JPH05216407A - Current position correction device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a current position correction device capable of correcting the position of the own vehicle in a short time even while traveling, even in a vehicle having no absolute position detection means. [Structure] Map information storage means 12 for storing map information data and display means 11 for displaying map information data
And a geomagnetic sensor 13 for measuring changes in geomagnetism, and a wheel speed sensor 14 for measuring the traveling distance and rotation angle of the vehicle. Further, an application range designating means 2 for designating a map matching application range, an application range enlarging means 3 for enlarging the map matching application range, and a vehicle on a road within the map matching application range set based on the map information data. Existence probability calculation means 4 for calculating the probability of existence, coefficient calculation means 5 for calculating the existence probability coefficient based on the calculation result, calculation result of the coefficient calculation means 5 and each sensor 1.
The control means 1 for correcting the position based on the measured values of 3 and 14 is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current position correcting device, and more particularly to a current position correcting device in a vehicle navigation system.

[0002]

2. Description of the Related Art In recent years, a GPS device for measuring the current position of a vehicle by radio waves from an artificial satellite and a current position measuring system having a wheel speed sensor and a geomagnetic sensor as positioning sensors have come to be mounted on a vehicle. It was This is the current position of the vehicle obtained by each measuring means, CD-
It is a system that displays the map information stored in a ROM or the like on a display means and further notifies the user of the route to the destination.

However, the current position data of the own vehicle obtained by each measuring means has an error, and when the traveling distance becomes long, the actual position and the display position may deviate greatly due to the accumulated error. .. It is necessary to correct the position to prevent this.

As a method of correcting the current position, there are (1) a manual method and (2) a system automatically. The former (1) method is a method of operating the 8-direction switch or the touch panel switch prepared on the panel of the system as shown in FIG. 9 to correct the current position on the display, and the latter (2) method. As shown in FIG. 10, the position is corrected by using an absolute position detecting means such as GPS or a beacon, or as shown in FIG. 11, the output from the geomagnetic sensor, the wheel speed sensor or the like is output by a software technique called map matching. This is a method of correcting the present position by calculation by comparing the obtained estimated traveling locus with the road shape on the map data.

[0005]

However, in the above-mentioned conventional example, in the case of the manual method, since the amount of map data is large, it is necessary to display the necessary map data or to perform strict current position setting. Since it takes time and the number of operations increases, there is an inconvenience that the vehicle must be stopped once.

Further, even in a system that performs map mapping, if the map is deviated beyond the limit of sensor performance or software algorithm, that is, the range where map mapping is applicable, global map mapping called secondary correlation is performed. Even if the method is used, there is a problem that the correction is difficult.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the prior art, and especially for a vehicle having no absolute position detecting means, the user's burden is small and the position of the vehicle can be corrected in a short time even while traveling. It is to provide a current position correction device capable of performing the following.

[0008]

Therefore, in the present invention, a map information storage means for storing map information data, a display means for displaying the map information data stored in the map information storage means, and a geomagnetic field. Geomagnetic sensor that measures changes, wheel speed sensor that measures the mileage and rotation angle of the vehicle, map matching application range specifying means that specifies the map matching application range, and map matching application range that expands the map matching application range On the road within the map matching applicable range set by the map matching applicable range designating means or the map matching applicable range expanding means based on the map information data stored in the map information storing means. Existence probability calculation means for calculating the probability that the vehicle exists and calculation of the existence probability calculation means An existence probability coefficient calculating means for calculating an existence probability coefficient based on the result, and a control means for correcting the position based on the calculation result of the existence probability coefficient calculating means and the measured values of the geomagnetic sensor and the wheel speed sensor and displaying the result on the display means. It has a configuration that includes. This aims to achieve the above-mentioned object.

[0009]

The existence probability calculating means obtains the existence probability of the own vehicle on each road within the preset range, that is, within the map matching application range, based on the map information data of the map information storing means. Further, the existence probability coefficient calculation means obtains the existence probability coefficient of the own vehicle on the road based on the existence probability. If there is a road whose existence probability coefficient is greater than or equal to a preset value, the control means recognizes that the own vehicle is present on the road with the highest existence probability coefficient, corrects the position if necessary, and displays it. Display on the means.
However, if there is no road whose existence probability coefficient is greater than or equal to a preset value, the map matching applicable range expansion means expands the map matching applicable range. Even if the map matching applicable range is expanded, the control means determines that the map matching applicable range needs to be moved and notifies the user if there is no road whose existence probability coefficient is equal to or more than a preset value. The user moves the map matching applicable range by the map matching applicable range specifying means. After setting the movement of the map matching applicable range, the existence probability coefficient calculating means obtains the existence probability coefficient for each road within the map matching applicable range. If there is a road whose existence probability coefficient is equal to or more than a preset value, the control means recognizes that the own vehicle exists on the road with the highest existence probability coefficient, corrects the position if necessary, and displays it. Display on the means.
However, if there is no road whose existence probability coefficient is greater than or equal to a preset value, the map matching applicable range expansion means expands the map matching applicable range, and the existence probability coefficient calculation means targets the roads within that range. Ask for. Then, if there is a road whose existence probability coefficient is equal to or greater than a preset value, the control means recognizes that the own vehicle exists on the road with the highest existence probability coefficient, and corrects the position if necessary. Although it is displayed on the display means, if there is no road whose existence probability coefficient is equal to or greater than the preset value even if the map matching application range is expanded, the position calculated based on the measurement data from the geomagnetic sensor and the wheel speed sensor is displayed. The current position is displayed on the display means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the embodiment of FIG. 1, the map information storage means 12 for storing map information data and the map information storage means 12 are shown.
Display means 1 for displaying map information data stored in
1, and a geomagnetic sensor 13 that measures changes in geomagnetism,
Wheel speed sensor 14 that measures the distance traveled and the rotation angle of the vehicle
It has and. Further, map matching applicable range specifying means 2 for specifying the map matching applicable range, map matching applicable range expanding means 3 for expanding the map matching applicable range, and map matching applicable range specification based on the map information data of the map information storing means 12. Existence probability calculation means 4 for calculating the probability that the vehicle exists within the map matching applicable range set by the means 2 or within the map matching applicable range expanded by the map matching applicable range expanding means 3. The existence probability coefficient calculation means 5 for calculating the existence probability coefficient based on the calculation result of the existence probability calculation means 4, the position based on the calculation result of the existence probability coefficient calculation means 5, and the measured values of the geomagnetic sensor 13 and the wheel speed sensor 14. The control means 1 is provided for making a correction and displaying it on the display means 11.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

.. The existence probability calculation unit 4 uses the following formula for each road within a range preset based on the map information data of the map information storage unit 12, that is, within the map matching application range, and the existence probability Fn of the own vehicle on the road is calculated. Ask for.

When -90≤θ≤90

Fn = 1− | sin θ | (1)

When −90> θ ≧ −180 or 90 <θ ≦ 180

Fn = 0 (2)

Here, θ is an azimuth on the assumption that the vehicle has moved to the road from the position of the own vehicle a unit time ago.

.. The existence probability coefficient calculation means 5 uses the existence probability data of the past m times to obtain the existence probability coefficient K on the road by using the following equation for each road within the map matching applicable range.

[0020]

[Equation 1]

For example, as shown in FIG. 3, the road L0 is branched into a road L1 and a road L2 at a point a, and the road L0 and the road L1 are divided.
Is θ = 0 and road L0 and road L2 are 0 at point a.
<Θ <90, 0 at point b <θ <90, θ at point c =
It is assumed to be 90. Then, the existence probability that the vehicle traveling on the road L0 exists on the road L1 is 1 from the equation (1).
However, the existence probability on the road L2 is smaller than 1 from the equation (1). Therefore, as shown in FIG. 4, the existence probability coefficient K is constant for the road L1 regardless of the traveling distance, but gradually decreases for the road L2.

.. If there is a road whose existence probability coefficient calculated by the existence probability coefficient calculation means 5 is KL or more, the control means 1 recognizes that the own vehicle exists on the road with the highest existence probability coefficient, If necessary, the position is corrected and the display means 1 is displayed.
Display in 1.

.. If there is no road whose existence probability coefficient calculated by the existence probability coefficient calculating means 5 is KL or more, the control means 1 instructs the map matching applicable range expanding means 3 to expand the map matching applicable range. Then, the above processes 1 to 3 are performed in the expanded map matching application range.

[0024]. Even if the map matching applicable range is widened, the control means 1 determines that the map matching applicable range needs to be moved if there is no road having an existence probability coefficient of KL or more and notifies the user (S1 in FIG. 2). ..

[0025]. The user moves the map matching applicable range using the map matching applicable range specifying means 2 (S2 in FIG. 2). Here, in the case where a touch switch is provided on the display of the display means 11 as shown in FIGS. 5 to 6, for example, after pressing the "correction" switch, the position near the vehicle position correction desired position on the display is displayed. By touching, the map matching application range can be moved within the same screen on a map up to a fixed scale. When the touch switch is not provided, the map matching application range displayed on the display is moved by an 8-direction switch or the like by pressing the "correction" switch as shown in FIG.

.. After setting the movement of the map matching application range, the control means 1 once moves the vehicle position to the center of the destination map matching application range (S2 in FIG. 2). Further, the existence probability coefficient calculation means 5 obtains the existence probability coefficient for each road within the map matching application range, as in the normal map matching described above (S3 in FIG. 2). Furthermore, the control means 1 determines that there is a road whose existence probability coefficient calculated by the existence probability coefficient calculation means 5 is KL or more (S in FIG. 2).
4), recognizing that the own vehicle exists on the road having the highest existence probability coefficient, corrects the position if necessary, and displays it on the display means 11 (S5 in FIG. 2).

[0027]. If there is no road whose existence probability coefficient calculated by the existence probability coefficient calculation means 5 is KL or more (S4 in FIG. 2), the control means 1 instructs the map matching application range expansion means 3 to expand the map matching application range. To do. Then, in the expanded map matching application range,
Existence probability coefficient calculation means 5 for roads within the range
Calculates the existence probability coefficient (S6 in FIG. 2).

Then, if there is a road whose existence probability coefficient calculated by the existence probability coefficient calculation means 5 is KL or more (S7 in FIG. 2), the control means 1 places it on the road with the highest existence probability coefficient. It recognizes that the own vehicle exists, corrects the position if necessary, and displays it on the display means 11 (S5 in FIG. 2).

.. If there is no road whose existence probability coefficient is KL or more even if the map matching application range is expanded (S7 in FIG. 2), the control means 1 measures data from the geomagnetic sensor 13 and the wheel speed sensor 14 as shown in FIG. The coordinate Pn (Xn, Yn) is calculated by the following equation based on
S8).

Xn = Xn-1 + Δdn-1 · cos θn-1 (4)

Yn = Yn-1 + Δdn-1 · sin θn-1 (5)

Here, (Xn-1, Yn-1) is the coordinate of the vehicle position Pn-1 before the unit time, Δdn-1 is the distance the vehicle has traveled from Pn-1 in the unit time, and θn-1 is the vehicle. Is the azimuth advanced from Pn-1 in a unit time. Then, the calculated coordinates are displayed on the display means 11 as the current position coordinates.

[0033]

Since the present invention is constructed and functions as described above, according to this, it is possible to manually move the map matching application range, and therefore, even in a vehicle having no absolute position detecting means, The burden on the user is small,
It is possible to provide an unprecedented excellent current position correction device that can correct the position of the vehicle in a short time even while traveling.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flow chart for explaining the operation of the embodiment of FIG.

3 to 4 are explanatory views for explaining existence probability coefficients in the present invention.

5 to 7 are explanatory diagrams for explaining movement of a map matching application range in the present invention.

FIG. 8 is an explanatory diagram for explaining a method of calculating position coordinates in the present invention.

9 to 11 are explanatory views for explaining a position correction method in a conventional example.

[Explanation of symbols]

 1: Control means 2: Map matching applicable range specifying means 3: Map matching applicable range expanding means 4: Existence probability calculating means 5: Existence probability coefficient calculating means 11: Displaying means 12: Map information storing means 13: Geomagnetic sensor 14: Wheels Speed sensor

Claims (1)

[Claims] 1. A map information storage means for storing map information data, a display means for displaying the map information data stored in the map information storage means, a geomagnetic sensor for measuring a change in geomagnetism, and a vehicle. In a current position correction device having a wheel speed sensor that measures the traveling distance and the rotation angle of the vehicle, a map matching applicable range specifying means for specifying a map matching applicable range, and a map matching applicable range expanding means for expanding the map matching applicable range. On a road within the map matching applicable range set by the map matching applicable range specifying means based on the map information data of the map information storing means or within the map matching applicable range expanded by the map matching applicable range expanding means The existence probability calculating means for calculating the probability that the own vehicle exists in the Presence probability coefficient calculating means for calculating the existence probability coefficient based on the calculation result of the calculating means, position correction is performed based on the calculation result of the existence probability coefficient calculating means and the measured values of the geomagnetic sensor and the wheel speed sensor, A current position correction device, characterized in that a control means for displaying on a display means is additionally provided.