WO2001029512A1

WO2001029512A1 - Improvements in or relating to vehicle navigation

Info

Publication number: WO2001029512A1
Application number: PCT/GB2000/004035
Authority: WO
Inventors: Jonathan Elwin Lincoln Bowes
Original assignee: JFDI ENGINEERING Ltd
Current assignee: JFDI ENGINEERING Ltd
Priority date: 1999-10-19
Filing date: 2000-10-19
Publication date: 2001-04-26
Anticipated expiration: 2002-04-19
Also published as: AU7934600A; GB9924554D0

Abstract

A vehicle navigation aid (10) operable to enable a vehicle to travel between two waypoints in a time not less than a minimum permissible time, the navigation aid (10) comprising a positioning means (14) operable to determine the position of the vehicle, a memory (16) containing the positions of one or more waypoints, and information relating to the minimum permissible time for the vehicle to travel between waypoints, and a processor (18), the processor (18) being operable to monitor the position of the vehicle relative to the one or more waypoints and the time taken for the vehicle to travel between waypoints, the processor (18) further being operable to alert the driver of the vehicle if the vehicle is in danger of travelling between said waypoints in a time less than the minimum permissible time.

Description

IMPROVEMENTS IN OR RELATING TO VEHICLE NAVIGATION

The present invention relates to vehicle navigation and in particular to assisting with the regulation of the speed of a vehicle when it is travelling.

For most vehicles whether they travel on land, sea or air, there exist certain conventions governing their operation which are in place to ensure the safety of the vehicle, its occupants, and others who happen to be in the vicinity of the vehicle when it is travelling. An example of such a convention is the imposition of vehicle speed limits on roads and waterways.

Exceeding a given speed limit may have consequences not readily apparent to the vehicle operator or occupants. Taking the example of cross-channel ferries, the sub sea geography of the English Channel is such that there exist sand bars and other areas of relatively shallow water at or near harbour entrances. While the depth of water over these sub sea features is sufficient so as to present no danger to a ferry as it passes, the water displaced by the motion of the ferry can interact with the features to create a phenomena known as a standing wave. Research has shown that the wake generated by a moving ship can build up to a wave of considerable size if the wake moves into a region of relatively shallow water. The wave thus generated can be a danger to others and it is not unknown for smaller water craft to be swamped and or sunk unexpectedly by such waves.

As to whether or not a standing wave will be generated depends on a number of factors including the speed of the ferry, the prevailing wind and tide conditions, and the depth of the water. However, it is widely recognised that by moderating the speed of the ferry in the vicinity of sub sea features likely to generate a standing wave greatly reduces the chances of one being created. According to a first aspect of the present invention there is provided a method of navigating a vehicle so as to enable it to travel between two waypoints in a time not less than a minimum permissible time, the method comprising the steps of: providing a vehicle with a navigation system operable to determine the position of the vehicle, the navigation system containing the positions of one or more waypoints, and information relating permissible vehicle speeds at and/or between said waypoints; calculating a maximum permissible vehicle speed between a first and a second waypoint; calculating the actual speed of the vehicle as it travels between said first and second waypoints; and generating sufficient information relating to any difference between the actual and maximum permissible vehicle speeds to enable the vehicle speed to be changed before arrival at said second waypoint in order that the time taken for the vehicle to travel between the waypoints is not less than the minimum permissible time.

The present invention is operable to assist the operator of a vehicle in maintaining predetermined speeds during the course of a journey so as enhance the safe operation the vehicle, the safety of the vehicle occupants and the environment surrounding the vehicle as it travels. The maximum permissible vehicle speed may be a legal requirement, for example a motorway speed limit, or derived from a function of the vehicle such as the loading of the vehicle or the experience of the vehicle operator.

The method may include the step of storing in the navigation system the distances between the waypoints. Such a step may be required where the vehicle is required to follow a route which is not a straight line between the waypoints, for example along a motorway. Where the route is a straight line, e.g. between two points on an open body of water, the distance therebetween can be calculated relatively easily by the navigation system.

Many vehicles today are provided with equipment which enables them to receive positional data from the network of satellites which form part of the Global Positioning System (GPS). GPS data can be used to determine with reasonable accuracy the position of the vehicle on the surface of the planet and, if required, the vehicle's elevation above sea level. GPS systems are fitted as standard to most commercial, recreational and military aircraft, commercial ships, ferries and pleasure craft. It increasingly common to find GPS systems fitted to cars and other road going vehicles.

Accordingly the navigation system may utilise GPS data to determine the position and direction of travel of the vehicle, and to assist in calculating the speed of the vehicle between waypoints.

In a preferred embodiment the step of calculating the average speed of the vehicle as it passes between waypoints includes the steps of; providing a timer; activating the timer as the vehicle passes the first of said waypoints; calculating from the timer and navigation system the estimated time of arrival of the vehicle at the next waypoint; and calculating the average speed of the vehicle between the waypoints.

In such an embodiment the method may also include the steps of: calculating a target time needed for the vehicle to pass a second of said waypoints at a maximum permissible speed; comparing the target time with the estimated time of arrival; and using any difference between the target time and estimated time of arrival as a basis for generating the information needed to change the vehicle speed.

In a further preferred embodiment the method includes the step of updating the information stored in the navigation system prior to the vehicle commencing a journey. Such updating may be achieved by any suitable means including wireless transmission, manual data input or the downloading of data from a data storage means.

The method may also include the step of updating information stored in the navigation system as the vehicle travels between waypoints. Such updated information may advantageously relate to conditions ahead of the vehicle which may affect the speed thereof. For example, the information may relate to the presence slow moving traffic, or a change in a condition of a traffic control signal.

Prior to generating the information to enable the vehicle speed to be altered, the method may include the step of calculating whether sufficient alteration of the vehicle speed can be safely achieved before the vehicle passes the second waypoint. Such a calculation may be based on such factors as the current speed of the vehicle, the distance remaining to the waypoint and/or a maximum permissible deceleration value for the vehicle.

Where the vehicle has an operator in control of the operation of the vehicle, the method includes the step of indication to the operator that the vehicle speed should be altered before the next waypoint is passed. Such indication may take the form of a visual display and/or information relayed audibly to the operator.

In an alternative embodiment the method of navigating a vehicle so as to enable the vehicle to travel between two waypoints in a time not less than a minimum permissible time, may comprise the steps of: providing a vehicle with a navigation system operable to determine the position of the vehicle, the navigation system containing the positions of two or more waypoints, and information relating the minimum permissible time for the vehicle to travel between waypoints; monitoring the actual time taken by the vehicle as it travels between said two or more waypoints; and generating sufficient information relating to any difference between the actual and minimum permissible times to enable the vehicle speed to be changed before arrival at said second waypoint in order that the time taken for the vehicle to travel between the waypoints is not less than the minimum permissible time.

The step of monitoring the actual time taken by the vehicle as it passes between waypoints may include the steps of; providing a timer; activating the timer as the vehicle passes a first of said waypoints; calculating from the timer and navigation system an estimated time period for the vehicle to travel between said first and next waypoint; comparing the minimum permissible time with the estimated time period; and using a difference between the minimum permissible time and estimated time period as a basis for generating the information needed to change the vehicle speed. As previously described above the method may include the step of. prior to generating the information to enable the vehicle speed to be altered, calculating whether sufficient alteration of the vehicle speed can be safely achieved before the vehicle passes the second waypoint.

According to a second aspect of the present invention there is provided a vehicle navigation aid operable to enable a vehicle to travel between two waypoints in a time not less than a minimum permissible time, the aid comprising a positioning means operable to determine the position of the vehicle, a memory containing the positions of one or more waypoints, and information relating to the maximum permissible vehicle speeds at and/or between the one or more waypoints, and a processor, the processor being operable to monitor the position of the vehicle relative to the one or more waypoints and to determine the speed of the vehicle between two given waypoints, the processor further being operable to alert the driver of the vehicle if the actual speed of the vehicle between said given waypoints is in danger of exceeding the maximum permissible speed therebetween and hence will travel between the waypoints in a time less than the minimum permissible time.

Alternatively there may be provided a vehicle navigation aid operable to enable a vehicle to travel between two waypoints in a time not less than a minimum permissible time, the navigation aid comprising a positioning means operable to determine the position of the vehicle, a memory containing the positions of one or more waypoints, and information relating to the minimum permissible time for the vehicle to travel between waypoints, and a processor, the processor being operable to monitor the position of the vehicle relative to the one or more waypoints and the time taken for the vehicle to travel between waypoints, the processor further being operable to alert the driver of the vehicle if the vehicle is in danger of travelling between said waypoints in a time less than the minimum permissible time. In such an embodiment the minimum permissible times between waypoints may be stored in the memory of the navigation aid in the form of, for example, a register or look-up table.

The apparatus may be adapted to receive information while travelling between waypoints, said information relating to conditions ahead of the vehicle which may affect both the maximum permissible speed between the waypoints and the average speed of the vehicle. Taking the example of apparatus adapted for use with a road vehicle, information relating to traffic congestion may be transmitted to the apparatus. Alternatively the apparatus may be adapted to receive advance warning that an approaching traffic light is about to change from green to red. The apparatus may be adapted to relay this information to a driver of the vehicle on the display and/or via an audible indication.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 shows a schematic representation of an apparatus according to an aspect of the invention; and Figure 2 shows a flow chart which describes a mode of operation of the apparatus of figure 1.

Referring firstly to figure 1 there is shown a schematic representation of a vehicle navigation device generally designated 10. The embodiment of the device 10 described hereafter is designed for use with road going vehicles such as cars, buses and goods vehicles. The device 10 comprises a display unit 12, a GPS receiver 14 having a memory 16, a processor 18 and a timer 20. The display unit 12 is provided within the vehicle at a position where it can readily be seen by the driver of the vehicle. The remaining components of the device 10 are positioned at a secure location within the vehicle, for example in the boot. The GPS receiver 14 is operable to determine the latitude and longitude of the vehicle, while the memory 16 contains the pre-programmed co-ordinates of waypoints which the vehicle may pass by during a journey. The waypoints may correspond to the position of roadside features such as bridges or service areas, traffic lights or sign posts indicating changes in the maximum permissible speed on a given stretch of road. The memory 16 also contains road information which includes the maximum permissible vehicle speed in the vicinity of the waypoints. The processor 18 is adapted to receive co-ordinates form the GPS receiver 14 and memory 16, and data from the timer 20 when it is activated. The processor 18 is linked to the display unit 12 so as to be able to present information to the vehicle driver.

Operation of the above device 10 will now be described with reference to the flow chart of figure 2. The components of the flow cart are numbered 22 to 46 with the numbers representing the following statements:

22 - System power up

24 - Update memory

26 - Start timer to coincide with commencement of journey?

28 - Start timer when vehicle reaches first waypoint 30 - Establish direction of travel and log next waypoint co-ordinates.

32 - Calculate target time for arrival at next waypoint.

34 - Estimate actual time of arrival at next waypoint.

36 - Is vehicle within threshold distance of next waypoint?

38 - Is estimated time of arrival at next waypoint within an acceptable band? 0 - Has driver been alerted? 2 - Is vehicle within a safety distance when warnings would be no longer appropriate? 4 - Inform driver of the amount by which the vehicle speed should be increased/decreased and the distance remaining to the next waypoint. 6 - Log the time as the vehicle passes the waypoint. Taking the example of a system fitted to a car, system power up may be effected when the ignition is switched on. The next optional step is the updating of the system to renew information relating to the position of the waypoints and the permissible speeds in the vicinity of the waypoints. For example, a stretch of road works may have been introduced at a position between two waypoints and a temporary speed restriction imposed. Alternatively the co-ordinates of a waypoint may have changed, or more waypoints may have been added. Updating of the system may be achieved by any suitable means, for example data bay be inputted from a smart card, via a wireless communication link, or manually.

As the journey commences the driver of the vehicle is prompted as to whether or not monitoring of the vehicle's speed is required from the commencement of the journey to a first waypoint. Taking the case where such initial speed monitoring is not required, the system begins to monitor the position of the vehicle relative to that of the waypoints stored in the memory. As the vehicle passes a waypoint, for example a motorway bridge, the timer is initiated. The processor 18 then calculates from positional data supplied by the GPS unit 14 the direction of travel of the vehicle and the next waypoint to be visited. The processor then calculates the distance between the waypoint the vehicle has just passed and the next waypoint and, using the maximum permissible speed information stored in the memory, calculates the time of arrival of the vehicle if the maximum permissible speed is maintained between the waypoints. This time will hereinafter be referred to as the target time.

Next, the processor 18 calculates the estimated time of arrival of the vehicle at the next waypoint based on the current speed of the vehicle. This may be achieved by a number of methods including, for example, noting the position of the vehicle at predetermined time intervals using the GPS unit 14 and then calculating the speed between the two positions. Alternatively, readings may be taken from the vehicle odometer at predetermined time intervals. These readings can also be used to calculate the average speed of the vehicle since passing the initial waypoint Once the estimated time of arrival has been calculated, it is compared with the target time and any discrepancy noted. The processor then calculates whether the vehicle is within a threshold distance of the approaching waypoint. The threshold distance, which will be discussed in greater detail below, is dependant upon a number of factors including the maximum permissible speed between the waypoints, the distance between the waypoints, and the deviation of the current vehicle speed from the maximum permissible vehicle speed.

It is well known that accidents can be caused the attention of a driver being distracted. To this end the system will only alert the driver when as the vehicle approaches a waypoint so as to not unduly distract the driver. Taking the example of a vehicle travelling between waypoints spaced 20 kilometres apart on a stretch of road where the speed limit is 100 kilometres per hour, the threshold distance may be 5 kilometres if the average speed of the vehicle is calculated to be 110 kilometres per hour, or 7 kilometres if the average speed is calculated to be higher. If the vehicle is not within the threshold distance, the processor 18 continues to calculate the vehicle's average speed, estimated time of arrival and the threshold distance to the next waypoint.

If, however the processor 18 calculates the vehicle to be within the threshold distance, then the current deviation between the target time and estimated time of arrival is examined to see whether or not it falls into an acceptable band. If the estimated time of arrival is deemed acceptable, the processor 18 continues to calculate the vehicle's average speed, estimated time of arrival and the threshold distance to the next waypoint.

If, on the other hand, the estimated time of arrival is deemed not acceptable, i.e. the vehicle is travelling too fast and the average speed of the vehicle when it passes the next waypoint would be greater than the maximum permissible speed between the waypoints, the processor 18 then acts to alert the driver.

The display 12 in the vehicle indicates to the driver that the vehicle's speed should be changed. This may be done either by telling the driver the amount by which the speed should be increased or decreased, or alternatively displays a target vehicle speed which should be matched by the driver. Optionally the display may indicate the distance remaining to the approaching waypoint. In addition to a visual indication to the driver, the display may produce an audible signal. This may take the form of a computerised voice which states that the vehicle speed needs to be modified and the amount by which it should be changed.

As the vehicle passes the waypoint the processor 18 logs the time from the timer 20, and restarts the procedure as the vehicle moves towards the next waypoint.

Before the processor 18 alerts the driver that a change in the vehicle speed is required, it first calculates whether any such change could be safely achieved by the vehicle in the time and distance remaining to the approaching waypoint. It will be well understood that sudden braking or acceleration of a road vehicle can be a danger to the vehicle itself and to other road users. To this end, the processor 18 calculates a safety distance from the approaching waypoint and if the vehicle is determined to be within this distance then no warning will be displayed to the driver. The safety distance may be a set distance or alternatively may be calculated by the processor 18 and dependent upon the vehicle speed. In undertaking such a calculation, the processor may be programmed with maximum safe deceleration value for the vehicle, with the safety distance being calculated such that the required deceleration of the vehicle is equal to or less than the safe value. Taking the examples given above for a possible threshold distance, the safety distance may be 200 metres from the waypoint.

Turning now to a system adapted for use with water craft and directed to the prevention of standing waves as described above, the waypoints in the memory would correspond to the co-ordinates of shallow water areas along the intended path of the craft. In such case the memory would include data relating to the tide state and hence the expected depth of water at and between the waypoints. Updating of the information prior to the craft leaving port would be required to take into account other factors including, for example, weather conditions which could affect the water depth, any reported changes in the position of sub sea features such as sand bars, and the displacement of the .craft due to the cargo onboard. From such information the processor 18 can calculate a maximum average speed for traversing a given stretch of shallow water which will greatly reduce the chances of a standing wave being generated.

Claims

1. A method of navigating a vehicle so as to enable the vehicle to travel between two waypoints in a time not less than a minimum permissible time, the method comprising the steps of: providing a vehicle with a navigation system operable to determine the position of the vehicle, the navigation system containing the positions of one or more waypoints, and information relating permissible vehicle speeds at and/or between said waypoints; calculating a maximum permissible vehicle speed between a first and a second waypoint; calculating the actual speed of the vehicle as it travels between said first and second waypoints; and generating sufficient information relating to any difference between the actual and maximum permissible vehicle speeds to enable the vehicle speed to be changed before arrival at said second waypoint in order that the time taken for the vehicle to travel between the waypoints is not less than the minimum permissible time.

2. A method as claimed in claim 1 wherein the navigation system includes information relating to the distances between the waypoints.

3. A method as claimed in claim 1 or claim 2 wherein the navigation system utilises GPS data to determine the position and direction of travel of the vehicle, and to assist in calculating the speed of the vehicle between waypoints.

4. A method as claimed in any preceding claim wherein the step of calculating the average speed of the vehicle as it passes between waypoints includes the steps of; providing a timer; activating the timer as the vehicle passes the first of said waypoints; calculating from the timer and navigation system the estimated time of arrival of the vehicle at the next waypoint; and calculating the average speed of the vehicle between the waypoints.

5. A method as claimed in claim 4 and including the steps of: calculating a target time needed for the vehicle to pass a second of said waypoints at a maximum permissible speed; comparing the target time with the estimated time of arrival; and using a difference between the target time and estimated time of arrival as a basis for generating the information needed to change the vehicle speed.

6. A method of navigating a vehicle so as to enable the vehicle to travel between two waypoints in a time not less than a minimum permissible time, the method comprising the steps of: providing a vehicle with a navigation system operable to determine the position of the vehicle, the navigation system containing the positions of two or more waypoints, and information relating the minimum permissible time for the vehicle to travel between waypoints; monitoring the actual time taken by the vehicle as it travels between said two or more waypoints; and generating sufficient information relating to any difference between the actual and minimum permissible times to enable the vehicle speed to be changed before arrival at said second waypoint in order that the time taken for the vehicle to travel between the waypoints is not less than the minimum permissible time.

7. A method as claimed in claim 6 wherein the navigation system utilises GPS data to determine the position and direction of travel of the vehicle.

8. A method as claimed in claim 6 or claim 7 wherein the step of monitoring the actual time taken by the vehicle as it passes between waypoints includes the steps of; providing a timer; activating the timer as the vehicle passes a first of said waypoints; calculating from the timer and navigation system an estimated time period for the vehicle to travel between said first and next waypoint; comparing the minimum permissible time with the estimated time period; and using a difference between the minimum permissible time and estimated time period as a basis for generating the information needed to change the vehicle speed.

9. A method as claimed in claim 8 including the step of, prior to generating the information to enable the vehicle speed to be altered, calculating whether sufficient alteration of the vehicle speed can be safely achieved before the vehicle passes the second waypoint.

10. A method as claimed in any preceding claim including the step of updating the information stored in the navigation system prior to the vehicle commencing a journey.

11. A method as claimed in claim 10 wherein updating of the information stored in the navigation system is achieved by wireless transmission

12. A method as claimed in claim 10 wherein updating of the information stored in the navigation system is achieved by manual data input

13. A method as claimed in claim 10 wherein updating of the information stored in the navigation system is achieved by the downloading of data from a data storage means.

14. A method as claimed in any preceding claim including the step of updating information stored in the navigation system as the vehicle travels between waypoints.

15. A method as claimed in any preceding claim including the step of indicating to an operator of the vehicle that the vehicle speed should be altered before the next waypoint is passed.

16. A method as claimed in claim 15 wherein said indication takes the form of a visual display

17. A method as claimed in claim 15 or claim 16 wherein the indication takes the form of information relayed audibly to the operator.

18. A vehicle navigation device operable to enable a vehicle to travel between two waypoints in a time not less than a minimum permissible time, the navigation device comprising a positioning means operable to determine the position of the vehicle, a memory containing the positions of one or more waypoints, and information relating to the maximum permissible vehicle speeds at and/or between the one or more waypoints, and a processor, the processor being operable to monitor the position of the vehicle relative to the one or more waypoints and to determine the speed of the vehicle between two given waypoints, the processor further being operable to alert the driver of the vehicle if the actual speed of the vehicle between said given waypoints is in danger of exceeding the maximum permissible speed therebetween and hence will travel between the waypoints in a time less than the minimum permissible time.

19. A vehicle navigation device operable to enable a vehicle to travel between two waypoints in a time not less than a minimum permissible time, the navigation device comprising a positioning means operable to determine the position of the vehicle, a memory containing the positions of one or more waypoints, and information relating to the minimum permissible time for the vehicle to travel between waypoints, and a processor, the processor being operable to monitor the position of the vehicle relative to the one or more waypoints and the time taken for the vehicle to travel between waypoints, the processor further being operable to alert the driver of the vehicle if the vehicle is in danger of travelling between said waypoints in a time less than the minimum permissible time.

20. A vehicle navigation device as claimed in claim 18 or claim 19 wherein the positioning means are a GPS positioning means.

21. A vehicle navigation device as claimed in any of claims 18 to 20, the navigation device including a timer operable to monitor the time taken for the vehicle to travel between waypoints.

22. A vehicle navigation device as claimed in any of claims 18 to 21, the navigation device including indication means adapted to communicate to an operator of the vehicle that the speed of the vehicle should be altered before the next waypoint is passed.

23. A vehicle navigation device as claimed in claim 22 wherein the indication means include a visual display.

24. A vehicle navigation device as claimed in claim 22 or claim 23 wherein the indication means are operable to provide an audible indication to the operator of the vehicle.

25. A vehicle navigation device as claimed in any of claims 18 to 24 wherein the navigation device is adapted to receive information while travelling between waypoints, said information relating to conditions ahead of the vehicle which may affect one or more of the following: the maximum permissible speed between the waypoints, the average speed of the vehicle, the minimum permissible time to travel between waypoints, and the actual time to reveal between waypoints.