JP3412273B2 - Vehicle navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention calculates a current position of a vehicle on the basis of detection of a traveling distance and a traveling direction of the vehicle, and displays the position of the vehicle together with a road map. Regarding

[0002]

2. Description of the Related Art In recent years, for example, a vehicle navigation device has been provided in which a traveling position of a vehicle is displayed on a display by superimposing it on a road map. This one calculates the current position of the vehicle from, for example, the departure point information input by the driver and the traveling distance and traveling direction of the vehicle obtained based on the signals from the vehicle speed sensor and the direction sensor mounted on the vehicle. It is like this.
In this case, for example, the signal from the sensor is processed at regular intervals, and the display is updated each time the vehicle travels a predetermined distance.

[0003]

However, in the case where the current position of the vehicle is calculated based on the signals from the vehicle speed sensor and the direction sensor as described above, the actual position of the vehicle is actually affected by the error of the sensor or the error of the road map. There is a circumstance in which a slight deviation occurs between the vehicle position and the calculated vehicle position. Therefore, as the traveling distance of the vehicle increases, the error accumulates and the deviation from the actual vehicle position increases,
For example, there is a defect that the calculated vehicle position is separated from the road on the road map.

In order to deal with such a drawback, it is also considered to perform so-called map matching for correcting the calculated vehicle position so as to ride on the road. As a conventional map matching method, a test point is set at a key point on the road, and when the vehicle position is within a predetermined range from the test point, the test point is set as the vehicle position. There was something. However, with such a conventional map matching method, the accuracy of position correction cannot be said to be sufficient, and the reliability is poor.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a candidate position having a high vehicle existence probability on the road when the calculated position of the vehicle deviates from the road. A vehicle navigation device is provided.

[0006]

According to a first aspect of the present invention, there is provided a vehicular navigation device, a traveling distance detecting means for detecting a traveling distance of a vehicle, a direction detecting means for detecting a traveling direction of the vehicle, and road map information. Road map information storage means for storing, and position calculation means for calculating the current position of the vehicle based on the detection of the traveling distance detection means and the direction detection means,
Display means for displaying the vehicle position calculated by the position calculating means together with the road map, wherein the position of the vehicle calculated by the position calculating means has deviated from the road in the road map. And a determination means for determining whether or not the vehicle position is on the road when the determination means detects the departure of the vehicle position from the road, with the current position of the vehicle as the center and the traveling direction of the vehicle at the time of departure as the main axis and orthogonal thereto. An existence range of an elliptical shape whose direction is a slave axis is set , and a main axis length A and a slave axis length of the existence range are set.
B is the distance error accuracy in the travel distance detection means,
Orientation error accuracy in the azimuth detection means and from the time of departure
The main axis direction and the sub axis direction of the vehicle up to the current vehicle position
Presence range setting means that is set based on the moving distance of
The present invention is characterized in that it comprises a candidate position determining means for determining the existence candidate position of the vehicle on the road based on the existence range set by the existence range setting means.

[0007] In this case, before Symbol said spindle length A and minor axis length B of the existence range of the elliptical shape, it is possible not to exceed the respective predetermined maximum value (the invention of claim 2).

On the other hand, the candidate position determining means regards the existence probability distribution of vehicles in the existence range as a normal distribution in both the main axis direction and the sub axis direction centering on the current position of the vehicle, It is effective to configure the existence candidate position at the position having the highest existence probability (the invention of claim 3 ).

At this time, the candidate position determining means sets a road defining line defining a road included in the existence range of the elliptical shape in order to set the existence candidate position at a position having the highest existence probability on the road. , The position closest to the center of the road regulation line is obtained as a temporary candidate position in a state of being enlarged by (main shaft length A / slave shaft length B) times in the slave axis direction around the current position of the vehicle. Later, the road regulation line in the expanded state,
A position corresponding to the tentative candidate position when the size is reduced in the slave axis direction by (slave shaft length B / spindle length A) may be set as an existence candidate position (the invention of claim 4 ) ). Further, among the positions where the road defining line that defines the road is in contact with the outer periphery of a similar ellipse whose center and axial direction coincide with the existence range of the ellipse, the position that is in contact with the outer periphery of the smallest ellipse is the candidate position. The present invention can also be configured as follows (invention of claim 5 ).

[0010]

When the present position of the vehicle is calculated by the position calculating means based on the traveling distance of the vehicle detected by the traveling distance detecting means and the traveling direction of the vehicle detected by the azimuth detecting means, The calculated position of the vehicle includes an error with respect to the actual position of the vehicle due to the distance error in the traveling distance detecting means and the heading error in the heading detecting means. Therefore, due to these distance error and heading error, even if the vehicle is actually traveling on a predetermined road, the calculated vehicle position gradually deviates from the actual position, and May leave.

Here, the displacement in the traveling direction of the vehicle is caused mainly by a distance error in the traveling distance detecting means,
The positional deviation in the lateral direction orthogonal to that is mainly caused by the azimuth error in the azimuth detecting means, but as a distance range in which the positional deviation occurs, the traveling direction of the vehicle is generally larger than the lateral direction. growing. Therefore,
The actual position of the vehicle exists within the range of an ellipse with the calculated vehicle position as the center, the traveling direction of the vehicle as the major axis, and the direction orthogonal thereto as the minor axis. Further, depending on the accuracy of the detecting means, the major axis and the minor axis may be opposite to that, but in any case, it exists within the range of the ellipse.

According to the vehicle navigation device of the first aspect of the present invention, when the judging means judges that the position of the vehicle calculated by the position calculating means has deviated from the road on the road map, the existence range setting means. Thus, the existence range of an ellipse centered on the current position of the vehicle and having the traveling direction of the vehicle at the time of departure as the main axis and the direction orthogonal to the main axis as the slave axis is set. Then, the candidate position determining means obtains the existence candidate position on the road of the vehicle based on the existence range of the elliptical shape. However, as described above, the actual vehicle exists within the existence range of the ellipse. ,
The existence candidate position can be accurately determined.

In this case, the calculated displacement of the vehicle
The range of deviation is the distance traveled by the vehicle and the direction of travel.
It depends not only on the accuracy of the output, but also on the moving distance of the vehicle.
It will also change depending on the separation. Therefore, the traveling distance
Distance error accuracy in the distance detecting means, and the azimuth detecting means
Azimuth error accuracy at the time of departure from the current vehicle position
On the basis of the travel distance of the vehicle in the main axis direction and the sub axis direction.
Based on the above, the main axis length A and the slave axis length B within the existing range are set.
Existence more accurately by configuring to set
Candidate positions can be determined. Therefore, according to the vehicle navigation device of the first aspect of the present invention, when the calculated vehicle position departs from the road, it is possible to obtain a candidate position having a high vehicle existence probability on the road.
As a result, so-called map matching for correcting the calculated vehicle position so as to ride on the road can be performed with sufficiently high accuracy, which is an excellent practical effect.

[0014] Also, the major axis length A and minor axis length B of the existence range of the elliptical shape, if so as not to exceed the respective predetermined maximum value (vehicle navigation apparatus according to claim 2), unnecessarily It is possible to prevent the existing range from being expanded.

On the other hand, since the traveling distance and the traveling direction, which are respectively detected by the traveling distance detecting means and the azimuth detecting means, are the values at the center of the range in which the error occurs, the candidate positions are set within the existing range of the elliptical shape. When determining, it can be said that the center position (current position of the vehicle) has the highest existence probability, and the probability decreases as the position approaches the outer circumference of the ellipse. Therefore, the existence position is set by regarding the candidate position determining means as the normal distribution of the existence probability of the vehicle within the existence range with respect to both the main axis direction and the slave axis direction centering on the current position of the vehicle. With this configuration (the vehicle navigation device according to claim 3 ), the candidate position having the highest vehicle existence probability on the road can be obtained.

At this time, assuming that the existing range is circular, the position closest to the center is considered to be the position having the highest vehicle existence probability. And to convert the ellipse to a circle,
The ellipse may be enlarged in the minor axis direction by (major axis length / minor axis length) times, and in order to convert the converted circle into the original ellipse, the circle is also converted into the minor axis direction ( Short axis length / long axis length) may be reduced. Therefore, in order to set a candidate position having the highest vehicle existence probability on the road, a road defining line that defines a road included in the existence range of the elliptical shape is set in the slave axis direction with the current position of the vehicle as the center. After the main axis length A / slave axis length B) is enlarged, a position closest to the center of the road defining line is obtained as a temporary candidate position, and the enlarged road defining line is set to the slave axis. If the position corresponding to the temporary candidate position when the size is reduced in the direction (slave axis length B / spindle length A) times is the existence candidate position (claim 4
Vehicle navigation device), with a relatively simple method,
It is possible to obtain a candidate position having the highest vehicle existence probability on the road.

If the existence probability distribution of vehicles in the existence range of the elliptical shape is a normal distribution in both the main axis direction and the slave axis direction, a similar ellipse whose center and axial direction coincide with the existence range is formed. The vehicle existence probabilities are the same along the outer peripheral line, and the smaller the ellipse, the greater the vehicle existence probability. Therefore, among the positions where the road defining line that defines the road is in contact with the outer periphery of a similar ellipse whose center and axial direction coincide with the existing range of the ellipse, the position that is in contact with the outer periphery of the smallest ellipse is the candidate position. With this configuration (the vehicle navigation device according to claim 5 ), the candidate position having the highest vehicle existence probability on the road can be obtained by a relatively simple method.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention (corresponding to claims 1 to 4 ) will be described below with reference to FIGS. First, FIG. 4 shows a schematic configuration of a vehicular navigation device according to the present embodiment. Here, the vehicular navigation device includes a vehicle speed sensor 1 functioning as a travel distance detecting means, and a direction sensor 2 as a direction detecting means. , A road map information storage means, a map memory 3, a control switch 4, a display means, a CRT display 5, a microcomputer 6, and the like.

Of these, the vehicle speed sensor 1 has a structure for detecting the traveling speed of the vehicle based on the rotation of the wheels, for example, and the speed detected by the vehicle speed sensor 1 is integrated by the microcomputer 6, The mileage of the vehicle is required. Therefore, the vehicle speed sensor 1 functions as the traveling distance detecting means according to the present invention. The direction sensor 2 is for detecting the traveling direction of the vehicle, and may be a well-known sensor such as a geomagnetic sensor, a vibration gyro, an optical fiber gyro, a gas rate gyro, or a steering angle sensor.

The map memory 3 is constructed by combining a large-capacity storage medium such as a CD-ROM and a drive device therefor, and the map memory 3 includes, for example, a prefecture unit or a Tokai region. The road map information corresponding to the road map in a predetermined range is stored. The road map information includes road shape, road width, road name, building, place name,
It is configured to include data for reproducing a road map including terrain and the like. Further, in this case, the information on the road shape is represented by the data of the road defining line that defines the road shape, and the road defining line is obtained by approximating the road shape by a set of straight lines (segments). It is supposed to be.

The control switch 4 is composed of various switches for the driver to input departure point information and to select a road map displayed on the CRT display 5. The microcomputer 6
Includes a CPU 7, a ROM 8, a RAM 9, an input / output circuit 10 and a bus line 11 for connecting them to each other, and the microcomputer 6 has a vehicle speed sensor 1, a direction sensor 2, a map memory 3 and a control unit. The switch 4 is connected.

This microcomputer 6 has the RO
Control program stored in M8 and the input / output circuit 1
The display content of the CRT display 5 is determined based on the signals from the vehicle speed sensor 1, the azimuth sensor 2, the map memory 3 and the control switch 4 input via 0, and the CRT display is determined via the CRT controller 12. The display control of No. 5 is performed.

At this time, the microcomputer 6 functions as the position calculating means according to the present invention, and the traveling distance of the vehicle obtained by processing the signal from the vehicle speed sensor 1 and the vehicle distance obtained by the direction sensor 2 are obtained. From the direction of travel,
The current position (calculated position) of the vehicle is calculated. Then, the road map is displayed on the CRT display 5, and the calculated vehicle position is displayed as an arrow pointer pointing in the traveling direction, for example, in superimposition on the display. The signal processing of the sensors 1 and 2 at this time is performed every predetermined time (for example, 1 second), and the display of the vehicle position is updated every time the vehicle travels for a predetermined distance (for example, 10 m). There is.

When the current position of the vehicle is calculated based on the signals from the vehicle speed sensor 1 and the direction sensor 2 as described above, the calculated vehicle position is a distance error due to the accuracy of the vehicle speed sensor 1 and the direction sensor. Due to the azimuth error due to the accuracy of 2 and the like, an error is included in the actual vehicle position, and there is a situation in which a slight deviation occurs from the actual vehicle position. Therefore, when the deviations due to the error are accumulated, the calculated vehicle position may be separated from the road on the road map. Therefore, as will be described in detail later in the description of the operation, the microcomputer 6 is
When the vehicle position deviates from the road, the vehicle position is corrected so as to be placed on the road, and the vehicle position is restored to the road.

At this time, in the present embodiment, the microcomputer 6 judges whether the calculated vehicle position has deviated from the road on the road map by its software configuration, and when it departs, the vehicle is Set the elliptical existence range centered on the present position of the vehicle and using the traveling direction of the vehicle immediately after departure as the main axis and the direction orthogonal to it as the slave axis, and based on the set existence range on the road of the vehicle. Is configured to determine the existence candidate position of. Therefore, the microcomputer 6 functions as a judging means, an existing range setting means, and a candidate position determining means in the present invention, in addition to the position calculating means.

Further, in the present embodiment, in setting the existence range, the main axis length A and the sub axis length B are set to the distance error accuracy in the vehicle speed sensor 1 and the azimuth error accuracy in the azimuth sensor 2. Is set based on the moving distances of the vehicle in the main axis direction and the sub axis direction from the time of departure to the current vehicle position. It should be noted that the main axis length A and the slave axis length B have maximum values (for example, both are 2
00m) is provided and it is designed not to exceed it.

Furthermore, in the present embodiment, when determining the existence candidate position, the existence probability distribution of the vehicles within the existence range is a normal distribution with respect to both the main axis direction and the slave axis direction centering on the current position of the vehicle. Assuming that there exists, the existence candidate position is determined at the position having the highest existence probability on the road. Specifically, as will be described later, the road regulation line included in the existing range is enlarged by (A / B) times in the slave axis direction around the current position of the vehicle as the center of the road regulation line. After determining a position closest to the temporary candidate position as a temporary candidate position, a position corresponding to the temporary candidate position when the enlarged road defining line is reduced by (B / A) times in the slave axis direction is the existence candidate position. It is what you ask for.

Next, the operation of the above structure will be described with reference to FIGS. First, FIG. 3 schematically shows a state when a departure occurs, and when the vehicle is traveling on the road L to the right in the figure, the position of the vehicle (calculated position) is The vehicle moves as shown by the arrow, and the vehicle departs from the road at the position Pr, and the deviation gradually accumulates to reach the current position Pf. Here, the positional deviation in the traveling direction of the vehicle is mainly caused by the distance error caused by the vehicle speed sensor 1, and the lateral positional deviation orthogonal thereto is caused mainly by the azimuth error caused by the azimuth sensor 2.

As will be described later, the actual vehicle existence range VEPR at the current position Pf is centered on the current position Pf.
At the same time, the traveling direction X ′ of the vehicle at the time of departure is set to be the main axis direction, and the direction Y ′ orthogonal to it is set to be the elliptical shape. In this case, the X'direction is
It is inclined by an angle θ with respect to the horizontal axis direction on the map (for example, the east-west direction). The existing range exists even when the vehicle is on the road L, and has a main axis length corresponding to the moving distance from the starting point to the start point and a slave axis length corresponding to the road width (the number of lanes). It is set to a flat elliptical shape.

The flowchart of FIG. 1 shows the procedure for determining the existence candidate position, which is executed when the microcomputer 6 detects the departure. Further, FIG. 2 is a diagram for explaining a processing method in that case. First, step S
In 1, a main axis (major axis) and a slave axis (minor axis) for setting the elliptical existence range VEPR are set on a plane including the vehicle existence range. In this case, as described above, the current position Pf is the center O, the main axis direction is the traveling direction X'of the vehicle at the time of departure, and the slave axis direction is the direction Y'which is orthogonal to it. In FIG. 2, for convenience of explanation,
With the center O (current position Pf) as the origin, the main axis direction X ′ and the sub axis direction Y ′ are respectively in the horizontal axis (X axis) direction and the vertical axis (Y
The XY plane is aligned with the (axis) direction (which means that the map is rotated and converted by the angle (−θ) around the current position Pf).

In the next step S2, the vehicle existence range VE
The PR main axis length A and the secondary axis length B are the existence range at the time of departure, the distance error accuracy (distance error coefficient) of the travel distance detection by the vehicle speed sensor 1, and the azimuth error accuracy (azimuth) in the azimuth sensor 2. It is set based on the error coefficient) and the moving distance in the X ′ direction and the moving distance in the Y ′ direction of the vehicle from the time of departure (Pr) to the current vehicle position (Pf). Specifically, the amount of expansion in the X'direction with respect to the existing range at the time of departure is
Multiply the distance moved in the X'direction by the distance error coefficient, and Y '
It is obtained by adding the directional movement distance multiplied by the azimuth error coefficient, and the expansion amount in the Y ′ direction is obtained by multiplying the Y ′ direction movement distance by the distance error coefficient and the X ′ direction movement distance by the azimuth error coefficient. It can be obtained by adding the product of.
However, the length A and the length B of the main shaft do not exceed the maximum values. As a result, the positive vertex of the X ′ axis is a (a = A / 2), and the positive vertex of the Y ′ axis is b (b = B / 2).

In this way, the main shaft length A and the slave shaft length B
When is set, the existence range VEPR of the elliptical shape is set as shown in FIG. The actual position of the vehicle lies within the existence range VEPR of the ellipse, and the probability of existence of the vehicle is that the center position O (current position Pf of the vehicle) has the highest existence probability and the outer periphery of the ellipse. The probability becomes lower toward the side, in other words, the probability distribution can be regarded as a normal distribution with respect to both the main axis direction and the slave axis direction with the current position Pf of the vehicle as the distribution center.

In step S3, the existing range VEPR
The road regulation line Lr of the road L included in is determined. In FIG. 2, one linear road regulation line Lr is present range VE
The case of being included in PR is illustrated. in this case,
It is conceivable that a plurality of road regulation lines may be included or that a polygonal road regulation line may be included. Existence range VEPR
It is possible that there is no road regulation line inside,
In this case, processing is performed as if the vehicle has entered a newly established road that does not exist on the map or has entered a facility such as a parking lot.

In the next steps S4 to S7, the existence range V
The position having the highest vehicle existence probability on the road L included in the EPR is obtained as the existence candidate position. As a method therefor, in this embodiment, the road defining line Lr included in the existence range VEPR is After the position closest to the center is obtained as a temporary candidate position in the state of being enlarged A / B times in the slave axis direction, the road regulation line in the enlarged state is set to B / A in the slave axis direction.
The position corresponding to the temporary candidate position when the size is reduced by a factor of 2 is set as the existence candidate position. This is because assuming that the existence range is circular, the vehicle existence probability is higher as the position is closer to the center, and thus the position closest to the center of the circle is converted in a conversion state such that the existence range VEPR is a circle with a radius a. Seeking,
This is a conversion to restore the original ellipse again.

That is, first, in step S4, the main axis segment m and the minor axis segment k of the road defining line Lr are obtained, and in step S5, the straight line Ll with the major axis segment m and the minor axis segment ak / b is obtained. . The straight line Ll is equal to the road defining line Lr enlarged A / B times (= a / b times) in the slave axis direction. In step S6, a perpendicular is drawn from the center O toward the straight line Ll, and the intersection is set as the temporary candidate position C. Finally, in step S7, a perpendicular is drawn from the point C toward the main axis, and the intersection of the perpendicular and the road regulation line Lr is obtained as the candidate position D.

When the candidate position D on the road regulation line Lr is obtained as described above, the current position Pf of the vehicle is corrected to the candidate position D and the vehicle is returned to the road L. And CRT
The display 5 displays the restored current position D, and the current position D is used as a new starting point for calculating the vehicle position and the existing range thereafter.

According to the present embodiment as described above, when the current position Pf of the vehicle departs from the road L, the candidate position D on the road L having a high vehicle existence probability can be obtained, and thus calculated. The so-called map matching for correcting the vehicle position so as to get on the road L can be performed with sufficiently high accuracy. Further, particularly in the present embodiment, on the road L, it is assumed that the vehicle existence probability distribution within the elliptical existence range VEPR is a normal distribution with respect to both the main axis direction and the slave axis direction centered on the current position Pf of the vehicle. It is also possible to obtain the advantage that the candidate position D having the highest vehicle existence probability in 1 can be obtained by a relatively simple method.

FIG. 5 shows another embodiment (corresponding to claim 5 ) of the present invention. In this embodiment, the method of obtaining the candidate position D in the elliptical existence range VEPR is different from that in the above-described embodiment.
Among the positions where the road defining line Lr that defines the road L is in contact with the outer periphery of a similar ellipse whose center and axial direction coincide with the EPR, the position that is in contact with the outer periphery of the smallest ellipse H is set as the existence candidate position D. I am doing it.

Here, if the vehicle existence probability distribution in the elliptical existence range VEPR is a normal distribution in both the main axis direction and the slave axis direction, a similar distribution in which the center and the axial direction coincide with the existence range is shown. The vehicle existence probabilities are the same along the outer circumference of the ellipse, and the smaller the ellipse, the greater the vehicle existence probability. Therefore, also in this embodiment, the candidate position D having the highest vehicle existence probability on the road L can be obtained by a relatively simple method.

In the above embodiment, the obtained candidate position D is corrected as it is as the current position of the vehicle, but the candidate position D is not unconditionally adopted, but other conditions such as the following It may be possible to determine whether or not to adopt it as the vehicle position in consideration of the pattern of the traveling locus and the like. In addition, the present invention is not limited to the above-described embodiment, and may be implemented with appropriate modifications within a range not departing from the gist, for example, the departure point information may be obtained by a radio wave from an artificial satellite. .

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a flow chart showing a procedure for determining existence candidate positions.

FIG. 2 is a diagram for explaining a procedure for determining existence candidate positions.

FIG. 3 is a diagram schematically showing a state when a detachment occurs.

FIG. 4 is a block diagram showing a schematic configuration of a vehicle navigation device.

FIG. 5 is a view corresponding to FIG. 2 showing another embodiment of the present invention.

[Explanation of symbols]

In the drawings, 1 is a vehicle speed sensor (traveling distance detection means), 2 is a direction sensor (direction detection means), 3 is a map memory (road map information storage means), 4 is a control switch, and 5 is a CR.
A T display (display means), 6 indicates a microcomputer (position calculation means, determination means, existence range setting means, candidate position determination means).

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-278982 (JP, A) JP-A-3-291519 (JP, A) JP-A-6-94469 (JP, A) JP-A-2- 275310 (JP, A) JP 1-140015 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/00-29/10

Claims (5)

(57) [Claims] 1. A traveling distance detecting means for detecting a traveling distance of a vehicle, a direction detecting means for detecting a traveling direction of the vehicle, a road map information storing means for storing road map information, the traveling distance detecting means and the direction. A position calculation means for calculating the current position of the vehicle based on the detection of the detection means, and a display means for displaying the vehicle position calculated by the position calculation means together with the road map, wherein the position calculation means A judgment means for judging whether the position of the vehicle calculated by the above-mentioned method has deviated from the road in the road map, and when the judgment means detects that the vehicle position has deviated from the road, And to set the existence range of the elliptical shape with the traveling direction of the vehicle at the time of departure as the main axis and the direction orthogonal to it as the slave axis ,
The main shaft length A and the slave shaft length B in the existing range are defined as the traveling distance.
Distance error accuracy in the distance detecting means, and the azimuth detecting means
Azimuth error accuracy at the time of departure from the current vehicle position
On the basis of the travel distance of the vehicle in the main axis direction and the sub axis direction.
And a candidate position determining means for determining a candidate existence position on the road of the vehicle based on the existence range set by the existence range setting means. apparatus. 2. The principal axis length A and the range of existence of the elliptical shape
The vehicle navigation device according to claim 1 , wherein each of the slave shaft length B and the slave shaft length B does not exceed a predetermined maximum value . 3. The candidate position determining means includes the existence range.
The vehicle's existence probability distribution within
Normal distribution for both the principal axis direction and the minor axis direction
To the position with the highest probability of existence on the road.
The vehicle navigation device according to claim 1 or 2, wherein the candidate position is set . 4. The candidate position determining means is the elliptical shape.
The road regulation line that regulates the roads included in
Centering on the current position of the vehicle in the secondary axis direction (spindle length
A / slave axis length B) In the enlarged state, the road regulation line
The position closest to the center of was determined as a temporary candidate position.
After that, the expanded road regulation line is
Axial length B / spindle length A) said temporary candidate when reduced
The vehicular navigation device according to claim 3, wherein a position corresponding to the position is configured as an existence candidate position . 5. The candidate position determining means defines a similar ellipse whose center and axial direction coincide with the existence range of the ellipse.
In the position where the road regulation line that regulates the road is in contact with the outer circumference
In claim 3, characterized in that it is configured so as to present the candidate position where to contact the outer circumference of the smallest ellipse
The vehicle navigation device described.