JPH07234990A - Road shape deciding device - Google Patents

Abstract

PURPOSE:To decide the shape of a road based on the minimum quantity of data by calculating the angles formed by the segments connecting the reference coordinate points together and deciding the road shape based on the arrangement of reference coordinate points calculated from those angles. CONSTITUTION:A reference coordinate point extracting means M3 extracts four nodes N1, N2, N3 and N4 to decide the shape of a road among many nodes N set on the road. An angle calculator means M4 calculates an angle theta1, formed between a vector V12 connecting together both nodes N1 and N2 and a vector V23 connecting together both nodes N2 and N3. The means M4 also calculates an angle theta2 formed between the vector V12 and a vector V24 connecting together both nodes N2 and N4 respectively. Then a changing rate is calculated from both angles theta1 andnd theta2 for decision of the road shape. Thus a road shape deciding means M5 compares the calculated changing rate with the prescribed reference value to decide the shape of the road.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road shape judging device for judging the shape of a road based on map information as a set of a plurality of coordinate points forming a road.

[0002]

2. Description of the Related Art A transmitter provided in front of an entrance of a curve transmits information about an approaching speed and a steering angle necessary for smoothly passing through the curve as information for giving an occupant of an automobile a road shape. (JP-A-3-14970
(See Japanese Patent Laid-Open No. 0) or a device for controlling an automatic cruise device of an automobile based on information of road gradient, road surface condition, and curve radius stored in a CD-ROM (Japanese Patent Laid-Open No. 4-15).
No. 799) is known.

[0003]

By the way, the former one is difficult to install on all roads because of the high equipment cost and maintenance cost, and the latter one is feasible because the amount of data is huge. There is a problem that is scarce.

The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately determine the road shape in front of the vehicle based on map information composed of a set of a plurality of coordinate points forming a road. To do.

[0005]

In order to achieve the above object, the invention described in claim 1 is a map information output means for outputting map information as a set of a plurality of coordinate points forming a road, A vehicle position output means for outputting the vehicle position on the road, a reference coordinate point extraction means for extracting at least four reference coordinate points on the road ahead of the vehicle position, and a line segment connecting the reference coordinate points. The angle calculation means for calculating the angle formed by and the road shape determination means for determining the road shape based on the arrangement state of the reference coordinate points obtained based on the angle.

According to a second aspect of the present invention, map information output means for outputting map information as a set of a plurality of coordinate points forming a road, and own vehicle position output for outputting the own vehicle position on the road. Means, reference coordinate point extracting means for extracting at least three reference coordinate points adjacent to each other on the road ahead of the vehicle position, and angle calculating means for calculating an angle formed by a line segment connecting the reference coordinate points, It is characterized by further comprising distance calculating means for calculating a distance between the reference coordinate points, and road shape determining means for determining the road shape based on the arrangement state of the reference coordinate points obtained based on the angle and the distance.

In addition to the structure of claim 1 or 2, the invention described in claim 3 sets a temporary vehicle position on a road ahead of the vehicle position by a predetermined distance. The reference coordinate point is extracted based on

Further, the invention described in claim 4 is characterized in that, in addition to the structure of claim 1 or 2, there is provided a display means for displaying the determined road shape to an occupant.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 show a first embodiment of the present invention, and FIG. 1 is a block diagram showing the overall configuration of the device of the present invention,
2 is a block diagram of the control system, FIG. 3 is a flow chart showing the operation, FIG. 4 is an explanatory diagram showing how to obtain the road shape, FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points, and FIG. FIG. 7 is a diagram showing a road shape determination standard.

In FIG. 1, NV is a navigation system for automobiles, in which a well-known navigation device 1,
Map information output means 2 using an IC card or CD-ROM
And a control unit 3 for performing various calculations to be described later.

The navigation device 1 receives a signal from the vehicle speed detecting means 6 in addition to the vehicle position information, road information, traffic information, etc. from the satellite communication device 4 or the near field communication device 5, and the map information output means. Based on the map information from 2, the current position of the vehicle and the route to the destination are calculated and displayed on the CRT 9 via the man-machine interface 8.

The map information output by the map information output means 2 is composed of a set of virtual nodes N arranged on the road, and each node N has a coordinate N (X, Y).
Stipulated by When a road has a bend, a branch, or an intersection, those singular points are given priority to the node N.
Has been selected as.

The control unit 3 performs various calculations to be described later based on the outputs of the navigation device 1, the map information output unit 2 and the vehicle speed detection unit 6, displays the results, and issues an alarm and vehicle speed control.

Reference numeral C denotes a vehicle speed adjusting device, which has an image creating means 11, an alarm means 12, and a vehicle speed adjusting means 13 inside. The image creating means 11 is composed of, for example, a head-up display, and displays the determined road shape in the front, the vehicle speed that can be passed, and the like. The warning means 12 is composed of a sounding means such as a buzzer or a chime, and gives various warnings to an occupant. The vehicle speed adjusting means 13 is composed of a brake device, an auto cruise device, etc., and automatically adjusts the vehicle speed so that the vehicle can pass through a curve.

FIG. 2 is a block diagram showing a control system according to the present invention. Map information output means M1 corresponding to the map information output means 2, vehicle position output means M2 corresponding to the navigation device 1, Reference coordinate point extraction means M3, angle calculation means M4, and road shape determination means M5 corresponding to the control unit 3.
And a display means M7 corresponding to the image creating means 11.

The reference coordinate point extracting means M3 is used to determine the road shape from a large number of nodes N set on the road.
The nodes N ₁ , N ₂ , N ₃ , and N ₄ (hereinafter referred to as reference nodes) are extracted.

The angle calculation means M4 has a reference node N.₁, N
₂Vector V that connects the two ₁₂And reference node
N₂, N₃Vector V that connects the two_{twenty three}With
Angle θ₁And the reference node N₁, N₂To
Vector V, which is the connecting vector₁₂And reference node N₂, N
_FourVector V that connects the two_{twenty four}Angle θ formed by₂
To calculate the angle θ₁And θ₂From the road shape
To calculate the change rate α. The calculation method of the rate of change α will be
Detailed description.

The road shape judging means M5 judges the road shape by comparing the rate of change α with a predetermined reference value.

Next, the operation of the first embodiment of the present invention will be described based on the flowchart of FIG.

First, the map information (that is, the coordinates N (X, Y) of the node N is read from the map information output means M1 and the own vehicle position P ₀ (X ₀ , Y) is read from the own vehicle position output means M2.
₀ ) is read, and the vehicle speed V ₀ is read from the vehicle speed detecting means 6 (step S1).

Next, the prefetch section S ₁ and the judgment section S ₂ are calculated (step S2). As shown in FIG. 4, the prefetch section S ₁ is set in front of the vehicle position P ₀ , and is the product of the current vehicle speed V ₀ and the predetermined time t ₁ (S ₁ = V ₀ ×
distance for stopping the predetermined time t ₁ within the case of performing either set, or the braking at a predetermined deceleration β as _{t 1) (S 1 = V} 0 t 1 - (βt 1 2/2)) Is set as. The look-ahead section S ₁ is for giving a passenger a time margin for braking or steering after determining the road shape in front of the vehicle.

The judgment section S ₂ is set within a predetermined range in front of the front end of the prefetch section S ₁ (hereinafter referred to as the temporary vehicle position). For example, the current vehicle speed V ₀ and the predetermined time t.
It is set as the product of the _{2 (S 2 = V 0 ×} t 2).

Next, the reference coordinate point extraction means M3, 4 nodes for determining the road shape N ₁ to N ₄ (hereinafter, referred to as the reference node N ₁ to N ₄₎ to extract (step S3). The second reference node N ₂ is set at the temporary vehicle position, the first reference node N ₁ is located at a position a distance a from the second reference node N ₂ , and the third reference node N ₃ is located at the second reference node N _2. Is set to the front position by the distance a, and the fourth reference node N ₄ is set to the front position by the distance a of the third reference node N ₃ . Here, a is set as a constant or the product of the vehicle speed V ₀ and the predetermined time t ₃ (a = V ₀ × t ₃ ).

If the node N does not exist at a position set by a multiple of the distance a with respect to the temporary vehicle position, the node N closest to that position is the reference node N ₁
~ N ₄ is extracted.

Further, in this embodiment, the reference nodes N _{1 to} N _{4 are used.}
However, when the number of nodes N set on the road is small (that is, when the nodes are sparse), the adjacent nodes N may be extracted as they are.

Further, as shown in FIG. 5 (A), the S-shaped curve has the strictest passage conditions among the composite curves, but when the distance a is set as a constant, a = 30 m.
By so doing, it is possible to reliably determine even a compact S-shaped curve in which two arcs having a radius of curvature R = 30 m are connected.

Further, as shown in FIG. 5 (B), when a bent road such as a crank road exists in the judgment section S ₂ , the node N (singular point) corresponding to the bent point is given priority. The reference nodes N _{1 to} N ₄ . This allows
It is possible to reliably determine a special road shape such as a crank road.

Next, the road shape is determined based on the coordinates of the _four reference nodes N _{1 to} N ₄ (step S4).

First, the angle θ is calculated by the angle calculation means M4.
Calculate ₁ and θ ₂ . That is, as shown in FIG.
Reference node N ₁ (X ₁ , Y ₁ ) and second reference node N
Vector V ₁₂ (X ₁₂ , Y ₁₂ ) connecting with ₂ (X ₂ , Y ₂ ).
And a vector V ₂₃ (X ₂₃ , Y) connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the third reference node N ₃ (X ₃ , Y ₃ ).
₂₃ ) and a vector V connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the fourth reference node N ₄ (X ₄ , Y ₄ ).
₂₄ (X ₂₄ , Y ₂₄ ) is calculated.

[0031] At this time, when the angle formed by the vector V ₁₂ and the vector V ₂₃ and theta _1, from the inner product of the vector V ₁₂ and the vector _{V 23, X 12 · X 23} + Y 12 · Y 23 = (X 12 2 + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2 · cos θ ₁ holds, and cos θ ₁ is obtained from this.

Further, the vector V₁₂And vector V_{twenty four}Success with
Angle θ₂Then, the vector V ₁₂And vector V_{twenty four}
From the dot product of X₁₂・ X_{twenty four}+ Y₁₂・ Y_{twenty four} = (X₁₂ ²+ Y₁₂ ²)^1/2・ (X_{twenty four} ²+ Y_{twenty four} ²)^1/2・ Cos θ₂… Holds, and from now on cosθ₂Is required.

Next, the change rate α is calculated by α = (cos θ ₁ −cos co ₂ ) / cos θ ₁ ...

As is clear from the equation, when the absolute value of the change rate α is small, it corresponds to the case where θ ₁ and θ ₂ are substantially the same and the bend of the road is small (that is, straight road), Conversely, when the absolute value of the rate of change α is large, θ ₁ and θ
₂ is very different and corresponds to a case where the road has a large bend (that is, a crank road or a sharp curve).

The direction of curve of the road is the vector V₁₂as well as
Vector V_{twenty three}Cross product of X₁₂・ Y _{twenty three}-Y₁₂・ X_{twenty three}Positive
It can be judged by the negative.

Thus, as shown in FIGS. 6 and 7, the road shape determination means M5 determines various road shapes according to the value of the change rate α.

If the road shape determined as described above is a curve (step S4), it is further determined whether the curve is an S curve or a crank road (step S4).
5). If the road shape is simply a curve, the advance notice of the curve is displayed on the display means M7 (step S
6) If the road shape is an S-curve or a crank road that is difficult to pass, a notice of the S-curve or crank road is displayed on the display means M7 (step S7).

Next, it is determined whether or not the current vehicle speed V ₀ is appropriate for the determined road shape (step S8), and the current vehicle speed V 0 is set.
_{When 0} is too high for the vehicle speed at which the vehicle can turn the curve ahead, the warning means 12 gives a warning to the occupant (step S9). If the vehicle speed is not decelerated to an appropriate vehicle speed at which the vehicle can surely turn the curve despite the warning (step S10), the vehicle speed adjusting means 13 automatically decelerates (step S11). Then, when the vehicle passes through the target curve or the vehicle speed V ₀ is decelerated to the proper vehicle speed (step S12), the automatic deceleration is stopped and the process returns to step S1.

On the other hand, if the answer to Steps S8 and S10 is NO and automatic deceleration is not required, it is judged whether or not the processing has been performed for the entire judgment section S ₂ (Step S1
3), the answer is returned to step S3 if not processing has been completed for the entire area of the determination section S ₂ comprising NO, the reference node N ₁ to N ₄ is shifted to the front side repeats the processing described above, As a result, the answer in step S13 is YE.
When S is reached and all processing is completed, the process returns to step S1.

As described above, the coordinates N of the plurality of nodes N
Since the road shape is determined based on the map information consisting of a set of (X, Y), it is not necessary to maintain the infrastructure, which requires high equipment costs and maintenance costs.
The road shape can be determined with the minimum amount of data that can be stored in the M or the IC card.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram corresponding to FIG. 2 of the first embodiment, FIG. 9 is an explanatory diagram of a difference, FIG. 10 is an explanatory diagram showing how to obtain a road shape, and FIG. 11 shows how to obtain a radius of curvature of an arc curve. Explanatory diagram, FIG. 12 is a diagram showing a road shape pattern, FIG. 13 is a diagram showing a road shape pattern, FIG.
FIG. 15 is an explanatory diagram showing a method of determining a non-circular curve, and FIG. 15 is a diagram showing criteria for determining a road shape.

In the second embodiment, the road shape is determined based on _three reference nodes N ₁ , N ₂ and N ₃ which are adjacent to each other. As shown in FIG. 8, the output of the angle calculating means M4 and the distance are calculated. It differs from the first embodiment in that the road shape is determined based on the output of the calculating means M6, and the other configurations are the same as those in the first embodiment.

In the map information of the second embodiment, as a rule for creating data, the distance (hereinafter referred to as a difference) between a line segment connecting adjacent nodes N and a road is set to a predetermined reference value k or less. The position of each node N is determined. That is, FIG.
As shown in (1), in the portion where the radius of curvature of the road is small, the difference is suppressed to the reference value k or less by setting the distance between the adjacent nodes N small.

Extraction of the _three reference nodes N ₁ , N ₂ and N ₃ is performed as follows. That is, the first reference node N ₁ on the most front side among the three reference nodes to be first extracted N _1, N _2, N ₃ is set to the tip of the pre-read interval S _1, nodes adjacent to the front N is the second reference node N ₂
And the node N adjacent to the node in front of it is set as the third reference node N ₃ . These three reference nodes N ₁ ,
N ₂ and N ₃ are sequentially extracted by shifting to the front side.

Next, a method of determining the road shape based on the coordinates of the _three reference nodes N _{1 to} N ₃ will be described. .

First, as shown in FIG. 10, angle calculating means
The first reference node N by M4₁(X ₁, Y₁) And the second group
Quasi node N₂(X₂, Y₂) Vector V connecting with₁₂(X
₁₂, Y₁₂) And the second reference node N₂(X₂, Y₂) And the first
3 reference node N₃(X₃, Y ₃) Vector V connecting with_{twenty three}
(X_{twenty three}, Y_{twenty three}) Is calculated.

That is, from the inner product of the vector V ₁₂ and the vector V ₂₃ , X ₁₂ · X ₂₃ + Y ₁₂ · Y ₂₃ = (X ₁₂ ² + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2・ Cos θ is established, and the angle θ is obtained from this.

Next, the distance calculating means M6 causes the first reference
Code N₁(X₁, Y₁) And the second reference node N₂(X₂，
Y₂) Distance L₁₂And the second reference node N₂(X₂, Y
₂) And the third reference node N₃(X₃, Y₃) Distance L_{twenty three}
And the first reference node N₁(X ₁, Y₁) And the third standard no
De N₃(X₃, Y₃) Distance L₁₃And are calculated.

L₁₂= (X₁₂ ²+ Y₁₂ ²)^1/2 … L_{twenty three}= (X_{twenty three} ²+ Y_{twenty three} ²)^1/2 … L₁₃= (X₁₃ ²+ Y₁₃ ²)^1/2 ... where the first reference node N₁(X₁, Y₁) And the third standard
Node N₃(X₃, Y ₃) And the vector connecting
Le V₁₃(X₁₃, Y₁₃).

As is apparent from FIG. 11, when it is assumed that the _three reference nodes N _{1 to} N ₃ exist on a common arc, that is, when the curve is an arc-shaped curve, L ₁₂ ≈L ₂₃
If so, the radius of curvature R of the arc-shaped curve is obtained by R = L ₁₃ / (2 sin θ) ... And it is possible to determine whether or not the curve can pass based on this radius of curvature R.

As described above, the three reference nodes N ₁ ...
When the angle θ and the distance L ₁₃ are obtained from N _3, the road shape can be determined based on the magnitude of the angle θ and the magnitude of the distance L ₁₃ . That is, as shown in FIG.
Is larger and the distance L ₁₃ is smaller, the radius of curvature of the curve is smaller, and as the angle θ is smaller and the distance L ₁₃ is larger, the radius of curvature of the curve is larger.

By the way, if the three reference nodes N _{1 to} N ₃ exist on a common arc, that is, if the curve is an arc-shaped curve, the road shape can be determined as shown in FIG. However, other than the arc-shaped curve, the curve entrance where the radius of curvature gradually decreases and the curve exit where the radius of curvature gradually increases can be determined as follows.

As shown in FIG. 14, three reference nodes N
Assuming that _{1 to} N ₃ are on a common circular arc, the radius of curvature R is calculated as described above, and the difference between the longer one of the vectors V ₁₂ , V ₂₃ and the circular arc of the radius of curvature R is obtained. If the calculated difference is within the range of the reference value k, it is confirmed that the _three reference nodes N _{1 to} N ₃ are on the arc of the radius of curvature R, but the calculated difference is the reference value k. If it exceeds, it is unlikely that the three reference nodes N _{1 to} N ₃ exist on the arc, and the _three reference nodes N _{1 to} N ₃ have non-arc curves with gradually changing radii of curvature (ie, It is determined to be on the curve entrance or the curve exit).

This will be described in more detail as shown in FIG.
And the first reference node N₁And the second reference node N₂Distance from
L₁₂Is the second reference node N₂And the third reference node N₃Distance from
Distance L _{twenty three}Larger than the first reference node N₁And the second standard
Code N₂Vector V connecting to ₁₂And three reference nodes N₁
~ N₃If the difference with the arc passing through exceeds the reference value k,
Road shape is a curve entrance with a gradually decreasing radius of curvature
Is determined. On the other hand, the distance L_{twenty three}Is the distance L₁₂Greater than
Vector V_{twenty three}The difference between the arc and the arc exceeds the reference value k.
If so, the road shape will be a curve exit with a gradually increasing radius of curvature.
It is determined that

Thus, in FIG. 15, the lower right region where the angle θ is large and the distance L ₁₃ is small corresponds to a sharp curve, intersection, branch road, etc. with a small radius of curvature R, and the angle θ is small and the distance L ₁₃ is small. The lower right region with a large radius corresponds to a gentle curve or straight road with a large radius of curvature R. Further, k _{1 to} k ₄ represent the standard value of the difference (k ₁ > k ₂ > k ₃ > k ₄ ),
If the point determined by the calculated angle θ and the distance L ₁₃ is, for example, in the lower left area of the reference value k ₂ , the road shape is an arc curve with a constant radius of curvature, and in the upper right area of the reference value k _2. If so, the road shape is a non-circular curve with a gradually changing radius of curvature.

When the determined road shape is a non-circular curve
The radius of curvature for determining whether the curve can pass or not
Is asked for. That is, obtained in FIG.
The radius of curvature R does not reflect the actual radius of curvature,
Near the exit (ie, the second reference node N₂And the third standard no
De N₃The actual radius of curvature of
Get smaller. Therefore, the first reference node N₁And the second standard
Node N₂The second reference node N on the line segment connecting₂Distance from
L_{twenty three}Position N₁'Takes 3 points N₁′, N₂, N ₃Through
If the radius of curvature R'of the arc
Make sure that the radius of curvature is appropriate for determining whether the curve can pass.
It

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made.

[0058]

As described above, according to the invention described in claim 1, at least four reference coordinate points are extracted and the angle formed by the line segment connecting the reference coordinate points is calculated. Since the road shape is determined based on the arrangement state of the reference coordinate points obtained based on the CD-ROM, there is no need to maintain the infrastructure, which requires high equipment costs and maintenance costs.
It is possible to determine the road shape with the minimum amount of data that can be stored in the IC card.

According to the invention described in claim 2,
At least three reference coordinate points are extracted, an angle formed by a line segment connecting the reference coordinate points and a distance between the reference coordinate points are calculated, and according to the arrangement state of the reference coordinate points obtained based on these angles and distances. Since the road shape is determined, it is possible to determine the road shape with the minimum amount of data that can be stored in a CD-ROM or IC card, without the need for infrastructure maintenance that increases equipment costs and maintenance costs. Becomes

According to the invention described in claim 3,
Since the reference coordinate points are extracted based on the provisional vehicle position set on the road a predetermined distance ahead of the vehicle position, sufficient time for the occupant to decelerate or steer according to the determined road shape. You can give yourself a margin.

According to the invention described in claim 4,
Since the display means for displaying the determined road shape to the occupant is provided, it is possible to reliably notify the occupant of the road shape.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a device of the present invention.

FIG. 2 is a block diagram of a control system

FIG. 3 is a flowchart showing the operation.

FIG. 4 is an explanatory diagram showing how to obtain a road shape.

FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points.

FIG. 6 is a diagram showing a road shape pattern.

FIG. 7 is a diagram showing criteria for determining a road shape.

FIG. 8 is a block diagram corresponding to FIG. 2 according to a second embodiment.

FIG. 9 is an explanatory diagram of a difference

FIG. 10 is an explanatory diagram showing how to obtain a road shape.

FIG. 11 is an explanatory diagram showing how to determine the radius of curvature of an arc curve.

FIG. 12 is a diagram showing a road shape pattern.

FIG. 13 is a diagram showing a road shape pattern.

FIG. 14 is an explanatory diagram showing a method of determining a non-circular curve.

FIG. 15 is a diagram showing criteria for determining a road shape.

[Explanation of symbols]

M1 map information output means M2 vehicle position output means M3 reference coordinate point extraction means M4 angle calculating means M5 road shape determining means M6 distance calculating means M7 display means N ₁ to N ₄ reference node (reference coordinate point) N ₁ to N ₃ Reference node (reference coordinate point) θ ₁ , θ ₂ angle θ angle L ₁₃ distance

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G09B 29/10 A

Claims (4)

[Claims] 1. A set of a plurality of coordinate points forming a road
Map information output means (M1) for outputting all map information, and own vehicle position output means (M2) for outputting the own vehicle position on the road
And at least 4 vehicles on the road ahead of the vehicle position
Reference coordinate point (N₁~ N _Four) Extracting reference coordinate point
Step (M3) and reference coordinate point (N₁~ N_FourAngle formed by the line segment
(Θ₁, Θ₂) And an angle calculation means (M4) for calculating the angle (θ₁, Θ₂) Based on the reference coordinate point
(N₁~ N_Four) Determine the road shape based on the array status
Road shape determining means (M5)
Road shape determination device. 2. A set of a plurality of coordinate points forming a road
Map information output means (M1) for outputting all map information, and own vehicle position output means (M2) for outputting the own vehicle position on the road
And at least at least adjacent to the road ahead of the vehicle position
Also 3 reference coordinate points (N₁~ N₃) To extract the reference coordinates
Point extraction means (M3) and reference coordinate points (N₁~ N₃Angle formed by the line segment connecting ()
Angle calculation means (M4) for calculating₁~ N₃) Distance (L₁₃) Is calculated
Distance calculation means (M6), the angle (θ) and the distance (L₁₃) Based on
Reference coordinate point (N₁~ N ₃Road shape depending on the arrangement of
Road shape determination means (M5) for determining
A road shape determination device characterized by: 3. A temporary vehicle position is set on a road ahead of the vehicle position by a predetermined distance, and the reference coordinate points (N _{1 to} N ₄ ; N _{1 to} N ₃ ) are set based on the temporary vehicle position. The road shape determination device according to claim 1 or 2, wherein 4. The road shape determination device according to claim 1, further comprising display means (M7) for displaying the determined road shape to an occupant.