Navigation system, and program and storage medium for use in the same

• US 7,065,447 B2
• Filed: 12/18/2003
• Issued: 06/20/2006
• Est. Priority Date: 12/18/2002
• Status: Expired due to Fees

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Shimizu, Takanori, Yamada, Kunihiro, Ishibashi, Noboru
• Primary Examiner(s): Chin, Gary
• Application Number:
  US10/737,900
• Publication Number:
  US 20040143387A1
• Time in Patent Office: 915 Days
• Field of Search: 701/202, 701/209, 701/210, 701/211, 340/995.13, 340/995.19, 340/995.2, 340/995.21, 340/995.22, 340/995.23
• US Class Current: 701/210
• CPC Class Codes: G01C 21/3415 Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096838 where the user preferences are taken into account or the user selects one route out of a plurality
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096866 where the complete route is shown to the driver
• CPC Class Codes: G08G 1/096872 where instructions are given per voice

Abstract

A navigation system that searches for a route to a destination based on stored map data and provides navigation guidance to the destination along the route includes a controller that acquires road congestion information associated with the route, searches for the route to the destination based on a calculated search cost and changes a search cost based on predicted secondary congestion that is predicted based on acquired road congestion information, wherein a recommendable route that can avoid congestion is searched based on the search cost that has been changed based on the predicted secondary congestion.

Claims

1. A navigation system that searches for a route to a destination based on stored map data and provides navigation guidance to the destination along the route, comprising:

a controller that;

acquires road congestion information associated with the route from outside a vehicle;

searches for the route to the destination based on a calculated search cost;

predicts secondary congestion that occurs due to current congestion based on acquired road congestion information; and

changes a search cost based on the predicted secondary congestion, wherein a recommendable route that can avoid congestion is searched based on the search cost that has been changed based on the predicted secondary congestion.

2. The navigation system according to claim 1, wherein the controller predicts the congestion at an intersection preceding a congested point indicated by the acquired road congestion information.

3. The navigation system according to claim 2, wherein the controller changes the search cost for a detour route from the intersection.

4. The navigation system according to claim 2, wherein the controller gradually changes stepwise the search cost for each possible detour route taken at each of a plurality of intersections preceding the congested point, depending on the distance between the congested point and the respective intersections.

5. The navigation system according to claim 4, wherein the controller increases the search cost for intersections near the congested point such that an increment of the search cost amounts for the intersections decreases stepwise with increasing distance from the congested point.

6. The navigation system according to claim 1, wherein the controller searches for a second route including a detour route for avoiding a congested point indicated by the road congestion information and changes the search cost for the second route.

7. A storage medium storing a set of program instructions executable on a data processing device and usable to search for a route to a destination based on stored map data and provide navigation guidance to the destination along the route, the instructions comprising:

acquiring road congestion information associated with the route from outside a vehicle;

searching for the route to the destination based on a calculated search cost;

predicting secondary congestion that occurs due to current congestion based on the acquired road congestion information;

changing a search cost based on the predicted secondary congestion; and

searching for a recommendable route that can avoid congestion based on the changed search cost.

8. The storage medium of claim 7, wherein the congestion is predicted at an intersection preceding a congested point indicated by the acquired road congestion information.

9. The storage medium of claim 8, wherein the search cost is changed for a detour route from the intersection.

10. The storage medium of claim 8, wherein the search cost is gradually changed stepwise for each possible detour route taken at each of a plurality of intersections preceding the congested point, depending on the distance between the congested point and the respective intersections.

11. The storage medium of claim 10, wherein the search cost is increased for intersections near the congested point such that an increment of the search cost amounts for the intersections decreases stepwise with increasing distance from the congested point.

12. The storage medium of claim 7, wherein a second route is searched including a detour route for avoiding a congested point indicated by the road congestion information and changes the search cost for the second route.

13. A storage medium storing a set of program instructions executable on a data processing device and usable to search for a route to a destination based on stored map data and provide navigation guidance to the destination along the route, the storage medium comprising:

map data used in searching for a route and navigation guidance along the route; and

the instructions comprising;

acquiring road congestion information associated with the route from outside a vehicle;

searching for the route to the destination based on a calculated search cost;

predicting secondary congestion that occurs due to current congestion based on the acquired road congestion information;

changing a search cost based on the predicted secondary congestion; and

searching for a recommendable route that can avoid congestion based on the changed search cost.

14. The storage medium of claim 13, wherein the congestion is predicted at an intersection preceding a congested point indicated by the acquired road congestion information.

15. The storage medium of claim 14, wherein the search cost is changed for a detour route from the intersection.

16. The storage medium of claim 14, wherein the search cost is gradually changed stepwise for each possible detour route taken at each of a plurality of intersections preceding the congested point, depending on the distance between the congested point and the respective intersections.

17. The storage medium of claim 16, wherein the search cost is increased for intersections near the congested point such that an increment of the search cost amounts for the intersections decreases stepwise with increasing distance from the congested point.

18. The storage medium of claim 13, wherein a second route is searched including a detour route for avoiding a congested point indicated by the road congestion information and changes the search cost for the second route.