AU2022319816A1

AU2022319816A1 - Underwater vehicle with a plurality of waterborne sound transducers forming a linear array

Info

Publication number: AU2022319816A1
Application number: AU2022319816A
Authority: AU
Inventors: Christian HÜCKING
Original assignee: ThyssenKrupp AG; Atlas Elektronik GmbH
Current assignee: ThyssenKrupp AG; Atlas Elektronik GmbH
Priority date: 2021-07-27
Filing date: 2022-07-13
Publication date: 2024-02-01
Also published as: WO2023006435A1; DE102021208105A1

Abstract

The invention relates to an underwater vehicle (20) with a plurality of waterborne sound transducers (22), a control unit (24), and a signal processing unit (26). The waterborne sound transducers form a linear array, wherein the waterborne sound transducers (22) are designed to emit waterborne sound signals and receive reflections of the waterborne sound signals. The control unit (24) is designed to control the underwater vehicle from a first position into a second position such that the underwater vehicle carries out - a rolling movement in order to rotate the linear array; or - a pitching movement or a movement along a vertical axis or a yawing movement or a movement along a transverse axis or a hybrid form thereof in order to move the linear array perpendicularly to the extension of the linear array. The signal processing unit (26) is designed to emit a first waterborne sound signal in the first position of the underwater vehicle (20) and to emit a second waterborne sound signal in the second position of the underwater vehicle (20), wherein the signal processing unit (26) is additionally designed to process reflections of the first waterborne sound signal and reflections of the second waterborne sound signal such that three-dimensional spatial information is produced.

Description

Underwater vehicle with a plurality of waterborne sound transducers forming a linear array

Description

The invention relates to the improvement of the (sonar) imaging of linear arrays made up of water sound transducers.

Water sound transducers are used for creating images or general spatial information of the surroundings by means of (active) sonar. The water sound transducers can be arranged in various configurations. One configuration is the linear array (also designated as a line array). The water sound transducers are arranged here, typically horizontally, on a line. The line can be completely straight or can have a curvature in the depth, i.e., in the measurement plane. In other words, the line is in a plane in which the image or the spatial information is represented. The fact that the linear array has a vertical opening angle of a few degrees is neglected in this consideration. The linear array enables imaging in two dimensions, i.e., the determination of two dimensional spatial information. The distance to an object can be determined via the signal time-of-flight (i.e., the time-of-flight of a ping) and the direction of the object in ?0 the plane in which the linear array is arranged (thus typically the horizontal direction) can be determined by means of direction forming, so-called beamforming.

A further configuration is the planar array. The water sound transducers are arranged here in an optionally curved plane. I.e., in addition to the horizontal extension, the ?5 planar array also has a vertical extension. It is thus possible to carry out the beamforming both vertically and horizontally. Together with the depth information, a three-dimensional image of the surroundings results. That is to say, an object in the image is determinable in its horizontal and vertical position relative to the underwater vehicle and its distance to the underwater vehicle. However, the planar array is significantly more expensive, since at least two times the number of water sound transducers have to be provided, but typically at least three times the number or even more water sound transducers are used than for a comparable linear array.

However, there are (autonomous) underwater vehicles in the underwater area, for example, for mine hunting, that are intended to be as cheap as possible since these underwater vehicles, for example, are also destroyed upon destroying a mine or at least there is an increased risk of destruction. Nonetheless, it would be desirable to not have to do without the advantages of the planar array.

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

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

Exemplary embodiments disclose an underwater vehicle having a plurality of water sound transducers which form a linear array, a control unit, and a signal processing unit. The water sound transducers are designed to emit water sound signals and receive reflections of the water sound signals. The control unit is designed to control the underwater vehicle from a first position to a second position such that the underwater vehicle executes a rolling movement in order to rotate the linear array. ?0 The position can comprise both the location position and the alignment (orientation) of the underwater vehicle.

Additionally or alternatively, the control unit is designed to control the underwater vehicle from the first position to the second position such that the underwater vehicle ?5 executes a pitching movement or a movement along the vertical axis or a yawing movement or a movement along the transverse axis or a mixed form thereof in order to move the linear array perpendicular to an extension of the linear array.

In other words, the linear array is displaced in parallel by the movement of the underwater vehicle. For the typical horizontal arrangement of the water sound transducers in the linear array, the predominant component of the movement of the underwater vehicle will be a pitching movement in order to move the linear array perpendicular to its extension. The extension of the linear array is understood as the direction in which the water sound transducers are arranged. However, a possible curvature of the line in the plane of the main emission direction of the sound waves is not considered in this case.

The signal processing unit is designed to emit a first water sound signal by means of the linear array in the first position of the underwater vehicle and to emit a second water sound signal by means of the linear array in the second position of the underwater vehicle. Reflections of the first water sound signal received by means of the linear array and reflections of the second water sound signal received by means of the linear array are then processed by the signal processing unit such that an item of three-dimensional (sonar) spatial information results. I.e., the signal processing unit will typically calculate two items of two-dimensional spatial information and superimpose the items of spatial information such that an item of three-dimensional spatial information results therefrom. The emission of a water sound signal (by means of the linear array), reception of the reflections (by means of the linear array), and generation of the associated two-dimensional spatial information is also designated as a measurement. Therefore, a first measurement results with the first ?0 water sound signal and a second measurement results with the second water sound signal. The item of three-dimensional spatial information can be determined based on the first and the second measurement.

Spatial information is understood in particular as an item of information which ?5 enables an object to be detected to be localized, i.e., its location to be determined. An item of two-dimensional spatial information can accordingly define the location of the object in two spatial directions. An item of three-dimensional spatial information can define the location of the object in three spatial directions. For example, the spatial information specifies the location of the object relative to the underwater vehicle. In a special case, the spatial information can also be output as an image, for example on a monitor.

The idea is to simulate a cross array (Mills cross) or a planar array using the linear array. For this purpose, two items of spatial information can be recorded or calculated using the linear array, in which the linear array has been rotated or displaced in parallel (or both). Of course, it is also possible to calculate the item of three-dimensional spatial information directly from the reflections of the two water sound signals.

In exemplary embodiments, the signal processing unit is designed to emit a water sound signal in each of a plurality of positions of the underwater vehicle and to process the reflections of the water sound signals such that an item of three dimensional spatial information results. That is to say, the item of three-dimensional spatial information is calculated from the reflections of at least three water sound signals. This is advantageous, for example, if the linear array is displaced in parallel to obtain more information. This enables the simulation of a planar array. If a plurality of water sound signals is used, an item of three-dimensional spatial information can also be generated.

In further exemplary embodiments, the control unit is designed to carry out a rolling ?0 movement between 800 and 1000, preferably between 850 and 950, for example 900, of the underwater vehicle in order to bring the water vehicle from the first position to the second position. This exemplary embodiment is advantageous to calculate the item of three-dimensional spatial information using precisely two water sound signals. Water sound signals which are emitted from linear arrays (nearly) perpendicular to ?5 one another are best suitable for this purpose. By means of beamforming, for example, the horizontal position of an object can be determined based on the reflections of the first water sound signal and, for example, the vertical position of the object can be determined based on the reflections of the second water sound signal.

Exemplary embodiments furthermore disclose the control unit which is designed to carry out a rolling movement by more than 900, preferably at least 1350, particularly preferably at least 1700, of the underwater vehicle and to assume a plurality of positions during the rolling movement. At the positions, the underwater vehicle can stop briefly, however, it can also not be externally recognizable when the underwater vehicle has assumed the positions. The signal processing unit is designed to emit a water sound signal and process reflections of the water sound signals at each of the positions such that an item of three-dimensional spatial information results. In addition to the pitching of the underwater vehicle in order to carry out a plurality of measurements using the linear array in parallel alignment, a complete rotation or a cyclic swinging (each as a result of the rolling movement) and, in both cases, regular measurements at small rotation angles are a possibility for simulating a planar array.

Exemplary embodiments disclose that the linear array is arranged on the bow of the underwater vehicle. This arrangement simplifies the corresponding movement of the linear array. Moreover, the object to be localized can thus best be targeted by the underwater vehicle.

Accordingly, a method and a computer program for simulating a planar array using a ?0 linear array, wherein the linear array comprises a plurality of water sound transducers, are disclosed, comprising the following steps: a) determining a first item of spatial information by emitting a first water sound signal by means of the linear array and receiving a reflection of the first water sound signal by means of the linear array in a first position of the linear array; b) determining a second item of spatial ?5 information by emitting a first water sound signal by means of the linear array and receiving a reflection of the first water sound signal by means of the linear array in a second position of the linear array, wherein the second position is obtained by rotating the linear array or by moving the linear array perpendicular to an extension of the linear array from the first position; c) combining the items of information of the first spatial information and the second spatial information to form an item of three dimensional spatial information.

Preferred exemplary embodiments of the present invention are explained hereinafter with reference to the appended drawings. In the figure:

Figure 1: shows a schematic frontal view of an underwater vehicle having a linear array of water sound transducers.

Before exemplary embodiments of the present invention are explained in more detail hereinafter on the basis of the drawings, it is to be noted that identical, functionally identical, or identically acting elements, objects, and/or structures are provided with the same reference signs in the different figures, so that the description of these elements represented in different exemplary embodiments is interchangeable or can be applied to one another.

Figure 1 shows a schematic frontal view of an underwater vehicle 20. The underwater vehicle 20 comprises a plurality of water sound transducers 22 which form a linear array, a control unit 24, a signal processing unit 26, and a body 28. The water sound transducers 22 are arranged below the body 28, advantageously on the bow of the body, i.e., at the tip or at least in the front quarter of the body 28 of the ?0 underwater vehicle 20. The linear array is represented as a horizontal linear array, i.e., the water sound transducers 22 are arranged horizontally. The slightly curved arrangement in the direction of the longitudinal axis of the body 28 does not contradict the horizontal arrangement.

?5 The control unit 24 controls the underwater vehicle 20. The control unit 24 can thus control the underwater vehicle 20 such that it executes a rolling movement, indicated by the arrow 30. The linear array can thus be rotated. Furthermore, the control unit 24 can actuate the underwater vehicle 20 such that it carries out a pitching movement upward (indicated by the arrow 32a) or downward (indicated by the arrow 32b). Alternatively, the control unit can also control the underwater vehicle 20 such that it executes a movement along the vertical axis of the underwater vehicle or the body thereof (indicated by arrow 32c). Both result in a parallel displacement of the linear array. With a vertically arranged linear array it is advantageous if the underwater vehicle carries out a yawing movement instead of the pitching movement or a movement along the transverse axis instead of the movement along the vertical axis.

The signal processing unit 26 processes the reflections of the water sound signals which are detected by the water sound transducers 22. Optionally, the signal processing unit 26 can also control when the water sound transducers emit the water sound signals. The signal processing unit 26 can do this, for example, when the underwater vehicle has assumed a predetermined position. The signal processing unit 26 calculates, for example, the beamforming based on the reflections of the water sound signals and can calculate the items of two-dimensional (sonar) spatial information via this in a classic manner. An item of three-dimensional spatial information can now be calculated from the reflections for two items of two dimensional spatial information. This is carried out in principle as with a planar array, however, it is advantageous to adapt the positions of the spatial information to one another beforehand. The position of the water sound transducers in relation to one another is thus fixed in a planar array. Upon the recording of two items of spatial ?0 information using the linear array, however, in addition to the desired movement, the underwater vehicle can also execute a movement undesired for the evaluation of the soundwaves, for example, due to propulsion or a flow.

Knowing the relative deviation of the locations at which the corresponding water ?5 sound signals have been emitted, the signal processing unit 26 can now perform a reconciliation of the items of spatial information, i.e., for example, the determined direction and distance of the second measurement can be corrected by the relative movement of the underwater vehicle between the first and the second measurement. Furthermore, it is possible to align the underwater vehicle based on the first measurement such that the linear array is directed onto the object to be detected during the second measurement, in particular if the linear array is rotated after the first measurement by an angle between 800 and 100°, for example 900, in order to carry out the second measurement. This is advantageous, for example, if the object to be detected is located in the edge area of the detection area of the linear array. If the linear antenna is rotated by 900, for example, to carry out the second measurement, the vertical opening angle of the linear antenna can otherwise be too small to detect the object.

The disclosed (water) sound transducers are designed for use underwater, in particular in the ocean. The sound transducers are designed to convert water sound into an electrical signal (such as voltage or current) corresponding to the sound pressure, the water sound signal. In addition, the sound transducers are designed to convert an applied electrical voltage into water sound. The sound transducers can accordingly be used as water sound receivers and/or as water sound emitters. The sound transducers have a piezoelectric material, for example, a piezo ceramic, as the sensory material. The sound transducers can be used for (active and/or passive) sonar (sound navigation and ranging). The sound transducers are not suitable for medical applications.

Although some aspects have been described in conjunction with a device, it is ?0 obvious 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 thereto, aspects which have been described in conjunction with or as a method step also represent a description of a corresponding block or detail or feature of a ?5 corresponding device.

Depending on the specific implementation requirements, exemplary embodiments of the invention can be implemented in hardware or in software. The implementation can be carried out using a digital storage medium, for example, a floppy disk, a DVD, a Blu-ray disk, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory, a hard drive, or another magnetic or optical memory, on which electronically readable control signals are stored, which can interact or interact with a programmable computer system such that the respective method is carried out. The digital storage medium can therefore be computer-readable. Some exemplary embodiments according to the invention thus comprise a data carrier which has electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is carried out.

In general, exemplary embodiments of the present invention can be implemented as a computer program product having a program code, wherein the program code acts to carry out one of the methods when the computer program product runs on a computer (for example the CPU - central processing unit and/or the GPU - graphics processing unit). The program code can, for example, also be stored on a machine readable carrier. Other exemplary embodiments comprise the computer program for carrying out one of the methods described herein, wherein the computer program is stored on a machine-readable carrier.

In other words, an exemplary embodiment of the method according to the invention is therefore a computer program which has a program code for carrying out one of the methods described herein when the computer program runs on a computer. A further ?0 exemplary embodiment of the method according to the invention is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded.

A further exemplary embodiment of the method according to the invention is ?5 therefore a data stream or a sequence of signals which represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can be configured, for example, so as to be transferred via a data communication connection, for example, via the Internet.

A further exemplary embodiment comprises a processing device, for example, a computer or a programmable logic component, which is configured or adapted so as to carry out one of the methods described herein.

A further exemplary embodiment comprises a computer on which the computer program for carrying out one of the methods described herein is installed.

In some exemplary embodiments, a programmable logic component (such as a field programmable gate array, an FPGA) can be used to carry out some or all functionalities of the methods described herein. In some exemplary embodiments, a field-programmable gate array can interact with a microprocessor so as to carry out one of the methods described herein. In general, the methods are carried out in some exemplary embodiments on the part of an arbitrary hardware device. This can be universally usable hardware such as a computer processor (CPU) or hardware specific for the method, such as an ASIC.

The above-described exemplary embodiments merely represent an illustration of the principles of the present invention. It is obvious that modifications and variations of the arrangements and details described herein will be apparent to other persons skilled in the art. It is therefore intended that the invention solely be restricted by the scope of protection of the following claims and not by the specific details which have been presented herein on the basis of the description and explanation of the ?0 exemplary embodiments.

List of reference numerals:

20 underwater vehicle

22 water sound transducer

24 control unit

26 signal processing unit

28 body of the underwater vehicle

30 arrow (rolling movement)

32 arrows (pitching movement, movement along the vertical axis)

Claims

1. An underwater vehicle (20) comprising the following features:

a plurality of water sound transducers (22) which form a linear array, wherein the water sound transducers (22) are designed to emit water sound signals and receive reflections of the water sound signals;

a control unit (24), which is designed to control the underwater vehicle from a first position to a second position such that the underwater vehicle

- executes a rolling movement to rotate the linear array; or

- executes a pitching movement or a movement along a vertical axis or a yawing movement or a movement along a transverse axis or a mixed form thereof to move the linear array perpendicular to an extension of the linear array;

a signal processing unit (26), which is designed to emit a first water sound signal by means of the linear array in the first position of the underwater vehicle (20) and to emit a second water sound signal by means of the linear array in the second position of the underwater vehicle (20);

wherein the signal processing unit (26) is designed to process reflections of the first water sound signal received by means of the linear array and reflections of the second water sound signal received by means of the linear array such that an item of three-dimensional spatial information results.

25

2. The underwater vehicle (20) as claimed in claim 1, wherein the signal processing unit (26) is designed to emit a water sound signal in each of a plurality of positions of the underwater vehicle and to process the reflections of the water sound signals such that the item of three-dimensional spatial information results.

3. The underwater vehicle (20) as claimed in either of the preceding claims,

wherein the linear array is arranged on the bow of the underwater vehicle.

4. The underwater vehicle (20) as claimed in any one of the preceding claims,

wherein the control unit (24) is designed to carry out a rolling movement between 800 and 1000 of the underwater vehicle in order to move the water vehicle from the first position to the second position.

5. The underwater vehicle (20) as claimed in any one of the preceding claims,

wherein the control unit (24) is designed to carry out a rolling movement by more than 900, in particular at least 1350, of the underwater vehicle and to assume a ?0 plurality of positions during the rolling movement;

wherein the signal processing unit (26) is designed to emit a water sound signal at each of the positions and to process reflections of the water sound signals such that an item of three-dimensional spatial information results.

6. The underwater vehicle (20) as claimed in any one of the preceding claims, wherein a single linear array is used to obtain the item of three-dimensional spatial information.

7. A method for simulating a planar array using a linear array, wherein the linear array comprises a plurality of water sound transducers, comprising the following steps:

a) determining a first item of spatial information by emitting a first water sound signal by means of the linear array and receiving a reflection of the first water sound signal by means of the linear array in a first position of the linear array;

b) determining a second item of spatial information by emitting a first water sound signal by means of the linear array and receiving a reflection of the first water sound signal by means of the linear array in a second position of the linear array, wherein the second position is obtained by rotating the linear array or by moving the linear array perpendicular to an extension of the linear array from the first position;

c) combining the items of information of the first spatial information and the second spatial information to form an item of three-dimensional spatial information.

8. The method as claimed in claim 7,

wherein the linear antenna is arranged on an underwater vehicle.

?5

9. A computer program comprising commands which, upon the execution of the program by a computer, prompt it to carry out the method as claimed in either of claims 7 and 8.