GB2409275A

GB2409275A - Off-road guidance instruction

Info

Publication number: GB2409275A
Application number: GB0425695A
Authority: GB
Inventors: Arne Friedrichs; Gerd Draeger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2003-12-12
Filing date: 2004-11-23
Publication date: 2005-06-22
Anticipated expiration: 2024-11-23
Also published as: GB2409275B; DE10358194A1; ITMI20042325A1; FR2863703A1; FR2863703B1; GB0425695D0

Abstract

A method for outputting destination guidance instructions for navigation systems prior to entering a known region which contains a predetermined route. The method involves; a) determining whether the vehicle is in an off-road region; b) determining an entry link to the predetermined route; c), if the distance is less than a predetermined distance to the entry link, determining the direction of the entry link; d) determining a difference in the direction of travel and the direction of the entry link; e) displaying guidance instruction, for example a turn-indicating arrow.

Description

DESCRIPTION

OUTPUTTING DESTINATION GUIDANCE INSTRUCTIONS

PRIOR TO ENTERING AN EXISTING ROUTE

The invention relates to a method and device for outputting destination guidance instructions in a navigation system for navigation situations prior to entering a region which is known to the navigation system and contains a predetermined route, wherein the invention particularly relates to travel assistance in the off-road region for navigation systems in motor vehicles. The off-road region is the territory which is located outside the map/route known to the navigation system, such as for example outside of the digitised network of streets stored in the system.

Navigation devices are known which guide vehicles on a previously calculated route. Navigation devices which have access to data material outside the driven route are able to guide the user to the destination via an alternative route which perhaps has to be newly calculated. However, if the user is located outside the digitalised network of streets, he is normally required to immediately turn around or the direction and distance to a known point on the route are shown in the form of a compass dial. The compass dial generally shows the direction of the shortest distance, i.e. 'as the crow flies', to a known road section on the map or route. The compass dial is understood as the direction with respect to north or as the direction of travel i.e. the direction of the vehicle with respect to the road section.

The compass dial has the disadvantage that the user cannot be given any real destination guidance information since no route data are known. Only road sections or entry points are known, to which the direction can be indicated. An entry point is a point at which the vehicle can travel into the region known to the navigation system and containing a predetermined route.

A proposal for a display in the off-road region is known from German Patent application DE 101 53 528 Al. In this proposal, a choice of various entry points for the route is made available to the driver, along with the distance and the direction to the respective entry point. Once again, only a compass dial is used to indicate direction.

A further disadvantage in displaying direction using a compass dial is that when the driver passes the entry point in close proximity thereto, the compass dial can very quickly turn by up to 180 . This can lead to the driver becoming considerably irritated and also to dangerous turning manoeuvres because the driver does not know in which direction he has to travel in order to reach the entry point.

In accordance with a first aspect of the present invention there is provided a method for outputting destination guidance instructions in a navigation system for navigation situations prior to entering a region which is known to the navigation system and contains a predetermined route, wherein the distance D between the current vehicle position and a predetermined entry point into the region known to the navigation system is determined, the method comprising the steps of: a) forming the direction difference between the direction of travel of the vehicle and an entry link Ek, b) generating an entry travel instruction which contains the direction difference A, and c) outputting the entry travel instruction graphically on a display of the navigation system and/or as voice output.

By use of the present invention, while still in the off-road region prior to reaching an entry point, the driver can be shown, in addition to the distance to this point, the direction he has to turn in order to reach the predetermined route after reaching the entry point. The driver is thus offered additional travel assistance which obviates irritations and the need for the driver to effect turning manoeuvres in proximity to the entry point and thus reduces inter alla the risk of accidents.

Advantageous embodiments, developments and improvements of the respective object of the invention are disclosed in the subordinate Claims.

Preferably, a direction difference can be generated and displayed when the distance is smaller than a predetermined threshold value Ds. In an alternative manner thereto, or in combination therewith, an entry travel instruction in accordance with the invention can also be produced when an angle or between the vehicle longitudinal axis and the direction to the entry point is smaller than a threshold value off. This is advantageous in that the entry travel instruction in accordance with the invention is only displayed when the vehicle is travelling in the rough direction of the entry point.

The present invention is particularly well suited for use in motor vehicles.

In an advantageous manner, the depiction of the entry travel instruction in accordance with the invention contains a turn-indicating arrow and/or it is given in the form of a "turn-by-turn" voice output, i.e. a voiced instruction expressed in an explicitly verbal manner. The entry travel instruction is thus given to the driver in a manner which is simple to understand.

A further improvement of the invention is the depiction of the turn indicating arrow in a corner of the display of the navigation system. Further information of the navigation system, e.g. the distance and direction to the entry point, can therefore also be displayed in a clearly visible manner.

As an advantageous alternative, the entry travel instruction in accordance with the invention can also be depicted in place of a compass dial. Providing the direction 'as the crow flies' is often, particularly in proximity to the entry point, not as suitable as depicting the direction which results from the difference between the vehicle direction and the digitalised street direction (entry link) continuing from the entry point. For streets which often continue straight ahead, the driver can thus recognise, even before reaching the entry point, in which direction, or streets, he has to turn.

In this regard, it is advantageous to additionally provide data regarding the street name of the entry link.

In a further advantageous manner, the entry travel instruction can be provided in a manner discretised to an approximate angle, preferably more approximate than about 30 decimal degrees, in a preferred manner within a 45 degree resolution. Therefore, the entry travel instruction does not keep changing when the direction of travel changes slightly. The driver thus receives clear, relatively constant instructions. He can more easily understand the entry travel instructions to a sufficient degree.

Further alternatives or additions to the above described features are as follows: the threshold Ds can be changed depending upon the vehicle velocity, i.e. a high velocity means a higher Ds and vice-versa.

The threshold Ds can be changed depending upon the street class which is attributed to the entry link, i.e. for example turning onto a motorway means a higher Ds and vice-versa.

I O 1; urthermore, an hysteresis can be defined with regard to Ds which prevents a display from vanishing and then immediately re-appearing, because a value momentarily fell short of or exceeded Ds in a particularly advantageous manner, the method in accordance with the invention is used in an off-board navigation system since in this case generally only very limited route corridors or even only the main routes are known and the vehicle is much more often located outside the known map or route in the so called off-road region. In the off-board navigation, the destination guidance device in the vehicle no longer calculates the route, but rather a service provider effects this task. This has the most recent map material and current traffic information. The communication relevant for navigation is thus effected via mobile radiocommunications between subscriber and service provider. However, the destination input, verbal travel recommendations and the precise destination guidance are still effected by the device in the vehicle.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a flow diagram of one embodiment of the method in accordance with the present invention; Figure 2 shows a topology of a route having three vehicle positions in the off-road region (angles not shown to scale); Figure 3 shows a depiction on a display of a navigation system in accordance with one embodiment of the method in accordance with the present invention for a vehicle position in the off-road region at a large distance from the entry point; Figure 4 shows a depiction corresponding to Figure 2 at a small distance from the entry point; and Figure 5 shows a depiction on a display of a navigation system in accordance with one embodiment of the method in accordance with the present invention for a further vehicle position in the off-road region at a small distance from the entry point.

In the Figures, like reference numerals designate like components, or components which are functionally the same.

Figure 1 shows a flow diagram of one embodiment of the navigation method in accordance with the invention which is used in particular in a motor vehicle. Once the method has been started 100, step 1 10 of the navigation system determines whether the vehicle is located outside the route corridor known to the system, i.e. in the off-road region. If this is not the case ("no" branch), the method ends in step 170. Otherwise ("yes" branch), the navigation system determines in step l 20 the direct distance D to the already determined entry point E. Thereafter, it is checked in step 130 whether the determined distance D is less than a predetermined threshold value Ds, e.g. 500 m. If this is not the case, the method ends in step l 70. However, if D is less than Ds, the direction of the entry link Ek, which is known to the navigation system, with respect to the vehicle direction is determined in step 140. The two directions are thus at an angle a of 60 decimal degrees with respect to each other for example. Thereafter, an entry travel instruction is generated by the navigation system in step 150. This is, for example, a turn-indicating arrow in the direction of the above-determined angle.

In addition thereto, a number for the distance D in metres can also be generated.

The generated entry travel instructions are displayed to the driver in step 160 on a display located in the motor vehicle in the visible region, prior to the method ending 170. After ending 170, the method can be restarted after a known time delay ol; for example, two seconds.

Figure 2 shows a topology of a route having three vehicle positions in the off-road region. A vehicle which is fitted with an off-board navigation device and the development in accordance with the invention requested a server to provide a route 10 from a starting point (S) 12 to a destination point (Z) 14. When the vehicle is at one position (Pi) 26, the navigation device is supplied with the route S-Z 10. In this case, the navigation device immediately determines that the current vehicle position is not within the route corridor 20 for the route S-Z 10.

Point Ep 16 is selected as the best entry point for the route S-Z 10. The navigation system determines the direct distance, e.g. of one hundred metres between vehicle and entry point, and the direction to the entry point Ep 16. The determined distance in this case is greater than the threshold value (Ds) 32 of e.g. fifty metros.

An entry travel instruction regarding the direction of the vehicle with respect to the direction of the entry link Ek 18 from the entry point Ep 16 is thus not generated. As illustrated in Figure 3, only the direction to the entry point Ep 16 and the current distance to Ep 16 are displayed to the driver on the display 40 of the navigation system in the form of a compass needle 42 and numerical data 44 respectively.

The distance (D) 22 to the entry point Ep 16 is small enough that it is less than the distance threshold Ds 32 of fifty metros, only when the vehicle is at position P2 24. The exemplified embodiment of the navigation system in accordance with the invention then determines, using the direction of travel and the direction of the entry link (Ek) 18, the angle (it) 30 therebetween which measures, for example, fifty decimal degrees. Furthermore, the angle (a) 28 between the straight line - connecting the vehicle position P2 24 and the entry point EP 16 - and the direction of travel is determined. This angle cc measures, for example, thirty decimal degrees. If this angle (a) 28 is lower than a predetermined threshold value ocs of, for example, sixty decimal degrees, which is the case in this example, then an entry travel instruction is generated by the navigation system in the form of a turn-indicating arrow.

The driver is then shown, as illustrated in Figure 4, on the display 40 of the navigation system in addition to the direction to the entry point Ep 16 a turn indicating arrow 46 in the form of a compass needle 42 in addition to the current distance to Ep 16 (fifty metros in this example) as numerical data 44. The turn indicating arrow 46 is turning down and to the left by forty-five decimal degrees since the direction of the entry link (Ek) 18 with respect to the current direction of travel is rotated to the left about the angle (is) 30 of, in this example, fifty decimal degrees. The size of the angle for the turn-indicating arrow 46 is rounded to a maximum of forty-five decimal degrees in the exemplified embodiment.

In a vehicle position P3 34 marked in Figure 2, for which the distance of fifty metros is within the distance threshold Ds 32 and the angle of zero decimal degrees is less than the angle threshold ocs, an arrow 46 having, in this example, a zero degree (no) change in direction (arrow pointing up, straight ahead) in addition to the direction to the entry point Ep 16 in the form of a compass needle 42 and in addition to the current distance to Ep 16 (fifty metres in this example) as numerical data 44 is displayed on the display 40, as depicted in Figure 5, because the vehicle is moving in the direction of the entry link Ek 18.

When the vehicle is moving in a direction which is clearly offset with respect to the entry link in a parallel and lateral manner, a 0 direction is also displayed.

Although the present invention is described above using a preferred exemplified embodiment, it should not be limited thereto and can be modified in many ways.

For example, such navigation assistance can be used in ships which can only travel in particular shipping lanes.

Finally, the features of the subordinate Claims can be essentially freely combined with each other and not combined in the sequence provided in the Claims insofar as they are independent of one another. /

Claims

1. A method for outputting destination guidance instructions in a navigation system for navigation situations prior to entering a region which is known to the navigation system and contains a predetermined route, wherein the distance D between the current vehicle position and a predetermined entry point into the region known to the navigation system is determined, the method comprising the steps of: a) forming the direction difference between the direction of travel of the vehicle and an entry link Ek, b) generating an entry travel instruction which contains the direction difference 0, and c) outputting the entry travel instruction graphically on a display of the navigation system and/or as voice output.

2. A method as claimed in Claim 1, wherein the direction difference is formed when the distance is smaller than a predetermined threshold value Ds and/or when a direction difference a between a straight line connecting the vehicle position and entry point - and the direction of travel is smaller than a predetermined threshold value crs.

3. A method as claimed in Claim 2, wherein one of the following provisions is also made: a) changing the threshold value Ds depending upon the vehicle velocity, wherein a higher velocity preferably means a higher threshold value Ds and vice-versa, b) changing the threshold value Ds depending upon the street class which is attributed to the entry link, and c) defining an hysteresis with regard to Ds which prevents a display from vanishing and then immediately re-appearing because a value momentarily fell short of or exceeded Do.

4. A method as claimed in Claim 1, wherein the entry travel instruction a) contains the depiction of a turn-indicating arrow, and/or b) is given in the form of a "turn-by-turn" voice output.

5. A method as claimed in Claim 4, version a), wherein the entry travel instruction is depicted in a corner of the display of the navigation system.

6. A method as claimed in Claim I, wherein the entry travel instruction is depicted in place of a compass dial.

7. A method as claimed in any of the preceding Claims, wherein the entry travel instruction is provided in a manner discretised to an approximate angle, preferably more approximate than 30 decimal degrees, in a preferred manner within a 45 degree resolution.

8. A method as claimed in any of the preceding Claims, wherein the street name of the entry link is provided.

9. A method as claimed in any of Claims 1 to 8 used in an off-board navigation system.

10. A navigation system which outputs destination guidance instructions tor navigation situations prior to entering a region which is known to the navigation system and contains a predetermined route, wherein the distance D between the current vehicle position and a predetermined entry point into the region known to the navigation system is determined and which contains devices which are suitable to generate and display entry travel instructions in accordance with the characterizing steps in a method as claimed in any of Claims 1 to 8.

1 1. A navigation system as claimed in Claim 10, which contains devices, preferably for displaying the entry travel instruction, installed in a motor vehicle. i

12. A navigation system as claimed in any of Claims 10 or 1 1, designed as an off-board navigation system.

13. A method for outputting destination guidance instructions in a navigation system, substantially as hereinbefore described, with reference to the] accompanying drawings.

14. A navigation system substantially as hereinbefore described, with I reference to and as illustrated in the accompanying drawings.