EP3898404A1 - Arrangement and method for locating an object in or below a body of water - Google Patents

Abstract

The present invention relates to an arrangement and a method which are able to locate an object in or below a body of water. An underwater driving vehicle (1) having a drive (6, 8, 9) and a travel direction changing unit (4.1, 4.2, 23.1, 23.2) moves the arrangement through the water. An underwater measuring body (2) is connected to the underwater driving vehicle (1) by a connecting element (3). The underwater measuring body (2) comprises a first multi-axis magnetometer (12.1) and a second multi-axis magnetometer (12.2, ...). Each magnetometer (12.1, 12.2, ...) measures a variable which correlates with the magnetic field about said magnetometer. A data storage unit (21, 22) automatically stores signals from the two magnetometers (12.1, 12.2, ...). An evaluating unit (28) is designed to automatically discover and evaluate a difference between the stored signals from the two magnetometers (12.1, 12.2, ...) in order to determine the position of the object relative to the underwater measuring body, and the distance and the position of the object relative to the surface of the floor of the body of water.

Description

Arrangement and method for locating an object in or under a body of water

The invention relates to an arrangement and a method which are able to locate an object in or under a body of water. For example, sea mines, aerial bombs and other weapons should be located so that they can then be neutralized. Such an object can often not be located with sufficient accuracy using optical methods.

The arrangement and the method take advantage of the fact that an object to be localized creates an anomaly in the earth's magnetic field which can be discovered.

A possible configuration for such an arrangement is that a

Surface ship is dragging a measuring body through the water. A magnetometer is installed on board this measuring body. An evaluation unit evaluates the signals from this magnetometer.

Another possible embodiment is an underwater vehicle with its own drive, which has a magnetometer and an evaluation unit for the signals from the magnetometer.

The invention has for its object to provide an arrangement and a method for localizing an object in or under a body of water, which are able to localize this object with greater certainty than known arrangements and methods.

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

Claims. The arrangement according to the invention and the method according to the invention are designed to localize an object, this object being located in or under a body of water, in particular completely or at least partially below the surface of the bottom of this body of water. The arrangement according to the invention is designed to be used completely below the surface of the water.

The arrangement according to the solution comprises

- an underwater propulsion vehicle,

an underwater measuring body which is arranged at a distance from the underwater drive vehicle during use of the arrangement,

- A connecting element which connects the underwater drive vehicle with the underwater measuring body, and

- a data storage unit.

The underwater propulsion vehicle includes

- a drive and

- a direction change unit.

The underwater measuring body includes

- a first magnetometer and

- At least a second magnetometer.

Each magnetometer of the underwater measuring body can measure a size, this size correlating with the magnetic field around this magnetometer and outputting a signal according to the size. The data storage unit can automatically store signals from the two magnetometers. The evaluation unit is designed to automatically evaluate stored signals from the two magnetometers in order to determine the position of the object relative to the underwater measuring body and the distance and position of the object relative to the surface of the water floor. The method according to the solution comprises the following steps:

- The arrangement is moved under water through the water.

- Each magnetometer measures a size related to the magnetic field around it

Magnetometer correlates and outputs a signal according to the size.

- The data storage unit automatically stores signals from the two

Magnetometers.

- The evaluation unit evaluates the stored signals from the two

Magnetometers to determine the position of the object relative to the underwater measuring body and the distance and position of the object relative to the surface of the water floor.

According to the solution, the underwater drive vehicle moves the entire arrangement through the water with the drive. This makes it possible to design the underwater measuring body without its own drive. Such a drive on board the underwater measuring body could falsify the measurements of the magnetometers on board the underwater measuring body. The connecting element between the

The underwater drive vehicle and the underwater measurement body can be designed so long that the distance between the underwater drive vehicle and the underwater measurement body is sufficiently large and the drive of the underwater drive vehicle does not significantly falsify the measurements of the magnetometers.

In addition, the drive-free underwater measuring body can be designed more simply than an underwater measuring body with its own drive. The underwater measuring element consumes only a little electrical energy during operation, usually only the energy required to operate the magnetometer and optional additional sensors. This energy can often be supplied via the connecting element, so that no voltage source is required on board the underwater measuring body.

According to the solution, the underwater propulsion vehicle comprises a direction change unit, for example a rudder and / or an elevator, and is able to change the direction of travel and / or the depth of the arrangement through the water. This enables the underwater measuring body without a movable

Direction change unit and without designing an actuator for such a unit. Such an actuator could also falsify the measurement results from the magnetometers and requires energy.

The following advantage occurs especially when objects are to be located that are at least partially below the surface of the water floor and thus completely or at least partially below the water. Of the

As a rule, underwater measuring bodies should be moved close to the bottom of the body of water, as close as possible to an object on or under the

To show surface of the water floor. The arrangement according to the solution is moved by the underwater propulsion vehicle through the water and can remain completely below the water surface during use. This will make the

Avoided the need for a surface vehicle to move the underwater measuring body through the water. If a surface vehicle would be used, there would necessarily be a larger vertical distance between the surface vehicle and the underwater measuring body, this distance from the

Depth of water depends and thus usually varies while driving. The connection must be long enough, often four times the depth of the water, so that the mechanical connection between the surface-mounted vehicle and the underwater measuring body is sufficiently well managed. The use of a solution

Underwater vehicle as a propulsion vehicle avoids the need to provide such a long mechanical connection. In addition, thanks to the invention, wave movements and wind have no influence on the arrangement according to the solution, because in use it remains permanently below the water surface.

The invention takes advantage of the fact that an object to be localized often causes an anomaly in the earth's magnetic field. Under a magnetic field anomaly, a local deviation of the actual magnetic field, for example measured as magnetic flux density in nano-Tesla, from a normal magnetic field

Roger that. The normal magnetic field is the earth's magnetic field, which is mainly caused by the earth's core and also by the ionosphere and the magnetosphere and is approximately an eccentric dipole field with a 12 degree inclination to the earth's axis. The local deviation caused is, for example, a deviation in the direction and / or the intensity of the magnetic field.

According to the solution, the underwater measuring body comprises several magnetometers. A magnetometer can be designed as a passive sensor. A magnetometer does not necessarily actively create a physical effect. This means that little electrical energy is required on board the underwater measuring body. In addition, the underwater measuring body is more difficult to discover during use than when the underwater measuring body produces a physical effect. The physical effect can have undesirable effects, especially on

Living creatures in the water, or detonating a weapon. In addition, especially in military applications, it is often not desired that the

Underwater measuring body is discovered. This risk is less with a purely passive sensor.

According to the solution, the underwater measuring body comprises at least two magnetometers, between which a distance inevitably occurs. Because of this feature, the arrangement can detect and locate an object in or under the water with greater certainty than if only a single magnetometer were present. One reason for this: An object to be localized often causes an anomaly in the magnetic field around the magnetometer. This anomaly warps the

Magnetic field lines near the object. However, the anomaly caused is several orders of magnitude smaller than the earth's magnetic field, for example a few percent of the magnetic flux density of the earth's magnetic field, so that a single magnetometer alone cannot often detect the anomaly with sufficient certainty. The magnitude of the anomaly also decreases sharply as the distance between the object and the magnetometer increases.

The feature that at least two magnetometers are present makes it possible to calculate differences between the measurement results of these two magnetometers spaced apart from one another. If the magnetic field has no abnormality near the Has underwater measuring body, so the measurement results of the two

Magnetometers ideally do not differ from one another, so the difference is ideally zero. In reality, due to measurement inaccuracies

Magnetometer differences, but these are below a predetermined

Tolerance if there is no abnormality. An anomaly, on the other hand, leads to a difference in the measurement results that lies above the specified tolerance. Because the underwater measuring body comprises at least two magnetometers, this is the

It is more likely that an anomaly can be detected through a significantly higher difference - compared to an underwater measuring body that has only a single magnetometer.

One degree of freedom in the design of the underwater measuring body is the distance between the two magnetometers. The smaller the distance, the larger it is

Probability that an object in the two magnetic fields causes an anomaly around the two magnetometers and therefore both magnetometers discover the object and localize it together. By evaluating the signals from these two magnetometers, it is often possible to automatically derive a characteristic of the object and / or the position of the object relative to the surface of the water floor. On the other hand, the smaller the distance between the magnetometers, the smaller the streak on the surface of the body of water that the underwater measuring body examines while traveling. With a smaller distance, the examination of an area of the surface of the water floor therefore often takes longer, but the objects to be discovered are actually discovered and localized with greater certainty.

In one configuration, the arrangement further comprises an evaluation unit. The evaluation unit can automatically evaluate the signals which the

Have generated magnetometers and which the data storage unit has saved. The evaluation unit can be attached on board the underwater drive vehicle, on board the underwater measuring body or on board a spatially distant platform, for example an overwater vehicle, another underwater vehicle or a land station. If the evaluation unit is arranged on board the platform, so the underwater drive vehicle does not need to move the evaluation unit through the water and to supply it with electrical energy during the journey.

In one embodiment, the evaluation unit can automatically detect a difference between the signals from the two or at least two magnetometers of the underwater measuring body and evaluate this difference.

Because of this feature, the arrangement is more likely to be one

To discover and find an object under the surface of the water floor

localize as if only a single magnetometer were present or as if signals from several magnetometers were evaluated independently of one another. Although the anomaly that an object creates is several

Orders of magnitude smaller than the normal magnetic field of the earth, an object in the vicinity of the underwater measuring body often leads to two different anomalies in the magnetic fields around the two magnetometers, so that a difference is brought about which the evaluation unit can detect and evaluate. Thus, this feature increases the likelihood that an object will actually be discovered and located.

As already mentioned, a degree of freedom in the design of the underwater measuring body is the distance between the two magnetometers. At a small distance, an object creates an anomaly in each of the two magnetic fields, the anomalies often differing from one another.

Each magnetometer is designed as a multi-axis magnetometer, i.e. as a vector sensor. The multi-axis magnetometer can in particular be designed as a three-axis magnetometer or a four-axis magnetometer. If the magnetometer can measure in more than three different directions, redundancy is achieved and noise in the signals can be better eliminated. A four-axis magnetometer, for example, can be implemented as a pair with two two-axis magnetometers. Each magnetometer designed as a vector sensor can detect the direction from itself to a source for an anomaly in the magnetic field. This anomaly often originates from an object to be discovered, which thus becomes an interfering element in the earth's magnetic field. Overall, the underwater measuring body measures at least two multi-axis magnetometers, i.e. at least two directions to one

Object. Knowledge of these two directions is often sufficient to determine the position of the object relative to the underwater measuring body and the distance and position of the object relative to the surface of the water floor.

According to this embodiment, the two magnetometers each calculate one

Gradients, i.e. a vector, and thus act together as a gradiometer.

The distance between the two magnetometers and the length of the

Connecting elements are known. The underwater propulsion vehicle is often able to measure its own geoposition. From the directions that the multi-axis magnetometers have discovered, the geoposition of the underwater drive vehicle at the time of the measurement and the known dimensions, it is often possible to determine the

At least geoposition of the object in or under the water

derive approximately.

According to the solution, the underwater measuring body comprises a first magnetometer and a second magnetometer. In one embodiment, the underwater measuring body comprises a third magnetometer. This third magnetometer is arranged with a distance between the first two magnetometers.

The use of a third magnetometer on board the underwater measuring body increases the measuring accuracy and provides redundancy.

If the underwater measuring body has only two magnetometers and these are not designed as vector sensors, the situation can arise that one

Object in or under the water always causes the same anomaly in the two magnetic fields around the two magnetometers, for example because the object always has the same distance to the two magnetometers while the arrangement is moved past the object. In this case, a

The evaluation unit does not detect any difference in the signals from the two magnetometers and may therefore not be able to detect or locate the object. The configuration with the third magnetometer also prevents this undesirable situation from occurring when the three magnetometers are not vector sensors.

It is possible that the third magnetometer is also designed as a multi-axis magnetometer. Thanks to this configuration, three directions to an object can be measured. This configuration further reduces the risk of a measurement error. The direction to an object and - in the case of an object under the water - the position of the object relative to the surface of the water floor can be determined with greater certainty. The design with the third

Magnetometer also provides redundancy: if one magnetometer fails, two magnetometers are still available.

An optional evaluation unit can discover at least one of the following differences in a further development of this embodiment:

a difference between the signals of the third magnetometer and the signals of the first magnetometer,

a difference between the signals of the third magnetometer and the signals of the second magnetometer.

This configuration further increases the likelihood that an object will be discovered because the object leads to an anomaly in a magnetic field around a magnetometer. This probability is greater if three magnetometers are used instead of just two.

In a preferred embodiment, the underwater measuring body comprises a fourth magnetometer. With regular use of the underwater measuring body points io

this fourth magnetometer is closer to the water floor than the first magnetometer and the second magnetometer.

This configuration further reduces the risk of measurement errors, in particular if the fourth magnetometer is also designed as a multi-axis magnetometer.

Preferably, the two or all magnetometers repeatedly measure the respective current magnetic field, e.g. with a given sampling rate. This creates a better picture of the surroundings of the underwater measuring body than just a measurement at a single point in time.

In a preferred embodiment, the underwater measuring body comprises at least one distance sensor. This distance sensor can measure the distance between itself and thus the underwater measuring body and the water bottom. The underwater measuring body is able to transmit signals from the distance sensor to the underwater drive vehicle. The underwater drive vehicle is designed to move the arrangement through the water as a function of signals from the distance sensor and, in particular, to control the direction change unit as a function of these signals.

In one embodiment, the underwater drive vehicle uses signals from the distance sensor on board the underwater measuring body to move the arrangement through the water. Thanks to the distance sensor, the

Underwater measuring body near the water floor is moved by the water, even if the water floor is mountainous. In particular, it is made possible for the vertical distance between the underwater measuring body and the body of water to remain within a predetermined barrier without the underwater measuring body colliding with the body of water.

If only a distance sensor on board the underwater drive vehicle were used to control the arrangement through the water, the risk is greater that the underwater measuring body is at a different distance from the Has the bottom of the water as the underwater drive vehicle and therefore the specified barrier is not observed or the underwater measuring body collides with the bottom of the water, although the underwater drive vehicle maintains the correct distance.

In one embodiment, the underwater measuring body comprises a position sensor.

This position sensor is able to measure the position (orientation) of the underwater measuring body in the water, in particular while the underwater measuring body is moved through the water, for example the orientation of the underwater measuring body relative to the surface of the water bottom. The position sensor can be implemented with the aid of several distance sensors. Data on the measured position are preferred together with signals from the magnetometers to the

Underwater drive vehicle transmitted and stored by the data storage unit. While an optional evaluation unit receives the signals from the

Analyzes magnetometers of the underwater measuring body, a control unit of the underwater drive vehicle and / or the evaluation unit uses evaluated signals from the position sensor. The control unit can use the signals from the position sensor to control the arrangement through the water. The evaluation unit can automatically take into account the measured position (orientation) of the underwater measuring body in the water.

The evaluation unit can use the signals from the position sensor to better locate an object under the water. The direction from the underwater measuring body to the object can depend on the position of the underwater measuring body in the water.

It is possible that the data storage unit is arranged on board the underwater measuring body. In a preferred embodiment, however, the data storage unit is arranged on board the underwater propulsion vehicle. The underwater measuring body is able to transmit signals from the magnetometers of the underwater measuring body to the underwater drive vehicle. These signals are then transmitted to the data storage unit and stored by it. This configuration further reduces the risk that the data storage unit generates a magnetic field which falsifies the measured values from the magnetometers. Rather, it enables a sufficiently large distance between the

Data storage unit and the magnetometers must be observed.

It is possible that both magnetometers are mounted directly on the hull of the underwater measuring body. In another embodiment, the underwater measuring body comprises

- a hull,

- a first spacer and

- a second spacer.

According to this other embodiment, the two spacers are attached to the fuselage, so that the fuselage is between the two spacers. The first magnetometer is attached to the first spacer. The second magnetometer is attached to the second spacer, in one embodiment in each case at the free outer end of the spacer.

This configuration makes it possible, on the one hand, to achieve a sufficiently large distance between the two magnetometers in a direction perpendicular to the direction of travel of the arrangement. On the other hand, the underwater measuring body according to this embodiment has a lower weight than when using a different geometric shape.

In one embodiment, the two spacers are designed as wings. These wings can be mounted on the fuselage in such a way that they achieve buoyancy when the underwater propulsion vehicle moves the underwater measuring body through the water.

In one embodiment, the arrangement comprises a motion sensor. This motion sensor is able to measure a movement of the underwater measuring body relative to the underwater drive vehicle. For example, a first 3D acceleration sensor is mounted on board the underwater propulsion vehicle and one second 3D acceleration sensor on board the underwater measuring body. A difference between the accelerations in one direction, which these two acceleration sensors measure, automatically becomes a movement of the

Underwater measuring body derived relative to the underwater drive vehicle.

This configuration makes it easier to ensure that the distance between the underwater measuring body and the water bottom remains in a predetermined range. A control unit on board the underwater drive vehicle receives signals from the motion sensor and controls the direction change unit and / or the drive in such a way that the distance remains in the predetermined range.

If a geoposition sensor on board the underwater propulsion vehicle is able to measure its geoposition, signals from the

Magnetometers and signals from the motion sensor the geoposition of a

Easily locate items in or under the water.

In one embodiment, the two magnetometers are fastened to a hull of the underwater measuring body in such a way that their distance from one another remains unchanged, in particular during use and during transport of the underwater measuring body to a place of use. In another embodiment, the distance between the two magnetometers can be changed, for example manually before use. In this embodiment too, the distance between the two magnetometers preferably remains constant during use. By changing the distance between the two magnetometers, the underwater measuring body can be adapted to a desired application.

An optional evaluation unit evaluates the signals from the magnetometers and, in one embodiment, determines at least one property of the localized object through the evaluation. This configuration can preferably be combined with the configuration that each magnetometer is designed as a multi-axis magnetometer. For example, the evaluation unit determined at least one of the following properties of the object: - the or a material from which the object or a component of the object is made,

- the size or maximum dimension of the object,

- the geometric shape of the object.

When viewed in the direction of travel of the arrangement, the underwater measuring body is preferably located behind the underwater drive vehicle. In this embodiment, the underwater drive vehicle is able to control the arrangement more easily than if the underwater measuring body were located in front of the underwater drive vehicle or vertically or obliquely next to the underwater drive vehicle.

The underwater measuring body is preferably supplied with electrical energy via the connecting element. As a result, there is no need to have a voltage source on board the underwater measuring body.

In one embodiment, a buoyancy body ensures that the weight of the underwater measurement body is approximately equal to the buoyancy that the water displaced by the underwater measurement body exerts on the underwater measurement body

(Buoyancy neutrality). This configuration makes it easier to move the underwater measuring body through the water at a desired distance from the water bottom.

In one configuration, the arrangement comprises a further underwater measuring body which is connected to the underwater drive vehicle via a further connecting means. The two underwater measuring bodies are preferably arranged next to one another, as seen in the direction of travel of the arrangement. With this configuration, a larger strip of the surface of the body of water can be examined than if the arrangement had only a single underwater measuring body. This saves time. For example, both underwater measuring bodies are attached to a drawbar, which pulls the underwater drive vehicle behind them.

In one embodiment, the underwater drive vehicle with the data storage unit is removed from the water after the journey. The data storage unit will read out, and the stored signals are transmitted to an evaluation unit on board a platform that is spatially remote from the during use

Was underwater propulsion vehicle. The evaluation unit automatically evaluates the transmitted signals.

The arrangement according to the invention is explained in more detail below on the basis of an exemplary embodiment shown in the drawings. Here show:

1 shows a side view of the arrangement according to the solution and a ship with an evaluation unit;

2 shows a top view of the underwater measuring body according to the solution;

Fig. 3 in a front view of the solution underwater measuring body.

The arrangement according to the solution of the exemplary embodiment travels through the water in a predetermined area, for example along a predetermined serpentine or meandering path, and in doing so searches the surface Mb of the sea floor. The arrangement is intended to discover and locate any object that lies on the surface Mb of the sea floor or that has completely or at least partially sunk into the sea floor or has buried itself. The object to be discovered triggers an anomaly in the earth's magnetic field. This anomaly can amplify the earth's magnetic field, for example if the object is a metallic object or contains metallic components. Examples of such metallic objects on or under the seabed surface Mb are mines, pipelines, refrigerators or objects made of wood, because wood under water can become metallic. An anomaly can also weaken the magnetic field, for example if the object is made of salt or lime.

The arrangement should at least approximate the respective geoposition of each object to be discovered and its position relative to the seabed. Determine the surface area Mb and save it in a data memory. After use, the arrangement is fetched on board a platform, for example a surface ship, and the data memory is read out and evaluated. It is also possible for information about a discovered object to be transmitted to a platform even during use. A discovered suspicious item is then examined in more detail.

1 shows the water surface WO, the seabed surface Mb and an object G under the seabed Mb surface. In addition, an exemplary embodiment of the arrangement according to the solution is shown in a side view in FIG. 1. The arrangement according to the solution comprises

an underwater propulsion vehicle 1,

- An underwater measuring body 2 and

- A connecting element 3, which connects the underwater measuring body 2 with the underwater drive vehicle 1.

In addition, a spatially distant ship S is shown with a data processing evaluation unit 28, which is described further below.

The underwater drive vehicle 1 is designed and comprises an unmanned autonomous underwater vehicle (AUV)

a vehicle casing 7,

an upper rudder 4.1 and a lower rudder 4.2, which are fastened to the vehicle casing 7,

a left flute rudder 23.1 and a right flute rudder 23.2, which are also fastened to the vehicle casing 7,

a distance sensor 5 which is fastened to the vehicle casing 7,

a 3D acceleration sensor 24,

a position sensor 27,

an electric motor 6,

a shaft 9 which is rotated by the electric motor 6, a propeller 8 which sits on the shaft 9 and is rotated together with the shaft 9,

a voltage source 10, which supplies the electric motor 6 with electricity,

an antenna 26,

a control unit 20,

- A data storage computer 21 and

a data memory 22.

The data storage computer 21 and the data storage 22 together form the data storage unit of the exemplary embodiment.

The underwater measuring body 2 of the exemplary embodiment comprises

a hull 13,

a left spacer in the form of a left wing 14.1 and a right spacer in the form of a right wing 14.2, both of which are attached to the fuselage 13,

an upper support element 15.1 and a lower support element 15.2, both of which are also attached to the fuselage 13,

- three distance sensors 11.1 to 11.3,

- A 3D acceleration sensor 25 and

- four magnetometers 12.1 to 12.4.

A front distance sensor 11.1 of the underwater measuring body 2 is attached to the hull 13, a left distance sensor 11.2 on the left wing 14.1 and a right distance sensor 11.3 on the right wing 11.2. A left magnetometer 12.1 is mounted on the left wing 14.1, a right magnetometer 12.2 on the right wing 14.2, an upper magnetometer 12.3 on the upper support element 15.1 and a lower magnetometer 12.4 on the lower support element 15.2. The two wings 14.1 and 14.2 preferably have the same dimensions, so that the four magnetometers 12.1 to 12.4 are arranged symmetrically to a central plane of the underwater measuring body 2. The fuselage 13, the two wings 14.1 and 14.2 and the are preferably two support elements 15.1 and 15.2 made of a non-metallic material, for example made of glass fiber reinforced plastic (GRP).

An alternative embodiment is also possible, in which the underwater measuring body 2 has no spacers 14.1, 14.2 and the two magnetometers 12.1, 12.2 are attached directly to the hull 13. It is also possible that the underwater measuring body 2 does not include any support elements 15.1, 15.2 and the two magnetometers 12.3, 12.4 are attached directly to the hull 13.

The connecting element 3 comprises a flexible rope which is connected to the underwater drive vehicle 1 and the underwater measuring body 2, so that the underwater driving vehicle 1 can pull the underwater measuring body 2 behind it. A data line is embedded in this cable, via which the data are transmitted from the underwater measuring body 2 to the underwater drive vehicle 1 and are partly transmitted to the control unit 20 and partly to the data storage computer 21. In the exemplary embodiment, an activation command or a switch-off command is transmitted to the underwater measuring body 2 if necessary, but no data.

In the exemplary embodiment, the underwater measuring body 2 does not have its own drive, but is pulled through the water by the underwater drive vehicle 1. The underwater measuring body 2 of the exemplary embodiment also does not have its own voltage source, but is supplied with electrical energy from the voltage source 10 of the underwater drive vehicle 1 via the connecting element 3. The two wings 14.1 and 14.2 and the two supporting elements 15.1 and 15.2 preferably do not change their respective position and dimensions relative to the fuselage 13 while the arrangement is being used. It is possible for a wing or a supporting element to be pushed together or folded away while the underwater measuring body 2 is being transported to an area of application. It is possible that at least one wing 14.1, 14.2 can be telescopically pulled apart or pushed together before use in order to change the distance between the magnetometers 12.1 and 12.2. In one embodiment, the underwater measuring body 2 is buoyancy-neutral, ie the buoyancy caused by the water displaced by the underwater measuring body 2 is equal to the weight of the underwater measuring body 2 (buoyancy neutrality). If necessary, a buoyancy body (not shown) is added, removed or changed on board the underwater measuring body 2. In another embodiment, the weight of the underwater measuring body 2 is greater than the buoyancy. The two wings 14.1 and 14.2 generate lift when the underwater measuring body 2 is moved by the water. This configuration enables the underwater measuring body 2 to rise or fall in the water by changing the speed at which the underwater measuring body 2 is pulled through the water. This effect is achieved without it being necessary to carry out an intervention on the underwater measuring body 2 or to change the underwater measuring body 2 in any other way during use.

Each distance sensor 5, 11.1 to 11.3 is designed as an altimeter and measures the distance between itself and the seabed without contact. For example, each distance sensor sends a pulse downwards. The seabed surface Mb reflects this pulse, the transit time is measured, and the distance sought is derived from the transit time. The three distance sensors 11.1 to 11.3 of the underwater measuring body 2 are arranged in a triangle and therefore deliver three signals at each sampling time, from which the current orientation of the underwater measuring body 2 relative to the seabed surface Mb can be calculated, in particular in particular the angle of rotation about the longitudinal axis, the angle of rotation about the transverse axis and the angle of rotation about the vertical axis of the underwater measuring body 2. The three distance sensors 11.1 to 11.3 thus together function as a position sensor for the underwater measuring body 2.

The optional 3D acceleration sensor 25 on board the underwater measuring body 2 measures the respective acceleration of the underwater measuring body 2 parallel to its own longitudinal axis, to its own transverse axis and to its own vertical axis. The 3D acceleration sensor 24 on board the underwater drive vehicle 1 measures the respective acceleration of the underwater drive vehicle 1 parallel to its own longitudinal axis, to its own transverse axis and to its own vertical axis. The position sensor 27 measures the direction in which the connecting element 3 extends from the underwater drive vehicle 1.

In the example of FIG. 1, the underwater drive vehicle 1 travels completely below the water surface WO in a direction of travel FR due to the rotation of the propeller 8 (from right to left in FIG. 1). The rudders 4.1, 4.2 and the elevators 23.1, 23.2 control the travel of the underwater drive vehicle 1. In one embodiment, the weight of the underwater drive vehicle 1 is less than the lift, and the elevators 23.1 and 23.2 hold the underwater drive vehicle 1 and thus the arrangement at a desired depth. If the drive of the underwater drive vehicle 1 fails, the arrangement rises up to the water surface WO and can be collected.

The underwater drive vehicle 1 travels along a predetermined travel route over the seabed surface Mb. In one embodiment, the antenna 26 measures the current geoposition of the underwater drive vehicle 1 from time to time, for example when the underwater drive vehicle 1 has surfaced or is in an shallow depth. The control unit 20 derives the current geoposition of the underwater drive vehicle 1 from the last measured geoposition and the signals from the 3D acceleration sensor 24. It is also possible that an interactive navigation system is present on board the underwater drive vehicle 1, so that the control device 20 knows the current geoposition without the underwater drive vehicle 1 having to appear. In both embodiments, the control unit 20 knows at least approximately the current geoposition at any time.

On the one hand, the arrangement should not collide with the sea floor during the journey. On the other hand, the distance between the underwater measuring body 2 and the seabed should be smaller than a predetermined barrier in order to ensure that every object to be discovered on or under the seabed is sufficiently safe. Surface Mb actually found. The anomaly generated is known to decrease sharply as the distance between the object and a magnetometer increases.

The signals from the three distance sensors 11.1 to 11.3 and from the optional 3D acceleration sensor on board the underwater measuring body 2 are transmitted to the control unit 20 of the underwater drive vehicle 1 via the connecting element 3. In addition, the signals from the distance sensor 5 and optional further distance sensors (not shown) on board the underwater propulsion vehicle 1 are likewise transmitted to the control unit 20.

The control unit 20 uses the signals from the position sensor 27 to determine the direction in which the connecting element 3 extends. With the help of this measured direction, a lateral offset of the underwater measuring body 2 relative to the direction of travel FR can be determined. This lateral offset is caused in particular by a water flow near the surface of the sea floor Mb. It is also possible to determine approximately how much the connecting element 3 sags, from which the distance between the underwater drive vehicle 1 and the underwater measuring body 2 can be approximately determined. The control unit 20 determines the movement of the underwater measuring body 2 relative to the underwater drive vehicle 1 from the signals from the two 3D acceleration sensors 24, 25. The control unit 20 controls the actuators for the two elevators as a function of the signals from the distance sensors 23.1 and 23.2 in order to ensure that the distance between the seabed and the underwater measuring body 2 remains large enough on the one hand and remains smaller than the predetermined barrier on the other hand. The control unit 20 also controls actuators for the two rudders 4.1 and 4.2 and the electric motor 6 so that the arrangement 1, 2, 3 travels along a predetermined route through the water.

2 shows a top view of the underwater measuring body 2 of the exemplary embodiment and the connecting element 3. The direction of travel FR is again from right to left. The left wing 14.1, the right wing 14.2 and the two magnetometers 12.1, 12.2 and the two are shown schematically Distance sensors 11.2 and 11.3 on the two wings 14.1, 14.2. The two support elements 15.1, 15.2 are perpendicular to the drawing plane of FIG. 2.

3 shows the underwater measuring body 2 from the front. The longitudinal axis of the underwater measuring body 2 and the direction of travel FR are perpendicular to the drawing plane of FIG. 3 and point towards the viewer. You can see both wings 14.1, 14.2, both support elements 15.1, 15.2 and all four magnetometers 12.1 to 12.4. In the example of FIG. 3, the underwater measuring body 2 is rotated about 20 ° about its own longitudinal axis.

In one possible embodiment, each magnetometer 12.1 to 12.4 is designed for a total field measurement, so it can only measure the size of an anomaly. In a preferred embodiment, however, each magnetometer 12.1 to 12.4 is designed as a three-axis magnetometer or four-axis magnetometer, for example as a flux gate, and is able to measure not only the size of an anomaly, but also the direction of the magnetometer a source for the anomaly, that is, an object to be discovered. 3 shows the four determined directions R.1 to R.4 from the four magnetometers 12.1 to 12.4 to the object G. More specifically: the projections of the four directions R.1 to R.4 in the drawing plane of FIG. 3 are shown. Of course, a direction R.1 to R.4 can also run obliquely to the plane of the drawing.

The signals from the four magnetometers 12.1 to 12.4 are transmitted from the underwater measuring body 2 via the data line in the connecting element 3 to the data storage computer 21 on board the underwater propulsion vehicle 1. The data storage computer 21 stores the signals from the magnetometers 12.1 to 12.4 in the data storage 22.

The signals from the magnetometers 12.1 to 12.4 are thus transmitted to the underwater drive vehicle 1 and there to the data storage computer 21. Of the

Data storage computer 21 stores the received signals in data storage 22. The data storage computer 21 preferably stores the measured and transmitted magnetometer signals additionally a time stamp and the geoposition of the underwater measuring body 2 at the time of the measurement in

Data memory 22, optionally also the speed of travel, the distance of the underwater measuring body 2 to the seabed, the orientation of the underwater measuring body 2 relative to the seabed surface Mb and / or the depth of the dive at the time of the measurement.

In one embodiment, the signals from the magnetometers 12.1 to 12.4 are evaluated by an evaluation unit on board the underwater propulsion vehicle 1. In the exemplary embodiment shown in the figures, on the other hand, the signals are only stored on board the underwater drive vehicle 1, namely in data memory 22, but are not evaluated on board the underwater drive vehicle 1. After the journey, the underwater drive vehicle 1 and the underwater measuring body 2 are taken out of the water. The data memory 22 is read out, and the stored and read out signals, in particular the georeferenced magnetometer signals with the time stamps and further associated information, are transmitted to the evaluation unit 28 on board the ship S and are automatically evaluated by the evaluation unit 28.

On the one hand, the evaluation unit 28 compares the signals from two magnetometers, which relate to the same point in time, with one another, ie carries out a total of six comparisons for each sampling point in time. If at least one comparison yields a significant difference, there is an anomaly, and an object G to be detected is located near the underwater measuring body 2 at the time of the measurement and causes this anomaly. Because with four magnetometers the two distances of the object G to at least two magnetometers differ, the anomalies also differ. Or the object G only causes an anomaly in the magnetic field around a magnetometer, but not in the magnetic field around another magnetometer. Because the underwater measuring body 2 has four magnetometers 12.1 to 12.4, which are not all in the same plane, the arrangement can detect and locate an object G with greater certainty than if less than four magnetometers were used would be. Redundancy is also provided in the event that a magnetometer fails.

The evaluation unit 28 preferably determines approximately the current direction from the underwater measuring body 2 to the object G and the distance between the object G and the underwater measuring body 2. For this purpose, the evaluation unit 28 uses the signals from each magnetometer 12.1 to 12.4 that detects an anomaly and therefore determined a direction to the source of this anomaly. In the example of FIG. 3, all four magnetometers 12.1 to 12.4 have each determined a direction R.1 to R.4 to the object G. Ideally, the four direction vectors R.1 to R.4 intersect at a point, and this point belongs to object G. The evaluation unit 28 also evaluates the signals from the distance sensors 11.1 to 11.3 on board the underwater measuring body 2 to determine the current position (orientation) of the underwater measuring body 2 in the water. The determined position is used by the evaluation unit 21 to determine the direction to the object G.

The evaluation unit 28 determines the geoposition of the object G and optionally a position and / or orientation of the object G relative to the seabed surface Mb. For this purpose, the evaluation unit 28 uses the following information:

the current geoposition of the underwater propulsion vehicle 1,

the current position of the underwater measuring body 2 relative to the underwater drive vehicle 1,

- The direction and distance of the object G in relation to the underwater measuring body 2, determined using the four directions R.1 to R.4, and

- Optionally, the driving speed of the underwater drive vehicle 1, which is calculated from signals from the 3-D acceleration sensor 24.

In one embodiment, the evaluation unit 28 derives at least one property of the object G from the signals of the magnetometers 12.1 to 12.4, for example from what material the object G is and how large it is and / or what shape it has. The evaluation unit 28 stores information about a determined object in a data memory (not shown) on board the ship S and / or outputs it in a form that can be detected by a human. This information includes

the geoposition of the object G, which the evaluation unit 21 has determined as described above,

- the depth of the object G below the seabed surface Mb,

- determined properties of the object and / or

- A time stamp, that is, the information when the magnetometers 12.1 to 12.4 have measured the anomalies that the object G causes in the magnetic field.

In one embodiment, the signals are already evaluated on board the underwater drive vehicle 1, and the underwater drive vehicle 1 transmits this information wirelessly via the object G to a spatially distant platform. For this purpose, the underwater drive vehicle 1 appears or at least travels to a shallower water depth and sends out the information about the object with the aid of the antenna 26. In one embodiment, the step of transmitting the information about the object G is triggered by an evaluation unit on board the underwater propulsion vehicle 1 having discovered an object G with certain predetermined properties. If the evaluation unit has not discovered such an object during the journey, the underwater drive vehicle 1 transmits information about discovered objects at the end of the journey wirelessly to a spatially distant platform.

In one embodiment, the underwater propulsion vehicle 1 and the underwater measuring body 2 are recorded on board a platform, for example on board the ship S, and the data memory 22 is read out. The two configurations, which transmit the information and read out the data memory 22, can be combined so that the determined information about objects is also available if the underwater propulsion vehicle 1 cannot be taken up again on the platform. In the embodiment just described, the evaluation unit 28 is arranged on board the underwater drive vehicle 1 and already evaluates the signals from the magnetometers 12.1 to 12.4 while the arrangement is traveling through the water. This configuration makes it possible to set a message about the discovery of an object with certain properties while the arrangement is in motion.

In another embodiment, the evaluation unit 28 is arranged on board a spatially distant platform, for example on board the surface ship S. The signals from the magnetometers 12.1 to 12.4 are stored in the data memory 22 and are not evaluated on board the underwater drive vehicle 1. Rather, the evaluation unit 21 on board the platform S evaluates the signals from the magnetometers 12.1 to 12.4 after the underwater propulsion vehicle 1 has been taken on board the platform S and the data memory 22 has been read out. This configuration saves the need to provide an evaluation unit 21 on board the underwater drive vehicle 1.

Reference numerals

Claims

Claims 1. Arrangement for locating an object (G) which is located in or under a body of water, being the arrangement - An underwater drive vehicle (1) with a drive (6, 8, 9) and one Direction change unit (4.1, 4.2, 23.1, 23.2), - An underwater measuring body (2) spaced from the underwater drive vehicle (1), a connecting element (3) which connects the underwater drive vehicle (1) to the underwater measuring body (2), - A data storage unit (21, 22), and - comprises an evaluation unit (28), the underwater measuring body (2) - A first multi-axis magnetometer (12.1), in particular a three-axis or four-axis magnetometer and - A second multi-axis magnetometer (12.2, ...), in particular a three-axis or four-axis magnetometer; includes, the arrangement being designed for use under water, each magnetometer (12.1, 12.2, ...) being designed to measure a quantity which correlates with the magnetic field around this magnetometer (12.1, 12.2, ...) and to output a signal in accordance with the quantity; and the data storage unit (21, 22) being designed to automatically store signals from the two magnetometers (12.1, 12.2, ...); the evaluation unit (28) being designed to automatically detect and evaluate a difference between the stored signals from the two magnetometers (12.1, 12.2, ...) in order to determine the position of the object relative to the underwater measuring body and the distance and position of the Determine the object relative to the surface of the water floor. 2. Arrangement according to one of the preceding claims, characterized in that the underwater measuring body (2) has a third multi-axis magnetometer (12.3), in particular a three-axis or four-axis magnetometer, the third magnetometer (12.3) - seen in the direction of travel (FR) of the arrangement through the water - between the first magnetometer (12.1) and the second magnetometer (12. 2) is located. 3. Arrangement according to one of the preceding claims, characterized in that the evaluation unit (28) is designed, instead of discovering and evaluating a difference between the first and the second magnetometer, a difference between - The signals of the third magnetometer (12.3) on the one hand and - The signals of the first magnetometer (12.1) and / or the second Magnetometers (12.2) on the other hand to discover and evaluate. 4. Arrangement according to one of the preceding claims, characterized in that the underwater measuring body (2) comprises a fourth magnetometer (12.4) which, when the underwater measuring body (2) is used regularly, has a smaller distance from the surface (Mb) of the water floor than the first Magnetometer (12.1) and the second magnetometer (12.2). 5. Arrangement according to one of the preceding claims, characterized in that the underwater measuring body (2) has at least one distance sensor (11.1, 11.2, 11.3) includes the or each distance sensor (11.1, 11.2, 11.3) being designed to measure the distance between the underwater measuring body (2) and a body of water, the underwater measuring body (2) being designed to transmit signals from the or each distance sensor (11.1, 11.2, 11.3) to the underwater drive vehicle (1), and the underwater propulsion vehicle (1) being designed to move the arrangement through the water depending on signals from the or each distance sensor (11.1, 11.2, 11.3). 6. Arrangement according to one of the preceding claims, characterized in that the underwater measuring body (2) comprises a position sensor (11.1, 11.2, 11.3), which is designed to measure the position of the underwater measuring body (2) in the Measuring water the data storage unit (21, 22) being designed to store signals from the position sensor (11.1, 11.2, 11.3) associated with signals from the magnetometers (12.1, 12.2, ...). 7. Arrangement according to claim 6, characterized in that the evaluation unit (28) is designed to evaluate the signals from the two magnetometers (12.1, 12.2, ...) Evaluate signals from the position sensor (11.1, 11.2, 11.3). 8. Arrangement according to one of the preceding claims, characterized in that the data storage unit (21, 22) is arranged on board the underwater drive vehicle (1) and the underwater measuring body (2) is designed to transmit signals from the two magnetometers (12.1, 12.2, ...) to the data storage unit (21, 22) on board the underwater propulsion vehicle (1). 9. Arrangement according to one of the preceding claims, characterized in that the underwater measuring body (2) - a fuselage (13), - A first spacer (14.1) and - comprises a second spacer (14.2), the two spacers (14.1, 14.2) being fastened to the fuselage (13), the fuselage (13) being located between the two spacers (14.1, 14.2), wherein the first magnetometer (12.1) is attached to the first spacer (14.1) and the second magnetometer (12.2) being attached to the second spacer (14.2). 10. Arrangement according to claim 9, characterized in that the two spacers (14.1, 14.2) - are designed as wings and - Are mounted on the hull (13) in such a way that they generate buoyancy when the underwater measuring body (2) is moved by the water. 11. Arrangement according to one of the preceding claims, characterized in that the arrangement comprises a motion sensor (24, 25), which is designed to measure a movement of the underwater measuring body (2) relative to the underwater drive vehicle (1). 12. Arrangement according to one of the preceding claims, characterized in that the distance between the two magnetometers (12.1, 12.2, ...) can be changed. 13. Use of an arrangement according to one of the preceding claims, for locating metallic objects (G), which are below the surface (Mb) of the water floor. 14. Method for locating an object (G) that is in or under a Bodies of water, using an arrangement which - An underwater drive vehicle (1) with a drive (6, 8, 9) and one Direction change unit (4.1, 4.2, 23.1, 23.2), - An underwater measuring body (2) spaced from the underwater drive vehicle (1), a connecting element (3) which connects the underwater drive vehicle (1) to the underwater measuring body (2), - A data storage unit (21, 22), and - comprises an evaluation unit (28), the underwater measuring body (2) - A first multi-axis magnetometer (12.1), in particular a three-axis or four-axis magnetometer and comprises a second multi-axis magnetometer (12.2, ...), in particular a three-axis or four-axis magnetometer, the method comprising the steps of: the arrangement is moved under water through the water, - each magnetometer (12.1, 12.2, ...) measures a variable that correlates with the magnetic field around this magnetometer (12.1, 12.2, ...) and outputs a signal according to the variable, - The data storage unit (21, 22) signals from the two magnetometers (12.1, 12.2, ...) automatically saved, and - The evaluation unit (28) automatically detects a difference between the stored signals from the two magnetometers (12.1, 12.2, ...) and evaluates the position of the object relative to the underwater measuring body and the distance and position of the object relative to Determine the surface of the water floor. 15. The method according to claim 14, characterized in that the data storage unit (21, 22) is on board the underwater propulsion vehicle (1), the signals from the underwater measuring body (2) are transmitted to the underwater drive vehicle (1) and the step of transmitting the stored signals to the evaluation unit (28) is carried out, after the underwater propulsion vehicle (1) has been taken out of the water.