JPH1089994A - Guidance method for crossing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a guidance method in which a branch crossing can be specified precisely even when many crossings exist in a narrow area. SOLUTION: In order to specify a branch crossing B as an object to be guided, the branch crossing is specified by the shape of a crossing such as a three-forked road, a crossroads, a five-forked road, a dead end or the like or by a guide such as a signal mechanism, a traffic mark or the like which can be confirmed from a distant place. In addition, an approach direction to the branch crossing B is extended up to an extension point P, and the branch crossing is specified by the shape and the mark of any extension crossing when one or a plurality of extension crossings exist on the extension point and by the number of crossings up to the branch crossing B from the extension crossing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intersection guidance method capable of providing an intersection guidance in an on-vehicle navigation device.

[0002]

2. Description of the Related Art Conventionally, an in-vehicle navigation device has been used to assist a vehicle traveling on an unfamiliar land. The in-vehicle navigation device includes, for example, a direction sensor, a distance sensor, a GPS receiver, a road map memory, a computer, and the like. The direction data input from the direction sensor, the traveling distance data input from the distance sensor, and the GPS reception are provided. It has a function to detect the vehicle position based on the position data input from the machine.

Further, such a navigation device may be provided with a route calculation function for automatically calculating a route from the current position of the vehicle to the destination by a computer in accordance with a destination setting input by a passenger. is there. If this function is used, it is possible to reliably reach the destination by traveling along the calculated recommended route without knowing the way to the destination.

[0004] By the way, the apparatus for calculating the recommended route as described above can guide the route of the vehicle at the intersection when the vehicle approaches the main intersection on the recommended route.
For example, Japanese Patent Application Laid-Open No. 7-103776 discloses the technique. The technology disclosed in the above publication is "Please turn right at the second intersection" or "3.
00m, turn left at the intersection ", etc., to guide the vehicle at the intersection.

According to this prior art, even when there are a plurality of intersections, it is possible to specify the number of the intersection to be turned.

[0006]

The conventional intersection guidance is
Drivers and fellow passengers have a rough description such as "Please turn right at the second intersection" or "300m ahead, turn left at the intersection" because the guide was mainly intended for the main arterial roads such as national roads and prefectural roads. (Hereinafter, abbreviated as "driver") was understood.

However, if all roads including narrow streets such as living roads are targeted for intersection guidance, it is not possible to specify an intersection to be turned with the above rough contents, and sufficient guidance on intersections is provided. You may not be able to do it. Therefore, an object of the present invention is to provide an intersection guidance method capable of providing accurate intersection guidance even when a large number of intersections exist in a narrow area.

[0008]

An intersection guidance method according to the present invention is used when a vehicle travels along a preset route.
A branch intersection to be guided on a route is specified by any one of the following (a) to (g) or a combination of two or more of them, and is transmitted to a driver. ). (a) The shape of the intersection, such as a three-way intersection, a crossroad, a five-way intersection, or an end point. (b) If there is a sign at a branch intersection that can be seen from a distance such as a traffic light or a traffic sign, (c) the direction of approach to the branch intersection. And the shape of any of the extended intersections when there is one or more extended intersections on the extension,
(D) the number of intersections from the extension intersection to the branch intersection, (d) a sign at any one of the extension intersections where the approach direction to the branch intersection is extended and one or more extension intersections exist on the extension, The number of intersections from the extension intersection to the branch intersection, (e) the shape of any one of the straight intersections when there is one or more straight intersections before reaching the branch intersection, the number of intersections from the straight intersection to the branch intersection,
(f) If there is one or more straight intersections before reaching the branch intersection, the mark at any one of the straight intersections, the number of intersections from the straight intersection to the branch intersection, and (g) the width of the road after the branch .

According to the above-mentioned method (a), the branch intersection to be guided is specified by the shape of the intersection such as a three-way intersection, a crossroad, a five-way intersection, or an end. This method is particularly effective when there is no intersection having the same shape before and after the branch intersection. For example, if there is only one fork when there is a continuous crossroad on a living road, etc., and that three-junction is a branch intersection, if the driver says "Please turn right (left) at the fork", Turn around the three-way intersection.

According to the above method (b), an intersection can be specified by a mark that can be confirmed from a distance. This method is particularly effective when there is no intersection of the same mark before and after the branch intersection. For example, if there is an intersection with a traffic light, etc., and there is no traffic light at the intersection before and after,
Speaking "turn right (left) at an intersection with a traffic light", the driver turns at an intersection with a traffic light.

The above-mentioned method (c) is to extend the approach direction to the branch intersection, and when there is one or more extended intersections on the extension, the shape of any one of the extended intersections and the branch from the extended intersection are determined. The branch intersection is specified by the number of intersections up to the intersection. In this method, when a plurality of intersections continue in front of a branch intersection, the driver has a view of the plurality of intersections, so that it is necessary to identify the branch intersection.
Instead of the characteristics of the branch intersection, the shape of the extended intersection ahead of the branch intersection is used.

[0012] For example, the content is "Please turn right (left) at the intersection just before the end". The above-mentioned method (d) is to extend the approach direction to the branch intersection, and when there is one or more extended intersections on the extension, a mark at any one of the extended intersections and a mark from the extended intersection to the branch intersection. The number of intersections indicates the branch intersection.

According to this method, when a plurality of intersections are continuous, the driver views the plurality of intersections in a field of view. Therefore, in order to specify the branch intersection, not the characteristic of the branch intersection, but the tip of the branch intersection. Use the extension intersection mark at. For example, "Please turn right (left) at the intersection just before the next traffic stop".

The above-mentioned method (e) is based on the shape of one of the straight-ahead intersections when one or more straight-ahead intersections are present before reaching the branch intersection, and the number of the intersections from the straight-ahead intersection to the branch intersection. Intersections are identified. In this method, when a plurality of intersections are consecutive before reaching the branch intersection, the driver passes through the plurality of intersections,
In order to specify the branch intersection, the shape of the straight-ahead intersection in front of the branch intersection is used instead of the characteristic of the branch intersection.

For example, when there is only one three-way intersection at a crossroad such as a living road, and the next intersection after the three-way intersection is a branch intersection, "turn right (left) after the three-way intersection". Please say, "I can specify the branch intersection. The above-mentioned method (f) is based on the case where one or a plurality of straight-ahead intersections are present before reaching the branch intersection, and a mark at any one of the straight-ahead intersections, and the number of the intersections from the straight-ahead intersection to the branch intersection. I have identified.

According to this method, when a plurality of intersections are continuous before reaching the branch intersection, the driver passes through the plurality of intersections. Use the sign for the straight ahead intersection in front of the intersection. For example, when there is an intersection with a traffic light on a living road and the next intersection is a branch intersection, the branch intersection can be specified by saying "Please turn right (left) at the next intersection of the traffic light".

In the above method (g), the branch intersection is specified by the width of the road after the branch. This method is effective when the road after the branch is extremely narrower or wider than the road before the branch. For example, "Please turn right (left) on the next narrow road". The present invention also includes a combination of the above methods (a) to (g). For example, by combining (a) and (c), it is possible to specify a branch intersection based on the shape of the branch intersection, the shape of the extension intersection, and the number of intersections from the extension intersection to the branch intersection. For example, "Please turn right (left) at the crossroads just before the end".

Further, according to the combination of (d) and (e), the content is "Please turn right (left) at the intersection just before the traffic light next to the three-way intersection".

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an in-vehicle navigation device that realizes an intersection guidance method. The in-vehicle navigation device includes a position detection unit 5 that detects a traveling position of the vehicle by using a distance sensor 1 and a direction sensor 2 that detect a moving amount and a change in direction of the vehicle, respectively.

The position detector 5 calculates the current position data of the vehicle at predetermined intervals by so-called self-contained navigation based on the vehicle movement data and the heading change data output from the sensors 1 and 2. The position detection unit 5 has a function of calculating a traveling locus by connecting the current position data of the vehicle, and correcting the vehicle position based on a comparison between the traveling locus and road data stored in a disk D described later. (So-called map matching method;
No. 0).

Note that the current position of the vehicle is detected by the GPS receiver 4 connected to the position detecting unit 5.
A GPS navigation system in which a radio wave transmitted from the S satellite is received by the GPS receiver 4 via the GPS antenna 3 and the position of the vehicle is detected based on the propagation delay time of the radio wave may be applied. Further, the current position of the vehicle obtained by the self-contained navigation may be corrected based on the current position of the vehicle obtained by the GPS navigation (see Japanese Patent Publication No. 7-92388).

The current position data of the vehicle detected by the position detector 5 is given to the controller 6. The control unit 6 functions as a control center of the navigation device.
PU 61, RAM 62, route calculating unit 63 for calculating a recommended route, traveling monitoring unit 64 for monitoring whether a vehicle has deviated from the recommended route, and route guiding unit 65 for searching for an intersection to be guided on the recommended route. And non-volatile memory 66
And so on.

When various calculation conditions such as a destination are input from the remote control key 10, the route calculation unit 63 stores the input destination data and the like in the RAM 62,
Route calculation road map data (described later) is read from a disk D described later. Then, the route calculation unit 63 performs a route search starting from the current position detected by the position detection unit 5 using, for example, the Dijkstra method or the potential method, and acquires a recommended route to the destination.

The control unit 6 is connected to a man-machine interface unit 8 for controlling an interface with a driver. In the man-machine interface section 8,
For example, a display device 9 having a display screen composed of a liquid crystal display element, a CRT, a plasma element, or the like, a remote control key 10 composed of, for example, a joystick remote control key for inputting a request for route calculation, etc. Is output as a voice.

The control unit 6 includes, for example, a CD-RO
M, a disk control unit 7 to which a disk D composed of a magneto-optical disk or the like is loaded is connected. Disk D
Is used to divide a road map (including highway national roads, motorways, general national roads, prefectural roads, city roads of designated cities, and other living roads) into a mesh shape. Alternatively, it stores display road map data, position detection road map data, route calculation road map data, and the like, which are composed of a combination of nodes corresponding to bending points and the like and links connecting the nodes.

Here, the "node" is generally a coordinate position for specifying a road intersection or a turning point.
A node representing an intersection is referred to as an intersection node, and a node representing a road bending point (excluding an intersection) is referred to as an interpolation point node. The vector connecting the nodes is a "link". The road map data for display (hereinafter referred to as “link data”) generally includes a link number, a pointer to a link start node and a pointer to a link end node, a link distance, a link direction, a road type or type, and a road. Includes data such as width, number of lanes, one-way traffic, right turn prohibition, left turn prohibition, toll road, various backgrounds, etc.

As described above, since the link data includes the information of the start point node of the link and the information of the end point node of the link, the point can be specified only by the link. If a link specifies the start point of a link, the link is called an "exit link" .If the end point of the link is specified, the link is called an "entry link". It is called "branch link". Further, the direction passing through the link can be calculated based on the start point coordinates and the end point coordinates of the link included in the link data. Therefore, 1
By specifying one link, the traveling direction of the vehicle can also be specified.

FIG. 2 illustrates four exit links for specifying an intersection (crossroad), and FIG. 3 illustrates four ingress links for specifying an intersection (crossroad). Table 1 shows a main part of a format (link table) for storing link data.
According to Table 1, the link table includes, for each link, a link number, a link width, a link distance, the number of interpolation points n, a link start point coordinate, an interpolation point coordinate, a link end point coordinate, a link start point branch number, and a branch link number. , The signal at the link start point
The sign flag, the link end point branch number and the branch link number, and the signal / sign flag at the link end point are stored.

[0029]

[Table 1]

The signal / sign flag indicates whether there is a traffic signal at the start and end points of the link, and if so, what kind of traffic signal, and whether there is a traffic sign at the start point and end point of the link, and This is a flag indicating what kind of traffic sign is. When the recommended route is acquired, the control unit 6 performs an intersection (excluding an intersection that goes straight ahead) that is an object of guidance existing along the recommended route before or while the vehicle is running, and is hereinafter referred to as a “branch intersection”. ) Is specified, and information on the branch intersection is stored in the guidance determination table in the nonvolatile memory 66.

[0031]

[Table 2]

The guidance discrimination table contains, for each branch intersection, "entrance link number", "branch intersection interval", "entry direction", "exit direction", "road width after branch", "intersection shape", "signal / Signs '', `` Number of extended intersections, each link number, link length, intersection shape, signal / sign '' and `` Number of straight-ahead intersections before branching, each link number, link length, intersection shape, signal / sign '' are provided. Have been.

FIG. 4 is a road map specifically showing the recommended route and the branch intersection. In FIG. 4, links L ₁ ,
The recommended route is composed of L ₂ , L _3, etc.
It is identified by the end point of the incoming link L ₂ is. Hereinafter, a method of creating the guidance determination table will be described based on a flowchart (FIG. 5) with reference to FIG.

FIG. 5 is a flowchart for explaining the process of creating the guidance determination table. First, focusing on an intersection existing along the recommended route, for example, intersection B (see FIG. 4), an approach direction along the recommended route and an exit direction along the recommended route are obtained (step S2). Approach direction is (if there are interpolation points of the interpolation point coordinates) start point coordinates of the entering link L ₂ intersection B can be calculated based on and end coordinates of the approach link L _2. Exit direction (if there is an interpolation point coordinates of the interpolation point) end point coordinate of the start point coordinates and egress link L ₃ of exit link L ₃ of intersection B can be calculated based on.

Next, it is determined whether or not the absolute value of the difference (branch angle) between the approach direction and the exit direction is equal to or greater than a predetermined angle (step S3). This “constant angle” is set based on a criterion as to whether or not an angle at which turn guidance is required. If the absolute value of the branch angle is equal to or greater than a certain angle, the intersection is specified as a branch intersection (step S4).
Then, the entry direction and the exit direction are stored in the "entry direction" column and the "exit direction" column of the guidance discrimination table, and the total link distance from the preceding branch intersection is calculated. The distance is stored in the column of “intersection intersection” in the guidance determination table (step S5). Branch intersection point spacing, in FIG. 4, is shown from the front of the branch intersection point A as the distance d ₂ to the intersection B.

Further, the road width of the exit link is obtained from the link table and stored in the guidance discrimination table (step S).
6) If there is a signal and a sign for the branch intersection, these are also stored in the guidance determination table (step S7). Further, the intersection shape of the branch intersection is calculated and stored in the guidance determination table (step S8). This intersection shape calculation processing will be described later.

Next, branch intersection point, for example, the approach direction to the branch intersection point B extending by a predetermined distance d _F, to the point and the extension point P (Step S9; see FIG. 4). Then, a distance d _F is set in front of the extension point P, and an intersection (excluding a branch intersection) located between the extension point P and the distance d _F in front is searched. The searched intersection is hereinafter referred to as “extended intersection”. The distance d _B (if, d _B is the branch intersection point distance d
Greater when than _2, and d _B = d _2. )
Search for intersection (branch intersection point is excluded) between the front distance d _B from the extension point P (step S10). The searched intersection is hereinafter referred to as a "straight ahead intersection."

[0038] In the example of FIG. 4, the extended intersection ahead of the branch intersection B is represented by the link L _4, before the intersection of the branch intersection point B is represented by the link L _1. It is needless to say that all the intersections before the branch intersection B are straight-ahead intersections (the intersection ahead of the branch intersection B does not follow the recommended route, so there is no room to discuss whether it is a straight-ahead intersection).

For each intersection searched in this way, data such as the link length, intersection shape, signals and signs are acquired, and stored in the "extended intersection" and "straight ahead intersection" columns of the guidance discrimination table. (Step S12).
Next, the intersection shape calculation processing will be described with reference to flowcharts (FIGS. 7, 8, and 9).

First, the approach link of the intersection to be calculated is specified (step T1), the link table is searched (step T2), and the link end point branch number and the branch link are obtained (step T3). Further, a branch angle is calculated based on a difference between the approach direction and the exit direction (step T4). When the search is completed for all branch links (step T5), the number obtained by adding 1 to the number of branches is N
(Step T6).

It is determined whether this N is 3, 4 or 5 or more (steps T7, S8, S9). If it is 3, the process proceeds from step T12 to step T17 (FIG. 8). If it is 4, the process proceeds from step T18 to step T19. Proceed to (FIG. 9). 5
If it is the above, the process proceeds to step T11 to specify an N (N ≧ 5) fork. Otherwise, it is determined that there is no feature of the intersection (step T10).

If it is determined that N = 3, step T12
Then, it is determined whether or not there is an exit link whose exit direction is substantially equal to the entry direction. In the case of YES, it can be determined that the intersection has a "U" shape as shown in FIG. In this case, it is determined whether another branch link is on the left or on the right (step T14). If it is on the left, it is identified as a left three-way junction (step T15). T16).

If there is no exit link whose exit direction is almost equal to the entrance direction in step T12, it is determined whether or not the directions of the two branch links are almost exactly opposite and almost perpendicular to the direction of the entrance link (step T13). In the case of YES, it is determined that the intersection is a collision as shown in FIG. 10B (step T17). In the case of NO, for example, FIG.
In this case, the process returns to step T9 in FIG. 7 because it can be estimated that the intersection is an irregular one as shown in FIG.

When it is determined that N = 4, it is determined whether or not there is an exit link whose exit direction is substantially equal to the entrance direction, and whether the entrance and exit directions of the other two links are exactly opposite (step). T18). In the case of YES, FIG. 11 (a)
It is specified as a crossroad as shown in FIG. If no,
Since it can be estimated that the intersection is an irregular one as exemplified in FIG. 11 (b) or (c), the process returns to step T9 in FIG. 7 in this case.

When the intersection shape is specified, it is stored in the guidance discrimination table. When the guidance determination table is completed in this way, a guidance content table that stores specific guidance content along the recommended route is created.

[0046]

[Table 3]

The guidance content table contains "entry link number"
It has columns for "branch intersection interval", "branch angle", "guidance content", and "guide start distance". Guidance start distance takes a distance d _B as described above. The guidance content is the road width after the branch (exit link) of the intersection stored in the guidance determination table,
Depending on the shape of the intersection, the presence / absence of traffic lights, presence / absence and types of signs, the intersection shape of the extended intersection, the presence / absence of traffic lights, the presence / absence and types of traffic signs, the intersection shape of the straight-ahead intersection before the branch, the presence / absence of traffic lights, and the presence / absence and type of traffic signs It is determined.

Hereinafter, the procedure of the determination will be described with reference to a flowchart (FIG. 12). According to the guidance discrimination table, branch intersections are sequentially traced (step U1), and guidance contents are set according to the type of the intersection (step U1).
2). The above processing is performed for all branch intersections on the recommended route (step U3). The prototype (model) of the voice guidance content is such as "Please turn right (left turn) △△△". In this case, whether to turn right or left,
It goes without saying that the determination is made based on the sign of the branch angle stored in the guidance determination table.

In step U2, this "@" is embodied as follows. (1) When the intersection shape is an end intersection
“Δ” is “end”. (2) In the case of an intersection with a signal “△△△” is defined as an “intersection with a signal”. (3) In the case of an intersection with a sign “△△△” is an “intersection with a sign XX”. Here, ○ is determined according to the type of the sign, and means, for example, one-way traffic, closed traffic, temporary stop, and the like. (4) When the branch intersection is a three-way intersection “△△△” shall be a “three-way intersection”, a “left three-way intersection” or a “right three-way intersection”. This (4)
Is preferably applied when the extended intersection or the straight ahead intersection before the branch is not a three-way intersection. (5) If the junction is a four-way intersection “△△△” shall be a “crossroad” or a “four-way intersection”. It is desirable that the condition (5) be applied when the extended intersection or the straight ahead intersection before the branch is not a crossroad. (6) When the junction is a five-way intersection “△△△” is a “five-way intersection”. It is desirable that the condition of (6) be applied when the extension intersection or the straight intersection before the branch is not a five-way intersection. (7) When specifying with an extended intersection (7-1) When the innermost extended intersection is an end intersection The number of extended intersections is counted, and the number is set as X.
“Δ” is “X before the end”.

(7-2) There is one intersection with a signal at the extended intersection
When there is one, the number from the branch intersection to the extended intersection with the signal is counted, and the number is set to X, and “△△△” is set to “X before the signal”. It is desirable to apply the condition (7-2) when there is no signal at the branch intersection or the straight ahead intersection before the branch. (7-3) When there is one marked intersection at the extension intersection
Count the number from the branch intersection to the extension intersection where the sign is located, set the number as X, and set “△△△” to “X before the sign”.
And It is desirable that this condition (7-3) be applied when there is no sign at the branch intersection or the straight ahead intersection before the branch. (8) When specifying at the straight intersection before the branch (8-1) When there is one intersection with a signal at the straight intersection
The number from the straight intersection to the branch intersection where the signal is present is counted, and the number is set to Y. "△△△" to "Y ahead of signal"
And It is desirable to apply the condition (8-1) when there is no signal at the branch intersection or extension intersection.

(8-2) There is one intersection with a sign at the straight-ahead intersection
When there is one, the number from the straight intersection with the sign to the branch intersection is counted, and the number is set to Y. "△△△" is "Y ahead of the sign". It is desirable that this condition (8-2) be applied when there is no sign at the branch intersection or extension intersection. (9) When there is no straight intersection before the branch
"" Is the "next intersection". (10) If there is a straight-ahead intersection before the branch, but the shape is different from the shape of the branch intersection, adjust `` △△△ '' to the shape of the branch intersection, `` next three-way '', `` next left three-way '', "Next right three-way", "Next cross-road", "Next four-way" or "Next five-way". (11) When the road width after branching the recommended route is different from the road width of the road before branching “△△△” indicates “road of XX m width”, “road of wide width”, “road of narrow width”, etc. And “OOm” is the width of the road after branching.

When the contents of the guidance content table are determined as described above, the intersection guidance is performed as the vehicle travels. When the current position data of the vehicle is given from the position detection unit 5, the control unit 6 drives the disk control unit 7 and reads road map data around the current position of the vehicle from the disk D via the disk control unit 7. Thereafter, display data is created based on the read road map data and the current position data of the vehicle, and the display data is provided to the display device 9 via the man-machine interface unit 8. The position is displayed together with the road map by a car mark.

Further, the control section 6 superimposes the recommended route calculated by the route calculation section 63 on the road map displayed on the display device 9. FIGS. 13 and 14 are flowcharts showing this intersection guidance processing. First,
When the current position is updated (step V1), the CPU 61
Refers to the guidance discrimination table, specifies the next branch intersection, and calculates the distance d to the branch intersection (step V2).

Next, the CPU 61 determines whether or not the distance d to the branch intersection has passed a fixed distance, for example, a long distance guidance position of 500 m (step V3). If the vehicle has passed the long-distance guidance position, the process proceeds to step V4, in which the intersection guidance having normal contents is performed once. Intersection guidance with normal contents
For example, the content is "Please turn right at the intersection at $ m".

Thereafter, when the current position is updated (step V5), the distance d to the branch intersection is calculated (step V6), and the distance d to the branch intersection is stored in the guidance content table (Table 3). It is determined whether the vehicle has passed the guidance start distance, for example, a short distance guidance position of 60 m (step V7). If the vehicle has passed the short-distance guidance position, in step V8, the above-described “guidance content” is acquired with reference to the guidance content table, and voice guidance is performed.

Upon completion of the voice guidance, it is determined whether or not the vehicle has passed the branch intersection (step V9).
It is determined whether there is a next route link (step V1).
1) If there is a next route link, the branch intersection is updated for the next guidance (step V13), and the process returns to step V1. If there is no next route link, destination arrival guidance is provided (step V12).

Although this embodiment has been described above, the present invention is not limited to the above-described embodiment.
Various changes can be made within the scope of the invention described in the claims.

[0058]

As described above, according to the intersection guidance method of the present invention, even if there are many intersections in a narrow area,
Since the branch intersection can be accurately specified, the driver can travel along the route without erroneously determining the intersection to be turned.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle-mounted navigation device according to the present invention.

FIG. 2 is a diagram illustrating an example of an exit link at an intersection.

FIG. 3 is a diagram illustrating an example of an approach link at an intersection.

FIG. 4 is a diagram showing a positional relationship between a link and a branch intersection on a recommended route.

FIG. 5 is a flowchart illustrating a process of creating a guidance determination table.

FIG. 6 is a flowchart (continuation of FIG. 5) for explaining a process of creating a guidance determination table.

FIG. 7 is a flowchart illustrating an intersection shape calculation process.

FIG. 8 is a flowchart (continuation of FIG. 7) for explaining an intersection shape calculation process;

FIG. 9 is a flowchart (continuation of FIG. 7) for explaining an intersection shape calculation process;

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

FIG. 11 is a diagram showing a specific example of an intersection shape.

FIG. 12 is a flowchart illustrating a guidance content determination process.

FIG. 13 is a flowchart illustrating an intersection guidance process.

FIG. 14 is a flowchart (continuation of FIG. 13) illustrating the intersection guidance process.

[Explanation of symbols]

 Reference Signs List 5 position detection unit 6 control unit 7 disk control unit 8 man-machine interface unit 9 display device 10 remote control key 11 audio output device 61 CPU 62 RAM 63 route calculation unit 64 running monitoring unit 65 route guidance unit 66 nonvolatile memory D disk

Claims (1)

[Claims] An intersection guidance method for providing a route guidance by voice when a vehicle approaches a guidance target intersection, wherein the vehicle is guided on a route when the vehicle travels along a preset route. An intersection guidance method characterized in that a branch intersection is specified by any one of the following (a) to (g) or a combination of two or more of them, and transmitted to a driver. (a) The shape of the intersection, such as a three-way intersection, a crossroad, a five-way intersection, or an end, and (b) a landmark at a branch intersection, such as a traffic light or traffic sign, that can be seen from a distance. (c) extend the approach direction to the branch intersection, and if there is one or more extension intersections on the extension, the shape of any extension intersection;
(D) the number of intersections from the extension intersection to the branch intersection, (d) a sign at any one of the extension intersections where the approach direction to the branch intersection is extended and one or more extension intersections exist on the extension, The number of intersections from the extension intersection to the branch intersection, (e) the shape of any one of the straight intersections when there is one or more straight intersections before reaching the branch intersection, the number of intersections from the straight intersection to the branch intersection,
(f) If there is one or more straight intersections before reaching the branch intersection, the mark at any one of the straight intersections, the number of intersections from the straight intersection to the branch intersection, and (g) the width of the road after the branch .