JPH10227652A - Navigator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigator for grasping the features of an intersection that is branched by a guidance audio. SOLUTION: A navigation controller 1 includes a map buffer 16 for storing various kinds of data for map display and path search, a path search processing part 36 for performing path search processing and path guidance processing, a guidance path memory 38, and an intersection guidance part 46. The path search processing part 36 extracts a next branch intersection based on data stored at the guidance path memory 38 on path guidance and at the same time specifies the features (for example, an intersection shape) of the intersection based on the map data stored in the map buffer 16, and guides the features of the specified intersection with a voice by the intersection guidance part 46.

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 providing voice guidance along a searched 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] Usually, a navigation device mounted on a vehicle is 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 lowest cost route from the departure point to the destination is automatically searched for by using simulation data such as the horizontal search (BFS) method or the Dijkstra method using the map data, and the search is performed. The route is stored as a guidance route, and the guidance route is drawn on the map image in a different color from the other roads and displayed thickly on the screen during traveling. In addition, when the vehicle approaches an intersection at which the course on the guidance route should be changed within a certain distance, the intersection is enlarged and displayed to show an arrow indicating the traveling direction, and the branching direction at this intersection is output by voice. Thus, the driver is guided to the destination.

[0004] For example, as an example of voice guidance,
It tells you to turn right or left at a certain point ahead, such as "turn right at 500m", "turn right at 300m", or "turn right at 100m".

[0005] The cost is a value obtained by multiplying a predetermined constant according to a road width, a road type (such as a general road or an expressway), a right turn, a left turn, and the like based on the distance. The degree of appropriateness is quantified. Even if there are two routes having the same distance, the cost differs depending on whether the driver specifies whether to use the expressway, whether to give priority to time or distance, and the like.

[0006]

In a conventional navigation apparatus that provides guidance by voice, a notification that a branch is taken at a distance of several hundred meters is provided only by voice. The driver must compare the enlarged image of the intersection displayed on the screen with the actual situation of the intersection to determine whether it is a junction, and that voice guidance is being used effectively No, the driver's burden was heavy.
For example, if a voice guidance such as "turn left (turn right) at the next intersection" can be provided, it is easy for the driver to understand. However, there is an error in detecting the position of the vehicle, and incorrect guidance is given especially when the intersection is approaching. There is a possibility that it will.

The present invention has been made in view of such a point, and an object of the present invention is to provide a navigation device capable of grasping the characteristics of an intersection branched by guidance voice.

[0008]

In order to solve the above-mentioned problems, a navigation device according to the present invention extracts a next intersection on a guidance route by means of an intersection extracting means, and a branch intersection by means of intersection characteristic specifying means. Since the voice guidance is performed by the voice guidance means using the characteristics of the specified branch intersection,
You can understand the features of the intersection just by listening to the voice guidance.

The characteristics of the branch intersection include the shape of the branch intersection, the number of signals from the current position of the vehicle to the branch intersection, the name of the road turning at the branch intersection, the width of the road turning at the branch intersection, and the like. By providing voice guidance, the driver can easily grasp the characteristics of the branch intersection.

In particular, when the number of signals up to the branch intersection is a feature of the branch intersection, the detection accuracy of the vehicle position is taken into consideration, and only when the signal is not included in the detection error range around the vehicle, It is preferable to provide voice guidance using the number of signals. In addition, other intersection shapes, branch road names,
When the width is a feature of a branch intersection, it is preferable to provide voice guidance based on these features only when the features of the branch intersection and the intersection before it are not the same.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A navigation apparatus to which the present invention is applied is characterized in that in route guidance, a feature of an intersection or a road to be turned from now on is guided by voice.
The contents of the voice guidance include the shape of the intersection such as a T-shaped intersection or a Y-shaped intersection, the number of signals to the intersection where the vehicle is about to turn, and
A road name such as a street, a road width such as a road having a width of △△ m, and the like can be considered. 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 an on-vehicle navigation apparatus according to an embodiment of the present invention. The navigation apparatus shown in FIG. 1 includes a navigation controller 1 that controls the entire system, a CD-ROM 2 that stores various map data necessary for map display, route search, and the like.
A disk reader 3 for reading map data recorded in the ROM 2, a remote control (remote control) unit 4 as an operation unit for a driver or a passenger to input various instructions, and detection of the position and orientation of the vehicle Receiver 5 and autonomous navigation sensor 6 that perform navigation, a display device 9 that displays a map image and a guidance route superimposed on the map image, and an audio unit 10 that outputs a predetermined guidance voice when performing route guidance
And

The above-described 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 the current 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 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 displays the map information on this map. For example, displaying a guidance route.

(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. The drawing unit described above includes a road name table storing names of roads and their kana readings, data of a background layer necessary for displaying buildings, rivers, and the like, names of municipalities, names of roads, and the like. The character layer data necessary to display is included.

In the above-mentioned road unit, a line connecting an intersection with a road and 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 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. An intersection node flag indicating whether or not this node is an intersection node, an adjacent node flag indicating whether or not this is a node at a boundary with another figure leaf, and whether or not a link has branched at this node. If so, a “node attribute flag” including, for example, branch road information indicating whether the shape of the branch corresponds to a T-junction or a Y-junction; 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 actual time required to travel this link is statistically calculated as a cost (for example, the actual time required to travel on an ordinary road or highway at an average speed is indicated by a multiplier. Value), e. Various road attribute flags including road attribute information associated with this link; f. A road type flag indicating the type of road such as whether the actual road corresponding to this link is an expressway or a general road, and the width of the road such as how many meters the road is; g. The route number assigned to the road corresponding to this link is included.

FIG. 4 is a diagram showing the detailed contents of the road name table included in the character layer of the drawing unit. As shown in the figure, the road name table includes road name records corresponding to the roads included in the target leaf, and each road name record includes: a. Route number, b. A road type code indicating the content of this road (expressway, city expressway, national road, etc.); c. Route codes corresponding to route numbers such as national roads and prefectural roads, d. Route name reading kana character string, e. Route name character string, etc. are included.

FIG. 5 is a diagram showing the detailed contents of the intersection unit. As shown in FIG. 5, the intersection unit forms, for each intersection, an intersection record including data on the intersection itself, an intersection direction information record including data on a destination of a road extending from the intersection, and the like. An intersection lane information record including data on each lane of the road and an intersection drawing record including image data necessary for displaying an enlarged image of the intersection are stored.

The intersection records, as shown in FIG. 6, correspond to each of the existing intersections: a. An "intersection information flag" including a signal flag indicating whether or not a signal is standing at this intersection; b. "Number of differences at intersection" indicating how many differences this intersection is, c. Storage location of the intersection drawing record corresponding to this intersection, d. Display coordinates for displaying the intersection name, e. Intersection character string to be displayed, f. Intersection name reading kana character string required for text speech when the intersection name is read aloud g. The link ID of each link constituting the intersection and the storage position of the intersection direction information record corresponding to the link (for the number of roads at the intersection) 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.
The map matching processing unit 34, the route search processing unit 36, the guidance route memory 38, the guidance route drawing unit 42, the mark image generation unit 44, the intersection guidance unit 46, and various operation screens for the user are displayed. A remote controller control unit 60 for transmitting the operation instruction to each unit, a cursor position calculation unit 62, and an operation screen generation unit 64 are provided.

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 controller 8, an instruction 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 reader 3, and the map data necessary for map display 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 unit 20 creates a map image necessary 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. 7 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, a guidance route that minimizes the cost under various conditions such as the shortest time, the shortest distance, and the priority on general roads 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. 8 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 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 vehicle position after the map matching processing, or generates a cursor mark having a predetermined shape.

The intersection guide section 46 provides guidance at the intersection where the vehicle is approaching by means of a display image and voice. When the vehicle actually navigates the route, the vehicle approaches within a predetermined distance from the intersection in front 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 above-mentioned guidance route memory 38 serves as guidance route storage means, the route search processing unit 36 serves as a branch intersection extraction means, the map buffer 16 and the route search processing unit 36 serve as intersection feature identification means, an intersection guidance unit 46, an audio signal. Part 1
0 corresponds to the voice guidance means, and the GPS receiver 5 and the autonomous navigation sensor 6 correspond to the own vehicle position detection means.

(4) Operation of Navigation Apparatus The entire navigation apparatus and the navigation controller 1 have the above-described configuration. Next, a detailed operation when voice guidance is provided at the time of route guidance will be described.
As described above, specific contents of the voice guidance include:
This may be based on the shape of an intersection such as a T-junction or a Y-junction, depending on the number of traffic lights up to the intersection about to turn, by the name of the road, or by the road width (road width). I do.

(4-1) Voice Guidance Based on the Shape of the Intersection FIG. 9 is a diagram showing an operation procedure of the navigation device when performing voice guidance by determining the shape of the intersection. In addition,
The route search has been completed as a prerequisite for voice guidance,
It is assumed that a guidance route is set as a set of nodes as shown in FIG. Also, it is assumed that voice guidance is not provided for an intersection that passes straight ahead.

When the route guidance mode key of the remote control unit 4 is depressed and the route guidance mode is set, the route search processing unit 36 sequentially reads the nodes that have not passed from the route guidance memory 38, and reads the next node on the guidance route. Is extracted (step 100), and the shape of the extracted branch intersection is specified (step 101). As described above, the attribute flag of the node in the connection node table (FIG. 3B) corresponding to each node indicates whether or not the link is branched at this node, and if so, the shape of the branch. The route search processing unit 36 checks the branch information in the node attribute flag of the node corresponding to the branch intersection, and includes branch information indicating whether the road corresponds to a T-junction or a Y-junction. It is checked whether the intersection is a Y-junction as shown in FIG. 10 (A), a T-junction as shown in FIG. 10 (B), or other.

By the way, even if the branch intersection is a T-junction, if the driver makes a right or left turn on a straight road as shown in FIGS. Since it may not be possible to recognize that the road is a crossroad, such a T crossroad is treated as a simple right turn or left turn. In addition, in the case of a branch intersection other than the Y-shaped road and the T-shaped road, the route search processing unit 36 checks the “number of connected nodes” in the connection node table to find out what difference the branch intersection is. (Or may be determined by reading the “number of difference roads at intersection” in the intersection record shown in FIG. 6), and when the “number of connected nodes” is 4, a crossroad is determined. Above n
In this case, the intersection shape is specified as an n difference road.

Next, the route search processing unit 36 calculates the distance to the branch intersection (step 102), and determines whether or not it is time for voice guidance (step 103).
For example, assuming that voice guidance is performed at 300 m and 100 m immediately before the branch intersection, it is determined whether or not the distance to the branch intersection calculated at step 102 is 300 m or 100 m. If it is not the voice guidance timing (if these distances do not match), then the route search processing unit 36 determines whether or not the vehicle has passed the branch intersection (step 105). Returning to step 102 (calculation of the distance to the branch intersection), the processing is repeated.

If it is determined in step 103 that the timing of voice guidance has been reached, the route search processing unit 36 next issues a voice guidance instruction to the intersection guidance unit 46 based on the shape of the intersection specified in step 101. Send
The guidance of the branch by voice is provided (step 104). The route search processing unit 36 sends a reading kana character string for voice output to the intersection guidance unit 46, and the intersection guidance unit 46 reads out the reading kana character string, and performs audio guidance based on the shape of the intersection from the audio unit 10. For example, FIG.
In the case of the Y-junction shown in FIG. 10A, “turn right at the Y-junction ahead of XX m”, and in the case of the T-junction shown in FIG.
Turn right at the T-junction m m away. ”In the case of FIG. 10 (C) or (D), turn right at the XX m ahead (left turn). In that case, "○○
In the case of the five-way intersection shown in FIG. 10 (F), voice guidance is given that "the five-way intersection XX m ahead is a left turn."

After the voice guidance, it is determined whether or not the vehicle has passed the branch intersection in step 105 described above. If the vehicle has passed the branch intersection, the process returns to step 100 and the next branch point is extracted.

As described above, in the navigation device according to the present embodiment, the shape of the next branch intersection is guided by voice at the time of route guidance, so that the driver can easily grasp the intersection to branch while driving. . Therefore, the load at the time of driving can be reduced and safety can be improved.

(4-2) Voice Guidance Based on Number of Signals to Branch Intersection FIG. 11 is a diagram showing an operation procedure of the navigation apparatus when voice guidance is performed by counting the number of signals from the current traveling position to the branch intersection. It is. When the route guidance mode key of the remote control unit 4 is depressed and the route guidance mode is set, the route search processing unit 36 sequentially reads the non-passed nodes from the route guidance memory 38, and reads the next branch intersection on the guidance route. Is extracted (step 200), and the distance to the extracted branch intersection is calculated (step 201).
Next, the route search processing unit 36 determines whether or not it is the timing of voice guidance (step 202), and if it is not the timing of voice guidance, determines whether or not the vehicle has passed the branch intersection (step 205). . If the vehicle has not passed, the process returns to step 201 (calculation of the distance to the branch intersection) described above, and the process is repeated.

If it is determined in step 202 that the timing for voice guidance has come, the route search processing unit 36 next counts the number of signals from the current traveling position to the next junction (step 203). As described above, the intersection record corresponding to each intersection node (FIG. 6)
Contains an intersection information flag indicating the presence or absence of a signal at this intersection, and the route search processing unit 36 determines the next vehicle position from the current vehicle position stored in the guidance route memory 38 based on the intersection information flag. The presence / absence of a signal at each node up to the branch intersection is checked, and the number of signals up to the next branch intersection is counted.

Next, the route search processing unit 36 issues a voice guidance instruction based on the counted signal number to the intersection guidance unit 46.
To guide the branch by voice (step 20).
4). As in the case of performing voice guidance using the above-described intersection shape, a read kana character string for voice output is sent from the route search processing unit 36 to the intersection guide unit 46, and the intersection kana character unit 46 converts the read kana character string. The voice is read out and voice guidance is provided from the audio unit 10 based on the number of signals. For example, voice guidance such as "turn right at the fourth traffic light" is performed. After the voice guidance, it is determined whether or not the vehicle has passed the branch intersection in step 205 described above. If the vehicle has passed the branch intersection, the process returns to step 200 and the next branch point is extracted.

As described above, the navigation device of this embodiment counts the number of signals up to the next branch intersection at the time of route guidance and performs voice guidance based on the number of signals.
The driver can easily grasp the branch point only by counting the number of signals entering the field of view while driving.

(4-3) Voice Guidance Based on Branching Road Name FIG. 12 is a diagram showing an operation procedure of the navigation device when voice guidance is performed by specifying a branching destination road name.
When the mode is set to the route guidance mode, the route search processing unit 36
Extracts the next branch intersection on the guidance route (step 300) and specifies the road name of the branch destination (step 301). As described above, the link record in the link table (FIG.
By examining (C)), the route number of the road corresponding to this link can be known. If the route number is known, a route name reading kana character string corresponding to this link can be specified by searching for a road name record in the road name table shown in FIG. 4 that matches the route number. .

Next, the route search processing section 36 calculates the distance to the branch point (step 302), determines whether or not it is the timing for voice guidance (step 303). Determines whether the vehicle has passed the branch intersection (step 305). If the vehicle has not passed, the process returns to step 302 (calculation of the distance to the branch intersection), and the process is repeated.

If it is determined in step 303 that the timing of voice guidance has come, the route search processing unit 36 next issues a voice guidance instruction based on the road name of the branch destination specified in step 301 to the intersection guidance unit. 46 to guide the branching by voice (step 304).
The route name reading kana character string specified in step 301 is sent from the route search processing unit 36 to the intersection guidance unit 46, and the intersection guidance unit 46 reads out this kana character string and reads it from the audio unit 10 based on the road name. Provides voice guidance. For example, a voice guidance such as "You are going to turn right on XX street ahead" After the voice guidance, it is determined in step 305 whether or not the vehicle has passed through the branch intersection. If the vehicle has passed through the branch intersection, the process returns to step 300 and the next branch intersection is extracted.

As described above, in the navigation device according to the present embodiment, voice guidance is performed by the name of the next branch destination during route guidance, so that when traveling to a famous street, etc. The driver only has to go straight until the name of the street appears on the guide sign or, if the driver knows the street itself, until the street appears, and the driver can easily grasp the branch point.

(4-4) Voice Guidance by Width of Branching Road FIG. 13 is a diagram showing an operation procedure of the navigation apparatus when voice guidance is performed by specifying the width of a branching road. When the mode is set to the route guidance mode, the route search processing unit 3
6 extracts the next branch intersection on the guidance route (step 400) and specifies the width of the branch destination road (step 401). As described above, in the link record (FIG. 3C) in the link table corresponding to the link to be branched, information about the width of the road corresponding to this link is stored in the road type flag. Is read, the width of the road at the branch destination can be specified.

Next, the route search processing unit 36 calculates the distance to the branch point (step 402), determines whether or not it is the timing for voice guidance (step 403). Determines whether the vehicle has passed the branch intersection (step 405). If the vehicle has not passed, the process returns to step 402 (calculation of the distance to the branch intersection) and the process is repeated.

If it is determined in step 403 that the timing of voice guidance has come, the route search processing unit 36 next issues an instruction for voice guidance based on the width of the road at the branch destination specified in step 401 to the intersection guidance. To the section 46 for guidance of branching by voice (step 40).
4). The kana character string for voice output is sent from the route search processing unit 36 to the intersection guidance unit 46, and the intersection guidance unit 46 reads out this kana character string and performs audio guidance by the width of the road from the audio unit 10. . For example, voice guidance such as "turn right on a road of width △△ m ahead of ○ m" is performed. After the voice guidance, it is determined in step 405 whether or not the vehicle has passed the branch intersection. If the vehicle has passed through the branch intersection, the process returns to step 400 and the next branch point is extracted.

As described above, in the navigation device of the present embodiment, the voice guidance is provided by the width of the next branch destination road at the time of route guidance, so that the driver can easily grasp the branch point only by checking the width of the road. And avoid accidentally entering extremely different width roads.

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, the shape of the intersection, the number of traffic lights, the name of the road, and the width of the road are given as the landmarks at the branch intersection, but any other features that can be easily recognized by the driver. Can be a landmark. For example, the road attribute flag of the link record shown in FIG. 3C includes information on the presence or absence of a median strip on the road corresponding to this link, and by reading this information, the median strip of the branch destination road is read. Voice guidance specifying the presence or absence of the message may be performed.

Further, in the case of performing voice guidance based on the number of signals, if the detection accuracy of the position of the own vehicle at the time of counting the number of signals is low, the counted number of signals may include an error. It is preferable to perform voice guidance in consideration of the detection error of the above. For example, before step 203 (counting of the number of signals) shown in FIG. 11, when looking at the front and rear of the guidance route centering on the own vehicle position, an intersection having a signal in a range having a detection error of the own vehicle position as a radius. An operation for determining whether or not there is an intersection is added, and the process of step 203 is performed only when there is no such intersection. If there is such an intersection, the exact number of signals is not guaranteed, so that voice guidance for branching based on the number of signals is not performed.

When voice guidance is performed based on the shape of an intersection or the width of a junction road (the same applies to the presence or absence of a median strip), an intersection having a similar shape or a similar intersection is provided before an intersection to be branched. If there is an intersection where a road with a width intersects, it is possible that the intersection immediately before the intersection may be erroneously branched. Therefore, perform voice guidance in consideration of whether or not intersections with the same feature continue. Is preferred. For example, after step 101 (identifying the shape of an intersection) shown in FIG. 9 and step 401 (identifying the width of a branching road) in FIG. 13, an operation for determining whether or not intersections having the same characteristics are continuous is added. If it is continuous, the voice guidance in step 104 or 404 is not performed.

In the above-described embodiment, the voice guidance is performed separately for each feature. However, the voice guidance may be performed by appropriately combining these features.

[0058]

As described above, according to the present invention, the next intersection on the guidance route is extracted by the branch intersection extracting means, and the characteristic of the branch intersection is specified by the intersection characteristic specifying means. Since the voice guidance is provided by the guidance means using the specified characteristics of the branch intersection, the characteristics of the intersection can be grasped only by hearing the voice guidance. The characteristics of a branch intersection may be the shape of the branch intersection, the number of signals from the current position of the vehicle to the branch intersection, the name of the road turning at the branch intersection, the width of the road turning at the branch intersection, etc. By performing the guidance, the driver can easily grasp the characteristics of the branch intersection.

[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 road name table included in a character layer of a drawing unit.

FIG. 5 is a diagram showing detailed contents of an intersection unit.

FIG. 6 is a diagram showing detailed contents of an intersection record.

FIG. 7 is a diagram showing a relationship between a drawing area and a display area of a VRAM.

FIG. 8 is a diagram showing an example of data stored in a guidance route memory.

FIG. 9 is a diagram illustrating an operation procedure of the navigation device when performing voice guidance by determining the shape of an intersection.

FIG. 10 is a diagram showing a specific example of an intersection shape.

FIG. 11 is a diagram showing an operation procedure of the navigation device when performing voice guidance by counting the number of signals from the current traveling position to the branch intersection.

FIG. 12 is a diagram illustrating an operation procedure of the navigation device when performing voice guidance by specifying a road name of a branch destination;

FIG. 13 is a diagram showing an operation procedure of the navigation device in a case where the width of a road at a branch destination is specified and voice guidance is performed.

[Explanation of symbols]

 Reference Signs List 1 navigation controller 10 audio unit 16 map buffer 36 route search processing unit 38 guidance route memory 46 intersection guidance unit

Claims (7)

[Claims] 1. A guidance route storage unit for storing guidance route data; a branch intersection extraction unit for extracting a next branch intersection on a guidance route based on the guidance route data; Intersection characteristic specifying means for specifying the characteristics of the branch intersection; and voice guidance means for guiding the branch road by outputting the characteristics of the branch intersection specified by the intersection characteristic specifying means by voice. Navigation device. 2. The navigation device according to claim 1, wherein the intersection feature specifying means specifies a shape of the intersection as a feature of the branch intersection. 3. The navigation system according to claim 1, wherein the intersection characteristic specifying unit specifies the number of signals from a current position of the vehicle on the guidance route to a next branch intersection as a characteristic of the branch intersection. apparatus. 4. The navigation device according to claim 1, wherein the intersection feature specifying means specifies a name of a road turning at a next branch intersection as a feature of the branch intersection. 5. The navigation device according to claim 1, wherein the intersection feature specifying means specifies a width of a road turning at a next junction as a feature of the junction. 6. The vehicle according to claim 3, further comprising a vehicle position detecting means for detecting a vehicle position, wherein the vehicle position is located around the vehicle position on the guidance route and within a detection error range of the vehicle position detecting means. A navigation device, wherein when there is no signal, guidance of a forked road is provided by the voice guidance means. 7. The method according to claim 2, wherein when a characteristic of a next intersection on the guidance route is not the same as that of an intersection before the guidance intersection, the branch guidance by the voice guidance unit is performed. A navigation device for providing guidance.