Route guidance device

• US 6,466,866 B1
• Filed: 12/03/2001
• Issued: 10/15/2002
• Est. Priority Date: 02/25/1999
• Status: Expired due to Term

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Xanavi Informatics Corporation (Hitachi, Ltd.)
• Inventors: Sato, Hiroyuki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/914,271
• Time in Patent Office: 316 Days
• Field of Search: 701/209, 701/210, 701/200, 701/205, 340/990, 340/995, 731/78.R
• US Class Current: 701/209
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01C 21/34 Route searching; Route guidance

Abstract

Frequent execution of auto-rerouting in the vicinity of a junction where a current-position skipping of a vehicle due to map-matching is likely to occur is prevented.

When the current position of the vehicle calculated by a current position calculating unit 11 is in the vicinity of a junction on a recommended route set by the route searching unit 13 and even if the current position of the vehicle is off the recommended route as a result of correction by a map matching unit 12, a route guidance unit 132 does not request a route searching unit 131 to search a newly recommended route extending from the corrected current position of the vehicle to a destination.

Claims

1. A route guidance device, in which a recommended route from a set starting point to a set destination is searched to be submitted to a user;

and, when a current position of a vehicle deviates from said recommended route, a recommended route from the current position of the vehicle to the destination is newly searched to be submitted to the user, said route guidance device comprising;

data storing means for storing road map data;

current position measuring means for measuring a current position of a vehicle;

map matching means for correcting the current position of the vehicle measured, for each specified interval, by said current position measuring means so as to be located on any road in a specified range from the current position among roads determined by the road map data stored in said data storing means; and

auto-rerouting preventing means for preventing a search for a new recommended route from the corrected current position of the vehicle to the destination even if the current position of the vehicle is corrected by said map matching means and deviates from said recommended route resultantly when the current position of the vehicle measured by said current position measuring means is in the vicinity of a junction on said recommended route among the roads determined by the road map data stored in said data storing means.

3. The route guidance device according to claim 1,

wherein said auto-rerouting preventing means judges that the current position of the vehicle is in the vicinity of the junction on said recommended route among the roads determined by the road map data stored in said data storing means from the time when the number of roads selected as to be within a specified range from the current position of the vehicle measured by said current position measuring means is increased to the time when the vehicle moves a specified distance in said map matching means.

4. The route guidance device according to claim 3,

wherein said auto-rerouting preventing means releases prevention of the search for a new recommended route from the corrected current position of the vehicle to the destination in the case where the current position of the vehicle is corrected, even when the vehicle has not moved said specified distance, by said map matching means and deviates from said recommended route resultantly when a value exceeds a predetermined reference value in said map matching means, said value being determined by a running distance of the vehicle from the time when said current position of the vehicle is in the vicinity of the junction on said recommended route and by an azimuth difference between a plurality of the roads selected as to be within the specified range from the current position of the vehicle measured by said current position measuring means.

2. The route guidance device according to clam 1,

wherein said auto-rerouting preventing means searches the junction on said recommended route, said junction being near the current position of the vehicle measured by said current position measuring means, among junctions of the roads determined by the road map data stored in said data storing means, and judges that the current position of the vehicle is in the vicinity of the junction on said recommended route among the roads determined by the road map data stored in said data storing means when the current position of the vehicle is within a specified distance from the junction in a traveling direction of the vehicle.