JP2938530B2 - Route search method for navigation device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a route search method of a navigation device having a function of searching for a route from a starting point to a destination.

(Prior Art) Navigation devices provide route guidance to a destination, and in-vehicle navigation devices have been actively developed in recent years.

Generally, since there are a plurality of routes between the departure point and the destination point, a route with the shortest time or the shortest distance to the destination point is created based on the road conditions of the map data stored in the storage device. Route search techniques have been devised.

(Problems to be Solved by the Invention) However, the shortest route is determined by the total of road link distances and required times between intersections stored as road data, and which side of the route is located on the left or right of the route. It is not considered.

Therefore, as shown in FIG. 5, when the vehicle 1 travels along the search route R1, the destination point 2 may be present on the right side in the traveling direction of the last road link L1 of the search route.

At this time, there is no practical problem if the road L1 is a local road with a narrow width in the same figure, but it is practically a destination point if there is a median strip or a wide road with two or more lanes on one side. It cannot be said that the route up to 2 has been created.

The present invention is to solve the above problem, and when a destination point exists on the right side in the traveling direction of the road link determined at the end of the route search processing, the destination point is located on the right side in the traveling direction of the road link. It is an object of the present invention to provide a method for performing a route search so that a is located.

(Means for Solving the Problems) According to the present invention, the problems described above are caused by a route searching means for searching for a route from road data provided with a road attribute data table and a problem that the destination point is located on the right side in the traveling direction. This is achieved by means for determining whether or not a problem occurs, and means for searching for a route in which the destination is located on the left side in the traveling direction if a problem occurs.

(Operation) In the route search method of the navigation device of the present invention, a route is searched from road data provided with a road attribute data table, and it is determined whether or not a problem occurs when the destination is located on the right side in the traveling direction of the searched route. If a problem occurs, the route is searched again so that the destination point is located on the left side in the traveling direction.

When it is determined whether or not a problem occurs when the destination is located on the right side of the traveling direction at the time when the destination is input, if the problem does not occur, the destination is moved to the right in the vehicle traveling direction. The route is searched from the map data without considering whether it is located or located on the left side in the traveling direction. If a problem occurs, the route is searched for such that the destination point is located on the left side in the traveling direction of the final road.

(Example) Hereinafter, an example is described based on a drawing.

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a system configuration of a navigation device according to the present invention, and FIG.
The figure shows an example of a road attribute data table included in the road data, and FIG. 4 is a view for explaining the flow of the route search processing.

In FIG. 2, an input device 8 is used to input a departure point and a destination point. In addition, the current position of the vehicle detected by the position detecting device 7 based on the outputs of the traveling distance sensor 5 and the direction sensor 6 can be input as the starting point.

The map data storage device 9 is composed of a large-capacity memory storing road maps, and a CD-ROM or the like is used as this memory. The map data recorded in the map data storage device includes a road layer including road link data, intersection data, node data, and the like, a background layer for outputting an object on the map to the display device 11, a municipal name, It is composed of a character layer for outputting a national road name and the like.

As shown in FIG. 3, the road link data (road data) includes data tables A and B that provide attribute information of the road link. The attribute data table A is composed of data such as a link distance, a required time, and a one-way flag, and is used when creating and determining a candidate for the shortest distance route or the shortest time distance route in the route search process. It is a data group.

The attribute data table B shown in FIG. 3 is a data group used to determine whether a practical problem does not occur when the destination is located on the right side in the vehicle traveling direction.

FIG. 4 is a flowchart of a route search method according to the present invention. The conventional route search processing is realized by the steps (1) to (5), and the processing according to the present invention is realized by the steps (6) to (13).

 The description will be made in the following order.

When a switch for starting a route search is pressed, the data processing device 10 shown in FIG. 2 starts a route search program (FIG. 4).

First, the coordinates on the map input as the destination are stored in the memory (step (1)). At this point, it is not yet clear whether the destination is located on the left or right side of the route.

Next, the coordinates on the map input as the starting point are stored in the memory (step (2)).

Based on the coordinates of the departure point and the destination point, data of a road layer in a predetermined range on the map is read from the map data storage device 9 into a memory built in the data processing device 10 as appropriate.
At this time, the road attribute data table of the road link data to be read into the memory does not need to read all the data, but only the data group shown in FIG. 3A from the viewpoint of processing time and saving of memory (step (3)).

Next, using the data of the road layer, several route candidates from the input departure point to the destination point are created, a route that satisfies predetermined conditions is determined, and node data constituting the route is stored in a memory. (Steps (4)-(5)).

At this time, data of the intersection that passes when entering the road link closest to the destination and searched as the last road of the route is also stored.

The route from the departure point to the destination point has been created by the processing of steps (1) to (5) in FIG.
As shown in FIG. 5, the destination point 2 may be located on the right side in the vehicle traveling direction. If the width of the road is narrow and parking is possible, or if it is easy to make U-turns or crossings, this is not a problem in practical use.

However, the development of the road network in recent years has been remarkable, and even in rural areas, roads having a width of four or more vehicles, such as a by-pass for bypassing the city, are not uncommon. On such roads, there is a large traffic volume, a median strip may be provided, and crossing the road or making a U-turn may be practically impossible. Also, due to recent road conditions, parking and U-turns are often not possible in urban areas even on roads that are not very wide.

In order to smoothly reach the destination by riding the traffic flow, in Japan it is necessary to select a route where the destination is located on the left side in the vehicle traveling direction. Therefore, the processing following step (6) is required.

If a tentative route can be found in steps (1)-(5), it is determined whether the destination point is located on the left or right side of the road traveling direction by the coordinates of the nodes constituting the road and the coordinates of the destination point. Judgment is made from the relationship (step (6)).

If the destination point is located on the left side in the direction of travel of the route, the route search process ends here.

When the destination is located on the right side of the route traveling direction, there is a practical problem even if the destination is located on the right side of the road by referring to the attribute data table of the road link that is the last road of the route. It is determined whether or not there is (Step (7)-(11)).

If there is no practical problem, the route search process is completed.

If there is a median strip on the last road, if there are four or more lanes, if parking is prohibited and U-turn is prohibited, the process jumps to step (12) to restrict the approach direction of the road link.
That is, the one-way flag of the attribute data of the road link is set, and it is considered that the road link cannot be entered from the intersection 3 (see FIG. 1).

Further, in step (13), the coordinates of the intersection are input as the coordinates of the departure point, and the route search is performed again.

By this re-route search, as shown in FIG. 1, a route R2 that starts at the intersection 3 and enters the final road link L1 from the intersection 4 is created, and the destination point is located in the route traveling direction.

Route R2 from intersection 3 created at this time to the destination
Is added to the route obtained by excluding the last road link from the route R1 obtained in the first route search stored in the memory.

By the above processing, a route from the first input departure point to the destination point is searched.

In this embodiment, after the first route search is completed, it is determined whether or not the destination is on the right side of the road link and whether or not a problem occurs due to the determination. At this point, it is determined whether a problem occurs if the destination is on the right side in the traveling direction by referring to the attribute data table of the road link closest to the destination (steps (7)-(11)). May be performed.

In this case, if no problem occurs even if the destination point is located on the right side in the route traveling direction, steps (3) to (5)
By performing the processing described above, the route can be searched.

If a problem occurs because the destination point is located on the right side of the route traveling direction, set the one-way flag in the road attribute data table of the final road to limit the approach direction before starting the route search process. Thus, a route is created such that the destination point is located on the right side in the traveling direction.

As is clear from the above description, when searching for a route from the departure point to the destination point, if the destination point is located on the right side in the traveling direction and a problem occurs, the destination point is located on the left side in the traveling direction. It is possible to search the route,
The driver can arrive at the destination along the flow of the exchange.

In the present embodiment, the description is made in accordance with the traffic situation of the left-hand traffic in Japan. However, in step (6) of judging the position of the destination in FIG. This route search method can also be applied to a right-hand foreign country by substituting the judgment as to whether or not the route exists.

(Effects of the Invention) As described above, according to the route search method of the present invention, when a problem occurs due to the destination point being located on the right side in the traveling direction, a route is searched such that the destination point is located on the left side in the traveling direction. And the driver can arrive at the destination along the traffic flow.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a route search method of the present invention, FIG. 2 is a block diagram of an in-vehicle navigation device, FIG. 3 is a diagram for explaining a road attribute data table included in road data, and FIG. FIG. 5 is a flowchart of a route search process according to the present invention, and FIG. 5 is a diagram for explaining a problem with the conventional route search method. 1… vehicle 2… destination point 3,4… intersection, L1… last road link R1, R2 …… search route

Claims (2)

(57) [Claims] 1. A route search method for a navigation device having a function of searching for a route satisfying a predetermined condition from a departure point to a destination point, wherein a route satisfying the condition is determined from road data having a road attribute data table. A step of searching; and, if the destination is located on the right side of the search route in the traveling direction, determining whether or not a defect occurs on the right side with reference to the road attribute data. Re-searching the route so that the destination point is located on the left side in the traveling direction of the route. 2. A route search method for a navigation device having a function of searching for a route satisfying a predetermined condition from a departure point to a destination point, wherein the destination attribute is referred to a road attribute data table included in the road data. If the vehicle is located on the right side in the traveling direction of the final road, it is determined whether the vehicle is located on the right side and a problem occurs. Searching for a route that satisfies the above condition from the map data without considering whether it is located on the left side. If a problem occurs, the condition is satisfied so that the destination point is located on the left side in the traveling direction of the final road. Searching for a route to be routed.