Vehicle navigation system providing for determination of a point on the border of a map stored in memory on the basis of a destination remote from the area covered by the map

• US 6,169,956 B1
• Filed: 02/27/1998
• Issued: 01/02/2001
• Est. Priority Date: 02/28/1997
• Status: Expired due to Term

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Ogawa, Satoshi, Coenen, Peter, Fukaya, Takaharu, Morimoto, Kyomi, Diels, Ole
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/032,026
• Time in Patent Office: 1,040 Days
• Field of Search: 701/209, 701/208, 701/201, 342/451, 342/452, 340/995
• US Class Current: 701/209
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096861 where the immediate route instructions are output to the driver, e.g. arrow signs for next turn
• 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
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

A vehicle navigation system includes a present position detector, an input device for inputting information required for route searching, inclusive of information identifying a starting point and a destination, an output device for outputting route guidance, an information memory containing map data for route guidance within a geographical area, and border line data for a border line defining a perimeter for the geographical area. A central processing unit determines whether or not the detected present position or starting point and the destination are within the geographical area stored in the information memory, determines a crossing point on the border line responsive to a determination that the present position or the starting point and the destination are not both in the geographical area and determines a travel route from the present position or starting point to the destination, which travel route passes through the crossing point. The information memory may be an element additionally containing data identifying locations outside of the geographical area in the form of remote location data which is correlated with respective border points. This system allows the user to be guided to a proper border crossing point even when the destination is outside of the geographical area covered by the map data stored in the information memory element, e.g. a CD-ROM.

Claims

1. A vehicle navigation system comprising:

present position detection means for detecting a present position of a vehicle;

input means for inputting information required for route searching, including information identifying a starting point and a destination;

output means for outputting information for route guidance;

an information memory containing stored therein map data required for route guidance within a geographical area and border line data for a perimeter border line defining a boundary for said geographical area;

route search means for determining whether or not the detected present position or the starting point and the destination are within said geographical area stored in said information memory, for determining a crossing point on the perimeter border line responsive to a determination that the present position or the starting point and the destination are not both in said geographical area, and for determining a travel route passing through the determined crossing point.

2. A navigation system according to claim 1 wherein said information memory further contains data identifying plural border points on said perimeter border line and data identifying various registered locations outside of said geographical area, correlated with said border points.

3. A vehicle navigation system according to claim 2 wherein said map data stored in said information memory is limited to said geographical area.

4. A vehicle navigation system according to claim 2, wherein the registered locations include cities and wherein the data identifying the registered locations includes names of the cities.

5. A vehicle navigation system according to claim 4, wherein the data identifying the registered locations further includes geographical coordinates of the registered locations.

6. A vehicle navigation system according to claim 2, wherein the data identifying the registered locations includes geographical coordinates of the registered locations.

7. A vehicle navigation system according to claim 1, wherein when the linear line intersects the perimeter border line at a plurality of intersection points, said route search means determines the crossing point by assigning priorities to the plural intersection points.

8. A vehicle navigation system according to claim 1, wherein said information memory contains map data for providing route guidance within a plurality of different geographical areas separated by plural internal border lines;

and

wherein said route search means calculates a linear line between the present position or the starting point and the destination, identifies points of intersection of said linear line and each of the plural internal border lines;

sets a crossing point on the basis of each of said points of intersection; and

searches for a route stretching over each of the plurality of areas connecting with the respective crossing points.

9. A vehicle navigation system according to claim 8, wherein said map data stored in said information memory is limited to said plurality of different geographical areas.

10. A vehicle navigation system according to claim 1 wherein said map data stored in said information memory is limited to said geographical area.

11. A navigation system according to claim 1 wherein said route search means calculates a linear line between the present position or the starting point and the destination, calculates a point of intersection of the linear line and the stored border line, and determines the crossing point on the border line on the basis of the calculated point of intersection.

12. A memory element comprising, encoded thereon:

map data for route guidance, said map data covering a single geographical area, and border line data for a perimeter border line defining a boundary for said geographical area; and

a route search program for calculating a linear line between a present position or starting point and a destination, responsive to a determination that the present position or the starting point and the destination area are not both in said geographical area, for calculating a point of intersection of the linear line and the stored border line, for determining a crossing point on the border line on the basis of the calculated point of intersection, and for determining a travel route passing through the determined crossing point.