not yet acquired, not so quickly or not with the precision can. This is relevant insofar as the underwater vehicle typically only works using passive sonar in order not to be discovered. However, active sonar, which can be safely used by other platforms, can locate targets over longer distances and with greater accuracy. Information about objects obtained in this way, which the underwater vehicle cannot or should not determine itself, can be transmitted to the underwater vehicle as external knowledge. The picture of the situation can be adjusted based on the information obtained about the objects. The adaptation takes place continuously in a control process, for example.

Furthermore, the message, ie the foreign knowledge, can contain target-independent information that can be used to adapt the picture of the situation. This can include, for example, environmental knowledge such as a sound velocity profile, which covers an area around the underwater vehicle in which the underwater vehicle cannot determine the sound velocity profiles itself. In addition to the speed of sound, other environmental information such as meteorological information (e.g. wind speed, wind direction) or oceanographic information (e.g. ground conditions, obstacles such as reefs, ground elevations, wrecks in the area, etc.) can also represent useful information for the submersible that it cannot obtain independently under water can determine. This would only be possible when the submersible climbs to periscope depth, which, however, massively increases the risk of the submersible being discovered. In addition to or as an alternative to the information, the situation picture can therefore also be adapted based on the environmental knowledge become. Adapting the situation picture based on the environmental knowledge can include a calibration of the sensors in order to be able to determine the self-knowledge more quickly or with greater accuracy. The update of the situation picture based on environmental knowledge, for example, also takes place continuously in a control process.

It is also possible, for example, to determine the volume of the underwater vehicle and to use the message to warn the underwater vehicle if it is too loud and there is a risk of being recognized by third parties. The underwater vehicle can output this information as tactical information. It is also possible to send text messages to the underwater vehicle, for example to send commands or mission-related information to the underwater vehicle. This can also be output as tactical information.

However, the digital message includes the absence of cooperative bi-static sonar information. This means that the message is not suitable for determining the position of the object from a runtime difference between the direct sound and the reflection of the message on an object. Furthermore, the message may include the absence of a position of the platform that sent the message. However, the message may include a time when the message was sent. However, this point in time is then not used to determine the transit time and thus the distance from the transmitting platform to the underwater vehicle, but rather, for example, to determine whether the information contained in the message is still relevant.

In exemplary embodiments, the sensor of the plurality of sensors which receives the message is designed to receive further digital messages sequentially, ie for example cyclically, in order to obtain further foreign knowledge. The signal processing unit is designed to process the further digital messages and, based on the further digital messages as part of the adaptation, to optimize the situation picture sequentially, ie for example cyclically, by means of a control. This has the advantage that the picture of the situation is continuously optimized based on external knowledge. So arises with each received Message containing information for the situational picture, a more precise situational picture. The regulation takes place, for example, by providing a corresponding variable (measured value) for the information obtained from the message in a method for iterative estimation of the situation picture, for example a Kalman filter.

In exemplary embodiments, the plurality of sensors include an array of waterborne sound receivers, each of which converts waterborne sound into an electrical signal corresponding to the sound pressure as a measured value. The signal processing unit receives information about an object as intrinsic knowledge from the electrical signals in order to generate the situational image of the underwater vehicle. This means that the underwater vehicle generates its own picture of the situation. The waterborne sound receiver (or also a plurality of waterborne sound receivers) for receiving the message can be arranged separately from the array and optimized for receiving the message.

In exemplary embodiments, the sensor for receiving the digital message is one hydronic receiver (or a plurality of hydronic receivers) of the array of hydronic receivers. That is, the array of hydrophones, or at least a portion thereof, is configured to receive the message. The message (i.e. the external knowledge) is accordingly received and the internal knowledge is generated by means of the array of waterborne sound receivers. The signal processing unit separates the digital message as external knowledge from the measured values for generating the situation picture as internal knowledge.

This is advantageous since a sonar system is typically already arranged on the underwater vehicle for the reception and evaluation of waterborne noise, which has a large array of waterborne noise receivers with directivity and sufficient computing power in the signal processing systems. It is thus not necessary to arrange an additional hydrophone on the underwater vehicle only for the purpose of receiving the message. Existing underwater vehicles can thus be adapted by retrofitting the signal processing software. In exemplary embodiments, situation image information is transmitted in the digital message. The signal processing unit can then decode the situation image information from the message and, based on the situation image information, validate and/or optimize the information about an object represented in the situation image, in particular a contact. The situation picture information can be compiled by a platform, for example a surface unit or a network, for example by means of radar. Furthermore, individual contacts can be received through the platform using the automatic identification system AIS and the information received can be encoded in the digital message. In this application, the information encoded in the message consists, for example, of position data and/or information on the speed and/or course of the recorded contacts. For contacts recorded via AIS, the MMSI number (Maritime Mobile Service Identity) offers the possibility of an exact identification of the contact. Furthermore, the MMSI number offers the possibility of taking additional information from a target database of the underwater vehicle. Additional information can be, for example, any selection of the following information: picture of the contact, information about the drive train or information from an acoustic database with spectrum and transient noise. Maintaining such (rarely or never changing) information significantly reduces the amount of data to be transmitted.

In other words, the platform can receive information sent by a third party (for example the AIS information), reduce an information content of the information in order to obtain information with reduced information content and encode the information with reduced information content as a message. Thus, not all of the information received from the third party needs to be sent, only the information relevant to the underwater vehicle.

In exemplary embodiments, the signal processing unit is designed to optimize direction formation by means of the array of waterborne sound receivers in order to adapt the situation image. For the correct determination of a bearing (ie the determination of the direction of a contact starting from the underwater vehicle) using passive sonar, knowledge of the speed of sound is essential required for the evaluation of the electrical signals of the array of waterborne sound receivers in the beamformer. An incorrectly assumed speed of sound in the beamformer leads to deviations in the bearing determined from the true bearing of a contact in an array of waterborne sound receivers. The speed of sound is therefore permanently measured locally on the underwater vehicle and taken into account in the sonar system. However, in the most unfavorable case, the measurements may contain errors or may not be representative of the sea area. The value of the speed of sound assumed for the beamformer can be edited manually by the sonar operator in existing systems. In principle, this allows a correction of the bearing results, but supposed systematic deviations in the bearing results must first be recognized.

The message received from the underwater vehicle can be used in various ways to support the sonar operator in the event of bearing errors due to incorrect parameterization of the beamformer. On the one hand, the position of the contact can be transmitted. From this externally provided target position and the underwater vehicle's own known position, a theoretically expected bearing to the target can be determined for each piece of data received. A bearing history based on the received positions for the contact is built up from a plurality of position values received one after the other. The course of bearing determined in this way can be displayed as an overlay over the results of the bearing-time record. Deviations between the sonar track in the bearing-time record and the course of the bearing based on the transmitted positions is an indicator of an incorrectly assumed sound velocity in the beamformer and/or incorrect knowledge of the own position.

Furthermore, with the transfer of environmental knowledge, current measurements of the speed of sound from the sea area can be made available to the underwater vehicle. The sonar operator can compare this data with the values available in the submersible and adjust the sound speed in the beamformer accordingly. In exemplary embodiments, the signal processing unit is also designed to optimize a detection of contacts in the electrical signals of the waterborne sound receivers of the array of waterborne sound receivers in order to adapt the situation image. For example, contacts that are difficult to locate with passive sonar systems due to their great distance from the underwater vehicle and/or a low acoustic signature pose a particular challenge for situational image processing. Information about the position and possibly also the type of a target that is difficult to locate passively can now be transmitted to the underwater vehicle by means of the message. This information can be used as follows.

On the one hand, for permanent 360° all-round monitoring, the beamformer is simultaneously controlled in different beams (engl.: viewing directions). The design of the discrete angular grid on which the beams lie is typically such that the drop in level between the main lobes of adjacent beams does not exceed a specific value for the entire frequency range covered. This value is e.g. 3dB. The maximum number of viewing directions that can be recorded at the same time is essentially limited by the available computing capacity, so that the drop in level cannot be arbitrarily reduced over the entire all-round view. Quiet targets whose true bearing is not exactly on the beam grid may not be detected or only with difficulty.

However, if the position of the contact has been communicated with the message, the expected bearing to the contact can be determined from the underwater vehicle's own known position. Within a limited sector around the supposed target bearing, the viewing direction density can then be locally increased in the beamformer. Compared to panorama surveillance, the drop in level is reduced within this sector, which increases the probability of the target being detected.

Furthermore, the detection step in both broadband and narrowband processing is designed to ensure that no contact is missed. However, the exact acoustic signature of a target is initially unknown and is also different for each target. Therefore, detectors evaluate signal properties that are generally valid for all contacts. This means that the existence of a broadband spectrum or the existence of LOFAR lines (LOFAR: LOw Frequency Analysis and Recording) is tested. However, this is more difficult than searching for a specific frequency pattern, for example. However, if the underwater vehicle knows the contact, ie information on the type of target is contained in the message, the acoustic signature of the contact can be derived from this knowledge, for example from a database. If the detection step for the expected bearing range is now optimized for the (putative) acoustic signature of the contact, the detection performance is improved compared to the standard passive detector. Such a detector can be implemented in parallel with a standard detector. An adjustment of the detection parameters controlled by adaptive algorithms is therefore advisable here.

Regardless of the improvement of the detection step, the information about a contact can be used for the classification of a contact. This information can be used to secure and complete the classification result developed in the submersible. On the one hand, a plausibility check supported by algorithms can be carried out by comparing the received results with the results of the classification analysis. On the other hand, the information provided externally can be used to enhance the classification results worked out by the underwater vehicle with further properties that have not yet been recorded. These can be, for example, LOFAR lines that have not yet been recorded or also photographs of the contact.

In exemplary embodiments, the signal processing unit is designed to carry out a target motion analysis (dt.

contact tracking analysis) to generate the situation picture of the underwater vehicle and based on the message to optimize the target motion analysis. In addition to the extraction of classification features, the passive sonars of an underwater vehicle can primarily only be used to determine bearings for a contact. However, the positions and states of motion of the detected targets are of interest for the construction of a sonar situation image. These target parameters are determined in passive sonar systems with the help of the so-called target motion analysis. In doing so, target information such as distance, course and speed are essentially compiled by suitable evaluation of bearing histories. Depending on the method and available sonar antennas, cross bearings and Doppler shifts can also be evaluated. Furthermore, target information from other data sources can already be taken into account in modern target motion analysis methods, such as distance measurements from passive ranging sensors or laser ranging sensors of the periscope. The underwater vehicle no longer needs to determine this information itself and thus run the risk of being discovered, but can instead be transmitted to the underwater vehicle by means of the message. In this way, information about the position and the movement status of the contact can be sent to the underwater vehicle. This knowledge can flow into the target motion analysis as additional information in order to improve its results. Furthermore, one

Plausibility check between the target solution developed by the submersible and the information provided externally is possible. The plausibility check can be carried out automatically using suitable data fusion and support the user in the decision-making process.

In exemplary embodiments, the signal processing unit is designed to estimate a performance of the hydrophones of the array of hydrophones and to optimize the estimate based on the message in order to improve the situation picture. Modern sonar systems of underwater vehicles typically have an integrated sonar performance suite that, based on environmental knowledge, estimates the current sound propagation conditions with the help of sound propagation models. This in turn allows an estimation of both the detection range of the own sonar sensors and the detection range of foreign, threatening sensors against the own underwater vehicle. The prediction of the propagation conditions can be used for tactical positioning of the underwater vehicle in order to remain acoustically undetected and to be able to optimally observe other targets with your own sonar sensors. Input variables for the Sonarperformance Suite can store own boat data (e.g. own position, own acoustic signature, performance data of own sonar sensors), environmental data (e.g. sound propagation profiles, depth profile of the bottom, bottom type, waves) and/or target data (position of the target, acoustic signature of the target, parameters of the target possibly carried acoustic sensors).

While own boat data is available practically without restrictions, the environmental data would either have to be determined by the boat's own measurements or taken from databases. It must be taken into account that both the measured and the assumed environmental data, in particular the sound propagation profiles, can deviate significantly from the actual conditions in individual cases. The required target data would first have to be compiled with the help of the sonar system. Both the environmental data and the target data can now be transmitted to the underwater vehicle in one message. For example, other platforms in the submarine's operational area can measure current sound velocity profiles at various positions and make this information available to the submarine vehicle. The possible consideration of the spatial variability of the sound propagation profiles in the propagation model allows more realistic predictions than when evaluating only locally measured or database-based sound propagation profiles. Furthermore, gliders can be used to continuously record environmental data and forward it by radio. Gliders can operate at different depths in the water and record environmental data. On the water surface, these can then be collected for a dive, for example, sent to an operations center, for example by radio. For example, information about the waves can be used to parameterize models for environmental noise more realistically. Thus, by using additional knowledge from the message about the environmental and target conditions, a more realistic estimation of detection ranges can be obtained with the help of the Sonarperformance Suite. This also improves the picture of the situation in that it is possible to estimate the distance up to which contacts can be expected to be detected. This can be an explanation as to why a contact transmitted by means of the message, for example, has not yet been detected by the underwater vehicle. A system is also disclosed that includes the underwater vehicle. Further, the system includes the platform. The platform is designed, for example by means of a coding unit, to encode information as a message and a waterborne sound receiver, which is designed to convert the message into waterborne sound. The signal processing unit of the underwater vehicle can process this message, in particular decode it, in order to obtain the situation image information and to adjust the situation image of the underwater vehicle based on the situation image information.

In one embodiment, the platform comprises, for example, an offshore wind turbine (or an offshore wind turbine thereof). In addition to their primary task of generating energy, wind farms offer a good infrastructure for means of communication and can serve as platforms for acoustic and non-acoustic sensors and actuators (e.g. sound receivers). These include, for example, AIS receivers (AIS: automatic identification system) and radar receivers for reconnaissance of the general situation, both above water and in the air, as well as sensors for recording environmental parameters. With the environmental sensors, environmental parameters relevant to the mission or navigation, such as the speed of sound, wind speed, wind direction, etc., can be measured and made available. In addition to radio communication and/or satellite communication or a fiber optic connection for sending and receiving data and for general communication, offshore wind farms are equipped with sonar transponders (waterborne sound receivers). In addition to the acoustic warnings, the transponders can also be used to send the information determined by the sensors and/or actuators and encoded in the message to the underwater vehicle.

In a further exemplary embodiment, the platform comprises, for example, a surface unit, for example a ship. Military surface units have a variety of means of communication and sensors. AIS receivers and radar receivers are used to clarify the general situation (overwater and air) and environmental sensors to measure mission and navigation-relevant parameters (wind speed, wind direction, sound speed profile) deployed. In addition, special surface units have both active and passive sonar systems or dipping sonars (immersion sonars) to generate the underwater situation and/or echo sounders to record depth profiles and sediment layers. Thus, the surface units have a large amount of information, which can be made available to the underwater vehicle in a targeted manner encoded as a message. The information can be acoustically radiated via active sonar transmitters, with underwater telephony transmitters or using a gateway buoy via underwater communication.

In a next exemplary embodiment, the platform comprises an (e.g. military or militarily usable) underwater unit. In addition to submarines, this also includes unmanned underwater vehicles and divers or combat swimmers. Examples of unmanned underwater vehicles include autonomous underwater vehicles (AUV) or remotely operated underwater vehicles (ROV) and gliders. In particular, unmanned underwater vehicles and other submarines can collect information that is not available to the underwater vehicle in the operation. This is, for example, information about the underwater situation and parameters recorded with environmental sensors such as sound velocity profiles, bottom types and depth profiles. This information can be encoded in the message and acoustically transmitted using underwater communication.

In another embodiment, the platform includes a gateway buoy. A gateway buoy is a communication buoy that has satellite or radio receivers or transmitters and waterborne receivers, for example. This can thus encode information received via satellite or radio into the message and radiate it acoustically by means of underwater communication. It forms an important element in the networking of surface and underwater units. Gateway buoys are used to enable surface units and aircraft that have no acoustic transmission capacity in the water (ie no waterborne sound receivers) to exchange information with the underwater vehicle. When using satellite communication, the gateway buoy can be reached from almost anywhere in the world, for example from headquarters or an operations center, and received information can be transmitted into the water layer send or relay information from the water layer to surface units. The communication channel formed in this way can be used both unidirectionally and bidirectionally. In addition, gateway buoys can collect their own information about rain, fog and current conditions, for example, or their own GPS position and encode it in the message and emit it acoustically using underwater communication.

In further exemplary embodiments, the platform can receive information sent by a third party (for example the AIS information), reduce an information content of the information in order to obtain information with reduced information content and encode the information with reduced information content as a message. Thus, not all of the information received from the third party needs to be sent, only the information relevant to the underwater vehicle.

Analogously, a method for improving the situation picture of an underwater vehicle is disclosed with the following steps: a) determining measured values from sensors of the underwater vehicle in order to generate intrinsic knowledge; b) receiving a digital message with the underwater vehicle; c) generating a situational picture of the underwater vehicle based on the self-knowledge; d1) Adjusting the situation picture based on the digital message; or d2) outputting information based on the digital message.

An underwater sound signal is also disclosed. The underwater sound signal includes position information, a reference value of a sound propagation value at the position specified by the position information, and differences of the sound propagation value from the reference value at the position for a plurality of predetermined depths. The underwater sound signal can be part of the message that is sent to the underwater vehicle. The position information can be the longitude and latitude of the position.

The following example is also disclosed: The example shows an underwater vehicle with a waterborne sound receiver that converts waterborne sound into an electrical signal that corresponds to the sound pressure. A signal processing unit decodes a message from the electrical signal in order to adapt, ie to adjust, a situational image of the underwater vehicle, which contains information on a plurality of objects, based on the message. The adaptation is done with the aim of optimizing the picture of the situation, that is, for example, to include targets that have not yet been discovered or to increase or improve the number or quality of existing information with regard to targets that have already been detected. This can be done in a continuous control process. Furthermore, the adaptation also includes that already existing information is validated based on the message. In this case, for example, the probability that an object is actually located at a position that has already been determined by the underwater vehicle is increased. This reduces the uncertainty that the object is in a different position or reduces the radius in which the object can statistically be located. In other words, the adjustment refers to both the manual and the machine (that is, automatic, supported by algorithms) adjustment and readjustment of significant manipulated variables such as sound velocity values. The decision as to whether the adjustment is to be made manually or automatically is less a question of technical feasibility and more based on operational and security-related considerations.

Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. Show it:

1 : a schematic representation of an underwater vehicle that receives messages from different platforms;

Fig. 2: a schematic block diagram of the signal processing process for adapting the picture of the situation of the underwater vehicle.

Before the following exemplary embodiments of the present invention are explained in more detail with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements, objects and / or Structures in the different figures are provided with the same reference symbols, so that the description of these elements presented in different exemplary embodiments can be interchanged or applied to one another.

1 shows a schematic representation of a system 10 in an exemplary embodiment, in which an underwater vehicle 20 receives messages by means of waterborne sound 22 in the form of underwater communication from various platforms. However, it is also possible that only one of the platforms shown is part of the system. The underwater vehicle 20 includes a plurality of sensors 24, 24'. The sensor 24 is a waterborne sound receiver, which converts waterborne sound 22 into an electrical signal 26 corresponding to the sound pressure. The other sensors 24' also convert corresponding measured values into electrical signals. The measured values and the associated electrical signals form the intrinsic knowledge of the underwater vehicle.

The underwater vehicle 20 also includes a guidance system 27 and a signal processing unit 28. The guidance system 27 is shown as part of the signal processing unit, but can also be a separate unit. Based on its own knowledge, the guidance system 27 generates a situational image of the underwater vehicle.

The signal processing unit 28 can process a digital message from the electrical signal 26 and, based on the digital message, adjust the situational image of the underwater vehicle 20 or output tactical information. This means that the picture of the situation is adjusted using the knowledge of others.

A ship 30a, a gateway buoy 30b and an operations center 30c are shown here as platforms. The ship 30a can send the message directly to the underwater vehicle using waterborne sound 22 . Alternatively, it is also possible (but not shown in the figure for reasons of clarity) to first send the message through the air, ie for example by radio, to the gateway buoy 30b. The gateway buoy then converts the message into waterborne sound 20 and then sends it to the underwater vehicle 20. The gateway buoy 30b can also do the same with a Make message to be sent from operations center 30c. The operations center 30c is shown sending the message via satellite communication 32 to a satellite 34, which also sends the message via satellite communication 32 to the buoy 30b. The buoy 30b can in turn send the message to the underwater vehicle 20 using waterborne sound 22 as underwater communication. It would also be conceivable for the operations center to set up a radio link to an aircraft instead of using satellite communication, which in turn would send the message to the buoy by radio link.

2 shows a schematic block diagram of the signal processing process in one embodiment. The waterborne sound receiver 24, in exemplary embodiments an array of waterborne sound receivers, receives the waterborne sound in step 36. The electrical signals 26 representing the waterborne sound form the input signal of the signal processing unit. In step 38, this first separates the message(s) 40 (foreign knowledge) from the environmental information 42 (self-knowledge), i.e. the waterborne noise that is generated, for example, by other objects. This step can already contain beamforming before the separation. In step 44, the situational image 46 can be created on the basis of the environmental information 42. In step 48, the situation image 46 is adjusted based on the information that the signal processing unit has decoded from the message 40. The adjusted situational image 50 is created. The adjusted situational image 50 is updated in a next processing cycle in step 44 using the self-knowledge. In step 48, the updated adjusted situational picture is adjusted again based on the message. A regulation is implemented in order to cyclically optimize the situation picture 50 . In the practical implementation of the method, steps 44 and 48 can also take place together. This means that own knowledge and knowledge from others flow simultaneously into the adjustment of the situation picture as soon as the situation picture has been created for the first time.

In other words, the signal recording (outboard) and the pre-processing steps such as beamforming take place first. Thereafter, signal processing steps for the detection, demodulation and possible decoding of any messages contained in the beam data are carried out. The demodulation including the optional decryption is also called called decoding. Furthermore, the information contained in the messages is evaluated and presented.

The (water) sound receivers disclosed are designed for use under water, in particular in the sea. The sound receivers are designed to convert waterborne sound into an electrical signal (e.g. voltage or current) corresponding to the sound pressure, the waterborne sound signal. The sound receivers have, for example, a piezoelectric material, for example a piezoceramic, as the sensory material. The sound receivers can be used for (active and/or passive) sonar (sound navigation and ranging). The sound receivers are not suitable for medical applications.

Although some aspects have been described in the context of a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to 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 constitute a description of a corresponding block or detail or feature of a corresponding device.

The embodiments described above are merely illustrative of the principles of the present invention. It is understood that modifications and variations to the arrangements and details described herein will occur to those 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. Reference list:

10 systems

20 underwater vehicle

22 water noise

24 sensors (e.g. waterborne sound receiver)

26 electrical signal

27 guidance system

28 signal processing unit

30 platform

32 satellite communications

34 satellite

36 step of signal processing

38 step of signal processing

40 digital message

42 environment information

44 step of signal processing

46 situation report

48 step of signal processing

50 adapted situation picture

Claims

Claims Underwater vehicle (20) with the following features: a plurality of sensors (24, 24 '), which are designed to determine measured values (26) to generate self-knowledge, wherein a sensor (24') of the plurality of sensors is designed, a receive digital message (40) to obtain foreign knowledge; a guidance system (27) which is designed to generate a situational image (46) of the underwater vehicle (20) based on its own knowledge; a signal processing unit (28) which is designed to process the digital message (40) and based on the digital message (40) to adapt the situation image (46) or to output tactical information. The submersible (20) of claim 1, wherein the digital message (40) includes the absence of cooperative bi-static sonar information. Underwater vehicle (20) according to one of the preceding claims, wherein the sensor (24 ') of the plurality of sensors is designed to sequentially receive further digital messages in order to obtain further foreign knowledge; wherein the signal processing unit (28) is designed to process the further digital messages and, based on the further digital messages for adjusting the situation picture, to sequentially optimize the situation picture by means of a control. Underwater vehicle (20) according to one of the preceding claims, the plurality of sensors comprising an array of waterborne sound receivers which are designed to convert waterborne sound into an electrical signal (26) corresponding to the sound pressure as a measured value; wherein the signal processing unit (28) is designed to obtain information about an object as intrinsic knowledge from the electrical signals in order to generate the situation image (46) of the underwater vehicle. The underwater vehicle (20) of claim 4, wherein the sensor for receiving the digital message is a hydronic receiver of the array of hydronic receivers; wherein the signal processing unit (28) is designed to separate the digital message (40) as external knowledge from the measured values as internal knowledge. Underwater vehicle (20) according to one of the preceding claims, wherein the signal processing unit (28) is designed to decode situation image information from the digital message (40) and based on the situation image information to validate the information on an object shown in the situation image and/or to optimize. Underwater vehicle (20) according to any one of the preceding claims, wherein the signal processing unit (28) is designed to decode environmental knowledge, in particular a sound velocity profile, from the digital message (40) and to adapt the situation image (46) with knowledge of the environmental knowledge. Underwater vehicle (20) according to any one of claims 4 to 7, wherein the signal processing unit (28) is designed to optimize direction formation by means of the array of waterborne sound receivers in order to adapt the situation image based on the digital message (40).

9. Underwater vehicle (20) according to one of claims 4 to 8, wherein the signal processing unit (28) is designed to adapt the situation image based on the digital message (40) to detect contacts in the electrical signals of the hydrophones of the array of hydrophones optimize.

10. The underwater vehicle (20) according to any one of claims 4 to 9, wherein the signal processing unit (28) is designed to carry out a target motion analysis based on the electrical signals of the underwater sound receivers of the array of underwater sound receivers in order to generate the situation image (46) of the underwater vehicle and based on the message (40) to optimize the target motion analysis.

11 . Underwater vehicle (20) according to any one of claims 4 to 10, wherein the signal processing unit (28) is designed to estimate a performance of the hydrophone of the array of hydrophones and to optimize the estimate based on the digital message (40) to the situation image (46) to improve.

12. System (10) comprising, the underwater vehicle (20) according to any one of the preceding claims; a platform (30) which is designed to encode information as a message (40) and a waterborne sound converter which is designed to convert the message (40) into waterborne sound, the signal processing unit (28) of the underwater vehicle being designed to transmit the message (40 ) to process the to obtain situational image information and to adapt the situational image (46) of the underwater vehicle based on the situational image information.

The system (10) of claim 12, wherein the platform (30) comprises any one of: a surface unit, a subsea unit, an offshore wind turbine, or a gateway buoy.

14. System (10) according to claim 12 or 13, wherein the platform (30) is designed to receive information sent by a third party, to reduce an information content of the information in order to obtain information with reduced information content and the information with reduced information content to encode as a message (40).

15. Underwater signal comprising position information; a reference value of a sound propagation value at the position specified by the position information;

Differences in the sound propagation value from the reference value at the position for a plurality of predetermined depths.

16. A method for improving the information situation in an underwater vehicle, having the following steps: a) determining measured values from sensors of the underwater vehicle in order to generate intrinsic knowledge; b) receiving a digital message with the underwater vehicle; c) generating a situational picture of the underwater vehicle based on the self-knowledge; d1) Adjusting the situation picture based on the digital message; or d2) outputting information based on the digital message.