Route Guidance System

1 . A route guidance system comprising an in-vehicle device and a central route advisory system in which the in-vehicle device comprises an audio emitter and a visual display unit adapted to provide audio and visual instructions to a user to perform manoeuvres required to complete an optimal route, wherein the optimal route is transmitted by the central route advisory system to the in-vehicle device in response to a route request from the user to a human operator in the central route advisory system to a specified destination.

2 . A route guidance system as claimed in claim 1 wherein the visual display unit is a monochrome display.

3 . A route guidance system as claimed in claim 1 or claim 2 wherein the system comprises a means for displaying on the visual display unit a junction or roundabout as the vehicle approaches it.

4 . A route guidance system as claimed in any one of the preceding claims wherein the system comprises a means for displaying on the visual display unit junctions as pictographs.

5 . A route guidance system as claimed in any one of the preceding claims wherein the system comprises means for displaying on the visual display unit roundabouts as pictographs.

6 . A route guidance system as claimed in claim 4 or claim 5 wherein the system comprises a means for indicating on the displayed pictograph the required manoeuvre.

7 . A route guidance system as claimed in claim 6 wherein the system comprises a means for supplementing the visual instructions to perform a manoeuvre with audible instructions to perform a manoeuvre.

8 . A route guidance system as claimed in any one of the preceding claims wherein the visual display unit provides a means of initiating an automatic route request in respect of a stored destination.

9 . A route guidance system as claimed in any one of the preceding claims wherein the system comprises a means for displaying on the visual display unit the proximity of speed-cameras.

10 . A route guidance system as claimed in any one of the preceding claims wherein the visual display unit is a color display unit.

11 . A route guidance system as claimed in claim 10 wherein the system comprises a means for displaying on the color display unit coloured road-maps of a particular region.

12 . A route guidance system as claimed in claim 10 or claim 11 wherein the system comprises a means for superimposing onto a coloured road-map the current position of the car.

13 . A route guidance system as claimed in any one of claims 10 to 12 wherein the system comprises a means for superimposing onto a coloured road-map the pictograph of a junction or roundabout.

14 . A route guidance system as claimed in any one of claims 10 to 13 wherein the system comprises a means for providing a user-face on the color display unit and a means for enabling a user to make a telephone call.

15 . A route guidance system as claimed in any one of claims 10 to 14 wherein the system comprises a means for providing a user-interface on the color display unit and means for enabling the user to receive a telephone call.

16 . A route guidance system as claimed in any one of claims 10 to 15 wherein the system comprises a means for providing a user-interface on the color display unit and means for enabling the user to receive a text-message.

17 . A route guidance system comprising an in-vehicle device and a central route advisory system in which the in-vehicle device comprises units adapted to provide instructions to a user to perform manoeuvres required to complete an optimal route, wherein the optimal route is determined by the central route advisory system using real-time historical traffic data acquired from monitored routes together with archive data acquired from non-monitored routes and transmitted by the central route advisory system to the in-vehicle device in response to a route request from the user to a human operator in the central route advisory system to a specified destination.

18 . A route guidance system comprising an in-vehicle device and a central route advisory system in which the in-vehicle device comprises units adapted to provide instructions to a user to perform manoeuvres required to complete an optimal route, wherein the optimal route is calculated by the central route advisory system using a traffic forecasting model and transmitted by the central route advisory system to the in-vehicle device in response to a route request from the user to a human operator in the central route advisory system to a specified destination.

19 . A route guidance system as claimed in claim 18 wherein the traffic forecasting model is time dependent.

20 . A route guidance system as claimed in claim 18 or claim 19 wherein the central route advisory system comprises a means of predicting future traffic conditions based on the time at which the route request was received together with the time dependent traffic forecasting model.

21 . A route guidance system comprising an in-vehicle device and a central route advisory system in which the in-vehicle device comprises units adapted to provide instructions to a user to perform manoeuvres required to complete an optimal route, wherein the optimal route is calculated by the central route advisory system taking into account the previous travelling direction of the vehicle, in response to a route request from the user to a human operator in the central route advisory system to a specified destination, and the optimal route is transmitted by the central route advisory system to the in-vehicle device.

22 . A route guidance system comprising an in-vehicle device and a central route advisory system in which the in-vehicle device comprises units adapted to provide instructions to a user to perform manoeuvres required to complete an optimal route, wherein the optimal route is calculated by the central route advisory system taking into account the previous travelling direction of the vehicle, in response to a route request from the user to a human operator in the central route advisory system to a specified destination, and the optimal route is transmitted by the central route advisory system to the in-vehicle device.

23 . A route guidance method comprising the steps of:

(a) receiving a call from a user's in-vehicle device indicating the user's desired destination;

(b) entering the user's desired destination into a route-guidance system;

(c) determining the current location of the user's vehicle;

(d) determining the potential routes to the desired destination;

(e) ascertaining traffic conditions along the potential routes;

(f) determining the optimal route to the desired destination using the distances of the potential routes and the traffic conditions along the routes;

(g) establishing route key-points along the optimal route;

(h) associating flags with the route key-points;

(i) transmitting the route key-points and flags to the user's in-vehicle device; and

(j) providing visual and audio instructions to the user as the user's vehicle approaches the route key-points along the optimal route.

24 . A route guidance method comprising the steps of:

(a) receiving a call from a user's in-vehicle device indicating the user's desired destination;

(b) determining the current location of the user's vehicle;

(c) entering the user's desired destination into a route-guidance system;

(d) determining the potential routes to the desired destination;

(e) ascertaining traffic conditions along the potential routes;

(f) determining the optimal route to the desired destination using the distances of the potential routes and the traffic conditions along the routes;

(g) establishing route key-points along the optimal route;

(h) associating flags with the route key-points;

(i) transmitting the route key-points and flags to the user's in-vehicle device; and

(j) providing instructions to the user as the user's vehicle approaches the route key-points along the optimal route.

25 . A route guidance method comprising the steps of:

(a) receiving a call from a user's in-vehicle device indicating the user's desired destination;

(b) entering the user's desired destination into a route-guidance system;

(c) determining the current location of the user's vehicle from a dual multi-frequency tone transmission from the user's in-vehicle device;

(d) determining the potential routes to the desired destination;

(e) ascertaining traffic conditions along the potential routes;

(f) determining the optimal route to the desired destination using the distances of the potential routes and the traffic conditions along the routes;

(g) establishing route key-points along the optimal route;

(h) associating flags with the route key-points;

(i) transmitting the route key-points and flags to the user's in-vehicle device; and

(j) providing instructions to the user as the user's vehicle approaches the route key-points along the optimal route.

26 . A route guidance method as claimed in claim 25 wherein the current position of the user's vehicle is determined from an ISDN sub-addressing transmission from the user's in-vehicle device.

27 . A route guidance method comprising the steps of:

(a) receiving a call from a user's in-vehicle device indicating the user's desired destination;

(b) entering the user's desired destination into a route-guidance system;

(c) determining the current location of the user's vehicle;

(d) determining the potential routes to the desired destination;

(e) ascertaining traffic conditions along the potential routes;

(f) determining the optimal route to the desired destination using the distances of the potential routes and the traffic conditions along the routes;

(g) establishing route key-points along the optimal route;

(h) associating flags with the route key-points;

(i) transmitting the route key-points and flags to the user's in-vehicle device;

(j) using a route convergence model to determine the direction in which the user's vehicle is travelling once the vehicle commences the journey along the optimal route; and

(k) providing visual and audio instructions to the user as the user's vehicle approaches the route key-points along the optimal route.

28 . A route guidance method as claimed in claim 27 wherein the in-vehicle device uses the route convergence model to display the current route on which the vehicle is travelling.