GB2544992A

GB2544992A - Navigation system

Info

Publication number: GB2544992A
Application number: GB1521263.2A
Authority: GB
Inventors: Recktenwald Benedict
Original assignee: Bentley Motors Ltd
Current assignee: Bentley Motors Ltd
Priority date: 2015-12-02
Filing date: 2015-12-02
Publication date: 2017-06-07
Anticipated expiration: 2035-12-02
Also published as: GB201521263D0; GB2544992B

Abstract

A navigation system receives classes of user-inputted intermediate destinations to visit between a start position and a final destination. The system defines an area in which to search for intermediate destinations within the classes, the area may be egg-shaped for example, and then calculates routes via the intermediate destinations. The size of the search area may be increased if low numbers of intermediate destinations are present. The system compares the estimated time to cover the routes via intermediate destinations with an optimal direct route and displays options for various routes via different intermediate destinations within the classes along with the estimated arrival time and a time-cost or penalty of visiting the intermediate destinations. Multiple routes may be presented to the user for their selection and multiple classes of intermediate destination may also be selected. An amount of fuel in a vehicle may prompt a search for fuel stations as an intermediate destination.

Description

Navigation system

Technical Field of the Invention

The present invention relates to a navigation system, such as a satellite navigation system and in particular to a method of selecting a route via one or more points of interest in certain classes.

Background to the Invention

Satellite navigation systems are well known and well used for guiding people, e.g. drivers from point A (usually the current location) to point B. Many such systems are also capable of adding further points to a journey. For example, a driver in Manchester (point A) may set a destination in London (point B) and add an intermediate destination point C, such as a particular restaurant to visit en route, or a certain petrol station on the way.

In certain systems, such as the Google Maps navigation system, if a user types in a class of intermediate destination, eg. “petrol station”, ratherthan specifying a particular petrol station of interest, a list of petrol stations is provided along with brief address details. These petrol stations are not necessarily near to the route and are not shown on the map, making it difficult to decide which petrol station to visit. In some cases, the results produced by the algorithm are off the route by many miles, or are in completely the opposite direction. Moreover, it is difficult to tell what time penalty will be incurred by changing the route to visit the intermediate destination. Furthermore, if a user wishes to travel via two intermediate destinations, say a restaurant and a petrol station, it is necessary to first choose one destination from those offered in the search results, then choose another, each time, without being presented with an visual indication of where the options are. Thus readily ascertaining the time penalty for stopping at the various possible intermediate destinations is impossible. US2010/0268449 discloses a system in which intermediate destinations within chosen classes can be added to a route, and can be selected according to whether they are in certain areas, specifically, near the user’s position, near the destination, within a “city vicinity” or along the route, i.e. in a corridor within a predetermined distance of the already defined route. If a plurality of intermediate destinations are to be added, they are added stepwise, with one being chosen, added to the route, and then the search for the next class beginning again, using the new route as the basis. If the distance of the route would be significantly increased by the addition of a further destination, the user is notified and may choose not to add the further intermediate destination.

Summary of the Invention

According to a first aspect of the invention, there is provided a computer implemented method of calculating a route comprising: receiving a start position and a user inputted final destination; receiving at least one user inputted selection of a first class of intermediate destination; defining an area including the start position and final destination; searching for first potential intermediate destinations withinthat area that fall within the first class; plotting routes from the start position to the final destination via the first potential intermediate destinations; and displaying at least one potential route from the start position to the final destination via one of the first potential intermediate destinations.

The method may display a plurality of potential routes from the start position to the final destination via the first potential intermediate destinations.

This presentation of a plurality of potential routes via various potential intermediate destinations allows the user to determine the optimum route to suit his requirements; for example, if the user has a preference for a particular sub-class of potential intermediate destination, for example, a particular chain of cafes, within the class of “cafes”, the user can choose the route incorporating the potential intermediate destination falling within that sub-class. Alternatively, if the user knows that he/she will wish to break the journey in the middle, he/she can choose the route where the chosen class of intermediate destination is closest to the half-way point.

This represents an improvement both over the methods discussed above, neither of which display a plurality of routes, and which, therefore do not assist the user in determining which route will be optimal for him/her, given the various competing factors, such as total length of time/distance travelled, where/when to break the journey and which potential intermediate destination within the class is optimal.

The method may further comprise receiving at least one user inputted selection of a second class of intermediate destination; searching for second potential intermediate destinations within the area that fall within the second class of second potential intermediate destinations; plotting routes from the start position to the final destination via the first and second potential intermediate destinations; and displaying at least one potential route from the start position to the final destination via at least one of the first potential intermediate destinations and at least one of the second potential intermediate destinations to the user.

The method may comprise displaying a plurality of potential routes from the start position to the final destination via at least one of the first potential intermediate destinations and at least one of the second potential intermediate destinations to the user.

Where both a first and a second class of intermediate destination are required, this technique is particularly effective; this is because the user does not need to first choose one particular first destination within the class, before looking for intermediate destinations within the second class, thus the relative proximity of the two classes can be taken into account, and the constraints of a corridor, does not apply.

Looking within a corridor, or only within the radius of certain points (e.g. home, current position, or final destination) substantially limits the number of routes on offer. The along the route method is also likely, where two intermediate destinations are required, to take the user off the route and then back onto it twice, when a faster/shorter route may be available by not returning to the original route, potentially taking into account destinations in both classes that are close to each other, but which might not even be within the threshold distance of the “along the route” algorithm.

The plurality of routes may comprise the temporally shortest route. The plurality of routes may comprise the spatially shortest route. The plurality of routes may comprise at least two routes including distinct potential intermediate first or second destinations (i.e. at least two options for at least one of the classes of destination). The plurality of routes may comprise at least two routes including distinct potential intermediate first and second destinations.

The method may comprise the step of defining the area based on the geodesic distance between the start position and the final destination. For example, the method may define the area as a rectangle, oval, or egg shape having a length which is a first percentage of the distance between the start position and the final destination and a width which is a second percentage of the distance between the start position and the final position. If the area is defined as egg-shaped, the start position may be at the narrower end - this increases the likelihood of calculating routes which initially head towards the destination, which is preferred by many drivers, who feel like they are not going in the “right direction”, if they initially head away from the final destination, even if the overall distance travelled may be lower.

The first percentage may be defined as at least 110%, it may be at least 120%.

The second percentage may be defined as at least 10%, it may be at least 20%, or at least 40%, such as at least 50%, or at least 75%.

Defining a broad searching area, such as one which has a length of 120% of the distance between the start position and the final destination and a width of 40% of the distance, improves the chances of locating first and second intermediate destinations which are on or near the same road between the start position and the final destination. Accordingly, as compared to the corridor method, which limits the likelihood of finding potential intermediate destinations in the required class, or the first method discussed above, which does not appear to define an area relative to the distance between the start position and the final destination, the prospects of finding an optimal route are much improved.

The method may display at least three potential routes.

The method may calculate the estimated time to travel along each displayed potential routes and calculate the estimated time it would take to travel directly from the start position to the final destination and may display the time penalty alongside each respective potential route.

The method may display the estimated time of arrival at the first potential intermediate destination. The method may display the estimated time of arrival at the second potential intermediate destination.

The first and/or second class may be a sub-class, such as a brand in the relevant class. The method may receive a sub-class and search based on the class in which the sub-class falls, as well as within the sub-class and display at least one potential route wherein the potential intermediate destination or destinations, are within the sub-class and at least one alternative, wherein at least one of potential intermediate destination or destinations are within the class, but not within the sub-class received.

The method may further receive an indication of the amount of fuel remaining, such as a signal indicating the expected range of the vehicle based on the amount of fuel remaing and may search for a further intermediate destination falling within the class of petrol stations and may calculate a route comprising a petrol station if it is determined that there is insufficient fuel to reach the any of the destinations without refuelling.

The method may comprise increasing the size of the defined area including the start position and the final destination, if fewer than a predetermined number of potential intermediate destinations are located within the area. The predetermined number may be one, or two, or three.

The method may comprise increasing the size of the defined area including the start position and the final destination, if fewer than a predetermined number of potential first intermediate destinations and potential second intermediate destinations are located within the area. The predetermined number may be at least one potential first or second intermediate destination and at least one of the other of the first and second intermediate destinations. The predetermined number may be at least one potential first or second intermediate destination and at least two of the other of the first and second intermediate destinations. The predetermined number may be at least one potential first or second intermediate destination and at least three of the other of the first and second intermediate destinations. The predetermined number may be at least two potential first or second intermediate destinations and at least two of the other of the first and second intermediate destinations. The predetermined number may be at least two potential first or second intermediate destinations and at least three of the other of the first and second intermediate destinations. in a second aspect of the invention, there is provided a navigation apparatus arranged to conduct the method defined above.

In a third aspect of the invention, there is provided a navigation apparatus arranged to send instructions via a communications network to a processing resource coupled to the navigation apparatus via a communications interface, the navigation apparatus being arranged, when in use, to send a start position; a user inputted final destination; and at least one user inputted selection of a first class of intermediate destination to the processing resource; the processing resource being arranged to receive the said position and destinations, to define an area including the start position and final destination; to search for first potential intermediate destinations within that area that fall within the first class of first potential intermediate destinations; and to plot routes from the start position to the final destination via the first potential intermediate destinations; and to output a signal to the navigation apparatus; the navigation apparatus arranged to receive the signal from the processing resource and display at least one potential route from the start position to the final destination via one of the first potential intermediate destinations.

The navigation apparatus according to the second or third aspect of the invention may be arranged to carry out the optional steps in the method of the first aspect of the invention as set out above.

The navigation apparatus of the second or third aspect of the invention may be a dedicated portable navigation device including a GPS receiver, a vehicle computer, such as an automotive HMI, or another type of computer, such as a mobile phone, having appropriate software and hardware. A fourth aspect of the invention provides an automobile comprising a navigation apparatus according to the second or third aspect of the invention. A fifth aspect of the invention comprises a computer program adapted to perform the method of the first aspect of the invention.

Detailed Description of the Invention

In order that the invention may be more clearly understood an embodiment/embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a front view of an automobile comprising a navigation device according to the invention;

Figure 2 shows a schematic diagram of a navigation system according to the invention;

Figure 3 shows a schematic diagram of information used in the method carried out by the navigation system of figure 2;

Figure 4 shows an exemplary display on the navigation apparatus of figures 1 and 2 as a result of the method of a first embodiment of the invention; and

Figure 5 shows an exemplary display on the navigation apparatus of figures 1 and 2 as a result of the method of a second embodiment of the invention.

With reference to figure 1, an automobile 100 is provided with a navigation apparatus 200. The navigation apparatus 200 may be a navigation apparatus as set out in US2011/0125398, the entire contents of which is hereby incorporated by reference, the navigation apparatus being in communication with a server as described therein to form a navigation system.

Suitable apparatus to carry out the invention will be well known to those skilled in the art and is disclosed in the above-referenced US2011/0125398, accordingly, this description focusses on the method carried out, and only briefly describes, with reference to figure 2, the navigation apparatus 200, and navigation server 150 with which it communicates via a communication channel 152. Those skilled in the art will appreciate that many computing operations may be carried out either in the navigation apparatus 200, or in the navigation server 150; indeed, a navigation server 150 is not necessarily an essential feature of the invention, although typically the industry is moving towards more operations being carried out at a server 150 and fewer operations being conducted by the navigation apparatus 200 itself (as discussed below).

The server 150 is provided with a memory 156 comprising software, which provides instructions to a processor 154, to allow the server 150 to provide services to the navigation apparatus 200, including transmitting data from a mass storage device 160 (which contains navigation data and map information) to the navigation apparatus 200, and processing the navigation data and sending the results of the processing calculations to the navigation apparatus 200.

The navigation apparatus 200 includes a processing resource comprising a processor 202 coupled to an input device 204, a display screen 206 and a loudspeaker 208. The processor 202 is also connected to a memory 214 and to an antenna/transceiver 224 for communication with e.g. GPS satellites and with the server 150.

The navigation apparatus 200 may also be connected to an ECU 300 and programmed to interrogate the ECU to obtain data from various sensors, for example a petrol gauge 301.

Application software stored in the memory 214 is run by the processor 202 to carry out route planning and navigation functionality. Alternatively, or additionally, the software can cause the antenna/transceiver 224 to transmit signals to the navigation server 150 such that route planning and navigation functions can be carried out by the processor 154 with reference to the memory 156 and mass storage device 160. In that case, the processor 154 causes instructions to be transmitted back from the navigation server 150 via communication channel 152. The application software provides an operational environment supporting the functions of the navigation apparatus 200 and also comprises a POI information entity. The POI information entity receives requests inputted by a user through the input device 204 for intermediate destinations and processes such requests such that they are communicated over the communications channel 152 to the server apparatus 150.

Correspondingly, the server apparatus 150 comprises a POI request server entity 270, which is capable of accessing POI data stored in the mass storage device 160, including points of interest, or “intermediate destinations” classified into classes and subclasses and tagged by longitude and latitude coordinates.

Operation of the navigation apparatus 200 will now be described, by way of example, in the context of a user travelling between a starting position and a final destination. As is conventional, the apparatus 200 ascertains its current position, by communication with GPS satellites. The user enters his final destination, in this example via the input device 204. The processor 202 then causes the display screen 206 to display a prompt to the user to enter any intermediate destinations. The user may then enter a class of intermediate destination, for example he may select a petrol station; the processor 202 then causes the display screen 206 to offer the option of sub-categories of petrol station, e.g. brands, and the user may select a brand, e.g. the brand for which he carries a loyalty card, for example Shell (RTM).

The processor 202 then causes the display screen 206 to display a prompt to the user to enter any further intermediate destinations. The user may then enter a second class of intermediate destination, for example he may select enter Starbucks (RTM), to select the brand (or subclass) “Starbucks” (RTM) in the class of cafes.

The navigation apparatus 200 transmits this information to the navigation server 150 via the communication link 152 and the computer implemented method carried out by the processor 154 of the server 150 then calculates a route.

With reference to figure 3, this route calculation begins by defining an area including the start position and final destination; in this embodiment, the area is an egg shaped area 3, with the narrower end of the egg-shape including the start position A, to increase the chances of initially travelling in the cardinal direction of the final destination B. The definition of the egg-shaped area is based on the geodesic distance between the start position and the final destination, having a length which is a first percentage of the distance between the start position A and the final destination B and a width which is a second percentage of the distance between them

For example, the method may define the area as a rectangle, oval, or egg shape start position and the final position. The first percentage may be defined as at least 110%, e g. 120%. The second percentage may be defined as at least 10%, e.g. 75%.

The next step of the method is searching for first potential intermediate destinations 1 within that area 3 that fall within the first sub-class of first potential intermediate destinations 1; searching for second potential intermediate destinations 2 within the area 3 that fall within the second class of second potential intermediate destinations 2. The method then plots potential routes from the start position A to the final destination B via the first and second potential intermediate destinations 1, 2; then displays potential routes 12, 13 from the start position A to the final destination B via at least one of the first potential intermediate destinations 1 and at least one of the second potential intermediate destinations 2 on the display screen 206.

This is notable in that the method does not first calculate the route from the initial position to the final destination, but rather searches for routes including the final destination and intermediate destinations, not constricted by the limitations of a corridor/tunnel a certain distance from the original route.

The method also calculates the optimal route from the start position to the final destination without stopping at either intermediate destination, in order to provide a baseline, from which the additional distance/time taken to travel to the intermediate destinations can be calculated.

The method then displays a plurality of potential routes from the start position to the final destination via the first potential intermediate destinations as shown for example in figure 3.

In figure 3, a bold line 10 between the initial position A and final destination B indicates the optimal route based on the user’s settings (e g. fastest route, shortest route, avoid toll roads etc.) for travelling direct, without any intermediate destinations; the expected time to travel this route 10 and its distance are calculated and may be displayed alongside the route 10. Dotted lines 11 from the direct route 10 indicate routes from the main route 10 to a first intermediate destination 1 and a second intermediate destination 2 which would fall within the threshold distance of an “along the route” algorithm, indicating a path 11 that could be followed to divert from the direct route 10 and back onto the direct route 10, in order to visit a first destination 1 and a second destination 2. The method of the invention does not display these dotted lines 11 on the display screen 206, they are merely included in the figure for information.

In addition to the first destination 1 and the second destination 2 that are within the threshold distance of an along the route algorithm, figure 3 shows three further first intermediate destinations 1 and two further second intermediate destinations 2 which fall within a larger egg-shaped area 3 containing the start position A and the final destination B, within which the method searched for the first and second intermediate destinations 1, 2. Also displayed, in dashed lines, on the display screen 206 shown in figure 3 are two potential routes including both a first intermediate destination 1 in the first class and a second intermediate destination 2 in the second class.

In this example, the first potential route 12 diverts to the west of the direct route 10 and after just over half way, reaches a first intermediate destination 1 which would fall outside the threshold of an along the route calculator, then continues to the second intermediate destination 2 that falls within the threshold about three-quarters of the distance along the route, and continues directly to the final destination B, along a road other than the direct route 10, but that is more direct from the second intermediate destination 2.

The second potential route 13 shown in dashed lines in this example diverts to the east of the direct route 10 and within a quarter of the total distance of the potential route 13, reaches a second intermediate destination 2 which would fall outside the threshold of an along the route calculator, then returns towards the direct route 10, to the first intermediate destination 1 that was within the threshold distance of an along the route calculator and is about a third of the distance along the route, before converging with the direct route 10 about halfway along its distance.

Figure 4 shows the image displayed on the display screen 206 with the two potential routes 12 and 13. In addition to showing the routes, the method calculates and the display screen shows the estimated time of arrival 14 at the first intermediate destination 1 on the first potential route 12 and the estimated time of arrival 15 at the second intermediate destination 2 on the first potential route 12, along with the additional time 16 that this route will take compared to travelling direct from A to B, which is calculated by the method of the invention, by subtracting the estimated time to travel the direct route 10 from the estimated time to travel the first potential route 12. Similarly, the method calculates and display screen shows the estimated time of arrival 17 at the second intermediate destination 2 on the second potential route 13 and the estimated time of arrival 18 at the first intermediate destination 1 on the second potential route 13, along with the additional time 19 that this route will take compared to travelling direct from A to B. Further information, such as the distance to each intermediate destination may be displayed together with the estimated time of arrival.

Optionally, the direct route 10 (not shown in figure 4) may also be displayed. Using the information displayed, the user may decide which route suits his personal requirements. For example, in the example given, the user may have little petrol left in the tank and therefore choose the second potential route 13, on the basi s that he will reach the petrol station 1 sooner by following that route and is therefore less likely to run out of petrol. Alternatively, if he has sufficient petrol in the tank, he may prefer to use more of it before filling up and select, via the input device 204 to follow the first potential route 12. Other influences that the navigation apparatus 200 may not be aware of may also be in play, for example, the user may choose the first potential route 12 over the second potential route 13 simply because the additional time taken (+5 min) is less than for the second potential route 13 (+6 min). Much of this is down to personal choice, eg. either the desire for a coffee early in the trip to help the user wake up, which would favour the second route, or late in the trip, so that he is close to his destination and can therefore spend more or less time drinking his coffee depending on whether he has gained or lost time over the course of the route so far.

It will be appreciated that this useful information is only available based on the technical steps of calculating potential routes from all the available inputs, including the intermediate destinations, rather than adapting an existing route based on the “along the route”, “near start position” or “near destination” algorithms.

Of course, it will be understood that although in the example above, subclasses of classes of first and second intermediate destination were inputted, that need not occur. Instead, the class, rather than the subclass may be inputted to provide a greater number of options and allow the user to determine the optimum route to suit his requirements; thus as mentioned above, if the user has a preference for a particular sub-class of potential intermediate destination, for example, a particular chain of cafes, within the class of “cafes”, the user can choose the route incorporating the potential intermediate destination falling within that sub-class.

In the example above, only two routes were displayed, obviously a predetermined number such as 2,3,4, or 5 routes may be displayed and where there are a large number of options for routes to show, the method may determine the temporally shortest route and the spatially shortest route and show both. Where a class (rather than a sub-class) of intermediate destination is inputted by the user, the method may also determine at least two routes including distinct potential first intermediate destinations 1 and second intermediate destinations 2 (i.e. at least two options for at least both of the classes of destination).

In a second embodiment, the method runs as discussed above, but in addition to searching within a sub-class also searches in the class within which that subclass falls. The second embodiment also takes account of the amount of petrol remaining in the petrol tank.

This is particularly useful if the chosen sub-class is uncommon. With reference to figure 5, the route calculation of the second embodiment begins by receiving indications of the intermediate destinations required, which in this example are a Shell (RTM) petrol station as the first subclass of intermediate destination 1 and a Starbucks (RTM) cafe as the second subclass of intermediate destination 2. In this example, having received a petrol station as an intermediate destination, the method of the processor interrogates the ECU 300 to determine the amount of fuel remaining and estimates the distance that can be travelled with the remaining fuel (the estimation step may be obviated by receiving an indication from the ECU of the estimated distance, if such data is available). Having carried out this step, the method defines an area including the start position A and final destination B; in this embodiment, the area is once again an egg shaped area (not shown), with the narrower end of the egg-shape including the start position A, to increase the chances of initially travelling in the cardinal direction of the final destination B. The definition of the egg-shaped area is based on the geodesic distance between the start position and the final destination, having a length which 120% of the distance between the start position A and the final destination B and a width which is a 75% of the distance between them.

The next step of the method is searching for first potential intermediate destinations 1 within that area that fall within the first sub-class of first potential intermediate destinations 1; searching for second potential intermediate destinations 2 within the area that fall within the second class of second potential intermediate destinations 2.

Having received a fuel station as an intermediate destination 1, the method of the second embodiment of the invention calculates the distance to each petrol station 1 that has been located within the searched area, in the example, there are two Shell (RTM) petrol stations 1 in the searched area, one of which is within range and one of which is out of range. The method then ignores any petrol stations 1 that are out of range.

Next, the method then carries out the step of counting the number of first potential intermediate destinations 1 falling within the first subclass and the number of second intermediate destinations 2 falling within the second subclass, and where the number is less than two (optionally less than one), the method conducts a further search for potential intermediate destinations falling within the same category, but outside the subclass. Thus, in this example, the count locates one first potential intermediate destination 1 (having ignored and removed from the count the fuel station 1 that was out of range). Where the number is less than two, the method carries out a search for first alternative potential intermediate destinations Γ which fall within the same class as the potential intermediate destinations 1 requested by the user.

In this example, the count locates four second intermediate destinations 2 and therefore does not conduct any further searching within the broader class in which the second intermediate destinations fall.

The method then calculates potential routes from the start position A to the final destination B via at least one second potential intermediate destination 2 and at least one first intermediate destination 1 or first alternative intermediate destination Γ; then displays the two fastest potential routes 20, 21 from the start position A to the final destination B via at least one of the first potential intermediate destinations 1 and at least one of the second potential intermediate destinations 2 and the fastest potential alternative route 22 via at least one of the first alternative potential intermediate destinations Γ and at least one second potential intermediate destination on the display screen 206.

Again the method also calculates the optimal direct route 23 from the start position to the final destination without stopping at either intermediate destination, in order to provide a baseline, from which the additional distance/time taken to travel to the intermediate destinations can be calculated.

In figure 3, a bold line 10 between the initial position A and final destination B indicates the optimal route based on the user’s settings (e.g. fastest route, shortest route, avoid toll roads etc.) for travelling direct, without any intermediate destinations.

In this example, the first fastest potential route 20 diverts to the west of the direct route 23, as does the second fastest potential route 21. They both reach the same first potential intermediate destination, having first reached a second potential intermediate destination.

The fastest potential route alternative route 22, on the other hand, in this example diverts to the east of the direct route 23 and within a quarter of the total distance of the potential route 22, reaches a first potential alternative intermediate destination Γ, travelling onward to a second intermediate destination 2 about half way along the route. Again this example includes a second intermediate destination 2which would fall outside the threshold of an along the route calculator.

Figure 5 shows the image displayed on the display screen 206 with the three potential routes 20, 21 and 22. In addition to showing the routes, the method also shows the other first potential intermediate destinations 1, first potential alternative destinations F and second potential intermediate destinations 2 that do not fall on any of the displayed routes, simply for information. The method also calculates and the display screen shows the estimated time of arrival 24 at the second intermediate destination 2 on the first potential route 20, the estimated time of arrival 25 at the first intermediate destination 1 on the first potential route 20, along with the additional time 26 that this route will take compared to travelling direct from A to B, which is calculated by the method of the invention, by subtracting the estimated time to travel the direct route 23 from the estimated time to travel the first potential route 20. Similarly, the method calculates and display screen shows the estimated time of arrival 27 at the second intermediate destination 2 on the second potential route 21 and the estimated time of arrival 28 at the first intermediate destination 1 on the second potential route 21, along with the additional time 29 that this route will take compared to travelling direct from A to B. Likewise, the method calculates and display screen 206 shows the estimated time of arrival 30 at the first alternative intermediate destination F on the fastest potential alternative potential route 22 and the estimated time of arrival 31 at the second intermediate destination 2 on the fastest alternative potential route 22, along with the additional time 32 that this route will take compared to travelling direct from A to B. Again, further information, such as the distance to each intermediate destination may be displayed together with the estimated time of arrival.

Optionally, the direct route 23 may also be displayed. Using the information displayed, the user may decide which route suits his personal requirements. For example, in the example given, the user may determine that since the fastest alternative route 22 is much faster than either the first or second potential routes 20, 21, he will choose that route. He may even choose to carry out a broader search, not limiting to the subclass of Shell (RTM) petrol stations, in order to find additional alternatives.

Again, it will be appreciated that this useful information is only available based on the technical steps of calculating potential routes from all the available inputs, including the intermediate destinations, rather than adapting an existing route based on the “along the route”, “near start position” or “near destination” algorithms, including the step of obtaining data indicating the range based on sensor readings and the discriminating step of identifying the number of potential intermediate destinations within range.

In the example three routes were displayed, obviously a different predetermined number such as 2, 4, or 5 routes may be displayed and where there are a large number of options for routes to show, the method may determine the temporally shortest route and the spatially shortest route and show both.

Whilst the example given in the second embodiment assumes that the user has imputed through the input device 204 that wishes to stop at a fuel station. However, the invention envisages a system in which the method monitors signals from the ECU or periodically interrogates it to determine whether sufficient fuel remains to reach the final destination and, if not, presents a message on the display screen requesting an input from the user as to whether to determine a route via a fuel station and, if the user inputs an affirmative response, carries out the method above to determine a route via a fuel station and present the options on the screen. In the event that e.g. two other intermediate destinations have already been inputted, the class of fuel stations would be added and the method would search for a route incorporating the fuel station as a third intermediate destination. Alternatively, it could be added as the only intermediate destination, if the navigation apparatus 100 is following a direct route from start position to final destination.

In a further embodiment, similar to the second embodiment, the method may conduct a count of the number of intermediate destinations in each class/subclass and in the event that fewer than a predetermined number of potential intermediate destinations are located, may increasing the size of the defined area including the start position and the final destination. The predetermined number may be set by a user and saved in the memory 214, it may be one, or two, or three.

The method may comprise increasing the size of the defined area including the start position and the final destination, if fewer than a predetermined number of potential first intermediate destinations and potential second intermediate destinations are located within the area. The predetermined number may be at least one potential first or second intermediate destination and at least one of the other of the first and second intermediate destinations. The predetermined number may be at least one potential first or second intermediate destination and at least two of the other of the first and second intermediate destinations. The predetermined number may be at least one potential first or second intermediate destination and at least three of the other of the first and second intermediate destinations. The predetermined number may be at least two potential first or second intermediate destinations and at least two of the other of the first and second intermediate destinations. The predetermined number may be at least two potential first or second intermediate destinations and at least three of the other of the first and second intermediate destinations.

As set out above, processing may take place either in the navigation apparatus 200 or at the server 150, but one efficient method involves the navigation apparatus 200 sending instructions via the communications network 152 to a processing resource 150 coupled to the navigation apparatus 200 via a communications interface, the navigation apparatus 200 sending a start position A (determined from GPS signals); a user inputted final destination B; and at least one user inputted selection of a first class/subclass of intermediate destination to the processing resource 150. The processing resource 150 will then receive the said position and destinations, define an area 3 including the start position A and final destination B; search for potential intermediate destinations 1, 2 within that area 3 that fall within the class/subclass of potential intermediate destinations 1, 2; and plot the routes 12, 13, 20, 21, 22 from the start position A to the final destination via the potential intermediate destinations 1, 2; and to output a signal to the navigation apparatus 200. The navigation apparatus 200 will then receive the signal from the processing resource 150 and display the potential routes 12, 13, 20, 21, 22 from the start position A to the final destination B via one of the potential intermediate destinations 12, 13, 20, 21, 22.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A computer implemented method of calculating a route comprising: receiving a start position and a user inputted final destination; receiving at least one user inputted selection of a first class of intermediate destination; defining an area including the start position and final destination; searching for first potential intermediate destinations within that area that fall within the first class; plotting routes from the start position to the final destination via each first potential intermediate destination; and displaying at least one potential route from the start position to the final destination via one of the first potential intermediate destinations.

2. A method according to claim 1 which displays a plurality of potential routes from the start position to the final destination via the first potential intermediate destinations.

3. A method according to claim 1 or 2 further comprising receiving at least one user inputted selection of a second class of intermediate destination; searching for second potential intermediate destinations within the area that fall within the second class of second potential intermediate destinations; plotting routes from the start position to the final destination via the first and second potential intermediate destinations; and displaying at least one potential route from the start position to the final destination via at least one of the first potential intermediate destinations and at least one of the second potential intermediate destinations to the user.

4. A method according to claim 3 comprising displaying a plurality of potential routes from the start position to the final destination via at least one of the first potential intermediate destinations and at least one of the second potential intermediate destinations to the user.

5. A method according to any of claims 2 to 4 wherein the plurality of routes comprise the temporally shortest route.

6. A method according to any of claims 2 to 5 wherein the plurality of routes comprise the spatially shortest route.

7. A method according to any of claims 2 to 6 wherein the plurality of routes comprise at least two routes including distinct potential intermediate first or second destinations

8. A method according to claim 7 wherein the plurality of routes may comprise at least two routes including distinct potential intermediate first and second destinations.

9. A method according to any of the preceding claims comprising the step of defining the area based on the geodesic distance between the start position and the final destination.

10. A method according to claim 9 wherein the area defined has a length which is a first percentage of the distance between the start position and the final position and a width which is a second percentage of the distance between the start position and the final position.

11. A method according to claim 10 wherein the defined area is is egg shaped having the start position is at the narrower end.

12. A method according to claim 10 or 11 wherein the first percentage is at least 110% and/or the second percentage is at least 20%.

13. A method according to claim 12 wherein the first percentage is at least 120% and/or the second percentage is at least 50%.

14. A method according to claim 12 or 13 wherein the second percentage is at least 75%.

15. A method according to any preceding claim which displays at least three potential routes.

16. A method according to any of claims 1 to 15 which calculates the estimated time to travel along the or each displayed potential route and calculates the estimated time it would take to travel directly from the start position to the final destination and displays the time penalty alongside each respective potential route.

17. A method according to any preceding claim comprising the step of displaying the estimated time of arrival at the or each first potential intermediate destination.

18. A method according to any of claims 3-17 comprising the step of displaying the estimated time of arrival at the or each second potential intermediate destination.

19. A method according to any of the preceding claims comprising receiving a first and/or second sub-class within a class and searching within that subclass

20. A method according to any preceding claim comprising receiving a first and/or second sub-class within a class; searching based on the class in which the subclass falls, as well as within the sub-class; and displaying at least one potential route wherein the potential intermediate destination or destinations, are within the sub-class and at least one alternative, wherein at least one of potential intermediate destination or destinations are within the class, but not within the sub-class received.

21. A method according to any preceding claim comprising receiving a signal indicative of the amount of fuel remaining; searching for a further intermediate destination falling within the class of fuel stations; and calculating a route comprising a fuel station if it is determined that there is insufficient fuel to reach the any of the destinations without refuelling.

22. A method according to any preceding claim comprising the step of increasing the size of the defined area including the start position and the final destination, if fewer than a predetermined number of potential intermediate destinations are located within the area.

23. A method according to claim 22 comprising increasing the size of the defined area including the start position and the final destination, if fewer than a predetermined number of potential first intermediate destinations and potential second intermediate destinations are located within the area.

24. A method according to claim 23 wherein the predetermined number is at least two potential first or second intermediate destinations and at least two of the other of the first and second intermediate destinations.

25. A navigation apparatus arranged to conduct the method defined in any of claims 1 to 24.

26. A navigation apparatus arranged to send instructions via a communications network to a processing resource coupled to the navigation apparatus via a communications interface, the navigation apparatus being arranged, when in use, to send a start position; a user inputted final destination; and at least one user inputted selection of a first class of intermediate destination to the processing resource; the processing resource being arranged to receive the said position and destinations, to define an area including the start position and final destination; to search for first potential intermediate destinations within that area that fall within the first class of first potential intermediate destinations; and to plot routes from the start position to the final destination via the first potential intermediate destinations; and to output a signal to the navigation apparatus; the navigation apparatus arranged to receive the signal from the processing resource and display at least one potential route from the start position to the final destination via one of the first potential intermediate destinations.

27. A navigation apparatus according to claim 26 arranged to carry out the method of any of claims 1 to 24.

28. An automotive human machine interface comprising the navigation apparatus according to any of claims 25 to 27.

29. An automobile comprising a navigation apparatus according to any of claims 25 to 27.

30. A computer program adapted to perform the method of any of claims 1 to 24.

31. A navigation apparatus or method of calculating a route substantially as described herein with reference to the accompanying drawings.