Vehicle navigation system

• US 6,285,950 B1
• Filed: 05/13/1999
• Issued: 09/04/2001
• Est. Priority Date: 05/13/1999
• Status: Active Grant

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Tanimoto, Satoshi
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US09/311,330
• Time in Patent Office: 845 Days
• Field of Search: 701/201, 701/208, 701/202, 701/204, 701/211, 340/992, 340/991, 340/994, 340/995
• US Class Current: 701/201
• CPC Class Codes: G01C 21/34 Route searching; Route guidance

Abstract

A vehicle navigation system estimates a travel time to a destination. Estimation of a travel time to a destination includes two steps of calculation. First, a travel time to an intermediate point forward of the present vehicle position is calculated based on the current average speed. Second, a travel time to the destination from the intermediate point is calculated based on the costs of road segments. A travel time to the destination from the present vehicle position is a sum of the travel time obtained by the first calculation and the travel time obtained by the second calculation. Since the current average speed reflects the road conditions to which the vehicle is presently subjected, the travel time to the intermediate point calculated with the current average speed is more accurate than a travel time that would be calculated by adding the costs between the present vehicle position and the intermediate position. As a result, a sum of the travel times obtained by the first calculation and the second calculation is more accurate than a travel time that is calculated by adding the costs throughout the road segments between the present vehicle position and the destination.

Claims

1. An on-board vehicle navigation system having a function of estimating a travel time for a vehicle to travel to a destination from a present vehicle position along a predetermined route, comprising on the vehicle:

a memory storing costs of road segments in an area including said present vehicle position and said destination;

a sensor for determining a current average travel speed of said vehicle;

means for calculating a first travel time to reach an intermediate point along the predetermined route from said present vehicle position based on said current average travel speed;

means for calculating a second travel time to reach said destination from said intermediate point based on said costs;

means for totaling said first and second travel times; and

means for communicating the total travel time to a user of the vehicle.

2. A navigation system according to claim 1, wherein said intermediate point is a next maneuver point or a point between said next maneuver point and said present vehicle position.

3. A navigation system according to claim 1, wherein said intermediate point is a point beyond a next maneuver point.

4. A navigation system according to claim 1, wherein said first travel time is calculated by dividing a distance between said intermediate point and said present vehicle position by said current average traveling speed.

5. A navigation system according to claim 1, wherein said second travel time is calculated by adding said costs of said road segments between said intermediate point and said destination.

6. A navigation system according to claim 5, wherein said costs are personalized to individual drivers.

7. A navigation system according to claim 1, further comprising means for displaying a total of said first and second travel times.

8. An on-board navigation system capable of guiding a vehicle to a destination from a present vehicle position, comprising on the vehicle:

means for searching an optimum route and guiding said vehicle along said optimum route to said destination;

a memory storing costs of links along said optimum route;

a sensor for determining a current average traveling speed of said vehicle;

means for calculating a first travel time to reach an intermediate point on said optimum route from said present vehicle position based on said current traveling speed;

means for calculating a second travel time to reach said destination from said intermediate point based on said costs; and

means for calculating and displaying a sum of said first and second travel times.

9. A navigation system according to claim 8, wherein said immediate point is a next maneuver point or a point between said next maneuver point and said present vehicle position.

10. A navigation system according to claim 8, wherein said intermediate point is a point on said optimum route beyond said next maneuver point.

11. A navigation system according to claim 8, wherein said first travel time is calculated by dividing a distance between said intermediate point and said present vehicle position by said current traveling speed.

12. A navigation system according to claim 8, wherein said second travel time is calculated by adding said costs of said links between said intermediate point and said destination.

13. A navigation system according to claim 8, wherein said costs are personalized to individual drivers.

14. In a vehicle navigation system, a method of estimating a travel time for a vehicle to travel to a destination from a present vehicle position along a predetermined route, comprising:

determining a current average traveling speed of said vehicle;

calculating a first travel time to reach an intermediate point along the predetermined route from said present vehicle position based on said current traveling speed;

calculating a second travel time to reach the destination from said intermediate point based on costs of road segments along the predetermined route between said destination and said intermediate point;

calculating a sum of said first and second travel times; and

communicating the total travel time to a user of the vehicle, where the method is conducted on the vehicle.

15. A method according to claim 14, wherein said intermediate point is a next maneuver point or a point between said next maneuver point and said present vehicle position.

16. A method according to claim 14, wherein said intermediate point is a point beyond a next maneuver point.

17. A method according to claim 14, wherein said first travel time is calculated by dividing a distance between said intermediate point and said present vehicle position by said current traveling speed.

18. A method according to claim 14, wherein said second travel time is calculated by adding said costs of said road segments between said intermediate point and said destination.