JPH1151682A - Navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigation system in which a comfortable traveling route can be set. SOLUTION: The navigation system 1 comprises a route searching section 36, a memory 40 for storing an intersection network list required for route searching, a transmission/receiving control section 51 for controlling reception of the pavement information, which is externally transmitted, by a portable telephone 7, and a received buffer 50 for storing the received pavement information. The pavement information is received at the transmission/receiving control section 51 before a route searching process is performed. The pavement information contains the pavement state data, e.g. freeze, snow or rain fall, and the route searching section 36 corrects the link cost based on the pavement information and executes the route searching process.

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 displaying map information around a vehicle and searching for a route.

[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] In addition, a car navigation system includes:
Some vehicles are equipped with a route guidance function that enables a driver to travel on a road to a desired destination without making a mistake. According to the route guidance function, a horizontal search (BF) is performed using the data of the search layer recorded on the CD-ROM to find the lowest cost route from the starting point to the destination.
An automatic search is performed by performing a simulation calculation such as the S) method or the Dijkstra method, and the searched route is stored as a guidance route. Then, while driving, the guidance route is drawn on the map image in a different color from the other roads and is drawn thicker, or is displayed on the screen, or the vehicle has approached an intersection at which the course on the guidance route should be changed within a certain distance. Sometimes, the intersection is enlarged and displayed to display an arrow indicating the traveling direction, thereby guiding the driver to the destination.

[0004] The cost is defined in the time dimension, and is the sum of the time required to pass a certain section and the time required to pass an intersection or the like. In general, set the average speed based on the width of the road and the type of road (general road or expressway, etc.), find the required time of the road, and add the time considering the right turn and left turn at the intersection to this , The cost can be obtained.

[0005]

The cost of each road used in the conventional route search is calculated on the basis of the average vehicle speed assumed according to the type of road and the like. In many cases, road conditions were not reflected, making it difficult to search for an optimal route. In particular, even on the same general road, roads with bad road conditions due to snowfall, freezing, etc.
Sometimes you may want to avoid driving as much as possible. Also, even for roads of the same width, it is necessary to pay attention to the surrounding conditions depending on the road conditions (curvature radius of curvature, presence or absence of inclination, etc.). May want to avoid if there is a detour. As described above, it is convenient if it is possible to set a comfortable route that avoids a road on which a more careful driving is required than usual.

[0006] In addition, not only when searching for a route, but also when displaying a normal map, the above-mentioned information on the road surface condition and the road condition is not displayed. It was not possible to take measures such as changing the traveling route in advance based on the map information. In other words, if the road surface condition and the road condition are displayed in advance, a comfortable travel route can be selected by the driver's will, which is convenient for the driver.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a navigation device capable of setting a comfortable traveling route.

[0008]

In order to solve the above-mentioned problems, a navigation apparatus according to the present invention receives road surface information indicating a road surface state of a road by communication, and performs a route search process in consideration of the road surface information. In this case, a route search is performed so as to avoid a route on which the vehicle is difficult to travel due to freezing, snowfall, rainfall, and the like. As a result, a comfortable travel route can be set.

In particular, it is preferable that the above-mentioned road surface information is received in a predetermined range including between two points to be searched for a route. By providing such road surface information in a predetermined range, it is possible to set a comfortable traveling route connecting two points. In addition, since the content of the road surface information changes every moment, the road surface information is received at a predetermined timing even after the first route search process is completed, and when the road surface information is changed after the vehicle starts running, the route search is performed again. By performing the processing, it is possible to set a comfortable traveling route according to a road surface condition that changes due to weather.

In addition, the navigation device of the present invention includes the slope of a road, the radius of curvature of a curve, the number of curves, and the like in map data for performing a route search, so that the road has many curves or slopes on a mountain road or the like. Since the route search is performed so as to avoid a route that is difficult to travel suddenly, a comfortable traveling route can be set.

Further, instead of performing the route search processing using the above-described information such as the road surface information and the inclination of the road, the information may be displayed simply overlaid on a map image. Even in this case, the driver can accurately grasp in advance the road surface condition in the direction of the destination, as well as the state of the ascending and descending roads and the curve while watching the display, and select a comfortable traveling route according to his own will. can do.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A navigation device according to an embodiment of the present invention applies information (road surface information) related to road surface conditions such as freezing, snowfall, rainfall, etc., of a road surface sent from outside the vehicle. It is characterized by receiving using wireless communication and performing a route search taking this road surface information into account. 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 to which the present invention is applied. 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, route search and the like are recorded, and a CD-ROM 2
A disk reading device 3 for reading map data recorded in a storage unit 2 and a remote control (remote control) unit 4 as an operation unit for a driver or a passenger to input various instructions
A GPS receiver 5 and an autonomous navigation sensor 6 for detecting the position and direction of the vehicle, and a portable device for receiving road surface information sent from a predetermined facility (for example, a road traffic information center (VICS center)). A telephone 7, a display device 9 for displaying a map image, a guidance route, and the like superimposed on the map image;
0.

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 mobile phone 7 sends a road surface information transmission request to the VICS center and receives the road surface information transmitted from the VICS center. 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 image data output from the navigation controller 1, and displays a guidance route on this map. Or

(2) Detailed Contents 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 The map data for each map includes a drawing unit composed of various data necessary for map display, a road unit composed of 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. Further, the drawing unit described above has a VI required for associating data handled by VICS with data handled by the navigation device itself.
It includes CS conversion layer data, background layer data required to display buildings or rivers, and character layer data required to display municipal names, road names, and the like.

In the above-mentioned road unit, a line connecting an intersection on a road with another adjacent intersection is called a link, and an intersection 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 includes a unit header for identifying the road unit,
A connection node table containing detailed data of all nodes,
A node table indicating the storage position of the connection node table and a link table storing detailed data of a link specified by two adjacent nodes are included.

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. If this node is not an intersection node, a "curvature radius" indicating the degree of curve near this node; f. Connection node records for the number of links indicating the link number of each link having this node at one end; g. A traffic regulation record indicating the specific contents of the traffic regulation corresponding to the number of the traffic regulation, if any, h. If this node is a node on the border with another figure, an "adjacent node record" indicating the position of the connection node table of the corresponding node of the adjacent figure, i. 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. Cost, which is the time required to drive this link, e. This link is the VIC managed by the VICS center
Various road attribute flags including a VICS link correspondence flag indicating whether or not the link corresponds to the S link, and a slope flag indicating a degree of slope of a road corresponding to the 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.

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, etc. 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, and an intersection guidance unit 46 are provided. Also, the navigation controller 1
A reception data buffer 50 for transmitting a road surface information transmission request via the mobile phone 7 and displaying the returned road surface information, a transmission / reception control unit 51, a road surface information drawing unit 52,
A modem 53, a remote controller control unit 60 for displaying various operation screens for the user and transmitting operation instructions from the remote controller unit 4 to the respective units, a cursor position calculator 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 performs image synthesis by superimposing each image data output from each of the mark image generating unit 44, the intersection guidance unit 46, and the operation screen generating unit 64 described later on the read map image data. The synthesized image is displayed on the screen of the display device 9.

FIG. 5 is a diagram showing the relationship between the map image data stored in the VRAM 22 and the display image read by the read control unit 24. In the figure, each of the areas A to D is a map image drawn based on the drawing unit included in the map data of the four figures read from the map buffer 16, and the map images of these four figures are shown. The data is stored in the VRAM 22. The area P is centered on the screen center position O by the read control unit 24 by the VRAM2.
2 shows the display image data read out from the display area 2, and when the vehicle travels and the screen center position O corresponding to the own vehicle position moves, the area P moves with the movement and the screen is scrolled.

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, the shortest distance, and the priority on a general road, a guidance route with the minimum cost is set in consideration of the road surface information sent from the VICS center. 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. 6 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 for storing data of an intersection network list necessary for a route search, and the stored data is read out by the above-described route search processing unit 36 and a predetermined route search process is performed. Done. 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 in 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 transmission / reception control unit 51 controls data transmission / reception via the mobile phone 7. When collection of road surface information is instructed by the remote control unit 4, a transmission request for road surface information is sent from the mobile phone 7 to the VICS center via the modem 53, and the road surface information returned in response to the transmission request is received. Send to data buffer 50. The reception data buffer 50 sequentially stores the road surface information sent from the transmission / reception control unit 51. The road surface information drawing unit 52 draws these roads in the VRAM 22 based on the road surface information stored in the reception data buffer 50 so that a frozen road, a snowy road, a road whose road surface is wet due to rainfall, and the like can be recognized. .

FIG. 7 is a diagram showing a specific example of road surface information received via the mobile phone 7. The road surface information packet shown in the figure includes a “secondary mesh code” including the target road and a “VICS link number” corresponding to the road.
And a "distance from the starting point" and "length" for specifying the position of the frozen road or the like with reference to one end of the VICS link, and a "road surface state" for specifying freezing or snowfall. This road surface information packet has basically the same configuration as the traffic congestion information packet used in the VICS information, and specifies the road (link) corresponding to the road surface information by using the VICS conversion layer shown in FIG. can do.

The above-mentioned map buffer 16 and the route search memory 40 are used as map data storage means, the mobile phone 7, the reception data buffer 50, the transmission / reception control unit 51, and the modem 53 are used as road surface information reception means, the route search processing unit 36, and guidance. The route memory 38 corresponds to the route search processing means. The map drawing unit 20, VRAM 22, reading control unit 24, image synthesizing unit 26, and road surface information drawing unit 52 correspond to map display means.

(4) Operation of Navigation Apparatus The entire navigation apparatus and the navigation controller 1 have the above-described configuration. Next, a detailed operation for searching for a route connecting a departure place and a destination 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 in addition to 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 for specifying this intersection network list), and (2) a figure number of a road unit including this intersection. , (3) Position on node table, (4) Longitude /
Latitude, (5) Flag indicating whether inside or outside VICS service area, (6) Number of nodes constituting intersection, (7) Sequential number of each adjacent intersection, (8) Cost to each adjacent intersection, (9) Each adjacent intersection Road type, width, (1
0) the sequential number of the previous intersection determined by the route search, (11) the total cost from the departure point to this intersection, (12) the search order of this intersection (in the case of the horizontal search method), etc. . However, (10) to (1)
2) is registered at the time of executing the route search. Also, in general,
This intersection network list is stored in the CD-ROM2
Are partially read out and stored in the route search memory 40, and are stored in the route search memory 40. May be created each time a route search is performed. In this embodiment, only the intersection is used as a search node, and the network list is expressed as an attribute of each node. However, the route search may be performed by expressing the network list as an attribute of a link.

FIG. 8 is a flowchart showing the operation procedure of the navigation device when the route search processing is performed after the cost is corrected using the road surface information. Remote control unit 4
Is pressed, the route search processing unit 36 sets the departure place and the destination of the route search (step 100).
The map data contained in the map leaf of a predetermined range determined by the departure place and the destination is read out to the map buffer 16, and all the intersection network lists contained therein are stored in the route search memory 40 (step 101). Next, or in parallel with the above-described operation, the transmission / reception control unit 51 reads the departure place and the destination of the route search from the guidance route memory 38, and transmits the road surface information for an area including these two points. The request is sent to the VICS center via the mobile phone 7 (step 102), and then the apparatus waits for reception of road surface information (step 103). The road surface information returned from the VICS center is stored in the reception data buffer 50 in order.

Next, the route search processing unit 36 corrects the link cost based on the road surface information stored in the reception data buffer 50 (step 104), and the intersection network list stored in the route search memory 40 is processed. Is updated in “cost to each adjacent intersection”.

The corresponding road link is specified based on the "secondary mesh code" and the "VICS link number" of the road surface information packet shown in FIG. 7, and the cost is corrected by the "distance from the starting point" and the "length". The ratio of the target road link is specified. The cost before correcting the road link is C,
Let the ratio of road links subject to cost correction be a (≤
1) If the multiplier set according to the road surface condition is b (> 1), the corrected cost is calculated by (1−a + ab) C. For example, the multiplier b during freezing is 10, and the multiplier b during snowfall is
Is set to 3, and the multiplier b during rainfall is set to 1.5, and the “cost to each adjacent intersection” in the intersection network list is corrected.

When the link cost correction processing is completed, the route search processing unit 36 performs a predetermined route search processing to search for a guide route between the departure point and the destination set in step 100 (step 105). ), A series of route search processing ends. The guidance route set in this way is drawn on the VRAM 22 by the guidance route drawing unit 42,
The guidance route is displayed so as to overlap the road in the map image.

As described above, in the navigation device according to the present embodiment, before performing the route search processing, the road surface information of the area including the destination and the departure place is acquired in advance, and the cost is corrected based on the road surface information. After that, a route search process is performed. Therefore, even when the road surface condition changes due to the weather, it is possible to perform cost correction in consideration of the change, and to set a comfortable route. In particular, when traveling on frozen roads or snowy roads, it is necessary to use anti-slip such as tire chains, and it is necessary to drive carefully, so avoiding such roads will make riding comfortable and comfortable. An easy traveling route can be set.

By the way, the above-mentioned road surface information changes every moment due to the influence of weather. If the running time becomes longer, the content of the road surface information received at the time of performing the route search processing matches the actual road surface condition. It may disappear. Therefore, when the traveling distance is long, it is preferable to reset the guidance route at appropriate intervals.

FIG. 9 is a flow chart showing the operation procedure of the navigation device in which the guidance route is reset at regular time intervals. The route search processing unit 36 monitors whether or not a certain time has elapsed (step 200). When the certain time has elapsed, the transmission / reception control unit 51 stores the current vehicle position and the guidance route memory 38. An instruction to collect road surface information for an area including the destination is sent. Upon receiving this instruction, the transmission / reception control unit 51 sends a road surface information transmission request to the VICS center via the mobile phone 7 (step 201), and waits for reception (step 202). V
When the road surface information is returned from the ICS center,
The route search processing unit 36 compares the newly received road surface information with the previously received road surface information to determine whether or not it has been changed (step 203). If there is no change, the process returns to step 200 to enter a waiting state at a constant interval. When there is a change, the route search processing unit 36 reads out map data included in a predetermined range of the map leaf determined by the current vehicle position and the destination into the map buffer 16 and includes the intersection network included in the map data. Is stored in the route search memory 40 (step 204). Next, the route search processing unit 36 performs a link cost correction process based on the newly received road surface information (Step 205), and performs a predetermined route search process (Step 206). In this manner, when the road surface information is changed, the guidance route is also changed in some cases, and a comfortable guidance route is set again in consideration of a road surface condition that changes due to weather.

Incidentally, in the above-described embodiment, VIC
Although the cost is corrected based on the road surface information sent from the S center, a more optimal travel route can be set by devising the contents of the map data stored in the CD-ROM 2. For example, when the road is curved or the road is inclined, the vehicle speed actually decreases, and it is necessary to pay attention to the presence of vehicles in the oncoming lane and excessive speed. It is preferable to avoid rough roads.

FIG. 10 is a flow chart showing the operation procedure of the navigation apparatus in the case of performing a route search after correcting the cost based on information on the radius of curvature and inclination of the road together with the road surface information sent from the VICS center. is there. First, the route search processing unit 36 sets a departure place and a destination for the route search (step 300), and reads out map data included in a predetermined range of the map leaf determined by the departure place and the destination into the map buffer 16. Then, all of the intersection network lists included in the list are stored in the route search memory 40 (step 301). In addition, the transmission / reception control unit 51 sends a road surface information transmission request to the VICS center via the mobile phone 7 (step 302), and receives the road surface information returned from the VICS center in response to the transmission request (step 303). ). Next, the route search processing unit 36 performs a link cost correction process based on the road surface information thus received, the curvature radius of the road curve included in the map data, and the degree of the road inclination ( Step 304).

For example, the radius of curvature of a node included in the connection node table shown in FIG. 3B corresponds to the radius of curvature of a road curve. If this value is small, it is necessary to reduce the vehicle speed. In addition, careful driving is required in consideration of the presence or absence of vehicles on the opposite lane. Therefore, assuming that the number of nodes other than the intersection nodes existing up to each adjacent intersection node is N, the above-mentioned “radius of curvature of the node” is examined for each of the N nodes. The addition is performed to correct the cost.

The road attribute flag of the link record shown in FIG. 3C includes a slope flag indicating the degree of slope of the road. As described above, the more the road has a slope, the more attention must be paid to excessive speed, and so on.In order to avoid such a route, a larger value is added as the slope becomes steeper. (Or multiplied) to correct the cost. After the cost correction is completed, the route search processing unit 36 performs a predetermined route search process (Step 305).

As described above, when the road is frozen or snow-covered, or when the road has a curve or a slope, the cost is increased. Route is set.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. In the above-described embodiment, the cost is corrected based on the road surface information, the radius of curvature of the road curve, the inclination, and the like, and a route search process is performed using the corrected cost to set a comfortable travel route. However, the display may be superimposed on the map image so that the road surface information, the curvature radius of the road curve, the inclination, and the like can be understood, and the driver himself / herself may select a route considered to be comfortable while watching the display. .
FIG. 11 is a diagram illustrating a display example based on road surface information.
In the figure, a shaded portion a indicates a frozen road, and a hatched portion b indicates a snow-covered road, and the driver can select an optimal route avoiding the frozen road or the snow-covered road while watching these displays. it can. Here, the display of the frozen road or the like based on the received road surface information is performed by the road surface information drawing unit 52 in the VRAM.
This is performed by writing predetermined image data into the area 22. The display of the curvature radius of the curve of the road and the like may be performed by previously including the image data necessary for the display in the map data drawing layer.

In the above embodiment, the radius of curvature of the curve is used. However, the cost may be corrected or displayed using the number of curves. FIG. 11 shows an example of display based on road surface information, but the display method can be changed as appropriate. FIG. 12 is a diagram showing a display example including the inclination of the road and the magnitude of the radius of curvature of the curve. In the figure, a mark “△” indicates the inclination of the road, and a number with a frame (“50 m”) indicates the radius of curvature of the curve.

In the above-described embodiment, the mobile phone 7
Although the road surface information has been received through the communication device, the communication device to be used may be other than the mobile phone. For example, the road surface information may be received by an optical beacon transceiver or a radio wave beacon transceiver, or the mobile phone 7 may be used to obtain the road surface information via the Internet.

[0055]

As described above, according to the present invention, road surface information indicating road surface conditions such as freezing, snowfall, and rainfall is received by communication, and a route search process is performed in consideration of the road surface information. Therefore, a route search is performed so as to avoid a route on which the vehicle is hard to travel, such as when the road surface is frozen, and as a result, a comfortable travel route can be set.

In particular, by receiving road surface information in a predetermined range including between two points to be searched for a route, a comfortable traveling route connecting the two points can be set. In addition, after the vehicle starts running, by receiving the road surface information that changes every moment and performing the route search process again, it is possible to set a comfortable driving route according to the road surface state that changes due to weather.

Further, according to the present invention, the map data for which the route is searched includes the slope of the road, the radius of curvature of the curve, the number of curves, and the like, so that there are many curves or steep slopes on mountain roads or the like. Since a route search is performed so as to avoid a difficult-to-travel route, a comfortable traveling route can be set.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a navigation system according to an embodiment to which the present invention is applied.

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 illustrating a relationship between a drawing area and a display area of a VRAM.

FIG. 6 is a diagram illustrating an example of data stored in a guidance route memory;

FIG. 7 is a diagram showing details of road surface information.

FIG. 8 is a flowchart showing an operation procedure of the navigation device in a case where a route search process is performed after a cost is corrected using road surface information.

FIG. 9 is a flowchart showing an operation procedure of a navigation device that resets a guidance route at regular intervals.

FIG. 10 is a flowchart showing an operation procedure of the navigation device in a case where a route search is performed after a cost is corrected based on road surface information and information on a curvature radius and an inclination of a road.

FIG. 11 is a diagram illustrating a display screen in which road surface information is drawn by being superimposed on a map image.

FIG. 12 is a diagram illustrating a screen in which a road inclination and a radius of curvature are drawn so as to be superimposed on a map image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Navigation controller 2 CD-ROM 3 Disk reading device 4 Remote control unit 7 Mobile phone 9 Display device 16 Map buffer 18 Map reading control unit 20 Map drawing unit 22 VRAM 24 Read control unit 36 Route search processing unit 38 Guidance route memory 40 Route search Memory 50 reception data buffer 51 transmission / reception control unit 52 road surface information drawing unit 53 modem

Claims (7)

[Claims] 1. Map data storage means for storing map data required for route search processing; road surface information receiving means for receiving road surface information indicating the road surface state of a road transmitted by a predetermined communication method; Route search processing means for performing a route search so as to connect between two predetermined points based on the map data stored in the data storage means and the road surface information received by the road surface information receiving means A navigation device comprising: 2. The road surface information receiving unit according to claim 1, wherein
A navigation device for receiving the road surface information for a predetermined range including between two points. 3. The map data according to claim 1, wherein the map data stored in the map data storage means includes information on at least one of a slope of a road, a radius of curvature of a curve, and the number of curves. A navigation device, wherein the route search processing means performs a route search in consideration of information on a slope of a road, a radius of curvature of a curve, and the number of curves included in the map data. 4. The road surface information receiving unit according to claim 1, wherein the road surface information receiving unit receives the road surface information at a predetermined timing even after an initial route search process by the route search processing unit is completed, The route search processing means, after the start of traveling of the vehicle,
When the road surface information is changed, a route search process is performed again. 5. Map data storage means for storing map data necessary for map display; road surface information receiving means for receiving road surface information indicating a road surface state of a road transmitted by a predetermined communication method; Map display means for creating a map image of the surroundings of the vehicle based on the map data stored in the storage means, and displaying the road surface information received by the road surface information receiving means so as to be superimposed on the map image; A navigation device comprising: 6. The map data according to claim 5, wherein the map data stored in the map data storage means includes information on at least one of a slope of a road, a radius of curvature of a curve, and the number of curves. A navigation apparatus, wherein the map display means superimposes information on the inclination of a road, the radius of curvature of a curve, and the number of curves included in the map data on the map image. 7. The navigation device according to claim 1, wherein the road surface condition indicated by the road surface information includes at least one of freezing, snowfall, and rainfall.