Navigation system for vehicle

• US 20090024319A1
• Filed: 07/15/2008
• Published: 01/22/2009
• Est. Priority Date: 07/17/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tsuji, Kenji
• Granted Patent: US 8,548,732 B2
• Time in Patent Office: Days
• US Class Current: 701/209
• CPC Class Codes: G01C 21/3673 Labelling using text of road map data items, e.g. road names, POI names

Abstract

A travel-estimated road, which a vehicle is estimated to travel, intersects with a cross road at an intersection. A search area shaped of a sector centering on the intersection is defined to have a central angle to include an extending direction of the cross road. An arc intersecting point is then defined where an outer circumference arc of the search area intersects with the cross road. A display position of the road name of the cross road on a road map is determined based on a line segment between the intersection and the arc intersecting point. Thus, the road name of the cross road can be displayed in a position, which is in proximity to the travel-estimated road so as to allow a user to clearly recognize that the displayed road name indicates the cross road irrespective of the configuration of the cross road.

Claims

1. A navigation system for a vehicle, the system comprising:

a displaying means having a display screen;

a detecting means for detecting a present position and a heading direction of the vehicle;

a storing means for storing road map data for displaying a road map including a road name of a road;

a display managing means for reading road map data from the storing means based on the detected present position, and displaying a peripheral road map and a vehicle mark indicating the present position and the heading direction such that the heading direction is shown upwardly in the display screen,

wherein the display managing means includes;

an angle calculating means for calculating, relative to a travel-estimated road, which is estimated for the vehicle to travel, an intersecting angle of an extending direction of a cross road intersecting with the travel-estimated road at an intersection;

a search area designating means for designating a search area shaped of a sector centering on the intersection to include the extending direction of the cross road;

an intersecting point retrieving means for retrieving an arc intersecting point between the cross road and an outer circumference arc of the designated search area; and

a display position determining means for determining a display position of a road name of the cross road based on a line segment between the intersection and the retrieved arc intersecting point.

2. The navigation system according to claim 1, wherein:

the search area designating means designates the search area with a first predetermined radius; and

when no arc intersecting point is retrieved with the first predetermined radius, the search area designating means re-designates a search area with a radius shorter than the first predetermined radius.

3. The navigation system according to claim 2, wherein

the search area designating means repeatedly designates a search area while gradually shortening a radius from the first predetermined radius until an arc intersecting point is successfully retrieved.

4. The navigation system according to claim 1, wherein:

the display position determining means defines the line segment between the intersection and the arc intersecting point and then defines an additional line segment by parallel translating the line segment orthogonally to an extending direction of the line segment by a predetermined distance; and

the display position determining means determines, as the display position of the road name of the cross road, a position based on the additional line segment to have no overlap with the travel-estimated road.

5. The navigation system according to claim 4, wherein:

the display position determining means finds an intersecting angle between (i) the line segment and (ii) a road portion of the travel-estimated road closer to the vehicle than the intersection; and

when the intersecting angle is less than 90 degrees, the display position determining means determines, as the display position of the road name of the cross road, a position defined by parallel translating the line segment upward in the display screen.

6. The navigation system according to claim 4, wherein:

the display position determining means finds an intersecting angle between the line segment and a road portion of the travel-estimated road closer to the vehicle than the intersection;

when the intersecting angle is in a range from 90 degrees to a predetermined angle greater than 90 degrees, the display position determining means determines, as a temporary display position of the road name of the cross road, a position defined by parallel translating the line segment upward in the display screen; and

when the travel-estimated road overlaps with the road name in the temporary display position, the display position determining means determines the display position of the road name of the cross road by shifting the temporary display position along an inclination of the line segment to a position to have no overlap with the travel-estimated road.

7. The navigation system according to claim 4, wherein:

the display position determining means finds an intersecting angle between the line segment and a road portion of the travel-estimated road closer to the vehicle than the intersection; and

when the intersecting angle is greater than a predetermined angle exceeding 90 degrees, the display position determining means determines, as the display position of the road name of the cross road, a position defined by parallel translating the line segment downward in the display screen.

16. The navigation system according to claim 1, further comprising:

a navigating means for navigating the vehicle along a guide route which is designated when a destination is specified, wherein

the display managing means regards as the travel-estimated road the guide route along which the vehicle is being navigated.

17. The navigation system according to claim 16, wherein:

the display managing means regards, as the travel-estimated road, a road following a road the vehicle runs when the vehicle is not navigated.

18. The navigation system according to claim 1, wherein:

the cross road is extended from the intersection to a right side and left side relative to the travel-estimated road;

when the vehicle runs a right side of the travel-estimated road, a road name is displayed with respect to the right side of the cross road; and

when the vehicle runs a left side of the travel-estimated road, a road name is displayed with respect to the left side of the cross road.

8. A navigation system for a vehicle, the system comprising:

a displaying means having a display screen;

a detecting means for detecting a present position and a heading direction of the vehicle;

a storing means for storing road map data for displaying a road map including a road name of a road;

a display managing means for reading road map data from the storing means based on the detected present position, and displaying a peripheral road map and a vehicle mark indicating the present position and the heading direction such that the heading direction is shown upwardly in the display screen,

wherein;

the display managing means displays a road name of a cross road, which intersects at an intersection with a travel-estimated road defined as a road the vehicle is estimated to travel, at a position in proximity to the cross road to have no overlap with the travel-estimated road; and

the display managing means includes a display position determining means for determining a display position of the road name of the cross road at either an upper or a lower side of the cross road based on an intersecting angle between (i) the cross road and (ii) a road portion of the travel-estimated road closer to the vehicle than the intersection.

9. The navigation system according to claim 8, wherein:

the display managing means includes;

an angle calculating means for calculating an intersecting angle of an extending direction of the cross road at the intersection, relative to the travel-estimated road;

a search area designating means for designating a search area shaped of a sector centering on the intersection to include the extending direction of the cross road; and

an intersecting point retrieving means for retrieving an arc intersecting point between the cross road and an outer circumference arc of the designated search area,

wherein

the display position determining means defines a line segment between the intersection and the arc intersecting point and finds an intersecting angle between the travel-estimated road and the cross road by regarding an extending direction of the line segment as the extending direction of the cross road.

10. The navigation system according to claim 9, wherein:

the search area designating means designates the search area with a first predetermined radius; and

when no arc intersecting point is retrieved with the first predetermined radius, the search area designating means re-designates a search area with a radius shorter than the first predetermined radius.

11. The navigation system according to claim 10, wherein

the search area designating means repeatedly designates a search area while gradually shortening a radius from the first predetermined radius until an arc intersecting point is successfully retrieved.

12. The navigation system according to claim 9, wherein:

the display position determining means defines the line segment between the intersection and the arc intersecting point and then defines an additional line segment by parallel translating the line segment orthogonally to an extending direction of the line segment by a predetermined distance; and

the display position determining means determines, as the display position of the road name of the cross road, a position based on the additional line segment to have no overlap with the travel-estimated road.

13. The navigation system according to claim 12, wherein:

the display position determining means finds an intersecting angle between the line segment and a road portion of the road estimated to run before the intersection; and

when the intersecting angle is less than 90 degrees, the display position determining means determines, as the display position of the road name of the cross road, a position defined by moving the line segment parallel upward in the display screen.

14. The navigation system according to claim 12, wherein:

the display position determining means finds an intersecting angle between the line segment and a road portion of the travel-estimated road closer to the vehicle than the intersection;

when the intersecting angle is in a range from 90 degrees to a predetermined angle greater than 90 degrees, the display position determining means determines, as a temporary display position of the road name of the cross road, a position defined by parallel translating the line segment upward in the display screen; and

when the travel-estimated road overlaps with the road name in the temporary display position, the display position determining means determines the display position of the road name of the cross road by shifting the temporary display position along an inclination of the line segment to a position to have no overlap with the travel-estimated road.

15. The navigation system according to claim 12, wherein:

the display position determining means finds an intersecting angle between the line segment and a road portion of the travel-estimated road closer to the vehicle than the intersection; and

when the intersecting angle is greater than a predetermined angle exceeding 90 degrees, the display position determining means determines, as the display position of the road name of the cross road, a position defined by parallel translating the line segment downward in the display screen.

19. The navigation system according to claim 8, further comprising:

a navigating means for navigating the vehicle along a guide route which is designated when a destination is specified, wherein

the display managing means regards as the travel-estimated road the guide route along which the vehicle is being navigated.

20. The navigation system according to claim 19, wherein:

the display managing means regards, as the travel-estimated road, a road following a road the vehicle runs when the vehicle is not navigated.

21. The navigation system according to claim 8, wherein:

the cross road is extended from the intersection to a right side and left side relative to the travel-estimated road;

when the vehicle runs a right side of the travel-estimated road, a road name is displayed with respect to the right side of the cross road; and

when the vehicle runs a left side of the travel-estimated road, a road name is displayed with respect to the left side of the cross road.