Junction guide device for providing guidance concerning looped branch road

• US 20010037176A1
• Filed: 04/25/2001
• Published: 11/01/2001
• Est. Priority Date: 04/27/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Mikame, Masami
• Granted Patent: US 6,597,986 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

A vehicle navigation system stores road data and a plurality of schematic diagrams of junctions. Each schematic diagram represents a common pattern of a road forking to a loop road at a junction and includes a representation of the loop road and the forking pattern at the junction. When a motor vehicle approaches a junction, the system automatically determines by using road data whether a guide route forks to a loop road at the junction, and displays an appropriate schematic diagram selected from the stored schematic diagrams. The displayed diagram enables the driver to know the forking direction of the guide route at the next junction and whether the guide route forks to a loop road at the junction.

Claims

1. A junction guide device for a vehicle comprising:

storage means storing road data;

control means programmed to set a guide route from a point of departure to a destination by referring to the stored road data; and

display means for displaying a forking direction of the guide route at least at a next junction concerning which guidance should be provided when a vehicle approaches the junction on the guide route,

wherein the storage means further stores a plurality of schematic diagrams which schematically represent predetermined common patterns of a road forking to a loop road at a junction, each diagram schematically representing an entire shape of the loop road, and

wherein the control means is further programmed to determine by using the stored road data whether the guide route forks to a loop road at a junction concerning which guidance should be provided, and cause the display means to display the schematic diagram corresponding to the junction upon determination that the guide route forks to the loop road at the junction.

2. A junction guide device as set forth in

claim 1

,

wherein the control means is further programmed to determine, by referring to the stored road data, which direction the guide route forks at each junction, and select and store the schematic diagram that represents the determined forking direction at each junction,

wherein the control means is further programmed to determine, by using the stored road data, whether the guide route forks to the loop road at a junction concerning which guidance should be provided, and identify a schematic diagram which corresponds to the junction and includes a representation of the loop road by referring to not only the schematic diagram which corresponds to the junction and represents the forking direction at the junction but also another schematic diagram which corresponds to another junction included in the loop road and represents the forking direction at the junction included in the loop load upon determination that the guide route forks to the loop road at the junction, and

wherein the display means displays the identified schematic diagram.

4. A junction guide device as set forth in

claim 1

,

wherein the storage means stores, as the road data, nodes and links which constitute a road, and the nodes and links which constitute a connection road have attributes of the connection road, and

wherein the control means determines whether the guide route forks to a loop road at a junction by using the links obtained by sequentially searching links that have the attributes of the connection road from a link that includes a node corresponding to the junction and has the attributes of the connection road to an end of a chain of links, if a node corresponding to the junction has the attributes of the connection road.

6. A junction guide device as set forth in

claim 1

,

wherein the schematic diagram of a common pattern of a road forking to a loop road at a junction represents the forking direction of the guide route at the junction and the looping direction of the loop road.

8. A junction guide device as set forth in

claim 6

,

wherein if the schematic diagram of a common pattern of a road forking to a loop road at a junction corresponds to a junction at which the guide route forks to a loop road and there exits a junction beyond the loop road, it also represents the forking direction of the guide route at a junction beyond the loop road.

10. A junction guide device as set forth in

claim 6

,

wherein the schematic diagram of a common pattern of a road forking to a loop road at the junction corresponds the junction at which the guide route forks to a loop road and there exits a meeting beyond the loop road, it also represents the direction from which another road joins the guide route at the meeting.

12. A junction guide device as set forth in

claim 1

,

wherein the control means selects, based on an estimated shape of the junction, the nearest one of the schematic diagrams to be displayed by the display means.

13. A junction guide device as set forth in

claim 4

,

wherein the control means determines the loop road by checking whether a difference between an initial direction at a start point of the link and a present direction.

3. A junction guide device for a vehicle comprising:

storage means storing road data;

control means programmed to set a guide route from a point of departure to a destination by referring to the stored road data; and

display means for displaying a forking direction of the guide route at least at a next junction concerning which guidance should be provided when a vehicle approaches the junction on the guide route,

wherein storage means further stores a plurality of schematic diagrams which schematically represent predetermined common patterns of a road forking to a loop road at a junction, each diagram schematically representing an entire shape of the loop road,

wherein the control means is further programmed to determine by using the stored road data whether the guide route forks to a loop road at each junction concerning which guidance should be provided, and determine and store a schematic diagram corresponding to the junction upon determination that the guide route forks to the loop road at the junction, and

wherein the control means is further programmed to cause the display means to display the stored schematic diagram corresponding to a junction if there exists the stored schematic diagram corresponding to the junction concerning which guidance should be provided.

5. A junction guide device as set forth in

claim 3

,

wherein the storage means stores, as the road data, nodes and links which constitute a road, and the stored nodes and links which constitute a connection road have attributes of the connection road, and

wherein the control means determines whether the guide route forks to a loop road at a junction by using the links obtained by sequentially searching links that have the attributes of the connection road from a link that includes a node corresponding to the junction and has the attributes of the connection road to an end of a chain of links, if a node corresponding to the junction has the attributes of the connection road.

7. A junction guide device as set forth in

claim 3

,

wherein the schematic diagram of a common pattern of a road forking to a loop road at a junction represents the forking direction of the guide route at the junction and the looping direction of the loop road.

9. A junction guide device as set forth in

claim 7

,

wherein if the schematic diagram of a common pattern of a road forking to a loop road at a junction corresponds to a junction at which the guide route forks to a loop road and there exits a junction beyond the loop road, it also represents the forking direction of the guide route at the junction beyond the loop road.

11. A junction guide device as set forth in

claim 7

,

wherein the schematic diagram of a common pattern of a road forking to a loop road at the junction corresponds the junction at which the guide route forking to a loop road and there exits a meeting beyond the loop road, it also represents the direction from which another road joins the guide route at the meeting.

14. A junction guide device as set forth in

claim 5

,

wherein the control means determines the loop road by checking whether a difference between an initial direction at a start point of the link and a present direction is larger than a reference.

15. A navigation method for a vehicle comprising the steps of:

setting a guide route to a destination by using road data stored in a memory device, the guide route including junction of roads;

checking whether a junction in the set guide route is a looped type by using the stored road data;

selecting, based on an estimated loop shape of the checked junction, the nearest one of a plurality of fixed looped road patterns stored in the memory device in generalized common forms respectively, if the checked junction is the looped type; and

displaying on a display device the set guide route along with the selected near one of the fixed looped road patterns based on an actual loop shape of the checked junction.

16. A navigation method as set forth in

claim 15

,

wherein the checking step checks a type of the junction by checking a difference between an initial direction at a start of the junction and a present direction, and determines the looped type if the checked difference is larger than a reference.