Navigation system for vehicle

• US 20030050752A1
• Filed: 07/02/2002
• Published: 03/13/2003
• Est. Priority Date: 07/04/2001
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Takada, Masayuki, Seto, Fumio, Ishiwaka, Takuo
• Granted Patent: US 6,629,035 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: G08G 1/0969 having a display in the form of a map
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles

Abstract

A navigation system 2 includes a map-gain timing judging part 15 to calculate a traveling speed the position of a vehicle detected by a GPS unit 13. A moving distance of the vehicle during the renewal of map is calculated by the traveling speed and a renewal time necessary for gaining the map information from the server 11 of a map information delivery apparatus 1. The system 2 further calculates a traveling direction of the vehicle by the position of the vehicle and also calculates a road distance from the present position of the vehicle to the margin of a map on display. When the road distance agrees with moving distance, it is started to gain a new map information from the server. Thus, when the vehicle reaches the margin of the map on display, the renewal of the map information is completed.

Claims

1. A navigation system for a vehicle, comprising:

a communication unit connected to a server for delivering a map information;

a map gaining unit connected to the communication unit thereby to gain the map information from the server through the communication unit;

a display unit connected to the map gaining unit thereby to display the map information gained by the map gaining unit, in the form of a map image;

a position detecting unit for detecting the position of the vehicle;

a renewal time calculating unit for calculating a renewal time necessary to renew the map, the renewal time including a time for gaining the map information;

a moving distance calculating unit for calculating a moving distance of the vehicle traveling during the renewal of the map;

a road distance calculating unit for calculating a road distance required for the vehicle to travel from its present position to a margin of the map displayed on the display unit;

a comparing unit for comparing the road distance with the moving distance; and

an extraction-area setting unit for establishing the area of a new map to be displayed next to the map presently displayed on the display unit when the road distance agrees with the moving distance;

wherein the map gaining unit transmits information about the area of the new map established by the extraction-area setting unit, to the server through the communication unit and further gains a new map information from the server thereby to carry out the renewal of the map displayed on the display unit.

2. The navigation system of claim 1, wherein the road distance calculating unit calculates a traveling direction of the vehicle by a positional change thereof and the road distance calculated by the road distance calculating unit is equal to a distance from the position of the vehicle to an intersection point between a straight line passing through the position of the vehicle with the same inclination as the traveling direction and a margin of the map presently displayed on the display unit.

3. The navigation system of claim 1, wherein the road distance calculated by the road distance calculating unit is equal to a distance along a road part extending from the present position of the vehicle up to an intersection point between a road on which the vehicle is traveling and a margin of the map presently displayed on the display unit.

4. The navigation system of claim 3, wherein, when a road that the vehicle is present branches off into branch roads before reaching the margin of the map on display, the road distance calculating unit calculates respective distances required for the vehicle to travel from the present position to the margin of the map through the branch roads and wherein a shorter distance of the calculated distances is established as the road distance.

5. The navigation system of claim 1, wherein the moving distance calculating unit calculates a traveling speed of the vehicle by a time change in the position of the vehicle thereby to calculate the moving distance by the calculated traveling speed and also the renewal time of map.

6. The navigation system of claim 5, wherein the moving distance calculating unit judges the sort of a road where the vehicle is present and adopts a speed predetermined corresponding to the sort of the road, as the traveling speed of the vehicle.

7. The navigation system of claim 5, wherein the moving distance calculating unit calculates the traveling speed of the vehicle by a time that the vehicle took to travel a predetermined road segment and a distance of the predetermined road segment.

8. The navigation system of claim 7, wherein the moving distance calculating unit calculates the traveling speeds of the vehicle with respect to a plurality of predetermined road segments and adopts an average of the so-calculated traveling speeds as the traveling speed of the vehicle.

9. The navigation system of claim 1, wherein the extraction-area setting unit determines the area of a map to be gained, on the ground of the present position of the vehicle, a traveling direction thereof and information about the size of a map to be displayed.

10. The navigation system of claim 1, wherein the extraction-area setting unit determines the area of a map to be gained, on the ground of the position of an intersection point between a road on which the vehicle is traveling and the margin of the map displayed on the display unit presently.

11. The navigation system of claim 1, wherein the communication unit measures an electric field strength of a radio wave transmitted to and from the server, while the renewal time calculating unit carries out correction of the renewal time by a value of the so-measured electric field strength.

12. The navigation system of claim 1, wherein the vehicle comprises a vehicle.

13. A navigation system for a vehicle, comprising:

communication means for communicating the navigation system with a server for delivering a map information;

map gaining means for gaining the map information from the server;

a display unit for displaying the map information gained by the map gaining means, in the form of a map image;

means for detecting the position of the vehicle;

means for calculating a renewal time necessary to renew the map, the renewal time including a time for gaining the map information;

means for calculating a moving distance of the vehicle traveling during the renewal of the map;

means for calculating a road distance required for the vehicle to travel from its present position to a margin of the map displayed on the display unit;

means for comparing the road distance with the moving distance; and

extraction-area setting means for establishing the area of a new map to be displayed next to the map presently displayed on the display unit when the road distance agrees with the moving distance;

wherein the map gaining means transmits information about the area of the new map established by the extraction-area setting unit, to the server through the communication means and further gains a new map information from the server thereby to carry out the renewal of the map displayed on the display unit.