Method and apparatus for detecting and correcting freeway-ramp-freeway situation in calculated route

• US 20100217512A1
• Filed: 02/24/2009
• Published: 08/26/2010
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Doi, Shinobu, Vu, Tien
• Granted Patent: US 9,927,251 B2
• Time in Patent Office: Days
• US Class Current: 701/200
• CPC Class Codes: G01C 21/3461 Preferred or disfavoured areas, e.g. dangerous zones, toll or emission zones, intersections, manoeuvre types, segments such as motorways, toll roads, ferries
• CPC Class Codes: G08G 1/096827 where the route is computed onboard

Abstract

A method detects a particular freeway-ramp-freeway situation in a calculated route and corrects the route by replacing the freeway-ramp-freeway situation with all-freeway segments. The method includes the steps of: establishing a calculated route to a destination; examining the calculated route to detect whether there is a first point where the calculated route exits a freeway and a second point where the calculated route enters a freeway; evaluating map data to determine whether the freeway exited and the freeway entered are the same freeway; and replacing road segments of the calculated route between the first point and the second point constituting the freeway-ramp-freeway situation with freeway segments between the first point and the second point, thereby avoiding the freeway-ramp-freeway situation.

Claims

1. A method of correcting a particular situation in a calculated route between a start point to a destination for a navigation system, comprising the following steps of:

establishing a calculated route between the start point and the destination where the calculated route includes a freeway;

examining the calculated route from one end to another end (forward direction) to detect whether there is a first point where the calculated route exits a freeway;

further examining the calculated route in the forward direction to detect whether there is a second point where the calculated route enters a freeway;

evaluating map data associated with the calculated route to determine whether the freeway exited at the first point and the freeway entered at the second point are the same freeway;

determining that a freeway-ramp-freeway situation exists in the calculated route when the freeway exited and the freeway entered are the same where the freeway-ramp-freeway situation is defined as a situation where a calculated route exits a freeway and immediately enters the same freeway; and

replacing road segments of the calculated route between the first point and the second point constituting the freeway-ramp-freeway situation with freeway segments between the first point and the second point, thereby changing the freeway-ramp-freeway situation to an all-freeway situation.

2. A method of correcting a particular situation in a calculated route as defined in claim 1, after conducting said step of establishing the calculated route, the method further comprising a step of changing the calculated route by dynamically evaluating a cost of the calculated route based on factors including current or estimated traffic conditions on the calculated route.

3. A method of correcting a particular situation in a calculated route as defined in claim 1, wherein said step of examining the calculated route to detect the second point is conducted within a predetermined distance from the first point on the calculated route.

4. A method of correcting a particular situation in a calculated route as defined in claim 1, wherein said step of evaluating the map data to determine whether the freeway exited at the first point and the freeway entered at the second point are the same is conducted by comparing link IDs of the first point and the second point while taking map mesh IDs into consideration when the first point and the second point belong to different map meshes from one another in the map data.

5. A method of correcting a particular situation in a calculated route as defined in claim 1, wherein said step of evaluating the map data to determine whether the freeway exited at the first point and the freeway entered at the second point are the same is conducted by comparing link IDs of the first point and the second point at the same or higher map layer level when the first point and the second point belong to different map meshes from one another.

6. A method of correcting a particular situation in a calculated route as defined in claim 1, before conducting said step of replacing the road segments of the calculated route, the method further comprising a step of comparing a first cost associated with the freeway-ramp-freeway situation with a second cost associated with the all-freeway situation and proceeding to said step of replacing the road segments unless the second cost is excessively higher than the first cost where the cost is determined based on factors including a distance and a time length.

7. A method of correcting a particular situation in a calculated route as defined in claim 1, before conducting said step of replacing the road segments of the calculated route, the method further comprising a step of examining a traffic regulation governing a location of the freeway-ramp-freeway situation and immediately proceeding to said step of replacing the road segments when the traffic regulation prohibits the freeway-ramp-freeway situation.

8. A method of correcting a particular situation in a calculated route as defined in claim 1, after conducting said step of determining that the freeway-ramp-freeway situation exists, the method further comprising a step of evaluating the map data to find a freeway segment that is connected to the first point and is oriented in the forward direction.

9. A method of correcting a particular situation in a calculated route as defined in claim 8, after conducting said step of finding the freeway segment that is connected to the first point, the method further comprising a step of evaluating the map data to find a freeway segment on the calculated route within a predetermined distance from the first point, and a step of evaluating the map data to find a freeway segment that is incoming to the second point.

10. A method of correcting a particular situation in a calculated route as defined in claim 9, after conducting said step of finding the freeway segment that is incoming to the second point, the method further comprising a step of retrieving all of freeway segments between the first point and the second point so that the retrieved freeway segments replace the road segments constituting the freeway-ramp-freeway situation.

11. An apparatus for correcting a particular situation in a calculated route between a start point to a destination for a navigation system, comprising the following steps of:

means for establishing a calculated route between the start point and the destination where the calculated route includes a freeway;

means for examining the calculated route from one end to another end (forward direction) to detect whether there is a first point where the calculated route exits a freeway;

means for further examining the calculated route in the forward direction to detect whether there is a second point where the calculated route enters a freeway;

means for evaluating map data associated with the calculated route to determine whether the freeway exited at the first point and the freeway entered at the second point are the same freeway;

means for determining that a freeway-ramp-freeway situation exists in the calculated route when the freeway exited and the freeway entered are the same where the freeway-ramp-freeway situation is defined as a situation where a calculated route exits a freeway and immediately enters the same freeway; and

means for replacing road segments of the calculated route between the first point and the second point constituting the freeway-ramp-freeway situation with freeway segments between the first point and the second point, thereby changing the freeway-ramp-freeway situation to an all-freeway situation.

12. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, after conducting said means for establishing the calculated route, the method further comprising means for changing the calculated route by dynamically evaluating a cost of the calculated route based on factors including current or estimated traffic conditions on the calculated route.

13. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, wherein said means for examining the calculated route to detect the second point is conducted within a predetermined distance from the first point on the calculated route.

14. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, wherein said means for evaluating the map data to determine whether the freeway exited at the first point and the freeway entered at the second point are the same is conducted by comparing link IDs of the first point and the second point while taking map mesh IDs into consideration when the first point and the second point belong to different map meshes from one another in the map data.

15. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, wherein said means for evaluating the map data to determine whether the freeway exited at the first point and the freeway entered at the second point are the same is conducted by comparing link IDs of the first point and the second point at the same or higher map layer level when the first point and the second point belong to different map meshes from one another in the map data.

16. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, before conducting said means for replacing the road segments of the calculated route, the apparatus further comprising means for comparing a first cost associated with the freeway-ramp-freeway situation with a second cost associated with the all-freeway situation and proceeding to said means for replacing the road segments unless the second cost is excessively higher than the first cost where the cost is determined based on factors including a distance and a time length.

17. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, before conducting said means for replacing the road segments of the calculated route, the apparatus further comprising means for examining a traffic regulation governing a location of the freeway-ramp-freeway situation and immediately proceeding to said means for replacing the road segments when the traffic regulation prohibits the freeway-ramp-freeway situation.

18. An apparatus for correcting a particular situation in a calculated route as defined in claim 11, after conducting said means for determining that the freeway-ramp-freeway situation exists, the apparatus further comprising means for evaluating the map data to find a freeway segment that is connected to the first point and is oriented in the forward direction.

19. An apparatus for correcting a particular situation in a calculated route as defined in claim 18, after conducting said means for finding the freeway segment that is connected to the first point, the apparatus further comprising means for evaluating the map data to find a freeway segment on the calculated route within a predetermined distance from the first point, and means for evaluating the map data to find a freeway segment that is incoming to the second point.

20. An apparatus for correcting a particular situation in a calculated route as defined in claim 19, after conducting said means for finding the freeway segment that is incoming to the second point, the apparatus further comprising means for retrieving all of freeway segments between the first point and the second point so that the retrieved freeway segments replace the road segments constituting the freeway-ramp-freeway situation.