JP2003337034A - Navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation system capable of searching an optimal route and executing a process rapidly. <P>SOLUTION: In the navigation system, an upper layer transition searching range rectangle specifying section 206 sets an upper layer transition searching range rectangle which can surely rise to an upper node of a second level region in the case searching processes corresponding to a stating place and a destination are carried out respectively in a first level region, and an upper node searching section 208 extracts the upper node in the upper layer transition searching range rectangle. A section 208 for searching a route between upper nodes searches the route, which connects the upper nodes corresponding to the starting place and the destination extracted by the upper node searching section 208, by using an exclusive network. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device for setting a route connecting a departure place and a destination by route search.

[0002]

2. Description of the Related Art Generally, a vehicle-mounted navigation device has a route search function for searching an optimal route to a predetermined destination with the current position of the vehicle as a starting point. According to this route search function, the route with the lowest cost connecting the starting point to the destination is automatically searched by using the map data by performing simulations such as the Dijkstra method and the horizontal search (BFS) method, and this search is performed. The route is stored as the guide route. Then, while the vehicle is traveling, draw this guide route on the map screen with a different color from other roads and draw it thicker, or expand the intersection when the vehicle approaches within a certain distance of the intersection where the course should be changed. The route guidance operation for guiding the driver to the destination is realized by displaying and displaying the arrow indicating the traveling direction.

In particular, the above-mentioned route search function is performed after the driver gets in the vehicle, and it is desirable that the processing be completed before the vehicle travels. Therefore, it has been conventionally proposed to speed up the processing. Has been done. For example, Japanese Patent Laid-Open No. 9-218047 discloses a "vehicle route calculation" that speeds up route search processing by using a departure area route network in which a route from a departure area to a destination area is calculated in advance. A device is disclosed. In this vehicle route calculation device, a pruning zone is provided around the departure area or the destination area,
This reduces the number of routes between the departure area and the destination area, and speeds up the route search processing.

[0004]

By the way, in the vehicle route calculation device disclosed in Japanese Patent Laid-Open No. 9-218047 mentioned above, in order to reduce the number of routes to be subjected to the route search processing, a departure area or a destination area. Since the pruning zone is provided in the vicinity of the area, the optimal link is processed to minimize the cost compared with the case where the route search processing is performed for all the links included in this pruning zone. It may be out of scope. Also, a departure area route network is created so as to connect the departure area and the destination area. However, if one departure area and one destination area are focused on, there is one route connecting them. Alternatively, the number of routes is limited to two, and the other routes are excluded at the stage of creating the departure area route network. Therefore, the position of the departure point in the departure point area or the position of the destination point in the destination area. Depending on the route, the other route may become the optimal route with the lowest cost, but the actual route search process does not select this optimal route. As described above, the conventional vehicle route calculation device has a problem in that the route to be searched is limited in order to speed up the process, and it may not be possible to search for the optimum route.

The present invention was created in view of the above points, and an object thereof is to provide a navigation device capable of searching for an optimum route and speeding up processing. is there.

[0006]

In order to solve the above-mentioned problems, the navigation device of the present invention corresponds to a hierarchical level 1 area and a level 2 area and a combination of two level 2 areas. The route search processing is performed using the map data of the hierarchical structure having the prepared dedicated network. Focusing on one level 1 area in the map data, using the link included in the level 1 area, By actually extending the search branch from the level 1 area of interest,
A route reaching a higher-level node included in the level 2 area including the level 1 area of interest or another level 2 area adjacent to this level 2 area is detected and made to correspond to one level 1 area of interest. Focusing on the first route information and the two level 2 areas, actually searching for a route connecting these level 2 areas using the links included in the level 2 areas, and combining the two level 2 areas of interest And second route information corresponding to the dedicated network prepared for. In addition, this navigation device,
A map data storage means for storing map data, a departure place / destination setting means for setting a departure place and a destination, a departure place /
When the departure place and the destination are set by the destination setting means, a search is performed using the first route information included in the map data stored in the map data storage means to determine the departure place and the destination. Using the second route information, a route between the upper node search means for extracting the upper node corresponding to each and the upper node corresponding to each of the starting point and the destination extracted by the upper node search means is searched using the second route information. And an upper node searching means. By using the first route information, it is possible to surely extend the search branch to the node in the level 2 area, and thus it is possible to perform the optimum route search. Moreover, since the first route information is associated with the original level 1 region that extends the search branch, when the map data of the portion required for the route search processing is read out, the departure place and the purpose When reading the data of the level 1 area including the ground, it becomes possible to read only the first route information corresponding to this level 1 area together,
The processing speed can be increased by reducing the amount of data to be read and the number of times of reading.

Further, the above-mentioned first route information is within a range in which the upper node can be always reached when the search branch is extended from an arbitrary point within a predetermined area including each of the starting point and the destination. Data that specifies a certain upper layer transition search range rectangle is included, and the upper node search means is
It is desirable to search for links included in the level 1 area within the upper layer transition search range rectangle. When searching the route to the upper node included in the level 2 area using the first route information, the upper node can be surely extracted by performing the search within the upper layer transition search range rectangle. Therefore, efficient route search processing becomes possible.

Further, the upper layer transition search range rectangle described above is
For each of the logical meshes generated by dividing one level 1 area of interest into a predetermined number and corresponding to each divided area, a link that spans the boundary of the logical mesh and a boundary node of the level 2 area It is preferable that the result of detecting the route to the upper node by searching the route connecting the two is set by changing the other level 2 area and taking the logical sum. This makes it possible to set an upper-layer transition search range rectangle that can reliably reach an upper node regardless of the place of departure or the destination.

Further, the above-mentioned map data includes data relating to the links included in the level 2 area, and the links included in the level 2 area are focused on two logical meshes and these two logical meshes are selected. When a route to be connected is actually searched, and this searched route has a link included only in the level 1 area, this link is set to level 2
It is desirable to include links that are upgraded according to the area. As a result, when the route search is performed using the dedicated network, all the links included in the level 1 area are taken into consideration, so that the optimum route search process can be performed.

Further, in the above-mentioned second route information, a route connecting two level 2 areas is searched for by using a plurality of search conditions, and each link constituting the route obtained as a result of the search shows which search condition. Is included in the search condition information, and the inter-upper-node search means may select, as the search target, one corresponding to the search condition specified in advance from the second route information. desirable. This allows
It is possible to reduce the number of links to be processed when performing a search process using a dedicated network.

Further, the above-mentioned second route information includes information about an aggregated link which corresponds to a route included in the dedicated network and which is created by aggregating a plurality of links satisfying a specific condition. When the route searched by the upper node searching means includes an aggregated link, the aggregated link expanding means expands the aggregated link into a plurality of original links before aggregation based on the second route information. It is desirable to further include As a result, it is possible to further reduce the number of links to be processed when performing the search processing using the dedicated network and speed up the processing.

Further, a level 1 area included in a predetermined area,
It is possible to read a part of the content corresponding to the starting point and the destination from the disk type recording medium in which the map data corresponding to the level 2 area and the dedicated network is recorded and the map data recorded in the disk type recording medium. It is desirable to further include a read instruction means for instructing, and a map data reading means for reading out a part of the map data from the disk type recording medium according to the instruction of the read instruction means and storing it in the map data storage means. Generally, it takes some time to read data from a disc type recording medium, but in the navigation device of the present invention, the level 1 area, the level 2 area, and the two level 2 areas respectively corresponding to the departure place and the destination are provided. Since it is only necessary to read a part of the map data corresponding to each of the dedicated networks specified by, it is possible to shorten the time to read the data from the disk type recording medium, which speeds up the route search process. can do.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A navigation device according to an embodiment of the present invention will be described below with reference to the drawings. (1) Overall Configuration of Navigation Device FIG. 1 is a diagram showing the overall configuration of a vehicle-mounted navigation device according to an embodiment of the present invention. The navigation device shown in FIG. 1 includes a navigation controller 1 for controlling the whole, a DVD 2 in which map data necessary for map display, route search, etc. is recorded, and a disk reader 3 for reading out the map data recorded in the DVD 2. A remote control (remote control) unit 4 as an operation unit for a user to input various instructions, a GPS receiver 5 and an autonomous navigation sensor 6 for detecting a vehicle position and a vehicle direction, a map image, a guide route, etc. And a display device 7 for displaying.

The disc reading device 3 described above can be loaded with one or a plurality of DVDs 2, and reads the map data from one of the DVDs 2 under the control of the navigation controller 1. The loaded disk is not necessarily a DVD, but may be a CD or a hard disk. Further, both DVD and CD may be selectively loaded.

The remote control unit 4 includes a search key for giving a route search instruction, a route guidance mode key used for setting a route guidance mode, a destination input key, up / down / left / right cursor keys, a map reduction / enlargement key, and a display screen. Various operation keys such as a setting key for confirming the item at the cursor position are provided, and an infrared signal according to the operation state of the key is transmitted to the navigation controller 1.

The GPS receiver 5 receives radio waves transmitted from a plurality of GPS satellites and performs a three-dimensional positioning process or a two-dimensional positioning process to calculate the absolute position and azimuth of the vehicle (the vehicle azimuth is the present time). Calculation based on the vehicle position in the vehicle and the vehicle position one sampling time ΔT before), and outputs them together with the positioning time. The autonomous navigation sensor 6 includes an angle sensor such as a vibration gyro that detects a vehicle rotation angle as a relative azimuth and a distance sensor that outputs one pulse for each predetermined traveling distance. Calculate the bearing.

The display device 7 displays a map image of the area around the vehicle together with the vehicle position mark, the departure point mark, the destination mark, etc. based on the drawing data output from the navigation controller 1 and guides the map image on this map. Display the route etc. (2) Detailed configuration and operation of the navigation controller
Work will now be described in detail the configuration of the navigation controller 1. The navigation controller 1 calculates the position of the vehicle, a data buffer 10 for displaying a map image around the position of the vehicle on the display device 7, a map read control unit 12, a map drawing unit 14, a VRAM 16, an image synthesizing unit 22. A vehicle position calculation unit 30, a route search processing unit 32, and a route guidance memory 3 for performing map matching processing, route search processing, route guidance processing and displaying the results.
4, a guide route drawing unit 38, a mark image drawing unit 40, a remote control unit 60 for displaying various operation screens for the user and transmitting operation instructions from the remote control unit 4 to each unit, a cursor position calculation unit 62, Operation screen generator 6
4 and.

The data buffer 10 temporarily stores the map data read from the DVD 2 by the disc reading device 3. When the vehicle position calculation unit 30 calculates the own vehicle position, the map read control unit 12 outputs to the disk reading device 3 a read request for map data in a predetermined range including the own vehicle position. In addition, the map read control unit 12 outputs a read request for map data necessary for route search to the disk reader 3 in response to a request from the route search processing unit 32.

The map drawing unit 14 creates map drawing data required for display based on the map data stored in the data buffer 10. Created map drawing data is VR
It is stored in AM16. The image composition unit 22 uses the VRAM 1
Map drawing data read from 6 and the guide route drawing unit 3
8, the drawing data output from each of the mark image drawing unit 40 and the operation screen generating unit 64 are overlapped to perform image combination, and the combined drawing data is output to the display device 7.

The vehicle position calculation unit 30 calculates the own vehicle position based on the detection data of the GPS receiver 5 and the autonomous navigation sensor 6, and when the calculated own vehicle position is not on the road in the map data. , Performs map matching processing for correcting the vehicle position. The route search processing unit 32 searches for a travel route that connects a preset destination and departure point under predetermined conditions. For example, under various conditions such as a recommended route (shortest time), a general road priority, and a road width priority, the travel route with the lowest cost is set as the guide route.
The specific contents of the route search will be described later. The guide route thus set by the route search processing unit 32 is stored in the guide route memory 34 as a set of nodes or a set of links from the starting point to the destination.

The guide route drawing unit 38 includes a route search processing unit 3
For selecting the route included in the map area drawn in the VRAM 16 at that time from the route data set by 2 and stored in the route memory 34, and displaying the route on the map image. Create guide route drawing data. The mark image drawing unit 40 creates drawing data for generating a vehicle position mark or a cursor mark having a predetermined shape at the vehicle position after the map matching process.

(3) Detailed Contents of Map Data The map data recorded on the DVD 2 of the present embodiment is read out in units of rectangular regions (areas) separated by predetermined longitude and latitude. In addition, this map data is hierarchically divided into five levels according to the degree of detail of road information corresponding to the display scale, and the lower level (the lowest is level 1) corresponding to the most detailed display.
The more detailed road information is included. Further, the lower level map data is set with a smaller area region, and conversely, the higher level map data is set with a larger area region. In this embodiment, the level 1, the level 2,
Five types of regions, level 3, level 4, and level 5, are set. Among them, route data is created by using the map data of the level 1 and 2 regions and the map data of a dedicated network prepared separately from these regions. Search processing is performed.

FIG. 2 is a diagram showing the format of the map data of this embodiment. As shown in FIG. 2, the map data of this embodiment includes a basic part of each region of levels 1 to 5 and a dedicated network. Each basic part of the level 1 to 5 regions includes the link drawing information and node information necessary for map matching, in addition to the map drawing information necessary for performing the map display processing corresponding to each level region. Has been. Further, the dedicated network stores route information that specifies a route connecting these two regions in correspondence with an arbitrary combination of two level 2 regions.

Further, of the levels 1 to 5 regions and the dedicated network described above, each of the levels 1 and 2 and the dedicated network is provided with an extension unit necessary for performing the route search processing at high speed. In particular,
An "extended path calculation adjacent data frame" is added to the basic part of the level 1 region as an expanded part. These basic parts and "extended route calculation adjacent data frame" are
For example, a specific level 1 that includes the origin of the route search process
When the region map data is read, it is read as a set of map data.

In addition, in the basic part of the level 2 region,
"Address data frame to dedicated network" is added as an extension. These basic part and "address data frame to dedicated network" are read as a set of map data when the map data of a specific level 2 region is read.

Further, in the dedicated network, "boundary node compatible data frame", "upper node compatible data frame", "aggregated link expansion data frame", and "upper layer migration search range data frame" are added as expansion parts. Identify the combination of two level 2 regions,
By specifying the dedicated network corresponding to this combination, along with the route information connecting the level 2 regions, "boundary node compatible data frame", "upper node compatible data frame", "aggregated link expansion data frame", "upper layer migration search" The “range data frame” is read as a set of map data.

Next, the contents of the map data of this embodiment are
It will be described in detail by showing the procedure for creating map data. In addition, this map data shall be created by a map data creation device. FIG. 3 shows a map data creation device 11
It is a block diagram showing 0 as a functional block. The map data creation device 110 shown in FIG. 3 uses the logical mesh generation unit 1 to create the map data 120 recorded on the DVD 2.
30, level 1 search range setting unit 132, upgrade processing unit 1
34, an upper layer migration search range rectangle creation unit 136, a dedicated network creation unit 138, and an aggregated link creation unit 140.

FIG. 4 is a flow chart showing the operation procedure of the map data creation device 110. Generation of Logical Mesh (Step 100) First, the logical mesh generation unit 130 performs a process of generating a logical mesh for each level 1 region. here,
A logical mesh is a segmented area obtained by dividing a level 1 region into a predetermined number.

FIG. 5 is a diagram showing a specific example of the logical mesh. In the example shown in FIG. 5, for example, the vertical direction and the horizontal direction of one level 1 region A are each divided into four equal parts, and 16 logical meshes B are generated corresponding to the entire level 1 region A. Setting Level 1 Search Range (Step 101) Next, the level 1 search range setting unit 132 sets the level 1 search range for all the logical meshes generated in the process of step 100 described above. Here, the level 1 search range is a range including a predetermined number of links centered on the logical mesh, and is set for each logical mesh.

FIG. 6 is a diagram showing a specific example of the level 1 search range. As shown in FIG. 6, the distance L that expands the logical mesh B vertically and horizontally is expanded by 1 km, and the number of links included in the expanded range is counted each time, and the count value is a predetermined number (for example, 1000). ) Is exceeded. When the count value does not exceed the predetermined number, the distance L is further increased by 1 km and the same counting operation and determining operation are repeated. Then, a rectangular area having a size determined by the distance L when the count value exceeds the predetermined number is set as the level 1 search range P. Of course, since the level 1 search range P is set for each logical mesh, the size of the level 1 search range P generally differs for each logical mesh B.

Link Upgrade Processing (Step 102) Next, the upgrade processing unit 134 extracts links that can reduce costs from the links included in the level 1 region and not included in the level 2 region. Then, the process of upgrading from the level 1 link to the level 2 link is performed.
Links in both Level 1 and 2 regions are better than links in Level 1 regions only
Generally, since the road width is wide, it is considered that the cost under various conditions is smaller than other narrow streets, but the entire route is better when traveling on a link included only in the Level 1 region like a wide area farm road. In some cases, the cost of can be reduced. In the upgrading process, such a link included only in the level 1 region is extracted and added to the basic part of the level 2 region. As a result, even when the search process is performed for the links included in the level 2 region, the links that are conventionally included only in the level 1 region and can be reduced in cost. The route search process used can be performed.

7 and 8 are diagrams showing a specific example of the upgrading process. First, the upgrade processing unit 134 extracts the representative node D from the nodes included in the logical mesh B to be processed. This representative node D
, The node closest to the center of the logical mesh B is selected. In FIG. 7, the representative node D is hatched to distinguish it from other nodes (white circles). In this way, the representative node D is set for each of all the logical meshes B included in all level 1 regions.

Next, the upgrade processing unit 134 uses the Dijkstra method for all the representative nodes D included in the other logical mesh B starting from the representative node D of one logical mesh B and using the Dijkstra method. The search is performed until the search branch by the link included in cannot be extended. There are three types of search (conditions): recommended route (time priority), general road priority, and road width priority. The setting of the search type is an example, and other search types may be included, or one or two of the three types of search conditions may be used. Such a search process is performed starting from the representative node D of all the logical meshes.

After the search processing between all the representative nodes is completed in this way, the promotion processing unit 134 extracts the promotion link using the search result. The extraction of the upgrade link is performed using the level 1 search range P set in the processing of step 101 described above. In this extraction process, as shown in FIG. 8, attention is paid to a search link connecting two representative nodes D included in each of the two logical meshes B, and included in the level 1 search range P corresponding to each logical mesh B. The range not set is set as the upgrade range, and the link of the level 1 region included in this upgrade range is selected as the upgrade link.

However, for a link that is partially included in the level 1 search range P on the side of the start representative node of the route search, if the starting end node seen in the search direction is not within this level 1 search range, the link is moved to level 2. It should be extracted as an upgrade link. Further, a link partially included on the destination representative node side of the route search is extracted as an upgraded link unless the terminal node seen in the search direction is within the level 1 search range.

After the extraction of the upgrade links to the level 2 has been completed for all the representative nodes in this way, the upgrade processing unit 134 performs a process of combining the extracted upgrade links. FIG. 9 and FIG. 10 are diagrams showing specific examples of the upgrade link combination processing. If the upgrade link extracted by the above-described upgrade process is originally included in the level 2 region, and if a new intersection is not added in the middle as shown in FIG. 9, the extracted upgrade is performed. Instead of adopting the link, the link originally included in the level 2 region is used.

Although the upgrade link extracted by the above-described upgrade process is originally included in the level 2 region, as shown in FIG. 10, when an intersection occurs in the middle, it is possible to reach the intersection. Multiple upgrade links,
A process of separately combining a plurality of promotion links existing at the intersection is performed.

In this way, the upgrade processing unit 134
Extracts the upgraded links from the links included in the level 1 region, and if the joining process is performed, the link after being joined is used. If the joining process is not performed, the original upgraded link is used as the level 2 link. It is added to the basic part of the level 2 region as a region link.

Level 1 which does not originally exist in Level 2
The link conditions of the region links are as follows: -The link ID can be expressed as a difference-The "link attribute" of the link cost record is the same-The attributes of the pay section and the free section are the same-Bypass flag Are the same, ・ There are two differences (no branch), and so on.

Level 1 upper layer transition search range rectangle setting processing
(Step 103) Conventionally, the route to the node included in the level 2 region is searched for using the link of the level 1 region around the departure point, and further the link of the level 2 region is made to the destination at the remote place. There is known a method of hierarchically searching using. In this method, conventionally, the number of search links, the number of extracted upper nodes, the distance, etc. are used as the search end condition when the search branch is extended from the level 1 region including the departure point of the route search to the level 2 region. .

Further, when searching for a route to a node included in the level 2 region using such a method,
In order to reduce the number of times the map data is read from a CD-ROM or the like and to speed up the processing, the map data of one level 1 region should include the data of links of adjacent level 1 regions that satisfy these search end conditions. There is a way to keep it.

However, the extent to which the search branch is extended to reach the node in the level 2 region is not constant when the road densities are different, such as in urban areas and suburbs. Therefore, to accommodate all road densities,
If a large number of search links and the like satisfying the search end condition are set, unnecessary links are searched, resulting in waste of processing. On the other hand, if the number of search links satisfying the search end condition is set to be small, the number of links to be searched becomes small, and it becomes impossible to search for an optimum route.

In the present embodiment, by only reading the map data (basic part and extended part) of one level 1 region,
The links that can surely follow the optimum links and reach the node in the level 2 region are extracted.
Hereinafter, a range including such a link is referred to as a "level 1 upper layer transition search range rectangle".

This level 1 upper layer transition search range rectangle is created by using the result of actually executing the search process on all the virtual meshes by paying attention to each logical mesh. Here, the "virtual mesh" basically corresponds to the level 2 region. However, if the level 2 region containing the logical mesh of interest and the level 2 region to be searched are close to or the same,
The level 2 region to be searched is divided and each divided region is set as a virtual mesh.

The upper-layer transition search range rectangle creation unit 136 determines the level 2 to be searched from one logical mesh of interest.
A search is performed for a virtual mesh corresponding to a region or a virtual mesh corresponding to a divided area of a level 2 region. FIG. 11 shows one logical mesh B to level 2
It is a figure which shows the specific example in the case of performing a search with respect to the virtual mesh C corresponding to a region. This search is performed for each of the forward direction and the backward direction from the logical mesh B (the direction from the departure place to the destination is the forward direction, and the direction from the destination to the departure place is the opposite direction), and the recommended route and the general route. It is performed under each road-first search condition. The target of the search is a link that connects each of all the links that straddle the boundary of the logical mesh B and each boundary node of the virtual mesh C that corresponds to the level 2 region. This search processing is performed using the links included in the level 1 region.

FIG. 12 is a diagram showing a specific example in which a search is performed from one logical mesh B to a virtual mesh C'corresponding to a divided area of a level 2 region. This search is performed in each of the forward direction and the backward direction from the logical mesh B under the respective search conditions of the recommended route and the general road priority. This point is the same as the case shown in FIG. The target of the search is a link that connects each of all the links that straddle the boundary of the logical mesh B and the link that spans the largest rectangle that is slightly larger than the virtual mesh C ′.

FIG. 13 is an explanatory diagram of the maximum rectangle Q set corresponding to the virtual mesh C'shown in FIG.
When the entire level 2 region corresponds to one virtual mesh C, there is always a boundary node for the road that intersects the boundary, so the search target can be limited to this boundary node. However, when the level 2 region is equally divided into a predetermined number (for example, 16 regions), nodes do not always exist at the boundary of each divided region (in many cases, no nodes exist). Moreover, since the case where such a virtual mesh C ′ is used is the case where the logical mesh B to be searched and the virtual mesh C ′ are very close to each other, it is necessary to consider the level 1 search range to some extent. is there. Therefore, in this embodiment, the virtual mesh C ′ generated corresponding to the divided area of the level 2 region
When using, all the logical meshes B that are wholly or partially included in this virtual mesh C ′ are extracted, and the level 1 search range P corresponding to each of these extracted logical meshes B is included. Is set to the maximum rectangle Q described above.

Specifically, the setting process of the upper layer transition search range rectangle is performed in the procedure shown in (1) to (3) below. (1) First, the upper layer migration search range rectangle creation unit 136 searches for a link that spans the boundary of the logical mesh B of interest from a link that spans the boundary node of the virtual mesh or the maximum rectangle. In this search,
The search result of the optimum route corresponding to the number of links that span the boundary node or the maximum rectangle of the virtual mesh is obtained.

(2) Next, the upper layer transition search range rectangle creation unit 136 follows the search end node on the virtual mesh side to the search start node on the logical mesh side for each search result, and includes it in the level 2 region. Link to Level 1
Detects nodes on routes that extend to links contained only in the region.

FIG. 14 is a diagram showing the relationship between the search result and the detection node. In FIG. 14, S indicates a search start node on the logical mesh side, E indicates a search end node on the virtual mesh side, and the other numbers 0 to 4 indicate the numbers of intermediate nodes. Further, Lv2 indicates a link included in the level 2 region, and Lv1 indicates a link included only in the level 1 region and not included in the level 2 region. In the example shown in FIG.
Following the search end node E, when passing through the node 2, the route extends from the link included in the level 2 region to the link included only in the level 1 region.

The upper layer migration search range rectangle creation unit 136 extracts this node 2 corresponding to the search result shown in FIG. 14 and stores it as an upper migration node, and starts the search on the logical mesh side from this upper migration node. Holds the route to the node S. If such an upper migration node is not found, the entire search result path (from the search end node E to the search start node S) is held.

The above-described storage operation and path holding operation of the upper migration node correspond to each of the links extending over the boundary of the logical mesh of interest, and the link node extending over the virtual mesh boundary node or the maximum rectangle. Iterate over all obtained search results. Further, the same operation regarding (1) and (2) is repeatedly performed by changing the search condition.

(3) With respect to one logical mesh B, when the holding operation of the routes corresponding to all the upper migration nodes is completed, the upper layer migration search range rectangle creation unit 136 then includes all of the retained routes. Such a maximum range is extracted, and the upper layer transition search range rectangle F corresponding to the combination of the one logical mesh B and the one virtual mesh of interest is set. Further, the data for specifying the upper layer migration search range rectangle F set in this way is stored in the upper layer migration search range data frame included in the extension part of the dedicated network.

The series of processes shown in (1) to (3) above are performed for all combinations of the logical mesh and the virtual mesh. FIG. 15 is a diagram showing a specific example of the upper layer transition search range rectangle set in this way. As shown in FIG. 15, when a large number of links c from the plurality of links a to the upper migration node b across the boundary of the logical mesh B are detected, the upper layer migration search range rectangle that includes all of these links c. F is set.

Extended Path Calculation Adjacent Data Frame Creation Processing
Processing (step 104) Next, the upper layer migration search range rectangle creation unit 136 creates an "extended path calculation adjacent data frame" that is an extension unit of the level 1 region, and stores it in association with the corresponding level 1 region. The creation of this data is performed based on the data on the route from the link that straddles the boundary of each logical mesh extracted when setting the upper layer migration search range rectangle to the upper migration node.

FIG. 16 is an explanatory diagram of data stored in the extended route calculation adjacent data frame corresponding to the level 1 basic part. In the example shown in FIG. 16, the level 1 region A is composed of 16 logical meshes B, and the paths to the upper migration nodes extracted corresponding to all the logical meshes B are extracted. At this time, only the route extending outside the level 1 region is extracted so as not to overlap. In FIG. 16, the branch portion extending around the level 1 region A shows the path thus extracted.

FIG. 17 is a diagram showing a data format relating to a route extending to an adjacent level 1 region. For example, as shown in FIG. 17A, focusing on a route extending from a level 1 region (target region) to be processed to an adjacent level 1 region, the data to be stored in the extended route calculation adjacent data frame In the case of creating, as shown in FIG. 17B, the target region extension corresponding to the region, is added as an extended route calculation adjacent data frame to the basic part of the target region. As shown in FIG. 18, when the link a1 of the level 2 region connected to the upper node R exists, the data of this link a1 is also stored in the extended route calculation adjacent data frame (only the level 1 region). The link a2 included in is not stored). This is so that the link regulation can be used as it is at the time of shifting to a higher level. Also,
In the example shown in FIG. 17, the target region extension created for the three level 1 regions adjacent to the target region has been described. However, in general, each target region extension is directly adjacent to the target region or further outside thereof. There is a target region extension corresponding to the level 1 region, and all of these are stored in the extension route calculation adjacent data frame of the target region.

Creation processing of data frame corresponding to upper node
(Step 105) Next, the upper layer migration search range rectangle creation unit 136 creates a "upper node corresponding data frame" which is an expansion unit of the dedicated network. The data of the upper migration node detected in step 103 described above is stored in this upper node correspondence data frame. However, even if there is a level 2 region node on the way to the upper migration node, only the data of this upper migration node is stored in the upper node corresponding data frame.

Creating a dedicated network (step 1)
06) As described above, the dedicated network is network data that stores only the information of links and nodes necessary for searching the route connecting these level 2 regions for each combination of level 2 regions. is there. Since only the links required for route search between two level 2 regions are stored, the amount of calculation for route search is much smaller than usual, which is very effective in speeding up the route search process. .

The dedicated network creation section 138 searches for each of the forward and backward directions for each combination of the two level 2 regions. This search is performed using a boundary node and a promotion node corresponding to each of the two level 2 regions. FIG. 19 is an explanatory diagram of a promotion node. A promotion node is a higher-level migration node that exists outside the level 1 region, and is a level 1
It is located outside the level 2 region that contains the region. In the example shown in FIG. 19, two upper migration nodes R1 and R2 located outside the level 1 region
Among them, only one upper migration node R1 becomes a promotion node.

A dedicated network is a network in which the search results under all the search conditions are not duplicated. Further, at this time, all of the search conditions used in the link are stored, and when the map data 120 is formatted (when a dedicated network for the map data 120 is created), the search condition A flag as search condition information indicating whether or not the link is used for is stored so as to correspond to each link. This makes it possible to reduce the number of links required for each search condition,
The search processing using the dedicated network can be speeded up.

Aggregated Link Creation Process Next, the aggregated link creation unit 140 performs a process of ignoring the link ID and combining the links with only two differential paths in order to further speed up the search process using the dedicated network. I do. The links combined in this way are called “aggregated links”. All the two difference links that do not meet the following non-joining conditions are to be joined. (Non-join condition) -Ferry attribute links are not joined. Here, the ferry attribute link is a link on the ferry route, and this link is excluded from the connection target. -Upgrade nodes are not combined. -Links within the VICS reflection distance are not combined. -Do not aggregate the adjacent nodes in the dedicated network pointed to by the boundary node of the basic part.

With respect to the aggregated links thus combined, the aggregated link IDs are assigned in ascending order from 0 for each dedicated network. In addition, the cost of the aggregated link is associated with the result of cost calculation performed in advance for each search type. In this way, the aggregated link creating unit 140 creates aggregated links for the links included in the dedicated network and updates some information regarding the route connecting the two level 2 regions to each other (step 107). .

Further, in order to understand which link is combined to create an aggregate link when linking, a plurality of link IDs to be combined with respect to the aggregate link ID
It is necessary to store the information of. For this purpose, the aggregated link creation unit 140 creates an “aggregated link expansion data frame”, which is an extension of the dedicated network, and stores it in association with the corresponding dedicated network (step 10).
8). When the aggregated link is included in the route extracted as the search result, the aggregated link is expanded to the normal link based on the information included in the aggregated link expansion data frame as shown in FIG. It is possible to perform guidance processing and drawing processing using the link of the level 2 region after being expanded.

Creation of Other Data Frames Next, the dedicated network creation unit 138 is a "boundary node corresponding data frame" which is an extension unit of the dedicated network.
Is created and stored in association with the corresponding dedicated network (step 109).

The adjacent node information included in the basic part of the level 2 region is related to the adjacent level 2 region. Therefore, in order to extend the search branch from any level 2 region to the dedicated network, it is necessary to know which node in the dedicated network corresponds to the adjacent node information of the level 2 region.

FIG. 21 is an explanatory diagram of adjacent node information. As shown in FIG. 21A, the adjacent node information is
When attention is focused on one boundary node of the level 2 region, this data is used to specify the adjacent node N1 in another level 2 region (adjacent region) that is adjacent via this boundary node.

The dedicated network creation unit 138 is shown in FIG.
As shown in (B), the node N2 in the dedicated network corresponding to the adjacent node information of the level 2 region is specified, and the "boundary node-corresponding data frame", which is an extension of this dedicated network, is created. Since the correspondence between one level 2 region and the boundary node of the dedicated network is 1: N (N is the number of dedicated networks), it is newly created when the search branch is extended from the level 2 region to the dedicated network. It is necessary to convert the data using the boundary node corresponding data frame, but since the boundary node information included in each dedicated network corresponds to one level 2 region, such conversion is not necessary.

Further, as described above, the information of the upper migration node is stored in the "upper node corresponding data frame" which is the expansion part of the dedicated network. Corresponds to which node included in which level 2 region. Therefore, like the upgrade node R1 shown in FIG. 19, when the upper migration node is included in another adjacent level 2 region other than the level 2 region including the level 1 region of interest, It is necessary to specify which node in the dedicated network this upper migration node corresponds to. The dedicated network creation unit 138 adds information for identifying the node in the dedicated network corresponding to the upgraded node, updates the content of the “upper node corresponding data frame” created in step 105 described above, and updates the relevant dedicated network. And stores the data (step 110).

The above-mentioned dedicated network is newly created in addition to the basic part of each level 1-5 region. Therefore, when extending a search branch from any level 2 region to one dedicated network, address information for reading data of this dedicated network is required. Dedicated network creation unit 13
When the dedicated network is created, 8 creates an "address data frame to the dedicated network" that includes the address information as an extension of the created dedicated network, and stores it in association with this dedicated network (step 111).

(4) Outline of Route Search Process Next, the route search process performed in the navigation device of this embodiment will be described. FIG. 22 is a flowchart showing the operation procedure of the route search processing performed by the navigation device of this embodiment. Further, FIG. 23 is a diagram showing an outline of the route search processing performed by the navigation device of the present embodiment. FIG. 24 is a functional block diagram of the route search processing unit 32 that performs route search processing. As shown in FIG. 24, the route search processing unit 32 includes a departure point / destination setting unit 200, a map data read range setting unit 204, an upper layer transition search range rectangle specifying unit 206, and an upper node searching unit 20.
8, an upper node route search unit 210, and an aggregated link expansion unit 212.

The above-mentioned data buffer 10 serves as map data storage means, the departure point / destination setting section 200 serves as the departure point / destination setting means, and the upper layer transition search range rectangle specifying section 206,
The upper node searching unit 208 is an upper node searching unit, and the upper node route searching unit 210 is an upper node searching unit,
The aggregated link expanding unit 212 corresponds to the aggregated link expanding means, respectively. In addition, DVD2 is a disk type recording medium,
Map data read range setting unit 204, map read control unit 12
Corresponds to the reading instruction means, and the disk reading device 3 corresponds to the map data reading means.

Setting of Departure Place / Destination (Step 200) When the user of the navigation device instructs the route search operation, first, the departure place / destination setting unit 200 in the route search processing unit 32 makes a route search. Set the starting point and destination to be targeted. For example, the vehicle position at that time calculated by the vehicle position calculation unit 30 is set as the departure place. In addition, when the user operates the joystick key or the like provided on the remote controller 4 to specify an arbitrary cursor position, the position is the position, or when the facility search is performed to search for the specific facility, the specific facility is the purpose. It is set as the ground. The starting point and the destination may be set using a method other than these.

Setting search conditions (step 201) When the search conditions are specified by the user, the upper node search unit 208 and the upper node route search unit 210
In each of them, the search condition for performing the search process is set. When the user does not specify the search condition, a default search condition (for example, recommended route) is set.

Readout of Map Data (Step 202) Next, the map data read-out range setting unit 204 includes the level 1 and the level 2 which respectively include the departure place and the destination set by the departure place / destination setting unit 200. The map data of the basic part and extension part of the region, the dedicated network corresponding to the combination of the level 2 region containing the departure place and the level 2 region containing the destination, and the map data of the extension part are read out. Actually, when the map data read range setting unit 204 designates two level 1 regions and two level 2 regions to be read and the corresponding dedicated network, the map read control unit 12 displays the instruction content. And the map data 120 recorded on the DVD 2 by the disc reading device 3
The corresponding map data is selectively read from the
It is stored in the data buffer 10. Also, the dedicated network that supports the combination of the two Level 2 regions is
It can be specified by the data of the extension "address data frame to dedicated network" of these level 2 regions.

As shown in FIG. 23, when the departure place S is specified, the level 1 region A1 including the departure place S is included.
Then, the level 2 region C1 including this level 1 region A1 is specified. Similarly, when the destination E is specified, the level 1 region A including the destination E is included.
2 and Level 2 including this Level 1 Region A2
The region C2 is specified. In addition, since the dedicated network is prepared in advance for each combination of the two level 2 regions, each of the starting point and the destination is included.
When one level 2 region is identified, the dedicated network determined by this combination is identified. In this way, the level 1 and 2 regions and the dedicated network are specified, and the map data including the extended parts thereof are read out and stored in the data buffer 10.

Of the upper node in the upper layer transition search range rectangle
Extraction (Step 203) Next, the upper layer transition search range rectangle specifying unit 206 identifies the upper layer transition search range rectangle corresponding to each of the starting point and the destination, and the upper node searching unit 208 determines the upper layer transition search range rectangle. A search process is performed within the upper layer node (upper node node) included in the upper layer migration search range rectangle corresponding to each of the starting point and the destination point. The extraction of this upper node is specified by the extension "upper layer migration search range data frame" of the dedicated network from the links corresponding to the basic part of the level 1 region and the extension "advanced route calculation adjacent data frame", respectively. The upper-layer transition search range rectangle is searched for. By this search, a plurality of upper nodes are extracted within the upper layer transition search range rectangle including the departure place, and a plurality of upper nodes are extracted within the upper layer transition search range rectangle including the destination. It should be noted that the cost to the departure place and each upper node on the side of the departure place and the cost to the destination and each upper node on the destination side are stored.

Search for route between upper nodes (step 20)
4) Next, the inter-upper-node route search unit 210 extends a search branch from each of the upper nodes extracted corresponding to the departure point side, and selects the optimum route up to each of the upper node extracted corresponding to the destination side. Search for a route. This search is based on the basic part of the level 2 region, dedicated network and its extension "upper node compatible data frame", "boundary node compatible data frame"
Is performed using the map data corresponding to each of. For example, which upper node in the level 2 region or dedicated network the upper migration node extracted in step 203 described above corresponds to can be known by using the data of the "upper node corresponding data frame". Also, when extending the search branch from the upper node in the level 2 region to the dedicated network,
It is possible to know to which node in the dedicated network the search branch can be extended from the boundary node of the level 2 region by using the data of the "boundary node corresponding data frame".

The above-described search between the upper nodes is continued until the optimum travel route connecting the departure place and the destination is determined. For example, this search is performed by sequentially extending the search branches for the route with the lowest cost. For example, as shown in FIG. 23, three upper nodes N11, N12, corresponding to the upper layer transition search range rectangle including the departure place S,
N13 is extracted, and the costs from the starting point S to the respective upper nodes are a1, a2, a3 (a1 <a2 <a3).
Then, first, one search branch is extended from the upper node N11 having the smallest cost a1. At this time, when there are a plurality of links connected to the upper node N11, the search branch is extended to all the links. Next, one of the upper nodes N12 and N13 and the newly searched node in the level 2 region or the dedicated network is extended from the node having the smallest cost at that time. In this way, the operation of determining the node with the lowest cost each time and extending the search branch from this node is repeated. If the destination of the search branch extending from a certain node is the node for which the search route has already been performed, the route with the lowest overall cost is selected from the plurality of routes to this node. In this way, the optimum travel route from each upper node on the departure point S side to all the upper nodes on the destination E side is searched.

The search ends when there is no possibility that the optimum route will be searched. For example, even if there are multiple search branches that do not reach the destination,
The search process ends when it becomes clear that the cost will be higher than the previously searched route even if the search using these search branches is performed.

Further, since a flag as search condition information indicating which search condition is used for each link constituting each route of the dedicated network is set, the link is set in step 201. The search process is performed only on the links corresponding to the search conditions.

Development of Aggregated Link (Step 205) Next, the aggregated link development unit 212 expands the dedicated network when the route extracted by the search by the upper node route search unit 210 includes the aggregated link. Based on the data of the section "Aggregated Link Expansion Data Frame", processing for expanding this aggregated link into the original link of the level 2 region is performed.

As described above, in the navigation device of this embodiment, by using the extended route calculation adjacent data frame of the level 1 region included in the map data,
Since the search branch can be surely extended to the node of the level 2 region, it becomes possible to perform the optimum route search. Moreover, this extended path calculation adjacent data frame is
Since it is associated with the original level 1 region that extends the search branch, when reading the map data of the part required for the route search process from the DVD 2, the level 1 region of the start point and destination is included. When data is read, only the data corresponding to this level 1 region can be read together, the amount of data to be read and the number of times of reading can be reduced, and the route search processing can be speeded up.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the embodiment described above,
Although the in-vehicle navigation device has been described, the present invention can also be applied to a case where a predetermined map search program is executed by a personal computer or the like to perform a route search.

[0085]

As described above, according to the present invention, the first
By using the route information of, the search branch can be surely extended to the node in the level 2 area, so that it is possible to perform the optimum route search. Moreover, since the first route information is associated with the original level 1 region that extends the search branch, when the map data of the portion required for the route search processing is read out, the departure place and the purpose This level 1 is used when reading the data in the level 1 area that includes the ground.
Only the first path information corresponding to the area can be read together, and the processing speed can be increased by reducing the amount of data to be read and the number of times of reading.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a vehicle-mounted navigation device according to an embodiment.

FIG. 2 is a format diagram showing detailed contents of map data.

FIG. 3 is a configuration diagram showing functional blocks of the map data creation device of the present embodiment.

FIG. 4 is a flowchart showing an operation procedure of the map data creation device of the present embodiment.

FIG. 5 is a diagram showing a specific example of a logical mesh.

FIG. 6 is a diagram showing a specific example of a level 1 search range.

FIG. 7 is a diagram showing a specific example of a upgrading process.

FIG. 8 is a diagram showing a specific example of a upgrading process.

FIG. 9 is a diagram showing a specific example of a combining process of upgrade links.

FIG. 10 is a diagram showing a specific example of a process for combining upgrade links.

FIG. 11 is a diagram showing a specific example in which a search is performed from one logical mesh B to a virtual mesh C corresponding to a level 2 region.

FIG. 12 is a diagram showing a specific example in which a search is performed from one logical mesh B to a virtual mesh C ′ corresponding to a divided area of a level 2 region.

FIG. 13 is an explanatory diagram of a maximum rectangle Q set corresponding to the virtual mesh C ′ shown in FIG.

FIG. 14 is a diagram showing a relationship between a search result and a detection node.

FIG. 15 is a diagram showing a specific example of an upper layer transition search range rectangle.

FIG. 16 is an explanatory diagram of data stored in an extended path calculation adjacent data frame corresponding to the level 1 basic part.

FIG. 17 is a diagram showing a format of data regarding a route extending to an adjacent level 1 region.

FIG. 18 is an explanatory diagram of a route extending to an adjacent level 1 region.

FIG. 19 is an explanatory diagram of a promotion node.

FIG. 20 is a diagram showing a specific example of development of an aggregated link.

FIG. 21 is an explanatory diagram of adjacent node information.

FIG. 22 is a flowchart showing an operation procedure of route search processing performed by the navigation device of the present embodiment.

FIG. 23 is a diagram showing an outline of route search processing performed by the navigation device of the present embodiment.

FIG. 24 is a functional block diagram of a route search processing unit that performs route search processing.

[Explanation of symbols]

1 Navigation controller 2 DVD 3 disk reader 10 data buffers 12 Map read control unit 14 Map drawing section 30 Vehicle position calculator 32 Route Search Processing Unit 34 Guided path memory 200 Origin / Destination Setting Section 204 Map data read range setting section 206 Upper layer transition search range rectangle specification unit 208 Upper node search unit 210 Route Search Unit between Upper Nodes 212 Aggregated Link Expansion Unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Sekine             1-8 Nishigotanda, Shinagawa-ku, Tokyo             Within Lupine Co., Ltd. (72) Inventor Tomonori Sato             1-8 Nishigotanda, Shinagawa-ku, Tokyo             Within Lupine Co., Ltd. (72) Inventor Satoshi Matsuzaki             1-8 Nishigotanda, Shinagawa-ku, Tokyo             Within Lupine Co., Ltd. (72) Inventor Masaaki Ohira             1-8 Nishigotanda, Shinagawa-ku, Tokyo Stock             Ceremony company MBA (72) Inventor Masayuki Arai             1-8 Nishigotanda, Shinagawa-ku, Tokyo Stock             Ceremony company MBA (72) Inventor Kenji Sugiyama             1-8 Nishigotanda, Shinagawa-ku, Tokyo Stock             Ceremony company MBA F-term (reference) 2C032 HB02 HB05 HB22 HC08 HC15                       HC24 HD16 HD30                 2F029 AA02 AB01 AB07 AB13 AC02                       AC08 AC14                 5H180 AA01 BB13 FF04 FF05 FF22                       FF27 FF32

Claims (7)

[Claims] 1. A route search using hierarchical map data having hierarchical level 1 and level 2 areas and a dedicated network prepared for each combination of the two level 2 areas. A navigation device that performs processing, wherein the map data is focused on one level 1 region,
A link included in the level 1 area is used to actually extend a search branch from the level 1 area of interest to the level 2 area including the level 1 area of interest or the level 2 area. Detecting a route reaching an upper node included in the other level 2 area adjacent to the other,
Focusing on the first route information corresponding to the one level 1 region of interest and the two level 2 regions, the route connecting these level 2 regions is actually used by using the link included in the level 2 region. And a second route information corresponding to the dedicated network prepared for the combination of the two level 2 areas of interest, and map data storage means for storing the map data. A starting point / destination setting means for setting a starting point and a destination; and, when the starting point and the destination are set by the starting point / destination setting means, stored in the map data storage means. An upper node searching means for performing a search using the first route information included in the map data to extract the upper nodes corresponding to the departure place and the destination, respectively; An inter-upper node search means for searching for a route between the upper node corresponding to each of the starting point and the destination extracted by the upper node searching means by using the second route information. Characteristic navigation device. 2. The first route information according to claim 1, wherein when the search branch is extended from an arbitrary point in a predetermined area including each of the departure place or the destination, the upper node is always included. Data that specifies an upper layer transition search range rectangle that is a reachable range is included, and the upper node search means searches for links included in the level 1 region within the upper layer transition search range rectangle. A navigation device characterized by performing. 3. The logical mesh generated according to claim 2, wherein the upper layer transition search range rectangle is divided into a predetermined number of one level 1 region of interest and is generated so as to correspond to each divided region. With respect to the result of detecting a path leading to the upper node by searching a path connecting between a link that crosses the boundary of the logical mesh and a boundary node of the level 2 area, other level 2 areas The navigation device is characterized in that it is set by changing the logical sum and taking the logical sum. 4. The map data according to claim 3, wherein the map data includes data related to links included in the level 2 area, and the links included in the level 2 area are focused on two logical meshes. A link that actually connects these two logical meshes is searched, and if the searched route has a link included only in the level 1 area, this link is upgraded to correspond to the level 2 area. A navigation device comprising: 5. The method according to claim 1, wherein the second route information is searched for a route connecting two level 2 areas using a plurality of search conditions, and is obtained as a result of the search. Search condition information indicating which search condition each link constituting the route corresponds to is included, and the upper node-to-upper node search means is specified in advance from the second route information as a search target. A navigation device, wherein a navigation device corresponding to the search condition is selected. 6. The method according to claim 1, wherein the second route information corresponds to a route included in the dedicated network and is created by aggregating a plurality of links satisfying a specific condition. When the aggregated link is included in the route searched by the inter-upper-node searching means, the aggregated link is not aggregated based on the second route information. The navigation device further comprising an aggregated link expanding means for expanding the original plurality of links. 7. The disk type recording medium according to claim 1, wherein the map data corresponding to the level 1 area, the level 2 area and the dedicated network included in a predetermined area is recorded, From the map data recorded on the disk-type recording medium, a read instruction means for instructing to read out a part of the contents corresponding to the departure place and the destination, and the read instruction means in response to the instruction of the read instruction means. A navigation device, further comprising: map data reading means for reading a part of the map data from a disk-type recording medium and storing the map data in the map data storage means.