NO20180282A1 - Vessel positioning - Google Patents

Description

VESSEL POSITIONING

TECHNOLOGICAL FIELD

The present specification concerns a controller, vessel, control centre or method of analysing vessel location information.

BACKGROUND

Ships are employed to transport cargo around the world. They can transport goods, bulk materials or oil, for example. Technology is being employed more and more in the industry to improve efficiency and safety, and reduce environmental impact and cost.

One example of technology used is ship positioning. This is useful for a number of factors including operational and safety related. For example, in busy shipping lanes, especially as the number and size of ships increases to meet global trade, positioning is important for collision avoidance.

The automatic identification system (AIS) is an automatic tracking system used for ship positioning, and in particular collision avoidance, and by vessel traffic services (VTS). AIS information supplements marine radar in collision avoidance methods for water transport. AIS is mandated by the International Maritime Organization's International Convention for the Safety of Life at Sea for vessels of a certain size or type.

AIS integrates a standardized VHF transceiver with a positioning system such as a GPS receiver, with other electronic navigation sensors, such as a gyrocompass or rate of turn indicator. Ships transmit their own information and receive information of other ships, which they can plot on a chart plotter. The information transmitted may include, broadcast every 2 to 10 seconds: Maritime Mobile Service Identity (a unique nine digit identification number), navigation status, rate of turn, speed over ground, positional accuracy, course over ground, true heading, true bearing and/or timestamp, for example, and broadcast every 6 minutes: IMO ship identification number, radio call sign, name, type of ship/cargo, dimensions of ship, location of positioning system on ship, draught of ship and/or destination, for example.

However errors can occur in AIS information. Where AIS is used to assist collision avoidance, it is clearly of high importance to be able to identify these errors. Therefore it is desirable to be able to identify errors in AIS information received from other vessels in real time, i.e. as it is received.

BRIEF SUMMARY

According to an aspect there is provided a controller for analysing vessel location information, configured to: receive positional information relating to a vessel location at a first time; calculate an expected new position relating to a second time of a vessel using the positional information and vessel manoeuvring characteristics; receive new positional information at the second time; compare the new positional information and expected new position of the vessel for verification of the vessel location.

The vessel location information and/or positional information and/or new positional information may be a location in a two-dimensional or threedimensional space. The two-dimensional space may be a surface for example a geographical area, for example the surface of the earth or sea.

A vessel may be a machine capable of transporting items. The vessel may be a waterborne vessel, for example a ship. The vessel may be a second vessel.

Positional information and new positional information may be grid references. Positional information and new positional information may be two locations within the same grid reference. Positional information may include vessel velocity and heading.

Vessel manoeuvring characteristics may define how the propulsion equipment can move and steer the vessel. The vessel manoeuvring characteristics of a ship may be defined by its design specification, hull, propulsors and/or rudders, for example.

The controller may comprise control circuitry and/or processor circuitry.

The step of calculating an expected new position may be completed before the second time.

The comparison of the new positional information and expected new position may involve correlating the two positions. The comparison may involve assessing the separation of the two positions. If a degree of correlation or separation exists, the controller may be configured to confirm that the vessel location is verified. If the vessel location is not verified the controller may be configured to produce a vessel location error signal.

The expected new position may comprise a positional envelope. The positional envelope may include all possible positions the vessel could move to, based on its vessel manoeuvring characteristics, within a time period between the first time and the second time.

The positional envelope may be an area across a two-dimensional plane. The positional envelope may be a volume across a three-dimensional plane. The positional envelope may include all the positions the vessel could move to based on its ability to, for example, change course, accelerate and decelerate. Its ability to change course, accelerate and decelerate may be represented by the vessel manoeuvring characteristics. Between the first time and the second time the vessel may have changed location, and this may be calculated by knowing its position at the first time and calculated how its position could have changed between the first time and the second time.

The controller may be further configured to receive vessel characteristics (e.g. one or more of vessel speed, vessel heading, vessel length, vessel width, vessel tonnage, vessel draught, vessel depth).

The vessel characteristics may be received in a data packet with the positional information. The vessel characteristics may be received from the same source as the positional information. The vessel characteristics may be received from a different source to the positional information. The vessel characteristics may include vessel physical characteristics (e.g. draught, length and width).

The vessel manoeuvring characteristics may be calculated from the vessel characteristics.

The vessel manoeuvring characteristics may be calculated using a formula. The vessel characteristics may be the inputs to the formula.

The vessel manoeuvring characteristics may be selected from a database using the vessel characteristics.

The database may be stored in the memory of the controller. The database may be stored remotely from the controller, wherein the controller is configured to be able to access the database. The database may be composed before the first time step, for example before the vessel starts its voyage.

The positional information may comprise one or more of geographical location, vessel speed, vessel heading, rate of change of speed or rate of change of course.

If the comparison of the new positional information and expected new position results in a vessel location error, the controller may be configured to control communication equipment to contact the vessel.

A vessel location error may occur if the new positional information does not fall within the expected new position. A vessel location error may occur if the new positional information falls outside of the expected new position. A vessel location error may occur if the new positional information is a different location to the expected new position. The communication equipment may contact the vessel and request confirmation of position. The communication equipment may contact the vessel to tell the vessel that its information is producing a vessel location error. The controller may control communication equipment to contact the vessel to request new positional information.

If the comparison of the new positional information and expected new position results in a vessel location error, the controller may be configured to control a secondary situational awareness sensor to verify the location of the vessel.

The secondary situational awareness sensor may comprise radar, lidar or a camera for example. The secondary situational awareness sensor may be attached to a drone or remote control device. The secondary situational awareness sensor may scan in the direction of the expected new position of the vessel to identify the location of the vessel.

If the comparison of the new positional information and expected new position results in a vessel location error, the controller may be configured to instruct a first vessel to alter course.

The controller may be located on the first vessel. The controller may be located remotely to the first vessel. The first vessel may be on a course where it may collide with the vessel. The first vessel may be in close proximity to the vessel. The instruction may be to steer away from the vessel. The instruction may be to avoid the vessel. The vessel may be a second vessel.

The controller may be further configured to receive AIS information. The AIS information may comprise positional information and vessel characteristics.

The controller may be configured to be activated in a collision avoidance situation.

The controller may be configured to be activated in a controlled zone. The controlled zone may include a port, restricted waterway or shipping lane for example.

According to an aspect there is provided an apparatus comprising a controller as described herein and an AIS transceiver for receiving AIS information from vessels.

The AIS transceiver may be able to transmit AIS information. The AIS transceiver may be able to receive AIS information.

According to an aspect there is provided an autonomous ship comprising the controller as described herein or the apparatus as described herein.

The autonomous ship may comprise no human crew. The autonomous ship may be substantially controlled by a controller. The autonomous ship may be the first vessel.

According to an aspect there is provided a control centre comprising the controller as described herein or the apparatus as described herein.

The control centre may be a remote control centre. The control centre may be a shore based control centre.

According to an aspect there is provided a method of analysing vessel location information, the method comprising the steps performed by the controller as described herein.

According to a further aspect there is provided a method for analysing vessel location information, comprising the steps:

receiving positional information relating to a vessel location at a first time; calculating an expected new position relating to a second time of a vessel using the positional information and vessel manoeuvring characteristics;

receiving new positional information at the second time; and

comparing the new positional information and expected new position of the vessel for verification of the vessel location.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore except where mutually exclusive any feature described herein may be applied to any aspect and/or combined with any other feature described herein.

BRIEF DESCRIPTION

Embodiments will now be described by way of example only, with reference to the Figures, in which:

Figure 1a illustrates a top down view of a ship and an expected new positional envelope;

Figure 1b illustrates a top down view of a ship and an expected new position;

Figure 2 illustrates two ships in a collision avoidance situation, with one ship including the controller as described herein;

Figure 3 illustrates two ships in a collision avoidance situation, and a remote control centre that includes the controller as described herein;

Figure 4 illustrates a schematic diagram of an apparatus according to various examples;

Figure 5 illustrates a flow diagram of a method according to various examples;

DETAILED DESCRIPTION

Figure 1a shows top down view of a ship and positional information across a two dimensional area, for example the sea. Figure 1a shows a ship 30 with a first position 32 located within the projected area of the ship 30. In the figure 1 example, the first position 32 is in the location of the AIS transceiver 33 which is typically located on the bridge of a ship. An expected new position 36 is shown in front of the vessel. The expected new position 36 may be a positional envelope including all of the places the ship could travel to after a time period. For example the expected new position has a front end 44, a back end 38 and two sides 42. Figure 1a shows two examples of new positional information 34 and 40. New positional information 40 is within the expected new position 36 whilst new positional information 34 is outside the expected new position 36. The new positional information 34 and 40 are received locations of the AIS transceiver 33 after the ship 30 has travelled over a time period. For example after a time period the AIS transceiver 33, still on the bridge, and in the same located with respect to the ship 30, could be in a new position represented by new positional information 34 and 40.

The expected new position 36 may comprise all the expected positions the AIS transceiver 33 of the ship 30 could be in after a time period. The time period can be any length of time, or it can be the period between transmissions of information from the ship 30. For example if the ship 30 is transmitting positional information, for example AIS information, at discrete time steps, for example a set frequency, then the time period can be the time between transmissions. The time period could be any period of time between two transmissions of data, for example between two AIS transmissions. In relation to the Figure 1a example, the time period may be the time between the transmissions of the first position 32 and new positional information 34 or new positional information 40.

For calculation of the expected new position 36 shown in Figure 1a, the ship 30 has an estimated forward speed and course at the time that the AIS transceiver 33 transmits the first position 32. Therefore if the ship 30 doesn’t change its course or speed, the AIS transceiver 33 may be located within the expected new position 36 after a time period because the ship 30 will have moved a distance defined by its estimated and/or received speed information and time period. The expected new position 36 is an envelope, in the Figure 1a example, which represents the ship 30’s ability to accelerate, decelerate and turn. The back end 38 may represent the limit whereby if the ship were to decelerate at its estimated maximum rate during the time period, then the AIS transceiver 33 would be positioned on the line 38. Based on the maximum deceleration of the ship, it is estimated to not be possible for the AIS transceiver to be positioned to the left of line 38 in the Figure 1a example. The front end 44 represents the limit whereby if the ship 30 were to accelerate at its estimated maximum rate during the time period, the AIS transceiver 30 would be positioned on the line 44. It is estimated that the ship 30 cannot accelerate fast enough in order for the AIS transceiver to be positioned to the right of line 44 after the time period. The sides 42 represent the limit whereby if the ship were to turn at its estimated maximum rate in the time period, it is estimated not be able to turn such that the AIS transceiver were in a position outside of the sides 42 after the time period.

The expected new position 36 may include allowances and/or factors for static and/or dynamic environmental conditions. For example environmental conditions may include wind, waves, currents and/or tides. The environmental conditions may be determined from hindcasts, forecasts and/or environmental monitoring systems linked to the controller. If environmental information is not available then the expected new position 36 may be calculated without account of environmental conditions. Alternatively if environmental information is not available then a factor may be applied to account for unknown environmental conditions.

If rate of change of speed and/or course information is available then this can be included in the determination of the expected new position 36. For example the rate of change of speed and/or course information may be received in AIS transmissions. For example the rate of change of speed and/or course information may be determined from historical AIS information (e.g. information relating to speed, course and/or position).

The size and shape of the expected new position envelope will vary depending on the type of ship, its received and/or estimated manoeuvring characteristics, its initial speed and course and/or rate of turn at the beginning of the time period, and/or the length of the time period. The shape is therefore not limited by the shape shown in Figure 1a.

After the time period, the ship 30 may transmit new positional information. If the new positional information is within the expected new position 36, i.e. new positional information 40 in Figure 1a, then it can be assumed that the positional information being transmitted is correct. However if the new positional information is not within the expected new position 36, i.e. new positional information 34, then it can be assumed that the positional information being transmitted is incorrect. If the positional information is incorrect then additional action can be taken, for example as described herein.

The expected new position 36 may be calculated as follows. A simple model of ship turning ability, for example, is used. The following equation can be used to derive the steady turning diameter (STD):

The STD can then be used to define the curve of lines 42 in Figure 1a. A similar formula can be derived for the maximum acceleration and deceleration of the vessel. The maximum acceleration and deceleration can be used to define the front end 44 and the back end 38 of the expected new position 36. However, in the case of AIS broadcast from ships, given the frequency of the information being broadcast, and the relative inability of the ships to be able to increase or decrease their speed, it is likely that there will be negligible change in speed between two sets of AIS information. Therefore, for simplicity, it can be assumed that the speed is constant and that the front end 44 and the back end 38 are coincident. Due to the assumptions made in defining the expected new position 36, factors can be applied to account for possible variations in actual ship manoeuvrability and/or environmental conditions. If rate of change of speed and/or course information is available then the expected new position 36 can be determined whilst taking into account the change of speed and/or course information.

The above method is an example of ways that the ship manoeuvrability can be estimated in order to define the expected new position 36. Other methods can be used, for example multi-physics models. Due to the assumptions made it is possible that whilst the model is representative of the majority of real-life scenarios and/or ships, the model is not representative of a small number of scenarios and/or ships, for example a scenario where a ship can turn faster than the above model predicts. Therefore safety factors may be applied to the model. The boundaries to the expected new position 36 may also have an allowance and/or be fuzzy to account for uncertainty in the expected new position 36 arising from missing and/or inaccurate data including unknown environmental conditions. The model may still provide a safety benefit even if the model is not representative in all scenarios and/or of all ships.

AIS information also includes ship identification number. It is possible to create a database of ship manoeuvring characteristics based on the ship identification number, for example. When the ship identification number is received, the controller can look up the ship manoeuvring characteristics in the database and use them to directly calculate the expected new position 36.

The above method can, for example, identify where another ship is transmitting AIS information that is incorrect, for example an incorrect speed, position, or length, which could affect navigational decision making whether by humans and/or controllers. Navigational decision making may include collision avoidance decisions.

Figure 1b shows a similar situation to Figure 1a, however here the expected new position 46 is a single point. This is a situation where the ship hasn’t moved significantly relative to the time period between transmitting positional information, for example AIS information. In this situation, the ship will not have had time to accelerate or turn significantly, and therefore the possibilities for the expected new position 46 are confined to a very small area, or point. In this situation obvious errors may become more apparent.

It’s possible that any of the information in the transmission is incorrect, for example the location, speed, course or even the ship dimensions or draught. The method identified above will be able to derive that one of the parameters is incorrect. For example if length is incorrect then the expected new position (36, 46) will be incorrect, and therefore if the new positional information (34, 40) falls outside of the expected new position (36, 46) then an error will be identified. Whilst at this stage it won’t be apparent what error has occurred, for example an error in draught could perhaps produce a similar error, the identification of an error means that additional actions can be taken, for example as described herein.

In the embodiments described in Figure 1a and Figure 1b, the first position 32 is shown to be coincident with the AIS transceiver 33, such that the position appears correct, i.e. the transmitted position is coincident with the actual position. However in alternative situations, the first position 32 could be incorrect, i.e. not be coincident with the AIS transceiver 33, such that even if the new positional information is correct, i.e. it is coincident with the AIS transceiver 33 after a time period, it may be outside the expected new position 36 due to the error in the first position 32. Therefore the method will still identify an error, whether the error is in the first position 32, the new positional information or both.

Figure 2 shows a first ship 50 that comprises a controller 54, an AIS transceiver 56, communication equipment 52 and sensors 58. The sensors are directional in the Figure 2 example, and the viewing cone 62 shows the direction of the sensor. The Figure 2 example also shows a second ship 60 and new positional information 64 relating to the second ship.

Figure 2 diagrammatically shows a collision avoidance situation, the first ship 50 and second ship 60 are relatively close and on courses such that they might come close to each other. In Figure 2 the second ship is broadcasting information, for example AIS information, in the manner shown in Figure 1a. The controller 54 on the first ship 50 is receiving this information via the AIS transceiver 56. The controller 54 is performing the method described and/or claimed herein in order to assess the information transmitted by the second ship 60. In Figure 2, the new positional information 64 is shown to be obviously wrong, and the method described above would identify this by finding that the new positional information 64 is outside of the expected new position. Therefore the controller 54 of the first ship 50 can identify that the second ship 60 is transmitting incorrect AIS information. As the AIS information may be contributing to the collision avoidance behaviour of the first ship, it is important that this information is correct. Therefore the first ship can take action based on this information. For example the controller 54 can control communication equipment 52 on the first ship 50 in order to communicate with the second ship 60 and request that AIS or positional information is confirmed. Alternatively the first ship 50 can take avoiding action, for example by maximising the distance between itself and the second ship 60 or avoiding an area which encompasses both the expected new position 36 and the new positional information 64. Alternatively the controller 54 on the first ship 50 can control sensors 58 in order to inspect the location of the second vessel. For example the sensors 58 could be visual (i.e. video cameras), or use lidar or radar. If the sensors are directional, as shown in Figure 2, they can be directed towards the new positional information 64. As can be seen in Figure 2, in doing so they would identify the correct location of the ship.

The embodiment shown in Figure 2 is most pertinent in the case where ship 50 is an autonomous ship. In this scenario there may be no crew on board to be able to visually identify close bearing ships from such that automated collision avoidance mechanisms and the accuracy of such become more important. Further, the human element on a non-autonomous ship can use seamanship knowledge in order to react to a second ship and avoid a collision, whereas an autonomous ship must use sensors and controllers in order to do so.

Figure 3 shows a similar situation to Figure 2. Figure 3 shows a first ship 70 that comprises a first controller 74, and AIS transceiver 76, communication equipment 72 and sensors 78. The sensors are directional in Figure 3, and the viewing cone 82 shows the direction of the sensor. Figure 3 also shows a second ship 80 and new positional information 84 relating to the second ship. Figure 3 further shows a remote control centre 90 which comprises a second controller 88 and communication equipment 86.

The first controller 74 is configured to receive positional information from the second ship 80 and communicate it to the remote control centre 90. The second controller 88 of the remote control centre 90 receives the positional information via the communication equipment 86 and processes the information. The second controller 88 may perform the method as described herein, i.e. identifying if there is a vessel location error in the second ship. After the second controller 88 has identified whether there is a vessel identification error, it controls the communication equipment 86 to communicate the vessel identification error to the first controller 74 and/or the first vessel 70.

In the situation where the first vessel 70 is an autonomous ship, for example if there is no human crew on the ship or the ship is controlled by a controller, the remote control centre 90 can communicate actions to the first ship 70 to take. In certain embodiments the remote control centre 90 can control the first ship 70 entirely. The remote control centre 90 may be a shore based control centre. The shore based control centre may be based on land. The shore based control centre may control a number of autonomous ships. The shore based control centre may control the logistics of the first ship. The shore based control centre may comprise human control, such that they can act on the results of the controller 88 for remotely controlling the first ship.

In the following description, the terms ‘connected’ and ‘coupled’ mean operationally connected and coupled. It should be appreciated that there may be any number of intervening components between the mentioned features, including no intervening components.

Figure 4 illustrates a schematic diagram of an apparatus 100 according to various examples. The apparatus includes a controller, an input device, and an output device. In some examples, the apparatus may be a module. As used herein, the wording ‘module’ refers to a device or apparatus where one or more features are included at a later time and, possibly, by another manufacturer or by an end user. For example, where the apparatus is a module, the apparatus may only include the controller, and the remaining features may be added by another manufacturer, or by an end user.

The controller, the input device, and the output device may be coupled to one another via a wireless link and may consequently comprise transceiver circuitry and one or more antennas. Additionally or alternatively, the controller, the input device and the output device may be coupled to one another via a wired link and may consequently comprise interface circuitry (such as a Universal Serial Bus (USB) socket). It should be appreciated that the controller, the input device, and the output device may be coupled to one another via any combination of wired and wireless links.

The controller may comprise any suitable circuitry to cause performance of the methods described herein and as illustrated in Figure 4. The controller may comprise: control circuitry; and/or processor circuitry; and/or at least one application specific integrated circuit (ASIC); and/or at least one field programmable gate array (FPGA); and/or single or multi-processor architectures; and/or sequential/parallel architectures; and/or at least one programmable logic controllers (PLCs); and/or at least one microprocessor; and/or at least one microcontroller; and/or a central processing unit (CPU); and/or a graphics processing unit (GPU), to perform the methods.

In various examples, the controller may comprise at least one processor and at least one memory. The memory stores a computer program comprising computer readable instructions that, when read by the processor, causes performance of the methods described herein, and as illustrated in Figure 4. The computer program may be software or firmware, or may be a combination of software and firmware.

The processor may be located on a ship, or may be located remote from a ship, or may be distributed between a ship and a location remote from a ship. The processor may include at least one microprocessor and may comprise a single core processor, may comprise multiple processor cores (such as a dual core processor or a quad core processor), or may comprise a plurality of processors (at least one of which may comprise multiple processor cores).

The memory may be located on a ship, or may be located remote from a ship, or may be distributed between a ship and a location remote from the ship. The memory may be any suitable non-transitory computer readable storage medium, data storage device or devices, and may comprise a hard disk and/or solid state memory (such as flash memory). The memory may be permanent nonremovable memory, or may be removable memory (such as a universal serial bus (USB) flash drive or a secure digital card). The memory may include: local memory employed during actual execution of the computer program; bulk storage; and cache memories which provide temporary storage of at least some computer readable or computer usable program code to reduce the number of times code may be retrieved from bulk storage during execution of the code.

The computer program may be stored on a non-transitory computer readable storage medium. The computer program may be transferred from the nontransitory computer readable storage medium to the memory. The nontransitory computer readable storage medium may be, for example, a USB flash drive, a secure digital (SD) card, an optical disc (such as a compact disc (CD), a digital versatile disc (DVD) or a Blu-ray disc). In some examples, the computer program may be transferred to the memory via a wireless signal or via a wired signal.

Input/output devices may be coupled to the system either directly or through intervening input/output controllers. Various communication adaptors may also be coupled to the controller to enable the apparatus to become coupled to other apparatus or remote printers or storage devices through intervening private or public networks. Non-limiting examples include modems and network adaptors of such communication adaptors.

The input device may comprise any suitable device for enabling an operator to at least partially control the apparatus, or to receive and provide information to the controller. For example, the input device may comprise one or more of a keyboard, a keypad, a touchpad, a touchscreen display, and a computer mouse. For example, the input device may comprise one or more of a VHF transceiver, an AIS transceiver, a radio transceiver or a situational awareness sensor (for example a radar or lidar sensor). The controller is configured to receive signals from the input device.

The output device may be any suitable device for conveying information to a user. For example, the output device may be a display (such as a liquid crystal display, or a light emitting diode display, or an active matrix organic light emitting diode display, or a thin film transistor display, or a cathode ray tube display), and/or a loudspeaker, and/or a printer (such as an inkjet printer or a laser printer). The controller is arranged to provide a signal to the output device to cause the output device to convey information to the user.

Figure 5 illustrates a flow diagram of a method according to various examples. At block 1, the method includes receiving positional information relating to a vessel location. At block 2, the method includes calculating an expected new position of a vessel using the positional information and vessel manoeuvring characteristics. At block 3, the method includes receiving new positional information corresponding to the expected new position. At block 4, the method includes comparing the new positional information and expected new position of the vessel for verification of the vessel location.

In one embodiment steps described are performed sequentially. Receiving the positional information in step 1 is completed at an earlier time step than receiving new positional information. Between the two time steps the expected new position is calculated. However in other embodiments step 2 can be completed after step 3. In this situation the calculation of the expected new position and the comparison between the expected new position and the new positional information are both completed on historical data.

Optionally an additional step of receiving vessel characteristics can be completed before step 2 i.e. the step of calculating an expected new position. The step of receiving vessel characteristics can be completed at the same time as step 1, or alternatively before or after step 1.

A vessel can transmit the vessel characteristics and positional information. For example if the vessel is a ship, then the ship can transmit the information via AIS. AIS information includes both vessel characteristics and positional information. The vessel characteristics can be transmitted at a different interval to the positional information. For example the vessel characteristics can be transmitted at a first frequency, and the positional information can be transmitted at a second frequency. In this situation the vessel characteristics can be stored in the memory of the controller for when they are required in order to calculate an expected new position.

The vessel characteristics and/or positional information can be received from a source other than the other vessel, for example a traffic management system and/or vessel management system. In the case of shipping, this can be a port system or waterway management system.

The vessel information can be both transmitted and received by an AIS transceiver. The AIS transceiver can then pass the information to the controller as described herein.

It should be appreciated that the method illustrated in Figure 5 may be performed ‘offline’ on data which has been measured and recorded previously. Alternatively it may be performed in ‘real-time’, that is, substantially at the same time that the data is measured. In this case, the controller may be coupled to a ship and may be an electronic engine controller or another on-board processor. Where the ship includes propulsion equipment, the controller may be an engine controller or a processor on-board the ship.

It will be understood that the invention is not limited to the embodiments abovedescribed and various modifications and improvements can be made without departing from the concepts described herein. For example, the different embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment containing both hardware and software elements.

Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims (17)

1. A controller (54, 74, 88) for analysing vessel (30, 60, 80) location information, configured to:

receive positional information (32) relating to a vessel location at a first time;

calculate an expected new position (36, 46) relating to a second time of a vessel using the positional information and vessel manoeuvring characteristics;

receive new positional information (34, 40, 64, 84) at the second time; compare the new positional information and expected new position of the vessel for verification of the vessel location.

2. The controller according to claim 1, wherein the expected new position comprises a positional envelope, and wherein the positional envelope includes all possible positions the vessel could move to, based on its vessel manoeuvring characteristics, within a time period between the first time and the second time.

3. The controller according to claim 1 or claim 2, wherein the controller is further configured to receive vessel characteristics (e.g. one or more of vessel speed, vessel heading, vessel length, vessel width, vessel tonnage, vessel draught, vessel depth).

4. The controller according to claim 3, wherein the vessel manoeuvring characteristics are calculated from the vessel characteristics.

5. The controller according to claim 3, wherein the vessel manoeuvring characteristics are selected from a database using the vessel characteristics.

6. The controller according to any one of the previous claims, wherein the positional information comprises one or more of geographical location, vessel speed, vessel heading, rate of change of speed or rate of change of course.

7. The controller according to any one of the previous claims, wherein if the comparison of the new positional information and expected new position results in a vessel location error, the controller is configured to control communication equipment (52, 72) to contact the vessel.

8. The controller according to any one of claims 1 to 6, wherein if the comparison of the new positional information and expected new position results in a vessel location error, the controller is configured to control a secondary situational awareness sensor (58, 78) to verify the location of the vessel.

9. The controller according to any one of claims 1 to 6, wherein if the comparison of the new positional information and expected new position results in a vessel location error, the controller is configured to instruct a first vessel (50, 70) to alter course.

10.The controller according to any one of the previous claims, wherein the controller is further configured to receive AIS information, and wherein the AIS information comprises positional information and vessel characteristics.

11.The controller according to any one of claims 1 to 10 wherein the controller is configured to be activated in a collision avoidance situation.

12.The controller according to any one of claims 1 to 10 wherein the controller is configured to be activated in a controlled zone.

13.An apparatus (100) comprising a controller according to claim 10 and an AIS transceiver for receiving AIS information from vessels.

14.An autonomous ship comprising the controller according to any one of claims 1 to 12 or the apparatus according to claim 13.

15.A control centre (90) comprising the controller according to any one of claims 1 to 12 or the apparatus according to claim 13.

16.A method of analysing vessel location information, the method comprising the steps performed by the controller according to any one of claims 1 to 12.

17.A method of analysing vessel (30, 60, 80) location information, comprising the steps:

receiving positional information (32) relating to a vessel location at a first time;

calculating an expected new position (36, 46) relating to a second time of a vessel using the positional information and vessel manoeuvring characteristics;

receiving new positional information (34, 40, 64, 84) at the second time; and

comparing the new positional information and expected new position of the vessel for verification of the vessel location.