Navigation system and method with intersection guidance

• US 6,510,386 B2
• Filed: 05/11/2001
• Issued: 01/21/2003
• Est. Priority Date: 06/05/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Sakashita, Naohiro
• Primary Examiner(s): Zanelli, Michael J.
• Application Number:
  US09/852,733
• Publication Number:
  US 20010049582A1
• Time in Patent Office: 620 Days
• Field of Search: 701/201, 701/211, 340/995
• US Class Current: 701/211
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01C 21/3658 Lane guidance

Abstract

In a vehicular navigation system which provides a recommended travel route, a control unit checks for the number of each road branching from an entering road of the travel route at an intersection when the entering road has a plurality of traffic lanes. If an exiting road of the travel route from the intersection has a largest number of traffic lanes among the branching roads, no intersection guidance is provided. If the exiting road has a smaller number of traffic lanes, an intersection guidance is provided. This intersection guidance may include guidance of turn direction and guidance of traffic lane to be taken.

Claims

1. A vehicular navigation system comprising:

means for determining a recommended travel route to a destination;

means for checking whether an intersection on the travel route is a guidance intersection which requires a guidance; and

means for providing a predetermined travel guidance about the guidance intersection when approaching the guidance intersection,

wherein the checking means includes;

first means for checking a relation of continuity of roads connected to the guidance intersection in consideration of the number of traffic lanes of each road; and

second means for causing the providing means to provide a guidance of turn direction at the guidance intersection when the travel route is determined to be not on-the-way because of no continuity of roads at the guidance intersection.

2. The vehicular navigation system as in claim 1, wherein:

the checking means determines the travel route to be on-the-way when an entering road of the travel route to the guidance intersection has a plurality of traffic lanes and an exiting road of the travel route from the guidance intersection has a maximum number of traffic lanes among roads which branch from the entering road at the guidance intersection; and

the checking means determines the travel route to be not on-the-way when the entering road has a plurality of traffic lanes and-the exiting road has a minimum number of traffic lanes among the roads which branch from the entering road at the guidance intersection.

3. The vehicular navigation system as in claim 1, wherein the checking means includes:

third means for checking whether a lane guidance is necessary for indicating a lane to be taken and causing the providing means to provide the lane guidance at the guidance intersection when the lane guidance is determined to be necessary.

4. The vehicular navigation system as in claim 3, wherein:

the third means performs a checking operation thereof when the travel route is on-the-way and when the travel route is not on-the-way.

5. The vehicular navigation system as in claim 3, wherein:

the third means determines that the lane guidance is necessary when the entering road has a plurality of traffic lanes and the lanes are directed to different directions.

6. The vehicular navigation system as in claim 3, further comprising:

means for detecting a lane which is taken presently among lanes of an entering road of the travel route to the guidance intersection, and

wherein the third means disables the providing means to provide the lane guidance when the detected lane is directed in the same direction as an exiting road of the travel route from the guidance intersection.

7. The vehicular navigation system as in claim 6, wherein:

the third means causes the providing means to provide the lane guidance when the detecting means fails to detect the lane.

8. The vehicular navigation system as in claim 3, wherein:

the third means eliminates, in a checking operation thereof, a lane which exists only around the guidance intersection.

9. The vehicular navigation system as in claim 1, wherein:

the first means eliminates, in a checking operation thereof, a lane which exists only around the guidance intersection.

10. A vehicular navigation method comprising the steps of:

determining a recommended travel route to a destination, the travel route including an intersection where an entering road and an exiting road of the travel route is connected;

checking a relation between the entering road and the exiting road in consideration of the number of traffic lanes of the exiting road relative to other roads branching from the intersection;

providing an intersection guidance before entering the intersection when the exiting road has less number of traffic lanes than the other roads so that the exiting road should be taken from the intersection.

11. The vehicular navigation method as in claim 10, wherein:

the checking step performs a checking operation thereof only when the entering road has a plurality of traffic lanes; and

the guidance providing step provides a guidance of traffic lane to be taken on the entering road before entering the intersection, when a present traffic lane on the entering road is directed in a different direction from that of the exiting road.

12. The vehicular navigation method as in claim 10, wherein:

the guidance providing step is disabled to provide the intersection guidance before entering the intersection when the exiting road has a largest number of traffic lanes among the other roads.