JP3514734B2 - Path finding method for in-vehicle navigation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to an in-vehicle navigation system.
The driver from the departure point to the destination
A suitable route between two points to present the travel route
To search for a route. [0002] 2. Description of the Related Art In recent years, information on roads has been stored.
When the driver inputs the departure point and the destination, the vehicle travels between the two points.
Navigation system that presents an appropriate route for
The device called is being put to practical use. navigation
The system also includes a navigation device that detects the traveling position of the vehicle
In conjunction with the proposed route
A device for instructing a driving operation has also been developed. [0003] How to express information about roads
Various methods have been considered. For example,
Drivers need to display a map on a screen such as a CRT
However, the map drawing information can be used as it is for route search.
Format and map drawing information
There is a format that has information for route search separately in each form.
Information structure is different. But generally do pathfinding
Each road on the road between
Numbers and types of intersections and roads
Is represented in the form attached to the number. Remembered
Even though the information format is different, such intersections and roads
The route search is performed after being converted into the format represented by. [0004] As a method of route search, a faster search is performed.
Various methods have been proposed so that
The shortest route of Dijkstra is
There is gorhythm. This is an intersection with nodes as nodes
The distance of each road connecting
While searching for the shortest route to the surrounding nodes
Increase the range of the node to reach the node corresponding to the destination.
It is a method of exploring short paths. That is, the destination from the departure point
Search for the shortest route among all routes to the ground
It is. [0005] [Problems to be Solved by the Invention]
There are differences, but in the case of route exploration, the purpose is from the starting point
Departure because you need to explore all the routes to the ground
The distance between the destination and the destination increases, and many intersections en route
, The route from the origin to the destination is huge
Number. Therefore, distance calculation is performed for all routes.
Searching for the shortest path requires a large amount of processing and high speed
Processing time is too long even with the processing equipment
Problem. [0006] The present invention has been made in view of the above problems.
And even when searching for long distances,
Efficient exploration by suppressing increase in throughput
The purpose of this study is to realize the route search method. [0007] Means for Solving the Problems To solve the above problems,
Route search method of the vehicle-mounted navigation system of the present invention
The law divides all roads into a number of irregularly shaped areas.
As well as remembering the connection between the regions separately,
Select an area that connects the two areas to which the origin and destination belong
And after that, route search for roads belonging to the selected area
I do. That is, the vehicle navigation system of the present invention
Stem path finding method stored information about roads
Car that derives route to destination based on map data
In a method of searching for a route of an on-board navigation system,
Map data includes roads within an area divided into multiple irregular shapes.
Areas that contain information about
To derive based on the road information contained in
Features. FIG. 1 shows the principle of the route search method of the present invention.
FIG. Information on roads and road connections
Is stored in the data. Route search based on this information
Between the two points entered as the origin and destination
The shortest path can be derived. In the present invention, all roads are multiple
It can be divided into irregular shaped areas, and within each area
And all points on the road go through the local road
By doing so, they can run each other. This means that
If it is a point, other roads in the area only via roads in the area
You can go to any point. [0010] The map data includes information on the aforementioned roads.
In addition, information on the above areas is
include. This regional connection information includes each region
Indicates whether it is possible to drive between adjacent areas.
You. If you want to find a route from your origin to your destination,
Deriving the area to which the departure and destination belong, and then
Select a region connecting two regions based on regional connection information
You. At this time, of course, a regional group connecting the two regions
Although it is thought that there are several types of matches,
Selected to minimize the total distance connecting representative points
You. And from the place of departure to the destination for the selected area
Route search up to. In this way, route search
The amount of target data at the time is greatly reduced. As in the present invention
In addition, by making the shape of the region irregular,
Be separated by chunks that can be searched efficiently
As a result, the search can be performed smoothly. [0011] [Example] First, how to divide roads into regions
An embodiment will be described.The shape of the area is a rectangle and a figure
(A) square, (b) equilateral triangle, (c) as shown in FIG.
Hexagons, and (d) irregular shapes are possible. Two places to which the departure place and the destination belong respectively
When selecting regions that connect between regions, connect the representative points of each region.
It is necessary to select an area so that the total distance
is there. Therefore, the shape corresponding to the actual point on the road for each area
To determine the representative point, and
The distance traveled between is stored as regional connection information,
They can be used to select a region. This is especially
In the case of the irregular-shaped area shown in FIG.
is necessary. [0013] However, the selection of an area is based only on road information.
Processing to limit the target area for path search based on
When searching for a route, the representative point is always
Not necessarily included. Therefore, the shortest distance when selecting a region
Does not require very high accuracy
And is constant as shown in FIGS. 2 (a), (b) and (c).
When dividing into regions in the shape of, the center of each region is set as a representative point
And keep the distance from the representative point in the adjacent area constant
Thus, it is possible to reduce the amount of calculation when selecting a region. [0014] Next, from point S on the road shown in FIG.
The procedure of processing is explained using the case of exploring the route to point G as an example.
I will tell. Points S and G belong to areas 14 and 10, respectively
You can see that. According to the regional connection information shown in FIG.
When an area connecting the area 14 and the area 10 is selected, FIG.
Areas 13, 13, 7, 8, 9, and 10 are selected as shown in
Is done. Therefore, the area shown in FIG.
A route search from the point S to the point G may be performed within the range.
(C) Compared to (a), the amount of data to be searched
Turns out to be much less. When the area is divided, the area on the road in the area
All points can drive each other only via roads in the area
Need to be able to Choose if this is not met
Even if a route search is performed for the area
May result in no route to the destination
Because there is. FIG. 4 is a diagram showing the example. Now
As shown in FIG.
Is partially accessible to other areas, but within that area
It is divided into three parts and each part runs mutually
Suppose there is no road. This area is considered as one area,
As shown in (a) of the above, it is selected as an area from point S to point G.
If it is specified, even if a route search is performed in this range,
There is no route because there is an unentry part
And So in the area all roads
Points must be able to drive each other only via roads within the area
is necessary. Therefore, as shown in FIG.
When divided into regions by shape, they cannot run each other within the region
If there is a portion, the area is changed as shown in FIG.
After the division, the regional connection information as shown in FIG.
Created. The distance between regions varies for this part
Therefore, set a flag etc. in the data and
Need to show. The route search method has been described above.
In-vehicle navigation system where this route finding method is executed
The stem will be briefly described. Fig. 5 is a car navigation system
FIG. 2 is a diagram illustrating a hardware configuration of an application system. Figure
In 5, 5, 1 is a microcomputer and 2 is C
D player, 3 is a display device such as CRT, 4
Is an input device for performing an operation. Roads and road connections
Information about the continuation is divided into regions as map data.
Stored in a storage medium such as a CD-ROM, and a CD player.
Read at 2. Local connection information in map data
Included at the same time. The microcomputer 1 is used in this system.
All the data in the CD player 2
The information on the roads that have been converted into a map
Display and present to the driver. The input device 4 is used for the entire system.
For entering the starting point and destination in addition to manipulating the body
Use a mouse or touch switch to enter the departure or destination.
The touch panel is preferable from the viewpoint of operability. The route search method of the present invention is executed with the configuration shown in FIG.
Example of processing by the microcomputer when
This is the flowchart shown in FIG. Step 1
01 is the departure place and the destination are input.
Correspondence relationship to which region the origin and destination belong respectively
Is derived by searching map data. Then
In step 103, the regional connection information is read and the
An area that connects the land and the area to which the destination belongs is selected. this
The selection is made so that the distance connecting the representative points of each region is the minimum.
Using the same route search method as Dijkstra, etc.
Is In step 104, roads in the selected area
And information about road connection, and step 10
Road from departure to destination limited to the area selected in 5
A road search is performed to determine the shortest route. here
When selecting a region, the total distance connecting the representative points of each region is
Be sure to select the area to minimize it.
Within the specified area combination from the departure point to the destination
Short paths do not always exist. However, regional selection
In the selected area,
The shortest path searched in
The road is rarely long. However, FIGS. 2 (a), 2 (b) and 2 (c)
The area is divided into a certain shape as shown
Assuming that the center of the
If you are connected to all, many regional groups
There may be cases where the matings have the same distance. For example, (a)
In, the combination of the region from n11 to n53
And (n₁₁, N_{twenty one}, N₃₁, N₄₁, N₅₁, N₅₂, N₅₃)When
(N₁₁, N_{twenty one}, N_{twenty two}, N ₃₂, N₄₂, N₄₃, N₅₃) Is the same
Distance, and there are many other such combinations.
This is the same in (b) and (c). In such cases
Selects a region along a straight line connecting the origin and destination
It is necessary to For example, in the above (a), n1
In the region from 1 to n53, the latter is more desirable than the former.
Combination of regions from 11 to 17 in (b)
11, 12, 13, 14, 15, 16, 17
Is most desirable. [0023] According to the present invention, an on-vehicle navigation system is provided.
Significantly reduces the amount of computation required for path finding in the stem
And the time required for path finding can be greatly reduced. Ma
In addition, since the shape of the area is irregular, search is efficient
Areas can be divided into groups that can be
It can be done smoothly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the principle of a route searching method according to the present invention. FIG. 2 is a diagram illustrating an example of a shape of a region division. FIG. 3 is a diagram showing road area division and area connection information. FIG. 4 is an illustration of the need for interconnection within a region. FIG. 5 is a diagram illustrating a hardware configuration of a vehicle-mounted navigation system. FIG. 6 is a diagram showing a processing example according to the route search method of the present invention. [Description of Signs] 1 ... microcomputer 2 ... CD player 3 ... display device 4 ... input device

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) G01C 21/00-21/36 G01C 23/00-25/00 G09B 23/00-29/14 G08G 1/00-9 / 02 G06F 17/60

Claims (1)

(57) [Claim 1] In a route search method of an in-vehicle navigation system for deriving a route to a destination based on map data storing information on roads, the map data is Areas divided into multiple irregular shapes to enable efficient exploration with shapes of different sizes
Includes information about the roads connecting each intersection ,
It has regional connection information indicating a connection relationship between the regions, and when exploring a route to a destination , based on the regional connection information, a route between the two regions to which the departure place and the destination belong respectively.
Selected irregularly shaped area that is needed to tie route exploration, select
A route search method for an in-vehicle navigation system, wherein a route to a destination is obtained based on information on a road included in a determined irregular-shaped area.