JPH11160091A - Navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigation system which can search a course accurately. SOLUTION: A navigation controller 1 comprises a map buffer 16, a course searching section 36, a course guide memory 38, a course search memory 40 and a receiving data buffer 50. A data to be stored in the course search memory 40 includes a table for specifying the urbanization level of each zone, and a table for correcting the cost based on the situation of road in a zone. Based on the information, the course searching section 36 corrects the cost for metropolitan zone, urban zone, and other zone before searching the course.

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 an optimum route connecting a departure place and a destination by a route search.

[0002]

2. Description of the Related Art Generally, an on-vehicle navigation device detects a current position of a vehicle, reads map data near the current position from a CD-ROM, and displays the map data on a screen. Also,
In the center of the screen, a vehicle position mark indicating the vehicle position is displayed, and the map data in the vicinity is scrolled according to the progress of the vehicle around the vehicle position mark so that the map information around the vehicle position can be always understood. Has become.

[0003] Most of the recent on-vehicle navigation devices are equipped with a route guidance function that enables a driver to travel to a desired destination without making a mistake on a road. According to this route guidance function, the route with the smallest cost connecting the departure point and the destination is automatically searched using the map data by performing a simulation such as the horizontal search (BFS) method or the Dijkstra method, and the search is performed. The route is stored as a guidance route. During driving, when the guidance route is drawn on the map image in a different color from the other roads and is drawn thicker, or displayed on the screen, or when the vehicle approaches an intersection where the course should be changed, within a certain distance, The driver is guided to the destination by enlarging and displaying the intersection and displaying an arrow indicating the traveling direction.

The cost is a value obtained by multiplying a road width, a road type (such as a general road or an expressway), a right turn, a left turn, and other predetermined constants based on the distance. The degree of appropriateness is quantified. Even if there are two routes with the same distance, the cost will be different by specifying whether the driver uses the expressway or not, and gives priority to the required time or mileage. Become.

[0005]

However, actual road conditions often differ from region to region. For example, in an urban area, the speed often decreases and it takes a long time because the area is often congested. However, in a rural area, the speed does not decrease so much and it does not take much time. However, in the above-described conventional navigation device, the cost is calculated based on the road width, the road type, and the like, and the road situation in each region is not considered, so that the searched route does not match the actual condition. In some cases, an accurate route search could not be performed.
In particular, traffic congestion is chronically occurring in large cities such as Tokyo. When searching for a route with a small cost based on the type or the like, an alternative route that can travel in a short time is often not selected as a search route.

Therefore, recently, in order to perform a route search in accordance with the actual situation, a traveling cost (actually measured cost) such as an actually measured traveling time is stored for a road once traveled.
In some cases, a route search is performed in consideration of the actual measurement cost, or a route search is performed based on traffic congestion information from a road traffic information center (VICS center). However, for roads that have not been traveled yet, actual costs are not stored,
Since it is not possible to receive traffic congestion information on all roads, there are cases where the searched route does not match the actual situation even if such measures are taken.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to provide a navigation device capable of performing an accurate route search.

[0008]

In order to solve the above-mentioned problems, a navigation apparatus according to the present invention specifies information on road conditions for each region, preferably a plurality of types of regions according to the level of urbanization. The region specifying data is included in the map data, and the route search processing means performs a route search process in consideration of the road conditions for each region. In general, road conditions such as whether or not the roads are congested are correlated with the level of urbanization, and the degree of congestion tends to be greater in larger cities and conversely in smaller areas. There is. Therefore, by considering the road conditions in each area, it is possible to perform a more accurate and accurate route search.

In particular, cost correction data corresponding to each of a plurality of types of regions according to the level of urbanization is included in the map data, and different cost corrections are made for each type of traveling region. It is possible to perform an accurate route search process using the traveling cost according to the above.

The above-mentioned area specifying data includes longitude data and latitude data for specifying the area, and the urbanization level of the area specified by these data. ) Can easily be determined by comparing the longitude and the latitude as to whether or not any of the area specifying data corresponds to the area identification data.

[0011] Further, there is provided traffic congestion information receiving means for receiving traffic congestion information sent from the road traffic information center,
A route search may be performed only on a road for which congestion information cannot be obtained, in consideration of the above-described road conditions for each area. Alternatively, when the actually measured travel costs are stored, a route search may be performed only on a road for which the actually measured travel costs are not obtained, in consideration of the road conditions in each region. At present, traffic information and measured costs are not available for all roads,
Since it can be obtained only for some roads, a more accurate route search process can be performed by combining these with the above-described route search in consideration of the road situation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A navigation device according to an embodiment of the present invention classifies each area into a large city area, an urban area, and other areas according to the level of urbanization, and reduces travel costs. It is characterized in that by performing weighting according to the level of urbanization, a route search based on actual conditions is performed in consideration of local road conditions. Hereinafter, a navigation device according to an embodiment will be described with reference to the drawings.

(1) Overall Configuration of Navigation Apparatus FIG. 1 is a diagram showing the overall configuration of a vehicle-mounted navigation apparatus according to an embodiment of the present invention. The navigation apparatus shown in FIG. 1 includes a navigation controller 1 for controlling the whole, a CD-ROM 2 on which various map data necessary for map display and route search are recorded, and a CD-RO
A disk reader 3 for reading map data recorded in M2, and a remote control (remote control) unit 4 as an operation unit for inputting various instructions by a driver or a passenger
A GPS receiver 5 and an autonomous navigation sensor 6 for detecting the position and direction of the vehicle, and a road traffic information center (VIC
S center), a beacon transceiver 7 and an FM multiplex broadcast receiver 8 for receiving road traffic information sent from various communication systems, a display device 9 for displaying a map image and a guidance route superimposed on the map image, a route, An audio unit 10 that outputs a predetermined guidance voice when performing guidance.

The above-mentioned disk reading device 3 can be loaded with one or a plurality of CD-ROMs 2 and any one of the CD-ROMs 2 is controlled by the navigation controller 1.
-Read map data from the ROM 2. The remote control unit 4 includes a search key for giving a route search instruction,
Route guidance mode key used for setting the route guidance mode, destination input key, left / right / up / down cursor keys, map reduction /
Various operation keys such as an enlargement key and a setting key for fixing an item at a cursor position on the display screen are provided, and an infrared signal corresponding to an 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, performs three-dimensional positioning processing or two-dimensional positioning processing, and calculates the absolute position and direction of the vehicle (the vehicle direction is currently Is calculated based on the own vehicle position and the own vehicle position one sampling time ΔT before), and these are output together with the positioning time. The autonomous navigation sensor 6 includes an angle sensor 12 such as a vibrating gyroscope that detects the vehicle rotation angle as a relative bearing, and a distance sensor 14 that outputs one pulse every predetermined traveling distance. Detect position and orientation.

The beacon transceiver 7 performs bidirectional communication mainly with radio wave beacon transceivers installed on highways via radio waves, and also mainly uses optical beacon transceivers installed on general roads. The two-way communication is carried out via light between the VICS center and the VI sent from the VICS center.
Receive CS traffic information. The FM multiplex broadcast receiver 8 is adapted to transmit a VI included in multiplexed data superimposed on general FM broadcast.
Receive CS traffic information. Comparing the above-mentioned radio beacon and optical beacon with FM multiplex broadcasting,
Although there is no fundamental difference in the point that the S traffic information can be received and its contents, the traffic information can be obtained in a wider reception area by FM multiplex broadcasting.

The display device 9 displays map information around the own vehicle together with a vehicle position mark, a departure point mark, a destination mark, etc., based on the image data output from the navigation controller 1, or guides the user on this map. Or show directions.

(2) Details of Map Data Next, details of the map data recorded on the CD-ROM 2 will be described. The map data recorded on the CD-ROM 2 is in units of figures separated by a predetermined longitude and latitude, and the map data of each figure can be specified and read by specifying a figure number. Becomes In addition, the map data for each map includes a drawing unit including various data necessary for map display, a road unit including data necessary for various processes such as map matching, route search, and route guidance, and an intersection. An intersection unit consisting of detailed data of the intersection is included. In addition, the drawing unit described above has a V required to identify the corresponding road based on the traffic congestion information sent from the VICS center.
The data includes the data of the ICS conversion layer, the data of the background layer required to display buildings or rivers, and the data of the character layer required to display names of cities, towns and villages, names of roads, and the like.

In the above-mentioned road unit, a line connecting an intersection on a road to another adjacent intersection is called a link, and a point connecting two or more links is called a node. FIG. 2 is a diagram showing the overall configuration of the above-described road unit. As shown in the figure, the road unit has a unit header for identifying a road unit, a connection node table storing detailed data of all nodes, and a node table indicating a storage position of the connection node table. And a link table storing detailed data of a link specified by two adjacent nodes.

FIG. 3 is a diagram showing the detailed contents of various tables included in the road unit. As shown in FIG. 3A, the node table includes node records # 0, # 1,... Corresponding to all the nodes included in the target leaf.
Is stored. Each node record is #
Node numbers are given in order from 0, and indicate the storage position of the connection node table corresponding to each node.

FIG. 3B shows the connection node table.
For each of the existing nodes, a. Normalized longitude / latitude, b. "Node attribute flag" including an intersection node flag indicating whether or not this node is an intersection node, an adjacent node flag indicating whether or not this node is a node at a boundary with another figure, c. "The number of connected nodes" indicating the number of nodes forming the other end of each link when there is a link having this node as one end of the link; d. No right turn or U
If there are traffic restrictions such as turn prohibition, the "number of traffic restrictions", e. Connection node records for the number of links indicating the link number of each link having this node at one end; f. A traffic regulation record indicating the specific content of the traffic regulation corresponding to the number of the traffic regulations, if any, g. If this node is a node at a boundary with another figure leaf, an “adjacent node record” indicating the position of the connection node table of the corresponding node of the neighboring figure leaf, h. If this node is an intersection node, the storage location and size of the corresponding intersection record in the intersection unit are included.

Further, as shown in FIG. 3C, the link table includes a plurality of link records in the order of link numbers corresponding to all the links included in the target figure. Each of these link records: a. A link ID, which is a code assigned to each link mainly for displaying a search route, b. Node number 1 and node number 2 identifying the two nodes located at both ends of the link; c. Link distance, d. The time required to travel on this link is obtained by calculation from the type of road, etc., and the time required for passing through this link is indicated in minutes, e. This link is the VIC managed by the VICS center
Various road attribute flags including a VICS link correspondence flag indicating whether the link is compatible with the S link, f. A road type flag indicating whether the actual road corresponding to this link is an expressway or a general road; g. The route number assigned to the road corresponding to this link is included.

FIG. 4 shows the VICS included in the drawing unit.
It is a figure showing the detailed contents of a conversion layer. As shown in the figure, the VICS conversion layer of the drawing unit has VICS
A conversion table is included. The VICS conversion table further includes a VICS unit header for identifying the VICS conversion table, a road link number table, and a VICS link conversion table. In the road link number table, data of each road link (each link included in a road unit is particularly referred to as a “road link” for distinguishing from a VICS link in the order of the road link number) is stored at any position in the VICS conversion table. This indicates that the link has been performed, and corresponds to all the links of the target figure.

In addition, the VICS link conversion table includes, for each of the existing road links, a. A VICS link information flag including a VICS link length indicating the relative length of the VICS link and the road link, and a vertical line distinction indicating whether the vertical line of the road link of interest is the same or different, b. The number of corresponding VICS links when looking at the road link of interest from one node to the other, c. Distance from one node direction of the VICS link to this road link start position (percentage as viewed from the distance of the entire VICS link), d. The number of corresponding VICS links when the road link of interest is viewed from the other node toward one node; e. The distance from the other node direction of the VICS link to this road link start position (percentage as viewed from the distance of the entire VICS link), f. 2 corresponding to each of the VICS links when viewed from one node of the road link toward the other node
Next mesh code, VICS link ID, distance to VICS link, g. Conversely, secondary mesh codes, VICS link IDs, and VIs corresponding to the respective VICS links when viewed from the other node of the road link toward the one node.
The distance to the CS link, and the like are included.

(3) Detailed Configuration and Operation of Navigation Controller Next, a detailed configuration of the navigation controller 1 shown in FIG. 1 will be described. The navigation controller 1 includes a map buffer 16 for displaying a predetermined map on the display device 9 based on the map data read from the CD-ROM 2, a map reading control unit 18, a map drawing unit 20, a VRAM 22, a reading control unit 24, Image synthesis unit 26
A data storage unit 30, a vehicle position / azimuth calculation unit 32 for performing calculation of the vehicle position, map matching processing, route search processing, and route guidance processing and displaying the results.
A map matching processing unit 34, a route search processing unit 36, a guidance route memory 38, a route search memory 40, a guidance route drawing unit 42, a mark image generation unit 44, an intersection guidance unit 46,
A received data buffer 50 for displaying VICS information received by the beacon transceiver 7 and the like, a VICS information drawing unit 52, and various operation screens for the user and an operation instruction from the remote control unit 4 are transmitted to each unit. Remote controller control section 60, cursor position calculation section 62,
An operation screen generating unit 64;

The map buffer 16 is provided in the disk reader 3
Is for temporarily storing the map data read from the CD-ROM 2 by the above method. Map reading control unit 1
When the center position of the screen is calculated by the control unit 8, a command to read map data in a predetermined range including the center position of the screen is sent from the map reading control unit 18 to the disk reading device 3, and the map data necessary for displaying the map is stored on the CD. Read out from the ROM 2 and stored in the map buffer 16; For example, map data corresponding to four sheets including the screen center position is read out and stored in the map buffer 16.

The map drawing section 20 creates a map image required for display based on the drawing units included in the map data of the four figures stored in the map buffer 16. The created map image data is stored in the VRAM 22, and the read control unit 24 reads one screen of map image data. The image synthesizing unit 26 adds the mark image generating unit 44, the intersection guidance unit 46,
Each image data output from each of the operation screen generating units 64 is superimposed to perform image synthesis, and the synthesized image is displayed on the screen of the display device 9.

The data storage unit 30 sequentially stores positioning position (own vehicle position) data output from the GPS receiver 5. Further, the vehicle position / direction calculation unit 32 calculates the absolute position and direction of the vehicle from the relative position and direction of the vehicle output from the autonomous navigation sensor 6. The map matching processing unit 34 uses the GP stored in the data storage unit 30
It is determined whether or not the own vehicle position by the S receiver 5 or the own vehicle position calculated by the vehicle position / azimuth calculation unit 32 exists on the road in the map data. The process of correcting the own vehicle position is performed. As typical methods of map matching, pattern matching and projection are known.

When the destination input key is pressed after the cursor is moved to a specific location on the map by operating the cursor keys of the remote control unit 4, the route search processing unit 36
At this time, the cursor position calculated by the cursor position calculator 62 is set as the destination of the route search. The set destination data is stored in the guidance route memory 38.
When the search key of the remote control unit 4 is pressed, the route search processing unit 36 sets the own vehicle position corrected by the map matching processing unit 34 as a departure point, stores the vehicle position in the guidance route memory 38, and A search is made for a traveling route connecting the departure point and the destination stored in the guidance route memory 38 under predetermined conditions. For example, under various conditions such as the shortest time, a guidance route that minimizes the cost considering road conditions in each region is set. As a typical method of the route search, the Dijkstra method and the horizontal search method are known. The guidance route set by the route search processing unit 36 in this way is stored in the guidance route memory 38.

FIG. 5 is a diagram showing an example of data stored in the guidance route memory 38. As shown in the drawing, the data of the guide route set by the route search processing unit 36 is a set of nodes NS, N1, N from the starting point to the destination.
, ND, and are stored in the guidance route memory 38.

The route search memory 40 is used to store data of an intersection network list necessary for the route search and data of travel costs (actually measured costs) such as actually measured travel times. Thus, these stored data are read, and a predetermined route search process is performed. The measured cost is calculated by the map matching processing unit 34.
It is obtained by acquiring the own vehicle position corrected by. The details of the intersection network list will be described later.

The guidance route drawing unit 42 stores the guidance route memory 3
8 from the guidance route data stored in
Those included in the map area drawn on the RAM 22 are selected, and a guidance route which is superimposed on a map image with a predetermined color and emphasized thickly is drawn. The mark image generating unit 44 generates a vehicle position mark at the position of the own vehicle after the map matching processing, or generates a cursor mark having a predetermined shape.

The intersection guide unit 46 provides guidance at the intersection where the vehicle is approaching by means of a display image and voice. When the actual route is guided, the own vehicle approaches within a predetermined distance from the intersection ahead of the guidance route. At this time, the guide map (the enlarged view of the intersection, the destination, the traveling direction arrow) of the approaching intersection is displayed on the screen of the display device 9, and the traveling direction is guided by audio through the audio unit 10.

The map buffer 16 and the route search memory 40 described above are used as map data storage means, the route search processing unit 36 is used as route search processing means, the route search memory 40 is used as measured cost storage means, the beacon transceiver 7, and FM multiplexing. The broadcast receiver 8 and the reception data buffer 50 correspond to the traffic jam information receiving means, respectively.

(4) Operation of Navigation Apparatus The entire navigation apparatus and the navigation controller 1 have the above-described configuration. Next, a description will be given of a route search operation in consideration of road conditions in each area.

(4-1) Classification of each region The road conditions in each region are correlated with the level of urbanization, for example, congestion occurs chronically in a large city but rarely in a local region. have. Therefore, if the level of urbanization in each region can be specified, the road conditions in each region can be grasped.If the driving cost is corrected according to the level of urbanization, the route search taking into account the local road conditions Becomes possible. Therefore, each region is classified according to the level of urbanization.

FIG. 6 is a diagram showing the classification of each area according to the level of urbanization. As shown in the figure, each region is classified according to the level of urbanization into one of "metropolitan areas", "urban areas", and "other areas". The area corresponding to "urban area" is indicated by a rectangular area.

FIG. 7 is a diagram showing an area type table which is information on road conditions for each area. As shown in the figure, the area type table as area identification data is
It is created only for areas where the level of urbanization is "metropolitan area" or "urban area". The "region type" indicating the level of urbanization and the "longitude / latitude of the northwest corner" and " Longitude / latitude ". As described above, since the area corresponding to the "metropolitan area" or "urban area" corresponds to the rectangular area, the "longitude /
The range of the area can be specified by "latitude" and "longitude / latitude of the southeast corner". The same applies to the case where "longitude / latitude of the northeast corner" and "longitude / latitude of the southwest corner" are set instead of "longitude / latitude of the northwest corner" and "longitude / latitude of the southeast corner". This area type table is stored in C
Those recorded in the D-ROM 2 and corresponding to a certain range determined by the departure place and the destination are partially read out and stored in the route search memory 40.

(4-2) Route Search Process Next, a specific route search process will be described. First,
An intersection network list used in the route search will be described. When performing a route search by the route search processing unit 36, a predetermined range including a departure place and a destination in advance (for example, one or a plurality of plots including all rectangular areas having a diagonal straight line connecting the departure place and the destination) May be set as a predetermined range, or a range having a radius of a straight line connecting the departure place and the destination may be set as the predetermined range.) An intersection network list is created and stored in the route search memory 40. The intersection network list is obtained by extracting intersections (including adjacent nodes other than the intersection nodes) from all the nodes included in the road unit and collecting various data necessary for the route search processing for each intersection. .

For example, the intersection network list includes, for each intersection, (1) an intersection sequential number (a serial number necessary to identify this intersection), (2) a picture leaf number of a road unit including this intersection, ( 3) Position on node table, (4) Longitude / latitude, (5) VIC
S: a flag indicating whether the service area is inside or outside, (6) the number of nodes constituting the intersection, (7) the sequential number of each adjacent intersection, (8) the cost to each adjacent intersection, (9) the type of road to each adjacent intersection, Width, (10) the sequential number of the previous intersection determined by the route search, (1
1) the total cost from the departure point to this intersection, (1
2) The search order of this intersection (in the case of the horizontal search method) is included. However, (10) to (12) are registered when executing the route search. In general, this intersection network list is recorded in advance on the CD-ROM 2, and one corresponding to a certain range determined by the departure point and the destination is partially read and stored in the route search memory 40. However, it may be created each time a route search is performed based on the road unit data in the map data. In this embodiment, only intersections are used as search nodes, and a network list is expressed as an attribute of each node. However, a route search may be performed by expressing a network list as an attribute of a link.

FIG. 8 is a flowchart showing the operation procedure of the navigation controller 1 when performing the route search processing using the above-mentioned intersection network list. For example,
Map data including the intersection network is stored in CD-RO in advance.
It is recorded in M2, and shows an operation procedure in the case where the cost is corrected after being read out.

When the search key of the remote control unit 4 is depressed, the route search processing unit 36 sets the departure place and the destination of the route search (step 100), and a predetermined range determined by the set departure place and destination. The map data included in the map leaf is read out to the map buffer 16, and all the intersection network lists included in the map data are stored in the route search memory 40 (step 101). Next, the route search processing unit 36 determines whether or not the traffic congestion information for the link included in the map data stored in the map buffer 16 has been received (step 102).

FIG. 9 is a diagram showing traffic congestion information included in the VICS information sent from the VICS center. The traffic congestion information packet shown in FIG. 3 indicates how much traffic is congested at a specific location of a certain VICS link, and "2" is used to specify an area including this VICS link.
Next mesh code ”and“ VICS corresponding to this road ”
A link number, a distance from a starting point (one end of a VICS link) for specifying a position where traffic congestion starts, a "length" indicating a section of traffic congestion, and a degree of traffic congestion (for example, when a vehicle is at or below a certain speed). The link corresponding to the traffic congestion information is obtained by using the VICS conversion layer shown in FIG. 4). Can be specified. In step 102, the route search processing unit 36
If the specified link is included in the link record of the map data stored in the map buffer 16, it is determined that the traffic congestion information has been received.

When the traffic congestion information is received, the route search processing unit 36 corrects the cost based on the traffic congestion information (step 103). Specifically, among the "costs to each adjacent intersection" in the above-mentioned intersection network list, for the link corresponding to the link for which the congestion information is received, for example, the degree of congestion included in the received congestion information is "congestion". In some cases, the cost is corrected to twice as much as usual, and when the degree of congestion is "congested", the cost is corrected to be three times as much as usual.

Next, the route search processing unit 36 determines whether there is an actually measured cost corresponding to the link included in the map data stored in the map buffer 16 (step 104).

FIG. 10 is a diagram showing actual measurement costs. As shown in the figure, the actual measurement cost is composed of a “link ID” for identifying each link, and an “average time required for passing through the link” in minutes. The actual measurement cost is created or updated every time the vehicle travels on the link based on the own vehicle position output from the map matching processing unit 34. For links that have passed once, an actual measurement cost is created, and for subsequent passes,
The average of the measured costs up to that time is calculated, and the measured costs are updated using this average value. The created or updated measured cost is stored in the route search memory 40. In step 104, the route search processing unit 36 reads the measured cost from the route search memory 40. If the link corresponding to the measured cost is included in the link record of the map data stored in the map buffer 16, the measured cost is Is determined to exist.

If there is an actual measurement cost, the route search processing unit 36 corrects the cost based on the actual measurement cost (step 105). Specifically, by replacing the “cost calculated by road type or the like” in the link record shown in FIG. 3C with the “mean value of time required for link passage” of the measured cost, the above-described intersection network "Cost to each adjacent intersection" in the list has been modified. However, here, the cost is not corrected for the link whose cost has been corrected based on the traffic congestion information in step 103.

Next, the route search processing section 36 corrects the cost based on the local road conditions (step 106).
Details of the cost correction will be described later.

When the cost correction based on the area type is completed, the route search processing unit 36 performs a predetermined route search process based on the intersection network list with the corrected cost, and sets the departure point set in step 100. A search is made for a guide route between the destination and the destination (step 107), and the passing nodes of the set guide route are sequentially registered in the guide route memory 38 from the departure place to the destination (step 108).

FIG. 11 is a diagram showing details of the cost correction processing based on the road conditions in the area in step 106 shown in FIG. First, the route search processing unit 36 specifies one intersection from the above-mentioned intersection network list, and reads its “longitude / latitude” (step 201). next,
The route search processing unit 36 searches the area type table shown in FIG. 7 to read “longitude / latitude of the northwest corner” and “longitude / latitude of the southeast corner” one record at a time (step 202) and specify the records. Whether the intersection is included in the rectangular area specified by these longitude and latitude,
It is determined whether or not the area is included in a large city or an urban area (step 203).

If the specified intersection is included in the metropolitan area or the urban area, the route search processing section 36 corrects the cost corresponding to the area type (the metropolitan area or the urban area) of the area (step 204). ).

FIG. 12 is a diagram showing a cost correction table which is information on road conditions for each area. As shown in the figure, the cost correction table as the cost correction data includes the area type (metropolitan area, urban area, and other areas).
Each of them includes a cost weighting coefficient corresponding to each road type. This cost correction table is recorded in the CD-ROM 2 in advance, read, and stored in the route search memory 40.

As to a specific cost correction procedure, first, the route search processing unit 36 determines the “region type” recognized in the determination processing in step 203 and the “each adjacent intersection” in the intersection network list for the intersection specified in step 201. Based on the "road type up to", a weighting coefficient is determined based on the cost correction table shown in FIG. Further, the “cost to each adjacent intersection” in the intersection network list is corrected by the weighting coefficient. However, here, the "cost to each adjacent intersection" corrected in the cost correction based on the traffic congestion information (step 103) or the cost correction based on the actual measurement cost (step 105) is not corrected.

When the specified intersection is not included in the metropolitan area or the urban area (No in step 203).
The route search processing unit 36 determines whether reading of all records from the region type table has been completed (step 205), and if not completed, reads the next record (step 202). If it has been completed, the cost corresponding to "other areas" is corrected based on the cost correction table (step 206). The specific cost correction procedure is the same as step 204.

When the cost correction (steps 204 and 206) is completed, the route search processing unit 36 specifies the next intersection from the intersection network list and determines its "longitude / latitude".
Is read (step 201).

As described above, by classifying each area according to the level of urbanization and correcting the cost according to the level of urbanization, it is possible to perform an accurate route search in consideration of the road situation in each area. Become. If there is traffic congestion information or measured costs received from the VICS center, priority is given to cost correction based on these information, so that a more realistic route search can be performed.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, a route search was performed in consideration of road conditions in each region by correcting costs according to the level of urbanization, but the road conditions were congested during morning and evening commuting hours, for example. For example, the same area often differs depending on the time zone. Therefore, by providing the cost correction table for each time zone, a more accurate route search can be performed. However, in this case, since it is necessary to switch the cost correction table to be used depending on the time of passing through each intersection, the route search process is not performed after all the cost corrections are completed as shown in FIG. In parallel with the route search processing, the cost to the adjacent intersection is corrected based on the passing time of each intersection and the cost correction table corresponding to this time. In this way, by correcting the cost in consideration of the time zone in which the vehicle travels in an urban area or a large urban area, a more accurate route search can be performed.

Further, in the above-described embodiment, the cost is corrected for the “cost to each adjacent intersection” included in the intersection network list, but the cost at the time of turning right and left (this cost is Is the cost added to the total, and is reflected in the total cost from the departure point to this intersection in the intersection network list)
The cost may be corrected according to the level of urbanization.

In the above-described embodiment, the cost correction table shown in FIG. 12 includes the weighting factors corresponding to the other regions, and the intersection of interest in step 206 in FIG. The cost is corrected according to this weighting factor when it is included in the area, but the cost is corrected when the intersection of interest is included in the metropolitan area and the urban area, and it is included in other areas May not be corrected. Although the weighting coefficient is stored in the cost correction table shown in FIG. 12, other information that can be corrected, for example, the average speed when traveling in each area is stored, and the cost is calculated up to the adjacent intersection. May be divided by the average speed to obtain a corrected cost.

Further, in the above-described embodiment, three types of areas having different road conditions, that is, a large city area, an urban area, and other areas have been described as an example. However, the classification method can be changed as appropriate. Further, as shown in FIG. 7, a rectangular area specified by longitude and latitude is set in order to specify a metropolitan area and an urban area. However, the method of specifying this area and the shape of the specified area are different from those described above. The present invention is not limited to this and can be changed.

Further, in the above-described embodiment, as shown in FIG. 6, it is assumed that there is an urban area around a large urban area.
Although the area type table shown in FIG. 4 is created, generally, the larger urban area is the larger urban area, and the larger urban area can be considered to be included in the urban area. In this case, a wide-area urban area and a large urban area included therein are set to create an area type table shown in FIG. 7, and it is determined whether or not a certain intersection is included in the large urban area or the urban area. In this case, first, it is determined whether or not it is included in a large city, and if it is included, it is only necessary not to determine whether or not it is included in a city.

[0062]

As described above, according to the present invention, a route search process is performed based on information on road conditions in each region, preferably on region specifying data for specifying a plurality of types of regions according to the level of urbanization. By taking into account the level of urbanization that correlates with the congested state of the roads, it is possible to perform an accurate route search based on the actual situation. In particular, cost correction data corresponding to each of a plurality of types of regions according to the level of urbanization is included in the map data, and different cost corrections are made for each type of traveling region, thereby realizing the actual situation. An accurate route search process can be performed using the traveling cost.

Further, there is provided traffic jam information receiving means for receiving traffic jam information sent from the road traffic information center,
A route search may be performed only on a road for which congestion information cannot be obtained, in consideration of the above-described road conditions for each area. Alternatively, when the actually measured travel costs are stored, a route search may be performed only on a road for which the actually measured travel costs are not obtained, in consideration of the road conditions in each region. At present, traffic information and measured costs are not available for all roads,
Since it can be obtained only for some roads, a more accurate route search process can be performed by combining these with the above-described route search in consideration of the road situation.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a vehicle-mounted navigation device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an entire configuration of a road unit.

FIG. 3 is a diagram showing detailed contents of various tables included in a road unit.

FIG. 4 is a diagram showing detailed contents of a VICS conversion layer included in a drawing unit.

FIG. 5 is a diagram showing an example of data stored in a guidance route memory.

FIG. 6 is a diagram showing classification of each area according to the level of urbanization.

FIG. 7 is a diagram showing a region type table for specifying the level of urbanization in each region.

FIG. 8 is a flowchart showing a general operation procedure of a route search process.

FIG. 9 is a diagram showing traffic congestion information included in VICS information.

FIG. 10 is a diagram showing measured costs created during traveling.

FIG. 11 is a flowchart showing an operation procedure when a cost is corrected based on a local road situation.

FIG. 12 is a diagram showing a cost correction table for correcting a cost based on a local road situation.

[Explanation of symbols]

 Reference Signs List 1 navigation controller 4 remote control unit 7 beacon transceiver 8 FM multiplex broadcast receiver 16 map buffer 36 route search processing unit 38 guidance route memory 40 route search memory 50 reception data buffer

Claims (7)

[Claims] 1. Map data storage means for storing map data including information on road conditions for each area, and considering the road conditions for each area based on the map data stored in the map data storage means. And a route search processing means for performing a route search process. 2. The route search processing means according to claim 1, wherein the information on road conditions for each area includes area specifying data for specifying a plurality of types of areas according to the level of urbanization. Is a navigation device that performs a route search process by setting search parameters corresponding to each of the plurality of types of regions based on the region specifying data. 3. The map search device according to claim 2, wherein the map data includes cost correction data corresponding to each of a plurality of types of areas corresponding to the level of urbanization. A navigation device that performs a process of correcting a traveling cost as the search parameter required for a route search process based on region identification data and the cost correction data. 4. The method according to claim 2, wherein the area specifying data includes longitude data and latitude data specifying the area, and an urbanization level of the area specified by the data. Navigation device. 5. The cost correction data according to claim 3 or 4, wherein a plurality of types of the cost correction data are prepared in consideration of a travel time, and the route search processing means calculates the cost of the travel cost based on the travel time at a passing point. A navigation device for performing a correction process. 6. The traffic congestion information receiving means for receiving traffic congestion information sent from a road traffic information center according to claim 1, further comprising: A navigation device that performs a route search only on roads other than the road corresponding to the traffic congestion information received by the unit, in consideration of the road conditions in each area. 7. The vehicle according to claim 1, further comprising an actual cost storage unit for storing an actual traveling cost of a road on which the vehicle actually travels, wherein the route search processing unit includes the actual traveling cost. A route search for roads other than the road corresponding to the above, taking into account the road conditions in each area.