NAVIGATION SYSTEM, ENLARGED INTERSECTION IMAGE DISPLAYING METHOD USED IN THE SYSTEM, AND MAP INFORMATION GENERATING METHOD

• US 20080208466A1
• Filed: 02/08/2008
• Published: 08/28/2008
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Iwatani, Tatsunori
• Granted Patent: US 8,131,466 B2
• Time in Patent Office: Days
• US Class Current: 701/211
• CPC Class Codes: G01C 21/3632 Guidance using simplified or iconic instructions, e.g. using arrows G01C21/365 takes precedence

Abstract

When a vehicle travels along a guidance path and approaches an intersection, a vehicle navigation system determines crossing points between a circle having its center set to the intersection and a predetermined radius, and an approach link and an exit link for the intersection. The system also sets a direction connecting the crossing point for the approach link and the intersection as an approach direction, and sets a direction connecting the intersection and the crossing point for the exit link as an exit direction. The system determines a traveling direction at the intersection based on an angular difference between the approach direction and the exit direction, and determines a display position of the intersection on a screen. Further, an enlarged intersection image is drawn such that the approach direction is aligned with a 12 o'"'"'clock direction on the screen.

Claims

1. An enlarged intersection image display method for a navigation system displaying an enlarged intersection image on a screen when a vehicle travels along a guidance path and approaches an intersection, the method comprising:

defining a circle having a predetermined radius, wherein a center of the circle is set to a first intersection;

determining crossing points between the circle and an approach link and an exit link of the first intersection;

setting a direction connecting the approach link crossing point and the first intersection as an approach direction, and setting a direction connecting the first intersection and the exit link crossing point as an exit direction; and

drawing, on a screen of a display, an enlarged intersection image such that the approach direction is aligned with a 12 o'"'"'clock direction on the screen, and a traveling direction arrow extending from the approach direction toward the exit direction.

2. The enlarged intersection image display method according to claim 1, the method further comprising:

calculating an angular difference between the approach direction and the exit direction;

calculating a coordinate position of the first intersection on the screen based on the angular difference; and

displaying the enlarged intersection image to overlap the coordinate position with the first intersection.

3. The enlarged intersection image display method according to claim 2, wherein the coordinate position is calculated by a method comprising:

determining a traveling direction at the first intersection based on the angular difference;

determining a horizontal coordinate position of the first intersection such that the first intersection is displayed at a center of the screen in a horizontal direction, if the traveling direction is a straight direction, a slight right turn direction, or a slight left turn direction;

determining the horizontal coordinate position of the first intersection such that the first intersection is displayed on a left side of the screen as viewed in a horizontal direction, if the traveling direction is a right turn direction or a sharp right turn direction; and

determining the horizontal coordinate position of the first intersection such that the first intersection is displayed on a right side of the screen as viewed in a horizontal direction, if the traveling direction of the vehicle is a left turn direction or a sharp left turn direction.

4. The enlarged intersection image display method according to claim 3, wherein the coordinate position is calculated by determining a vertical coordinate position of the first intersection such that the first intersection is displayed in an upper position of the screen as viewed in a vertical direction, regardless of the traveling direction.

5. The enlarged intersection image display method according to claim 1, the method further comprising:

determining whether a distance from the first intersection to a second subsequent intersection on the guidance path is less than or equal to a preset distance;

setting a direction connecting the first intersection and the approach link of the first intersection as an approach direction for the first intersection;

setting a direction connecting the first intersection and the second intersection as an exit direction for the first intersection, if the distance between the first intersection and the second intersection is less than or equal to the preset distance;

drawing the enlarged intersection image including the first and second intersections such that the approach direction for the first intersection is aligned with a 12 o'"'"'clock direction on the screen; and

drawing a first traveling direction arrow extending from the approach direction for the first intersection toward the exit direction.

6. The enlarged intersection image display method according to claim 5, the method further comprising:

determining a crossing point between a link exiting from the second intersection and a second circle having a predetermined radius, wherein a center of the second circle is set to the second intersection;

setting a direction connecting the first intersection and the second intersection as an approach direction for the second intersection, and a direction connecting the second intersection and the exit link crossing point of the second circle as the exit direction for the second intersection; and

drawing, on the screen of a display, a second traveling direction arrow extending from the approach direction for the second intersection to the exit direction for the second intersection.

7. The enlarged intersection image display method according to claim 5, the method further comprising:

calculating an angular difference between the approach direction for the first intersection and the exit direction for the first intersection;

calculating a coordinate position on the screen of the display for the first intersection based on the angular difference; and

displaying an enlarged intersection for the first intersection at the calculated coordinate position.

8. The enlarged intersection image display method according to claim 7, wherein the coordinate position is determined by a method comprising:

determining the traveling direction at the first intersection based on the angular difference;

determining a horizontal coordinate position on the screen of the display for the first intersection such that the first intersection is displayed at a center of the screen in a horizontal direction, if the traveling direction is a straight direction, a slight right turn direction, or a slight left turn direction;

determining a horizontal coordinate position on the screen of the display for the first intersection such that the first intersection is displayed on a left side of the screen as viewed in a horizontal direction, if the traveling direction is a right turn direction or a sharp right turn direction; and

determining a horizontal coordinate position on the screen of the display for the first intersection such that the first intersection is displayed on a right side of the screen as viewed in a horizontal direction, if the traveling direction of the vehicle is a left turn direction or a sharp left turn direction.

9. The enlarged intersection image display method according to claim 8, wherein the method of determining the coordinate position further comprises:

determining a vertical coordinate position on the screen of the display for the first intersection such that both the first and second intersections are displayed on the screen.

10. A map information generating method for generating map information including voice information used to announce a traveling direction at an intersection, the method comprising:

retrieving shape data from map information for each link connected to an intersection node;

setting predetermined links as an approach link and an exit link;

determining crossing points between a circle having a predetermined radius and its center set to a first intersection, and an approach link and an exit link;

setting a direction connecting the crossing point for the approach link and the first intersection as an approach direction, and setting a direction connecting the first intersection and the crossing point for the exit link as an exit direction;

calculating an angular difference between the approach direction and the exit direction;

determining a traveling direction at the first intersection based on the calculated angular difference;

determining a voice code for announcing the traveling direction; and

adding the voice code to intersection data contained in the map information.

11. The map information generating method according to claim 10, the method further comprising:

determining the voice code for all possible combinations of approach links and exit links.

12. The map information generating method according to claim 10, the method further comprising:

determining whether a distance from the first intersection to a second subsequent intersection on the guidance path is less than or equal to a preset distance;

setting a direction connecting the first intersection and the approach link of the first intersection as an approach direction for the first intersection, and setting a direction connecting the first intersection and the second intersection as an exit direction for the first intersection, if the distance between the first intersection and the second intersection is less than or equal to the preset distance;

calculating an angular difference between the approach direction and the exit directions for the first intersection in order to determine the traveling direction at the first intersection based on the calculated angular difference;

determining a crossing point between a link exiting from the second intersection and a second circle having a predetermined radius with its center set to the second intersection;

setting a direction connecting the first intersection and the second intersection as an approach direction for the second intersection, and setting a direction connecting the second intersection and the crossing point for the link exiting from the second intersection as an exit direction for the second intersection;

determining voice codes for announcing traveling directions at the first and second intersections; and

adding the voice codes to the intersection data.

13. A navigation system for displaying an enlarged intersection image on a screen when a vehicle travels along a guidance path and approaches an intersection, the system comprising:

a guidance path memory configured to store a guidance path;

an approach detecting unit configured to detect whether the vehicle is approaching a first intersection on the guidance path;

an enlarged intersection image generating unit configured to determine crossing points between a circle having a predetermined radius with its center set to the first intersection, and an approach link and an exit link, set a direction connecting the crossing point for the approach link and the first intersection as an approach direction, set a direction connecting the first intersection and the crossing point for the exit link as an exit direction, generate an enlarged intersection image such that the approach direction is aligned with a 12 o'"'"'clock direction on a screen, and generate a traveling direction arrow extending from the approach direction toward the exit direction; and

a display unit for displaying the enlarged intersection image.

14. The navigation system according to claim 13, further comprising:

an audio assist unit configured to retrieve a voice code for announcing a traveling direction corresponding to an angular difference between the approach direction and the exit direction, and announce the traveling direction using the voice code.

15. The navigation system according to claim 13, wherein the enlarged intersection image generating unit calculates an angular difference between the approach direction and the exit direction to calculate a coordinate position of the first intersection on a screen of the display unit such that the enlarged intersection image is displayed with the first intersection overlapping the coordinate position.

16. The navigation system according to claim 15, wherein the enlarged intersection image generating unit determines a horizontal coordinate position of the first intersection such that the first intersection is displayed at a center of the screen in a horizontal direction if the traveling direction is a straight direction, a slight right turn direction, or a slight left turn direction, determines the horizontal coordinate position of the first intersection such that the first intersection is displayed on a left side of the screen as viewed in a horizontal direction if the traveling direction is a right turn direction or a sharp right turn direction, and determines the horizontal coordinate position of the first intersection such that the first intersection is displayed on a right side of the screen as viewed in a horizontal direction if the traveling direction of the vehicle is a left turn direction or a sharp left turn direction.

17. The navigation system according to claim 16, wherein the enlarged intersection image generating unit determines a vertical coordinate position of the first intersection such that the first intersection is displayed in an upper position of the screen, regardless of the traveling direction.

18. The navigation system according to claim 13, wherein the enlarged intersection image generating unit is configured to determine whether a distance from the first intersection to a second subsequent intersection on the guidance path is less than or equal to a predetermined distance, and set a direction connecting the first intersection and the approach link as an approach direction for the first intersection, set a direction connecting the first intersection and the second intersection as an exit direction for the first intersection, generate the enlarged intersection image including both the first and second intersection such that the approach direction is aligned with a 12 o'"'"'clock direction on the screen, and draw a first traveling direction arrow extending from the approach direction for the first intersection toward the exit direction for the first intersection, if the distance is less than or equal to the preset distance.

19. The navigation system according to claim 18, wherein the enlarged intersection image generating unit is configured to determine a second crossing point between a link exiting from the second intersection and a second circle having a predetermined radius with its center set to the second intersection, set a direction connecting the first intersection and the second intersection as an approach direction for the second intersection, set the direction connecting the second intersection and the crossing point for the second circle as an exit direction for the second intersection, and generate a second traveling direction arrow image that extends from the approach direction for the second intersection toward the exit direction for the second intersection.

20. The navigation system according to claim 19, wherein the enlarged intersection image generating unit is configured to calculate an angular difference between the approach direction for the first intersection and an exit direction for the first intersection, calculate a coordinate position for the first intersection on the screen in accordance with the angular difference, and display an enlarged intersection image with the first intersection located at the coordinate position.