Navigation system

• US 20060167616A1
• Filed: 01/26/2006
• Published: 07/27/2006
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Hitachi, Ltd.
• Inventors: Endo, Yoshinori, Yamane, Kenichiro, Machii, Kimiyoshi, Fujiwara, Junsuke
• Granted Patent: US 7,912,635 B2
• Time in Patent Office: Days
• US Class Current: 701/117
• CPC Class Codes: G01C 21/3492 employing speed data or traffic data, e.g. real-time or historical traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096741 where the source of the transmitted information selects which information to transmit to each vehicle
• CPC Class Codes: G08G 1/096775 where the origin of the information is a central station
• CPC Class Codes: G08G 1/096811 where the route is computed offboard
• CPC Class Codes: G08G 1/096816 where the complete route is transmitted to the vehicle at once
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data

Abstract

The present invention aims to provide a technique that can download traffic information in a more efficient manner, in a navigation system including a traffic information distribution server and a terminal unit. The information distribution server narrows down whereas possible traffic information to that to be used for the processing at the terminal unit before downloading the information to the unit. For example, the traffic information distribution server includes: a traffic information obtaining unit for obtaining traffic information pertaining to a link configuring a route or the periphery of the link (e.g., mesh area including the link), and to a predicted running duration of the link; and a sending unit for downloading the obtained traffic information to the terminal unit. Means for narrowing down the object for download may be possessed by the server or the terminal unit.

Claims

1. A traffic information distribution server, wherein the server comprises:

a traffic information obtaining unit for obtaining traffic information relating to a link configuring a route or a link belonging to an area including the link configuring the route, and to a predicted running duration of the link; and

a sending unit for downloading the obtained traffic information to a terminal unit.

2. A traffic information distribution server as claimed in claim 1, wherein the traffic information obtaining unit obtains the traffic information relating to the link configuring the route or the link belonging to the area including the link configuring the route, and to a predicted running duration of the link, by extracting or creating the traffic information from traffic information stored in a memory unit of the traffic information obtaining unit.

3. A traffic information distribution server as claimed in claim 1, wherein if a plurality of pieces of traffic information exist relating to the same link the traffic information obtaining unit sets a representative value using the plurality of pieces of traffic information.

4. A traffic information distribution server as claimed in claim 1, wherein the traffic information distribution server further comprises a unit for removing traffic information already sent to the terminal unit from the object to be sent to the terminal unit.

5. A traffic information distribution server as claimed in claim 1, wherein the traffic information distribution server further comprises a unit for removing from the object to be sent to the terminal unit, traffic information which is different from the traffic information already sent to the terminal unit by a predetermined or less value.

6. A traffic information distribution server as claimed in claim 1, wherein the traffic information distribution server further comprises:

a unit for searching a route from a starting location to a destination; and

a unit for obtaining a predicted running duration of each of the links configuring the searched route.

7. A terminal unit, wherein the terminal unit comprises a unit for sending to a traffic information distribution server as claimed in claim 6, information on a starting location and a destination, a request for searching a route to the destination, and a request for sending traffic information on the searched route or the periphery of the searched route, and for receiving from the traffic information distribution server, information on the route to the destination, and traffic information relating to a link belonging to the route or an area including the route.

11. A terminal unit comprising a download request unit for requesting the traffic information distribution server as chimed in claim 1 to download traffic information,

wherein the download request unit requests the traffic information distribution server to download traffic information if a matching with a predetermined condition occurs for any of the values of:

difference between a preset spot for obtaining information and the current location;

difference between a predicted running duration of a route and the actual running duration;

difference between a duration of received traffic information and the predicted running duration; and

difference between the duration of received traffic information and the current time;

dispersion in statistical values of statistical traffic information when the terminal unit retains the statistical traffic information.

12. A traffic information distribution server as claimed in claim 1,

wherein the traffic information belongs to any of the time-space cells partitioned by links or areas on a map and durations;

and

wherein the traffic information obtaining unit obtains a predicted running trajectory on the time-space cells obtained from a predicted running duration of the route, and obtains traffic information belonging to a time-space cell including the predicted running trajectory obtained.

8. A terminal unit comprising:

a route search unit for searching a route from a starting location to a destination by using a link cost stored in a memory unit possessed by the route search unit; and

a download request unit for requesting a traffic information distribution server for distributing traffic information to download traffic information relating to a link belonging to the searched route or to an area including the searched route,

wherein the route search unit reperforms route search by using, for a link whose link cost is included in traffic information downloaded from the traffic information distribution server, the link cost, and for other links, a link cost stored in the memory unit possessed by the route search unit.

9. A terminal unit comprising as claimed in claim 8, wherein the download request unit comprises:

expandingly extracting a link and predicted running duration of the link based on predetermined error values in time and space, with respect to a lid configuring the route or to all the links belonging to an area including the route, and in a predicted running duration of the link; and

making a request for downloading the traffic information.

10. A terminal unit as claimed in claim 8,

wherein the memory unit stores statistical traffic information created by statistical processing, and

wherein the download request unit makes a request for downloading traffic information having dispersion of a predetermined or more value in the statistical traffic information relating to a link configuring the route and to a predicted running duration of the link, and relating to the predicted running duration of the link or of a link belonging to an area including the link.