Navigation device and method

1. A route-planning device, comprising:

a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road;

a goal identification section for identifying a goal position; and

a search route module arranged to:

receive a request to provide a search route for a vacant parking space;

set a current position of a navigation device associated with a vehicle as a start position of the search route;

determine a route from the start position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the start position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route, distances between the start position and positions of the roads and/or sub-roads of the possible route, and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function; and

output the determined route as the search route.

2. The route-planning device according to claim 1 , wherein the position of each road or sub-road is a mid-point of the road or sub-road.

3. The route-planning device according to claim 1 , wherein a parameter is used in the cost function to weight the importance of the distances between the goal position and the positions of the roads and/or sub-roads of the possible route, and wherein the search route module is further arranged to receive a value of the parameter from a user of the navigation device.

4. The route-planning device according to claim 1 , wherein the maximum length is a predetermined travel distance or a predetermined travel time.

5. The route-planning device according to claim 1 , wherein the route-planning device is the navigation device associated with the vehicle.

6. The route-planning device according to claim 5 , further comprising an input section for receiving commands from a user, wherein the request to provide the search route for the vacant parking space is received from the user via the input section.

7. The route-planning device according to claim 1 , wherein the route-planning device is a route-planning server, said route-planning server being arranged to be in communication with the navigation device associated with the vehicle and further comprising: a receiving section for receiving, over a network, the request to provide the search route from the navigation device; and a sending section for sending, over the network, the search route determined by the search route module.

8. A route-planning device, comprising:

a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road;

a goal identification section for identifying a goal position; and

a search route module arranged to:

receive a request to provide a search route for a vacant parking space;

determine a first route from the goal position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the goal position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function;

determine a second route from a current position of a navigation device associated with a vehicle to a point on the first route using the map information; and

output the second route and at least a portion of the first route as the search route.

9. The route-planning device according to claim 8 , wherein a parameter is used in the cost function to weight the importance of the distances between the goal position and the positions of the roads and/or sub-roads of the possible route, and wherein the search route module is further arranged to receive a value of the parameter from a user of the navigation device.

10. The route-planning device according to claim 8 , wherein the maximum length is a predetermined travel distance or a predetermined travel time.

11. A computer-implemented method of providing a search route using a route-planning device comprising a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road, the method comprising:

receiving a request to provide a search route for a vacant parking space;

identifying a goal position;

setting a current position of a navigation device associated with a vehicle as a start position of the search route;

determining a route from the start position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the start position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route, distances between the start position and positions of the roads and/or sub-roads of the possible route, and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function; and

outputting the determined route as the search route.

12. A computer-implemented method of providing a search route using a route-planning device comprising a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road, the method comprising:

receiving a request to provide a search route for a vacant parking space;

identifying a goal position;

determining a first route from an identified goal position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the goal position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function;

determining a second route from a current position of a navigation device associated with a vehicle to a point on the first route using the map information; and

outputting the second route and at least a portion of the first route as the search route.

13. A non-transitory computer readable medium comprising computer software including a set of instructions executable by a route-planning device that comprises a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road, that, when executed, cause the route-planning device to perform a method of providing a search route, the method comprising:

receiving a request to provide a search route for a vacant parking space;

identifying a goal position;

setting a current position of a navigation device associated with a vehicle as a start position of the search route;

determining a route from the start position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the start position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route, distances between the start position and positions of the roads and/or sub-roads of the possible route, and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function; and

outputting the determined route as the search route.

14. A non-transitory computer readable medium comprising computer software including a set of instructions executable by a route-planning device that comprises a storage section storing map information, wherein the map information comprises data representative of roads and/or sub-roads of a road network, each road and/or sub-road having a length and at least one parking space associated therewith, and wherein the map information further comprises probability information for each road and/or sub-road corresponding to the likelihood of finding a vacant parking space on the road and/or sub-road, that, when executed, cause the route-planning device to perform a method of providing a search route, the method comprising:

receiving a request to provide a search route for a vacant parking space;

identifying a goal position;

determining a first route from an identified goal position that visits a plurality of the parking spaces using the map information, wherein said determining comprises evaluating a predetermined cost function for each of a plurality of possible routes from the goal position of up to a maximum length, the cost function being based at least on the probability information for the roads and/or sub-roads of the possible route and distances between the goal position and positions of the roads and/or sub-roads of the possible route, and selecting the best route from the plurality of possible routes as the determined route based on maximizing or minimizing the result of the cost function;

determining a second route from a current position of a navigation device associated with a vehicle to a point on the first route using the map information; and

outputting the second route and at least a portion of the first route as the search route.