Navigation method, navigation system, and information communications apparatus used in the navigation system

• US 6,427,117 B1
• Filed: 04/17/2000
• Issued: 07/30/2002
• Est. Priority Date: 07/14/1999
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Equos Research
• Original Assignee: Kabushikikaisha Equos Research
• Inventors: Ito, Yasuo, Sugawara, Takashi, Kitano, Satoshi, Yamakawa, Hiroyuki, Gorai, Naoki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): NGUYEN, THU V
• Application Number:
  US09/551,403
• Time in Patent Office: 834 Days
• Field of Search: 701/23-26, 701/28, 701/200-204, 701/206-213, 701/215-224, 340/988-995
• US Class Current: 701/209
• 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: G01C 21/3608 using speech input, e.g. using speech recognition
• CPC Class Codes: G01C 21/3629 Guidance using speech or audio output, e.g. text-to-speech text to speech systems per se G10L13/00
• CPC Class Codes: G01C 21/3644 Landmark guidance, e.g. using POIs or conspicuous other objects
• CPC Class Codes: G01C 21/3679 Retrieval, searching and output of POI information, e.g. hotels, restaurants, shops, filling stations, parking facilities G01C21/3611 takes precedence

Abstract

A navigation system includes a navigation center and at least one moving body. The navigation center of the navigation system comprises memory means for storing navigation information; updating means for constantly updating the navigation information stored in the memory means; route searching means for setting a route from a current position of the moving body to a destination on the basis of the newest navigation information updated by the updating means; dividing means for dividing the searched route into at least two portions; extracting means for extracting navigation data concerning at least a head portion of the divided route from the memory means; transmitting means for transmitting to the moving body the extracted navigation data; and control means. After transmitting the navigation data for the head portion to the moving body and before transmitting navigation data for a remaining route, the control means controls each of the route searching means, the dividing means, the extracting means and the transmitting means so that each means performs the respective processes. This arrangement enables a user of the moving body to be provided with route guidance which is conducted using the navigation data formed based on the newest navigation information that reflects various road conditions.

Claims

1. A navigation method in which navigation data concerning a route from a current position of a moving body to a destination is transmitted from a navigation center to the moving body, and then route guidance is carried out at the moving body using the navigation data received from the navigation center, the method comprising the steps of:

(a) updating navigation information which includes various information concerning routes, the navigation information being stored in memory means provided in the navigation center;

(b) conducting a route search for setting a route from a current position of the moving body to a destination on the basis of the newest navigation information updated in the updating step (a);

(c) dividing the route set at the route searching step (b) into at least two portions;

(d) extracting navigation data concerning at least a head portion of the route divided at the dividing step (c) from said memory means storing the newest navigation information updated in the updating step (a);

(e) transmitting the navigation data extracted at the extracting step (d) from the navigation center to the moving body;

(f) conducting a route search for setting a route from a current position of the moving body to the destination on the basis of the newest navigation information updated in the updating step (a) after transmitting the navigation data for the head portion to the moving body but before transmitting navigation data for a remaining portion of the route;

(g) dividing the route set at the route searching step (f) into at least two portions;

(h) extracting navigation data concerning at least a head portion of the route divided at the dividing step (g) from said memory means storing the newest navigation information updated at the updating step (a); and

(i) transmitting the navigation data extracted at the extracting step (h) from the navigation center to the moving body.

2. The navigation method as claimed in claim 1, wherein the moving body transmits to the navigation center a request for the route searching to set the route from the current position of the moving body to the destination when reaching a predetermined request transmission point on the head portion for which navigation data has been received from the navigation center and along which the moving body is moving, and wherein the steps (f) to (i) are executed each time when the navigation center receives the request from the moving body.

3. The navigation method as claimed in claim 2, further comprising the steps of:

making at least one judgement from a group of judgements including a judgement as to whether or not the predetermined request transmission point on the head portion is within an area wherein communication between the moving body and the navigation center is either impossible or of poor quality and a judgement as to whether or not a part of the head portion of the route including a position where the moving body, which has reached the request transmission point, is expected to be located when transmission of the navigation data for the head portion from the navigation center is completed, is partially or completely within an area wherein communication between the moving body and the navigation center is either impossible or of poor quality; and

changing the request transmission point to another point when either of said judgements is affirmative;

wherein the judging step and the changing step are executed before the step (e) or (i).

4. The navigation method as claimed in claim 3, wherein the step of changing the request transmission point is performed by increasing road length of the head portion.

5. The navigation method as claimed in claim 4, wherein the division of the route at each of the steps (c) and (g) is carried out by dividing the route into a plurality of segments, wherein each of the portions of the route divided at the dividing step (c) or (g) is established using one or more of the segments as a unit, and wherein the step of changing the request transmission point is performed by increasing the road length of the head portion by at least one segment.

6. The navigation method as claimed in claim 3, wherein the step of changing the request transmission point is performed by decreasing road length of the head portion.

7. The navigation method as claimed in claim 6, wherein the division of the route at each of the steps (c) and (g) is carried out by dividing the route into a plurality of segments, wherein each of the portions of the route divided at the dividing step (c) or (g) is established using one or more of the segments as a unit, and wherein the step of changing the request transmission point is performed by decreasing the road length of the head by at least one segment.

8. The navigation method as claimed in claim 1, wherein when the navigation center detects that the moving body reaches a predetermined route search point on the head portion whose navigation data has been received from the navigation center and along which the moving body is moving, the navigation center automatically executes the steps (f)-(i), whereby the moving body receives from the navigation center navigation data for a remaining portion of the route.

9. The navigation method as claimed in claim 1, wherein when traffic situation or road condition of an untraveled route of the head portion is changed while the moving body is on the route corresponding to the head portion whose navigation data has been received from the navigation center, the steps (f)-(i) are executed.

10. The navigation method as claimed in claim 1 wherein the steps (f) through (i) are executed each time when the navigation center receives a request from the moving body for transmission of the navigation data and the guidance data.

11. A navigation system in which navigation data concerning a route from a current position of a moving body to a destination is transmitted from a navigation center to the moving body, and then route guidance is carried out at the moving body using the navigation data received from the navigation center, the system comprising:

memory means provided in the navigation center for storing navigation information which includes various information concerning routes;

updating means provided in the navigation center for updating the navigation information stored in said memory means;

route searching means provided in the navigation center for setting a route from a current position of the moving body to a destination on the basis of the newest navigation information stored in said memory means;

dividing means provided in the navigation center for dividing the route set by said route searching means into at least two portions;

extracting means provided in the navigation center for extracting navigation data concerning at least a head portion of the route divided by said dividing means from said memory means storing the newest navigation information updated by said updating means;

transmitting means provided in the navigation center for transmitting from the navigation center to the moving body the navigation data extracted by said extracting means;

control means provided in the navigation center for controlling each of said memory means, said updating means, said route searching means, said dividing means, said extracting means and said transmitting means; and

receiving means provided in the moving body for receiving the navigation data transmitted from said transmitting means of the navigation center,

wherein said control means controls said route searching means to set a route from a current position of the moving body to the destination on the basis of the newest navigation information stored in said memory means, controls said dividing means to divide the route set by said route searching means into at least two portions, controls said extracting means to extract navigation data concerning at least a head portion of the route divided by said dividing means from said memory means storing the newest navigation information updated by said updating means, and then controls said transmitting means to transmit from the navigation center to the moving body the navigation data extracted by said extracting means, after transmitting the navigation data for the head portion to the moving body but before transmitting the navigation data for the route which is newly set by said route searching means.

12. The navigation system as claimed in claim 11, wherein the moving body transmits to the navigation center a request for the route searching to set the route from the current position of the moving body to the destination when reaching a predetermined request transmission point on the head portion for which navigation data has been received from the navigation center and along which the moving body is moving, and wherein said control means controls each of said route searching means, said dividing means, said extracting means and said transmitting means so that each means performs the respective processes, each time when the navigation center receives the request from the moving body.

13. The navigation system as claimed in claim 12, further comprising:

judging means for making at least one judgement from a group consisting of a judgement as to whether or not the predetermined request transmission point on the head portion is positioned within an area wherein communication between the moving body and the navigation center is either impossible or of poor quality and a judgement as to whether or not a part of the head portion of the route including a position where the moving body, which has reached the request transmission point, is expected to be located when transmission of the navigation data for the head portion from the navigation center is completed, is partially or completely within an area wherein communication between the moving body and the navigation center is either impossible or of poor quality; and

changing means for changing the request transmission point to another point when either of said judgements is affirmative;

wherein the judgement by said judging means and the change of the request transmission point by said changing means are executed before the navigation data is transmitted to the moving body via said transmission means.

14. The navigation system as claimed in claim 13, wherein the division of the route by said dividing means is carried out by dividing the route into a plurality of segments, wherein each of the portions of the route divided by said dividing means is established using one or more of the segments as a unit.

15. The navigation system as claimed in claim 14, wherein the change of the request transmission point by said changing means is performed by increasing road length of the head portion by at least one segment.

16. The navigation system as claimed in claim 14, wherein the change of the request transmission point by said changing means is performed by decreasing road length of the head portion by at least one segment.

17. The navigation system as claimed in claim 14, wherein each segment is established so as to have the same number of bits.

18. The navigation system as claimed in claim 17, wherein the change of the request transmission point by said changing means is performed by increasing road length of the head portion by at least one segment.

19. The navigation system as claimed in claim 17, wherein the change of the request transmission point by said changing means is performed by decreasing road length of the head portion by at least one segment.

20. The navigation system as claimed in claim 14, wherein each segment is established so as to have a substantially uniform road length.

21. The navigation system as claimed in claim 20, wherein the change of the request transmission point by said changing means is performed by increasing road length of the head portion by at least one segment.

22. The navigation system as claimed in claim 20, wherein the change of the request transmission point by said changing means is performed by decreasing road length of the head portion by at least one segment.

23. The navigation system as claimed in claim 11, wherein when the navigation center detects that the moving body reaches a predetermined route search point on the head portion whose navigation data has been received from the navigation center and along which the moving body is moving, said control means controls each of said route searching means, said dividing means, said extracting means and said transmitting means so that each means performs the respective processes, whereby the moving body receives from the navigation center navigation data for a remaining portion of the route.

24. The navigation system as claimed in claim 11, wherein when traffic situation or road condition of an untraveled route of the head portion is changed while the moving body is on the route corresponding to the head portion whose navigation data has been received from the navigation center, said control means controls the route searching means to set a route from a current position of the moving body to the destination on the basis of the newest navigation information stored in said memory means, controls said dividing means to divide the route set by the route searching means into at least two portions, controls said extracting means to extract the navigation data concerning at least the head portion of the route divided by said dividing means from said memory means storing the newest navigation information updated by said updating means, and then controls said transmitting means to transmit from said transmitting means of the navigation center to the moving body the navigation data extracted by said extracting means.

25. An information communications apparatus used in a navigation system in which navigation data concerning a route from a current position of a moving body to a destination is transmitted from a navigation center including the information communications apparatus to the moving body, and then route guidance is carried out at the moving body using the navigation data received from the navigation center, the apparatus comprising:

memory means for storing navigation information which includes various information concerning routes;

updating means for updating the navigation information stored in said memory means;

route searching means for setting a route from a current position of the moving body to a destination on the basis of the newest navigation information stored in said memory means;

dividing means for dividing the route set by said route search means into at least two portions;

extracting means for extracting navigation data concerning at least a head portion of the route divided by said dividing means from the memory means storing the newest navigation information updated by said updating means;

transmitting means for transmitting the navigation data extracted by said extracting means from the navigation center to the moving body; and

control means for controlling each of said memory means, said updating means, said route searching means, said dividing means, said extracting means and said transmitting means,

wherein said control means controls the route searching means to set a route from a current position of the moving body to the destination on the basis of the newest navigation information stored in said memory means, controls said dividing means to divide the route set by said route search means into at least two portions, controls said extracting means to extract navigation data concerning at least a head portion of the route divided by said dividing means from the newest navigation information, and then controls said transmitting means to transmit from the navigation center to the moving body the navigation data extracted by said extracting means, after transmitting the navigation data for the head portion to the moving body but before transmitting the navigation data for the route which is newly set by said rout searching means.