GB2589381A

GB2589381A - Navigation guidance method and system

Info

Publication number: GB2589381A
Application number: GB1917510.8A
Authority: GB
Inventors: Bryden Percy Iain; Brice Modral Owen
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2021-06-02
Also published as: GB201917510D0

Abstract

There is provided a navigation guidance method and system for a sailing boat 101, which periodically calculate a predicted route associated with a bearing, the predicted route comprising a first path to the bearing and a second path from the bearing to a predetermined bearing and wherein the length of the predicted route is calculated based on a target time and a predicted boat speed. The predicted route partially defines a boundary, which indicates whether the sailing boat will arrive at a destination late or on time. The intended application is to manoeuvre sailing boats into advantageous positions prior to the start of a race.

Description

NAVIGATION GUIDANCE METHOD AND SYSTEM

FIELD OF INVENTION

This invention relates to a navigation guidance method and system for a sailing boat.

BACKGROUND

In a sailing boat race, it is very important to arrive at the start line at a precise time. Arriving too early results in a time penalty; arriving too late puts the boat in a disadvantageous position for the rest of the race. In addition, the helmsman must also consider the relative positions of other boats taking part in the race. For example, various racing rules govern which boats have right of way in order to avoid collisions. Additionally, the sail of a boat can produce turbulent airflow for another boat, so-called "dirty air." These considerations can be tactically leveraged by a boat's crew to manoeuvre a boat into an advantageous position relative to other boats before the race starts.

Various on-board systems are used to present information to crew members which allows the crew to navigate towards a destination in order to arrive at the destination at a target time. However, these known systems provide estimations which are highly sensitive to small variations in speed and heading.

An example of such a known system is shown in figure 1 which depicts a sailing boat 101 sailing towards a starting line 102. As will be described in more detail below, the system shown in figure 1 provides an estimation of the amount of time it will take the sailing boat 101 to arrive at the destination 102 according to a number of calculated routes to the destination.

However, the system of figure 1 is only able to provide accurate guidance for a limited number of calculated routes (numbered 108 to 111) to the starting line 102. A limited amount of information may be provided that is associated with each particular route. However, this is not reflective of real racing conditions, as the number of possible navigation options available to the sailing boat crew greatly exceeds the limited number of routes displayed by the system of figure 1. Known systems are therefore unable to provide accurate guidance for a large number of navigation options. Additionally, each route is calculated based on the sailing boat's heading so small variations in the sailing boat's heading produce large variations in the arrival time estimations. Equally, small variations in heading are exacerbated the further the sailing boat is from the destination.

The above considerations apply equally when the sailing boat is heading towards any target destination other than a starting line, such as a waypoint of a route.

SUMMARY OF INVENTION

The invention is defined by the independent claims, to which reference is now drawn.

Preferred features are laid out in the dependent claims.

In a first aspect of the invention, a navigation guidance system for a sailing boat, comprises a location module for identifying a current location associated with the sailing boat, a timing module configured to identify a target time for the sailing boat to arrive at a destination at a predetermined bearing, a database configured to receive and store a predicted boat speed that is based on input data, a calculation module configured to periodically calculate a predicted route associated with a bearing wherein the predicted route comprises a first path onto the bearing and a second path from the bearing onto the predetermined bearing and wherein the length of each predicted route is defined by the target time and the predicted boat speed, a processor configured to define a first boundary defined at least in part by the end of the predicted route distal to the current location, and a display configured to display a visual representation of the first boundary, the predicted route, the current location of the sailing boat, and the location of the destination.

In an embodiment of the invention, the calculation module calculates a predicted route for each of a plurality of bearings.

In another embodiment of the invention, the predicted boat speed is compared to a target boat speed.

In another embodiment of the invention, the calculation module is further configured to periodically calculate a location associated with the predicted route where the predicted boat speed will reach or exceed the target boat speed.

In another embodiment of the invention, each calculated location defines an auxiliary boundary beyond which the sailing boat is predicted to achieve or exceed the target boat speed.

In another embodiment of the invention, the display is further configured to display a visual representation of the auxiliary boundary.

In another embodiment of the invention, the calculation module is initiated by a trigger event.

In another embodiment of the invention, the trigger event is a predefined time or a predetermined proximity to the destination.

In another embodiment of the invention, the predicted boat speed is obtained from performance related information for the boat.

In another embodiment of the invention, the predicted boat speed is a near-instantaneous boat speed determined using input data In another embodiment of the invention, the predicted boat speed is determined by calculating a true wind speed and a true wind direction from the input data.

In another embodiment of the invention, one or more boat performance configurations are adjusted in response to the displayed visual representation.

In another embodiment of the invention, the display forms part of a computing device.

In another embodiment of the invention, the computing device is a desktop computer, a laptop computer, a tablet computer, a personal digital assistant, a mobile telephone, a smartphone, a smart watch or a pair of smart glasses.

In another embodiment of the invention, the display forms part of an augmented reality system.

In another embodiment of the invention, the input data is provided manually.

An embodiment of the invention further comprises sensors for at least partially providing input data.

An embodiment of the invention further comprises a communication source for at least partially providing input data.

In another embodiment of the invention, the display further comprises an interactive portion for at least partially providing input data.

In another embodiment of the invention, the input data comprises wind data and/or boat speed data.

In another embodiment of the invention, the predicted route is calculated based on known route parameters associated with the route.

In another embodiment of the invention, the known route parameters include one or more scaling parameters, route curvature parameters and/or acceleration or deceleration parameters.

In another embodiment of the invention, the destination is a boundary line, a waypoint on a journey or a specified location.

In another embodiment of the invention, the display is further configured to display a visual representation of the destination.

In another embodiment of the invention, the one or more points of intersection between the destination and the first boundary define the locations where the sailing boat is predicted to arrive at the destination exactly at the target time.

In another embodiment of the invention, the boundary is an isochronic line associated with the target time.

In a second aspect of the invention, a navigation guidance method for a sailing boat, comprises identifying the current location associated with the sailing boat, identifying a target time for the sailing boat to arrive at a destination at a predetermined bearing, obtaining a predicted boat speed based on input data, periodically calculating a predicted route associated with a bearing, the predicted route comprising a first path onto the bearing and a second path from the bearing onto a predetermined bearing and wherein the length of the predicted route is calculated based on the target time and the predicted boat speed, displaying a first boundary defined at least in part by the end of the predicted route distal to the current location, the predicted route, the current location of the sailing boat, and the location of the destination.

An embodiment of the invention further comprises calculating a predicted route for each of a plurality of bearings.

An embodiment of the invention further comprises comparing the predicted boat speed to a target boat speed.

An embodiment of the invention further comprises periodically calculating a location associated with the predicted route where the predicted boat speed will reach or exceed the target boat speed.

An embodiment of the invention further comprises displaying a visual representation of the auxiliary boundary.

In another embodiment of the invention, the step of periodically calculating a predicted route associated with a bearing is initiated by a trigger event.

An embodiment of the invention further comprises obtaining the predicted boat speed from performance related information for the boat.

In another embodiment of the invention, the predicted boat speed is a near-instantaneous boat speed determined using input data.

In another embodiment of the invention, the predicted boat speed is determined by calculating a true wind speed and a true wind direction from the input data.

An embodiment of the invention further comprises adjusting one or more boat performance configurations in response to the displayed visual representation.

In another embodiment of the invention, the step of displaying the first boundary is performed with a computing device.

In another embodiment of the invention, the step of displaying the first boundary is performed with an augmented reality system.

An embodiment of the invention further comprises manually providing the input data.

An embodiment of the invention further comprises at least partially providing input data from sensors.

An embodiment of the invention further comprises at least partially providing input data from a communication source.

An embodiment of the invention further comprises at least partially providing input data from an interactive portion of a display.

The navigation guidance method of any preceding claim, wherein the input data comprises wind data and/or boat speed data.

An embodiment of the invention further comprises calculating the predicted route based on known route parameters associated with the route.

An embodiment of the invention further comprises displaying a visual representation of the destination.

An embodiment of the invention further comprises defining the locations where the sailing boat is predicted to arrive at the destination exactly at the target time with the one or more points of intersection between the destination and the first boundary.

DETAILED DESCRIPTION

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: figure 1 shows a display image from a known positioning guidance system; figure 2 shows a schematic diagram of an example system architecture according to an embodiment of the invention; figure 3A shows a first example route that a boat may take to a destination, figure 3B shows a second example route that a boat may take to a destination; figure 3C shows a third example route that a boat may take to a destination; figure 3D shows a fourth example route that a boat may take to a destination; figure 4 shows a first example display image from a navigation guidance system according to an embodiment of the invention; figure 5 shows a second example display image from a navigation guidance system according to an embodiment of the invention; figure 6 shows a third example display image from a navigation guidance system according to an embodiment of the invention; figure 7 shows a fourth example display image from a navigation guidance system according to an embodiment of the invention; and figure 8 shows a flow diagram of an example process for obtaining graphical features within the display of figures 4 to 7.

Figure 1 illustrates a known positioning guidance display 100 for providing a boat helmsman with guidance for arriving at a destination at a target time.

Figure 1 shows a sailing boat 101 heading towards a destination 102 which in the example of figure 1 is a starting line. Port laylines 103a, 103b and starboard laylines 104a, 104b extend from markers defining the destination 102. A layline is known in the art as a straight line extending from a marker which indicates the optimum course a sailing boat should take in order to pass the marker on the windward side without having to change direction. The directions the laylines extend therefore signify an optimum angle to the wind which, when travelled along at a target speed, provides the fastest route to the destination. The direction of the laylines is dependent upon the prevailing wind speed and direction and may be calculated using methods and techniques known in the art.

The display 100 includes a heading indicia 105 which indicates the current heading of the sailing boat 101 which may be based on data received from suitable means such as a compass. The display 100 also includes a time to gun indicia 106 and a time to burn indicia 107. The time to gun indicia 106 indicates the amount of time remaining before a sailing race commences. In the example shown in figure 1, the remaining time until the race starts is 1 minute 20 seconds. The time to burn predicts how early or late the sailing boat 101 would arrive at the starting line or a chosen point of that starting line. In the example of figure 1, display 100 also indicates four suggested routes 108, 109, 110 and 111. Although not displayed here, known systems such as those shown in figure 1 would often provide a time to burn for each of a finite number of specific suggested routes. In addition to the above, display 100 also provides port end indicia 112a and starboard end indicia 112b, which indicate a time to burn and an estimated time to sail to the port and starboard ends of the starting line respectively. In the example shown in figure 1, the starboard end time to burn indicia 112b indicates that the time to burn for the sailing boat 101 when arriving at the starboard end of the start line on time is 59 seconds based on the sailing boat's current performance and a predicted performance based on the current wind speed and direction and bearing to sail to reach the starboard end. In other words, if the sailing boat adjusted its course towards the starboard end of the line, the boat would arrive at the starboard end of the start line 59 seconds before the scheduled start of the race.

The example positioning guidance display 100 shown in figure 1 has significant problems.

Firstly, the time to burn calculations are significantly affected by small changes in data associated with the sailing boat, such as the sailing boat's heading and performance. Additionally, small changes in wind conditions can also result in large variations in the calculated time to burn. Faster boats and increased distance from a destination produce even greater variations in the calculated results. Crew members who are presented with displays such as that shown in figure 1 often do not appreciate why the calculated numbers fluctuate so much and their ability to effectively use the calculated data to tactically position their sailing boat is diminished. As indicated above, this can have a substantial impact on how the boat performs in racing conditions.

Secondly, the display 100 only predicts the time to burn for a very small number of tactical options, which mostly involve sailing parallel to laylines. However, race start situations are highly complex and require the sailing boat to be manoeuvred in an unrestricted manner, which the simplified options of display 100 cannot provide.

Finally, there is no guidance as to how the time to burn may be utilised to the crew's tactical advantage. Merely displaying the calculated time to burn provides crew members with no indication of what tactical manoeuvres should be performed during that time that will most effectively position their boat in the time preceding the start of a race.

Crew members therefore require a more sophisticated solution to the above problems which enables them to effectively and accurately position their boat in racing conditions.

Embodiments of the invention are directed towards an improved guidance method and system for a boat, as further described below.

Figure 2 shows an embodiment of a guidance system 200 which includes a computing device 210. The computing device may be any suitable computing device, such as a desktop computer, a laptop computer, a tablet computer, a personal digital assistant, a mobile telephone, a smartphone, a smart watch, smart glasses or any other computing device. The computing device 210 includes a processor 211, a memory 212, a local database 213, a user interface 214 and a display 215.

The processor 211, memory 212 and local database 213 combine to provide means for storing data, executing logic commands and performing arithmetic calculations. In some embodiments, the processor 211 may run one or more server processes for communicating with client devices. The server processes may comprise computer readable program instructions for carrying out the operations of the present invention. The computer readable program instructions may be source code or object code written in or in any combination of suitable programming languages including procedural programming languages such as C, object orientated programming languages such as C#, C++, Java, scripting languages, assembly languages, machine code instructions, instruction-setarchitecture (ISA) instructions, and state-setting data.

The computer readable program instructions may be stored on a non-transitory, tangible computer readable medium, such as local database 213. The computer readable storage medium may include one or more of an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk.

User interface 214 enables a user to interact with the guidance system 200 and provide feedback and notifications to the user. For example, the user interface 214 may enable the user to access system settings, input data manually, or enable the selection of particular modes of operation of the guidance system 200. In some embodiments, the user interface 214 may be provided in the form of a widget embedded in a web site, as an application for a device, or on a dedicated landing web page. Computer readable program instructions for implementing the user interface 214 may be downloaded to the client device from a computer readable storage medium via a network, for example, the Internet, a local area network (LAN), a wide area network (WAN) and/or a wireless network. The instructions may be stored in a computer readable storage medium within the client device.

The display 215 also enables the user to interact with the guidance system 200. The display may be any suitable device for displaying information to the user. In some embodiments, the display may form part of an augmented reality (AR) system which enables graphical elements calculated by the guidance system 200 to be overlaid onto a user's field of view of their physical environment. In some embodiments, the display may also have at least one interactive portion, thereby enabling the user to make adjustments to the performance and configuration of the boat. In other embodiments, the interactive portion enables a user to manually provide input data, such as wind speed data, to the guidance system 200.

The system 200 further includes a navigation device 220 which incorporates the computing device 201 and further comprises a calculation module 221, a timing module 222 and a location module 223. In preferred embodiments, the guidance system 200 is implemented in, located on or associated with a boat.

The calculation module 221 stores instructions which enables the processor to calculate parameters and graphical elements to be displayed on display 215. For example, the calculation module 221 may calculate a straight-line distance between the guidance system 200 and a destination, a predicted boat speed, port and/or starboard layline position and a target speed. The graphical elements to be displayed on the display may include proximity indicia, boat heading indicia, destination location indicia and layline indicia. In some embodiments, the processor 211, memory 212 and local database 213 form the calculation module 221.

The timing module 222 enables the guidance system 200 to monitor a target time for arriving at the destination. In some embodiments, the timing module 222 includes a countdown timer for providing a countdown to the target time. In other embodiments, the timing module 222 includes a communications unit for receiving accurate time information from a suitable communications source, such as a GPS signal. The timing module 222 may display the target time and/or countdown time as a time indicia on the display 215.

The location module 223 identifies the spatial location of the guidance system 200. In some embodiments, the location module 223 includes a communications unit for receiving location information from a suitable communications source. For example, the location module 223 may communicate with radio-navigation satellites, such as a GPS satellite 230, to receive location data. The location module 223 may display the location of the guidance system 200 as location indicia on the display 215. The location module may also store location information associated with one or more destinations.

In preferred embodiments, the navigation device receives input data from sensors 240 which may be a plurality of sensors configured to measure ambient conditions. The sensors 240 collects sensor data from each of the plurality of sensors and passes the sensor data to other guidance system components for analysis and/or storage. The sensors may be configured to provide sensor data either continuously or periodically.

In an embodiment, the sensors 240 may include one or more wind sensors, compasses and boat speed sensors. The one or more wind sensors measure an apparent wind angle and an apparent wind speed, which may be thought of as the direction and strength of the wind experienced by an observer on board the boat. The wind sensor may be any suitable means for measuring wind strength and wind direction, for example the wind sensor may comprise an anemometer and a wind vane. The compasses may be any suitable means for identifying the heading of the sailing boat relative to due north, such as a gyroscopic or magnetic compass. The boat speed sensors may be any suitable means for measuring the speed of the sailing boat relative to the water or land and may be, for example, a paddlewheel or sonic sensor.

The input data collected by the sensors 240 may be communicated to the calculation module 221 for data analysis and/or data processing or to the local database 213 for storage.

In an alternative embodiment, input data may be provided by data received from a suitable communications source such as a GPS satellite 230, as further described below. In an alternative embodiment, input data may be manually provided via, for example, the interactive portion of a display as described above. In another embodiment, input data may be partially provided by a combination of one or more of the sensors, communication source or manually input data.

In one embodiment, the positional guidance device 200 may communicate with one or more external systems 260 via a communications network 250. For example, the data collected by sensors 240 may be communicated to a remote database via communications network 250. The communications network 250 may also enable the positional guidance device 200 to communicate with one or more mobile devices 270 to send data to and/or receive data from the mobile devices. The communications network 250 may be any suitable known means of connecting the positional guidance device to the external devices.

For example, the communications network 250 may be provided by a local area network (LAN), wireless local area network (WLAN), wide area network (XNAN), satellite link, cellular communication networks and the like. Communications via the communications network 250 may be in any suitable known wired and/or wireless protocols. Suitable wired communications may be performed via USB or Ethernet connections. Suitable wireless communications may be performed via Bluetooth, VViFi, Internet communication protocols, cellular communication protocols, RFID, NFC or the like.

Figures 3A to 3D are schematic diagrams of different example routes from a first sailing boat location 301 to a destination 302 that a sailing boat may take during a race. Each of these predetermined routes may be modelled by the system using different route metrics associated with each route. In preferred embodiments, the length of each route is calibrated to indicate a distance that the sailing boat is predicted to travel during a target time, for example the amount of time left until the start of a race.

Route metrics are additional mathematical parameters which may be included in the calculations performed by the system to adjust for different routes that the boat may take to arrive at the destination, as further described below with reference to figures 3A to 3D. The parameter values may be determined by analysing boat performance data collected over a variety of weather conditions and boat configurations and may vary significantly from boat to boat.

In a first example, the boat 301 may follow a straight line 310 to the destination 302, as shown in figure 3A where the boat sails towards the destination at a bearing of theta_1 from due north. The route metrics associated with this route may include a scaling parameter. The calculations performed by the system assume that the sailing boat 301 is performing at optimum performance. However, a sailing boat 301 may not always sail at the predicted performance. The route metrics may account for this discrepancy by including a scaling parameter. For example, if the boat speed is predicted to be 20 knots but is measured to be 15 knots then a suitable scaling parameter may be applied to ensure that the calculated boundary lines correspond to the boat's actual performance.

Another example of a route the boat 301 may take to the destination 302 is shown in figure 3B. It is often advantageous in a sailing boat race to arrive at a destination at a target angle and at a target speed. The target angle and target speed are often known in advance of arriving at the destination and ensure the sailing boat favourably starts the next stage of the race. Therefore, the boat's route to the destination may mostly include sailing in a straight line 311 at a bearing of theta_2 from due north, with a turn 312 onto the target angle when arriving at the destination. Additionally, the boat may accelerate or decelerate at any point on this route to arrive at a target speed. Further, the sailing boat will also accelerate or decelerate during the turn onto the target angle due to the changing wind conditions.

Therefore, in addition to a scaling parameter, the route metrics may additionally include route curvature parameters to account for the rate of curvature when turning onto the known target angle and acceleration parameters to account for the rate of acceleration and deceleration of the boat during the curve and elsewhere on the route. In situations where the acceleration parameters cannot be obtained directly, for example where there is limited or no access to a network 250, a predicted boat speed may be used instead of the acceleration parameters to calculate the predicted route of the boat 301.

Another example of a route the boat 301 may take to the destination 302 is shown in figure 3C. It is often advantageous to sail to a destination along a layline running from the destination, as described above with reference to figure 1. Therefore, another route the boat 301 may take is to sail in a straight line 314 at a bearing theta_3 from due north towards a layline 313 before turning 315 onto the layline. Again, the route metrics associated with this route may include scaling parameters, route curvature parameters and acceleration parameters to account for the sailing boat's route.

A final example of a route the boat 301 may take to the destination 302 is shown in figure 3D. The route shown in figure 3D is the same as the route shown in figure 3B but includes an initial path 316 from a current heading theta_4 onto a bearing theta_5 where the sailing boat 301 sails towards the destination 305 in a straight line 317. The inclusion of the first turn 316 advantageously enables a more accurate prediction of the sailing boat location at a target time. As also shown in figure 3B, the route of figure 3D also includes a final path 318 from the bearing theta_5 onto a target angle theta_6 just before arriving at the destination 305 at the target time, so that the sailing boat is travelling at a predetermined target angle at the target time.

As indicated above, the boat may accelerate or decelerate at any point on this route to arrive at a target speed. Further, the sailing boat will also accelerate or decelerate during each turn due to the changing wind conditions. Therefore, in addition to a scaling parameter, the route metrics may additionally include route curvature parameters to account for the rate of curvature when turning onto the known target angle and acceleration parameters to account for the rate of acceleration and deceleration of the boat during the curve and elsewhere on the route.

In some embodiments, each of the routes described above may be calculated using route metrics associated with a particular manoeuvre, such as a tack or a gybe. For example, the route metrics may include route parameters to account for the sailing boat trajectory when executing a manoeuvre and acceleration parameters to account for the rate of acceleration and deceleration of the boat during the manoeuvre. Accordingly, the relative positions and the shape of each route indicia 504 on the display screen can be adjusted by changing the route metrics and route parameters associated with each maneouvre. For example, executing a manoeuvre with a smaller rate of turn (i.e. a turn involving a bigger arc) would require additional time and space to execute the manoeuvre. Accordingly, the calculated boat positions take into account the time taken to execute a particular manoeuvre, such as a tack or a gybe.

Route metrics therefore enable a variety of different route options to be accounted for and displayed to a user, thereby providing the user with greater flexibility and tactical options during the race.

In the embodiments shown in figures 4 to 7, the prevailing wind direction is from the top of the page to the bottom of the page.

Figure 4 illustrates a first example graphic user interface display 400 for guiding a sailing boat to a destination during a starboard upwind start to a race in accordance with an embodiment of the invention.

The display 400 shows a sailing boat 401 heading towards a destination, which in the example of figure 4 is a race starting line 402. In other embodiments, the destination may also be a defined point rather than a line. For example, the destination may be a specified target location, such as a favoured point on the starting line that is identified in advance as the optimum location for the sailing boat to cross the starting line.

It will be appreciated that the destination does not have to relate to a starting line or position. For example, the destination may be a race finish line, a single point on the finish line, or a waypoint on the race course during the race.

Laylines (not shown in figure 4) may be displayed extending from one or more of an upwind marker, downwind marker and the favoured starting point(also not shown in figure 4).

The display 400 includes heading indicia 403, route indicia 404a to 404j and proximity indicia 405. The heading indicia 403 may indicate the current heading of the sailing boat 401, the route indicia 404 may indicate one or more predicted routes identifying a preferred course that the boat should ideally follow, and the proximity indicia 405 may indicate a set distance from the sailing boat. For example, the proximity indicia 405 may indicate distances of 50m and 100m from the sailing boat. The display may also include course limit indicia (not shown in figure 4). The course limit indicia may indicate an area within which the boat must remain during the race as may be defined by rules associated with a race.

The display 400 also includes one or more boundary indicia which each define a boundary, as further described below. The position of the boundary indicia relative to the location of the sailing boat provides tactical information to a user by indicating the calculated position of the sailing boat at the target time, hence indicating whether the sailing boat is predicted to arrive at a destination earlier or later than a target time. Further, boundary indicia may also indicate whether the sailing boat will have achieved a target speed by the target time. The locations of the boundary indicia are calculated as described further below and are updated periodically to provide real-time information to the user. Accordingly, the locations of the boundary indicia change with time.

The display 400 shown in figure 4 includes a boundary indicia 406 that connects the distal end of each predicted route calculated from the current location of the sailing boat. In other words, the boundary indicia 406 indicates a locus of positions where the sailing boat could be positioned at the target time if sailed at a predicted speed towards the destination along a predetermined route. The first boundary indicia 406 therefore defines an isochronic line associated with a plurality of predicted boat locations at a target time.

In preferred embodiments, the predetermined route is any of the routes described with reference to figures 3A to 3D. In particular, the predetermined route is in accordance with the description of figure 3D above, which includes an initial turn onto a bearing towards the destination, proceeding in a straight line towards the destination and a final turn onto a target heading just before arriving at the destination. For example, for an upwind start, the target heading may be the best upwind angle. Alternatively, for a reaching start, the target heading may be a bearing to a waypoint in the journey, or a predetermined bearing that optimises the acceleration of the sailing boat towards a waypoint on the journey.

Since boundary indicia 406 represents a locus of predicted locations of where the sailing boat will be at a target time, overlaying the boundary indicia 406 with the location of the destination 402 advantageously enables the identification of the point, or points, of intersection between the boundary 406 and the destination. In embodiments where the destination is a defined point, only a single point of intersection will exist. These points of intersection represent the locations where the sailing boat is predicted to arrive at the destination exactly at the target time.

The system may be further configured to calculate a position on each predicted route whereby the sailing boat will achieve a target boat speed based on known parameters, such as acceleration parameters for the boat and the ambient wind conditions. Each of these locations can define an auxiliary boundary 407 which in turn defines a first zone 408 that indicates the locations where the sailing boat 401 will achieve the target boat speed. In some embodiments, a plurality of different target boat speeds may be used whereby the system defines a plurality of auxiliary boundaries, each auxiliary boundary corresponding to a different target speed.

Accordingly, the graphical elements shown in display 400 provide an intuitive way to make strategic decisions during a sailing race in a time efficient manner. For example, a helmsman or other user of the system may easily identify the following information with certainty from the example display shown in figure 4: * firstly, if the sailing boat 401 proceeds along predicted routes 404f or 404g then it will arrive at the destination before a target time, i.e. too early, because the section of the boundary 406 corresponding to those predicted routes is located on the opposite side of the destination 402 from the sailing boat 401.

* secondly, if the sailing boat 401 proceeds along predicted routes 404a to 404d or 404i or 404j, then the sailing boat will not arrive at the destination by the target time because the section of the boundary 406 corresponding to those predicted routes is located on the same side of the destination 402 as the sailing boat 401; * thirdly, the sailing boat 401 can accelerate to a target speed by a target time by following predetermined routes 404a to 404e. However, due to the prevailing wind direction, the sailing boat will decelerate on predicted routes 404f to 404j to such an extent that the sailing boat will not achieve the target speed by the target time; and * finally, the sailing boat 401 can arrive at the destination exactly on time by following either predicted route 404e or predicted route 404h. However, the sailing boat 401 can only arrive at the destination at the target time and at the target speed by following predicted route 404e.

Figure 5 illustrates a second example graphic user interface display 400 for guiding a sailing boat to a destination during a port upwind start to a race in accordance with an embodiment of the invention. For consistency, equivalent features are denoted with the same reference numerals in figure 5 as for figure 4.

In the example of figure 5 it is possible to derive the following: * firstly, if the sailing boat 401 proceeds along predicted routes 404a to 404f then it will arrive at the destination before a target time, i.e. too early.

* secondly, if the sailing boat 401 proceeds along predicted routes 404g to 404j then the sailing boat will not arrive at the destination by the target time; * thirdly, the sailing boat 401 will achieve a target speed at the target time if the sailing boat proceeds to follow predicted routes 404e to 404j. Due to the prevailing wind direction, the sailing boat will decelerate on predicted routes 404a to 404d to such an extent that it will no longer travel at a target speed; and * finally, it is possible to arrive at the destination at the target time and at a target speed by following a route between predicted routes 404f and 404g.

Accordingly, if the sailing boat 401 does not change heading from the current heading 403 then the sailing boat 401 is predicted to achieve the target speed but will not arrive at the destination 402 before the target time.

Figure 6 illustrates a third example graphic user interface display 400 for guiding a sailing boat to a destination during a starboard reaching start to a race in accordance with an embodiment of the invention. For consistency, equivalent features are denoted with the same reference numerals in figure 6 as for figures 4 and 5.

In the embodiment shown in figure 6, layline 409 is displayed extending from a downwind marker 410 that defines the termination of the start line at the destination 402.

In the example of figure 6 it is possible to derive the following: * firstly, since no section of boundary 406 is located on the opposite side of the destination 402 from the sailing boat 401, it is not possible for the sailing boat 401 to arrive early; * secondly, if the sailing boat 401 proceeds along predicted routes 404a to 404c or predicted routes 404e to 404j then the sailing boat will not arrive at the destination 402 at the target time; * thirdly, the sailing boat 401 will achieve a target speed at the target time if the sailing boat proceeds to follow predicted routes 404a to 404h. Due to the prevailing wind direction, the sailing boat will decelerate on predicted routes 404i and 404j to such an extent that it will no longer travel at a target speed; and * finally, it is possible to arrive at the destination exactly at the target time and at a target speed by proceeding along predicted route 404d.

Figure 7 illustrates a fourth example graphic user interface display 400 for guiding a sailing boat to a destination during a port reaching start to a race in accordance with an embodiment of the invention. For consistency, equivalent features are denoted with the same reference numerals in figure 7 as for figures 4 to 6.

* firstly, since no section of boundary 406 is located on the opposite side of the destination 402 from the sailing boat 401, it is not possible for the sailing boat 401 to arrive early; * secondly, the sailing boat 401 cannot arrive at the destination 402 at the target time regardless of which route is selected and so will inevitably arrive late; and * finally, the sailing boat 401 will achieve a target speed at the target time if the sailing boat proceeds to follow predicted routes 404c to 404j. Due to the prevailing wind direction, the sailing boat will decelerate on predicted routes 404a and 404b to such an extent that it will no longer travel at a target speed by the target time.

Further to the embodiments shown in figures 4 to 7, in some embodiments the system does not perform calculations for a plurality of predicted routes. Instead, the system only calculates a single predicted route which is used to define a boundary that indicates whether the sailing boat 301 will arrive at the destination 302 early, late, or at the target time. This advantageously allows the system to operate on devices with poor computational power, such as smart watches. In these embodiments, the visual representation of the route described above may be in the form of a line where the destination, boundary and current location of the sailing boat are positioned relatively on the line. In this embodiment, the line extends from the current boat location for a first distance, where the first distance represents how far the boat is calculated to travel on the predicted route within the time left until the target time. Accordingly, over time the first distance will get smaller as the time until the target time diminishes. The boundary described above is located at the end of the line distal to the current boat location. The destination is positioned a second distance from the current sailing boat location, where the second distance and the first distance are calculated with the same scaling factor. Accordingly, if the first distance and the second distance are the same then the sailing boat is predicted to arrive at the destination at the target time. In other words, the relative locations of the boundary and the destination indicate whether the boat will arrive early or late.

The boundary indicia described above are calculated as further described below with reference to figure 8, which is an example flowchart illustrating how on-board data may be used to produce the example graphical display shown in figures 4 to 7.

In the example flowchart of figure 8, on-board data is measured and collected in step 801. For example, the sensors 109 may collect data for the boat speed, apparent wind direction and apparent wind speed. Apparent wind is the wind experienced by an observer in the same frame of reference as the sail boat. The apparent wind speed and direction are therefore easily measured by on board instruments. However, as is well known in the art, a component of the apparent wind speed and direction is caused by the sailing boats motion and so the measured apparent wind is not a suitable measurement for use in all calculations. The apparent wind will vary considerably, for example whether the boat is sailing upwind or downwind, whereas the true wind is not affected by the boat's course. It is therefore preferable to perform calculations using the true wind, which is relatively stable, rather than the readily measured apparent wind.

In step 802, the true wind direction and speed may be calculated in ways known in the art.

For example, a vector analysis of the boat speed, apparent wind direction and apparent wind speed may be performed, thereby deriving the true wind direction and true wind speed. Alternatively, the true wind speed and true wind direction may be derived from the following mathematical formula: V7-mr = I [V Aw Sill(BAw)12 [VAw COS(BA,") -boad2 Brw = arctan F vAw cos(BAw) -vboat Where: vTW is the true wind speed; vAW is the apparent wind speed; vboat is the boat speed; TW is the true wind direction; and HAW is the apparent wind direction.

In step 803, the predicted boat speed is identified. The predicted boat speed may be based on the calculated true wind and a database of stored data. Alternatively, the predicted boat speed may be derived from data gathered by on board sensors. Further, the predicted boat speed may be manually input by a user of the system. This advantageously allows the system to operate when data cannot be retrieved over a network 250, or where sensors have not been fitted to the sailing boat.

vA w sin (BA w) In some embodiments, the stored data includes polar data, which is known in the art to be performance related information for a particular boat in different wind conditions. In particular, polar data provides a boat's optimum speed for given wind speeds and wind angles. This data is usually displayed as a graph plotted in polar coordinates where the radial and angular components of the polar plot are the true wind speed and true wind direction respectively. The optimum boat speed for a given true wind direction and speed may be obtained by inspection from the polar plot or by graphical solution.

In some embodiments, multiple databases of polar data may be utilised. For example, some sailing boats may be configured in a number of different ways to ensure that the performance of the boat can be adapted to different conditions. Accordingly, each boat configuration may be associated with a different database of polar data containing performance related data for the particular configuration.

Polar data may be obtained from a variety of sources, for example through computer modelling or by gathering and storing a dataset of boat performance.

The stored data may also include tide maps containing data associated with local tidal patterns, such as how the speed and direction of the water flow changes with time for a given locality. As a destination may be fixed to the ground, fides and currents will cause the body of water and therefore also the boat, to move relative to the destination Tide data can be used in ways known in the art to predict boat speed and direction relative the ground.

The stored data may also include wind maps containing data associated with measured, predicted or observed wind patterns, which may also be used in the calculation.

In alternative embodiments, the optimum boat speed is calculated from GPS data. GPS data may contains COG and SOG or alternatively, recording the GPS data of a sailing boat will provide a history of the latitude and longitude of the sailing boat over time. Analysis of the latitude and longitude can identify the average speed the sailing boat has travelled at, known as the speed over ground (SOG), and the direction of travel of the sailing boat, known as the course over ground (COG). Other instrumentation can provide heading data.

The average wind direction may be estimated using the COG or heading if the boat is sailing at a known or input angle to the wind In another embodiment, the user may manually input data to obtain an optimum boat speed. For example, the user may input a boat speed to be used as the predicted boat speed for calculations.

In step 804, the system calculates a predicted route associated with a given bearing. In preferred embodiments, the predicted route originates at the current location of the sailing boat and is calculated using route metrics, as described above. The length of the route is calibrated according to the target time. For embodiments where the destination is a starting position, the target time may be the time left until the start of the race. However, for embodiments where the destination is a finishing position or an intermediate waypoint during the race, the target time may be the time the sailing boat would take to arrive at the destination while sailing on the current bearing of the sailing boat. Accordingly, the predicted route indicates the distance that the sailing boat is predicted to sail according to the route within the target time.

In step 805 the system repeats the calculation of step 804 for all likely bearings that the sailing boat is likely to take when travelling to the destination. Therefore, in step 805 the system calculates a plurality of predicted routes which indicate how far the sailing boat could travel towards the destination in an amount of time equal to the target time. The system only performs calculations for a selection of bearings that the sailing boat is likely to take. For example, sailing boats will typically approach a destination from one known direction due to the layout of the race course. Performing calculations for approaching the destination from the other direction would therefore not be useful to the helmsman. The calculations may therefore be performed using one hemisphere of all possible bearings.

Additionally, as sailing boats cannot sail directly into the wind, certain bearings may be improbable, undesirable or impossible and so the system need not perform calculations for those bearings. Accordingly, there is a range of bearings which may be used by the system. In some embodiments, the range of bearings is approximately 150 degrees.

However, it will be appreciated that this range of bearings will vary, for example due to different sailing boat configurations. To save processing power, in some embodiments the system may only calculate routes associated with bearings at predefined intervals, rather than calculating a route for each bearing within the range of bearings. In specific embodiments, the calculated routes are associated with bearings at an interval of between 1 to 30 degrees. This means that, over a range of 150 degrees, the number of calculations performed may vary between 150 and 5 computations. In preferred embodiments, the calculated routes are associated with bearings at an interval of 5 degrees.

In step 806 the system identifies a boundary that joins the end of each predicted route calculated in step 805 that is distal to the sailing boat. Since the boundary connects locations that each define where a sailing boat may arrive within the same target time, the boundary may be known as an isochronic line.

In step 807 the system displays a boundary indicia on a user interface which shows the location of the calculated boundary to a user.

In some embodiments, the system also displays the boat's current location on the user interface relative to the calculated boundary in step 808. This allows the user to identify the relative difference between the calculated boundary and the current location of the boat and use that knowledge to tactically position the sailing boat as described above. However, it will be understood that the boat location may not always be displayed, for example in embodiments where AR headsets are used as a display.

Finally, in step 809 the system repeats the above steps periodically in time to update the relative positions between the boat's current location and the calculated boundary. In some embodiments, the calculations are performed at a frequency sufficient to provide a smooth animated graphic without consuming too much computer memory. For example, in a specific embodiment, the calculations are performed at a frequency of several times per second to provide real-time information to the helmsman.

As will be appreciated by one of skill in the art, the invention described herein may be embodied in whole or in part as a method, a data processing system, or a computer program product including computer readable instructions. Accordingly, the invention may take the form of an entirely hardware embodiment or an embodiment combining software, hardware and any other suitable approach or apparatus.

While the invention has been described above in detail with reference to various specific embodiments, it will be appreciated by those skilled in the art that various modifications may be made to those embodiments without departing from the scope of the appended claims.

Claims

CLAIMS1. A navigation guidance system for a sailing boat, comprising: a location module for identifying a current location associated with the sailing boat; a timing module configured to identify a target time for the sailing boat to arrive at a destination at a predetermined bearing; a database configured to receive and store a predicted boat speed that is based on input data; a calculation module configured to periodically calculate a predicted route associated with a bearing wherein the predicted route comprises a first path onto the bearing and a second path from the bearing onto the predetermined bearing and wherein the length of the predicted route is defined by the target time and the predicted boat speed; a processor configured to define a first boundary defined at least in part by the end of the predicted route distal to the current location; and a display configured to display a visual representation of the first boundary, the predicted route, the current location of the sailing boat, and the location of the destination.
2. The navigation guidance system of claim 1, wherein the calculation module calculates a predicted route for each of a plurality of bearings, or wherein the calculation module is further configured to periodically calculate a location associated with the predicted route where the predicted boat speed will reach or exceed the target boat speed, or wherein each calculated location defines an auxiliary boundary beyond which the sailing boat is predicted to achieve or exceed the target boat speed, or wherein the display is further configured to display a visual representation of the auxiliary boundary.
3. The navigation guidance system of claim 1, wherein the predicted boat speed is compared to a target boat speed.
4 The navigation guidance system of claim 1, wherein the calculation module is initiated by a trigger event, or wherein the trigger event is a predefined time or a predetermined proximity to the destination.
5. The navigation guidance system of claim 1, wherein the predicted boat speed is obtained from performance related information for the boat, or wherein the predicted boat speed is a near-instantaneous boat speed determined using input data, or wherein the predicted boat speed is determined by calculating a true wind speed and a true wind direction from the input.
6. The navigation guidance system of claim 1, wherein one or more boat performance configurations are adjusted in response to the displayed visual representation.
7. The navigation guidance system of claim 1, wherein the display forms part of a computing device, preferably wherein the computing device is a desktop computer, a laptop computer, a tablet computer, a personal digital assistant, a mobile telephone, a smartphone, a smart watch or a pair of smart glasses, or wherein the display forms part of an augmented reality system.
8. The navigation guidance system of any preceding claim wherein the input data is provided manually, or further comprising sensors for at least partially providing input data, or further comprising a communication source for at least partially providing input data, or wherein the display further comprising an interactive portion for at least partially providing input data, or wherein the input data comprises wind data and/or boat speed data.
9. The navigation guidance system of any preceding claim, wherein the predicted route is calculated based on known route parameters associated with the route, or wherein the known route parameters include one or more scaling parameters, route curvature parameters and/or acceleration or deceleration parameters.
10. The navigation guidance system of any preceding claim wherein the destination is a boundary line, a waypoint on a journey or a specified location, or wherein the display is further configured to display a visual representation of the destination, or wherein the one or more points of intersection between the destination and the first boundary define the locations where the sailing boat is predicted to arrive at the destination exactly at the target time, or wherein the boundary is an isochronic line associated with the target time.
11. A navigation guidance method for a sailing boat, comprising: identifying the current location associated with the sailing boat; identifying a target time for the sailing boat to arrive at a destination at a predetermined bearing; obtaining a predicted boat speed based on input data; periodically calculating a predicted route associated with a bearing, the predicted route comprising a first path onto the bearing and a second path from the bearing onto a predetermined bearing and wherein the length of the predicted route is calculated based on the target time and the predicted boat speed; displaying a first boundary defined at least in part by the end of the predicted route distal to the current location, the predicted route, the current location of the sailing boat, and the location of the destination.
12. The navigation guidance method of claim 11, further comprising calculating a predicted route for each of a plurality of bearings, or further comprising periodically calculating a location associated with the predicted route where the predicted boat speed will reach or exceed the target boat speed, wherein each calculated location defines an auxiliary boundary beyond which the sailing boat is predicted to achieve or exceed the target boat speed, or further comprising displaying a visual representation of the auxiliary boundary.
13. The navigation guidance method of claim 11, further comprising comparing the predicted boat speed to a target boat speed.
14. The navigation guidance method of claim 11, wherein the step of periodically calculating a predicted route associated with a bearing is initiated by a trigger event, or wherein the trigger event is a predefined time or a predetermined proximity to the destination.
15. The navigation guidance method of claim 11, further comprising obtaining the predicted boat speed from performance related information for the boat, or wherein the predicted boat speed is a near-instantaneous boat speed determined using input data, or preferably wherein the predicted boat speed is determined by calculating a true wind speed and a true wind direction from the input data.
16. The navigation guidance method of claim 11, further comprising adjusting one or more boat performance configurations in response to the displayed visual representation.
17 The navigation guidance method of claim 11, wherein the step of displaying the first boundary is performed with a computing device, preferably wherein the computing device is a desktop computer, a laptop computer, a tablet computer, a personal digital assistant, a mobile telephone, a smartphone, a smart watch or a pair of smart glasses, or wherein the step of displaying the first boundary is performed with an augmented reality system.
18. The navigation guidance method of any of claims 11 to 17 further comprising manually providing the input data, or further comprising at least partially providing input data from sensors, or further comprising at least partially providing input data from a communication source, or further comprising at least partially providing input data from an interactive portion of a display, or wherein the input data comprises wind data and/or boat speed data.
19. The navigation guidance method of any of claims 11 to 18, further comprising calculating the predicted route based on known route parameters associated with the route, or wherein the known route parameters include one or more scaling parameters, route curvature parameters and/or acceleration or deceleration parameters.
20. The navigation guidance method of any of claims 11 to 19 wherein the destination is a boundary line, a waypoint on a journey or a specified location, or further comprising displaying a visual representation of the destination, or further comprising defining the locations where the sailing boat is predicted to arrive at the destination exactly at the target time with the one or more points of intersection between the destination and the first boundary, or wherein the boundary is an isochronic line associated with the target time.