JPH0820257B2 - Vehicle direction detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for detecting a traveling direction of a vehicle by using geomagnetism.

<Prior Art> A device of this type disclosed in Japanese Patent Laid-Open No. 59-100812 is mounted on a vehicle in a posture in which a pair of windings are horizontal, and the windings allow two directions orthogonal to each other in a horizontal plane. When a geomagnetic sensor in which the geomagnetism is decomposed and detected as a component and a vehicle equipped with this geomagnetic sensor are orbited in a uniform geomagnetism, circles on the plane coordinates ( The output circle) is drawn, and the normal direction of the vehicle is composed of an arithmetic unit that determines the direction from the center coordinate position of the output circle to the coordinate position indicated by the geomagnetic components as the traveling direction of the vehicle.

However, when the vehicle body is magnetized while the vehicle is running, the circle moves with respect to its center coordinates, and therefore, when it is not magnetized, or when it is previously magnetized and corrected, the two geomagnetic components are deviated from the center coordinate position. The direction toward the coordinate position indicated by is determined as the traveling direction of the vehicle, and an error occurs in the measurement of the traveling direction.

Therefore, conventionally, the vehicle is orbited while being magnetized, and the coordinate position indicating the magnetized and corrected normal center of the circle is obtained based on a plurality of geomagnetic component pairs detected during the traveling. It was

In addition, a roadside transmitting station (hereinafter referred to as “sign post”) indicating the position and road direction of each point on a road is provided at each predetermined interval point, and when the vehicle passes through the sign post, the road side It is also proposed to draw a straight line and correct the center coordinate position of the output circle at the intersection of a plurality of straight lines.

<Problems to be Solved by the Invention> However, in the former case described above, it is necessary to orbit the vehicle every time the vehicle body is magnetized to obtain the center coordinate position of the output circle, and thus it is possible to travel in the orbit. It is required to search for a place that has a wide area and does not disturb the earth's magnetism and to perform the orbital driving.Therefore, there is a problem that the correction causes a great burden on the driver. It was

Further, in the latter case, there is a problem that the center coordinate position of the output circle cannot be corrected unless the vehicle passes through the plurality of sign posts.

<Object of the Invention> The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to quickly and easily correct the center coordinate position of an output circle moved by a drooping magnetizing magnetic field or the like. An object of the present invention is to provide a vehicle traveling azimuth detecting device.

<< Structure of the Invention >> In order to achieve the above object, the vehicle traveling direction detection apparatus according to the present invention decomposes and detects a geomagnetic component into two components orthogonal to each other in a horizontal plane, and the detected geomagnetic components are In the vehicle traveling direction detection device, which determines the traveling direction of the vehicle based on the direction from the center coordinate position of the output circle that should include the above position to the indicated coordinate position, the direction from the roadside transmitter station installed on a straight road. When the current traveling direction of the vehicle is detected by the roadside transmitting station traveling direction detecting means a for detecting the current traveling direction based on the information and the current traveling direction of the vehicle by the roadside transmitting station traveling direction detecting means a, the traveling direction is set as an inclination. Two points on a straight line passing through the coordinate positions indicated by the current geomagnetic components and on the circumference corresponding to the radius of the output circle centered on the coordinate positions are extracted as the center coordinate candidates of the output circle. When the two center coordinate candidates are extracted by the center coordinate candidate extracting means b and the center coordinate candidate extracting means b, the first center coordinate having the center coordinate candidate closer to the current center coordinate as the new center coordinate. Correction means c
And a distance calculation means d for calculating the distance between the corrected center coordinates and the current coordinate position indicated by both geomagnetic components, after the center coordinates have been corrected by the first center coordinate correction means c and a fixed time has passed. When the distance calculated by the distance calculating means d is larger than the distance corresponding to the radius of the output circle by a predetermined amount or more, the first center among the two center coordinate candidates extracted by the center coordinate candidate extracting means b. Second center coordinate correction means e having the other center coordinate candidate not selected by the coordinate correction means c as the new center coordinates.

<< Operation >> In the present invention, the center coordinate position of the output circle is automatically corrected by teaching the road direction from the sign post.

<< Embodiment >> A preferred embodiment of a vehicle position detecting device according to the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of the present invention. The current traveling position and traveling locus of the vehicle are displayed on a map to guide the traveling.

These displays are performed on the display unit 200 configured by a CRT or the like, and the current traveling position of the vehicle is obtained by the CPU 201. In this CPU 201, the detection signals from the distance sensor 202 and the geomagnetic direction sensor 203 are sent to the sensor interface 2
The current position of the vehicle relative to the reference position is obtained by inputting via 04 and integrating these. The reference position is from the key input unit 205 composed of a keyboard to the CPU 20.
It is possible to give one.

The map data displayed on the display unit 200 is stored in the external storage device 206 such as a compact disc device or a ROM, and the map displayed on the display unit 200 is V
It is designed to be performed via a RAM (VIDEO RAM) 207.

Further, in the processing of the CPU 201, the display control of the display unit 200 is performed using the RAM 209 according to the contents stored in the system ROM 208.

In the figure, 210 is a receiving antenna for receiving a transmission radio wave from a sign post described later, the signal received by this receiving antenna 210 is subjected to processing such as amplification in a receiving circuit 211, and is passed through a receiving interface 212. It is designed to be input to the CPU 201.

The structure of the sign post 300 is shown in FIG.
This sign post 300 is a storage circuit 3 that stores transmission data.
01, an omnidirectional transmission antenna 302 for transmitting a radio wave containing the transmission data, and a transmission circuit 303 for transmitting from the transmission antenna 302.

Further, FIG. 4 shows the transmission contents of the sign post 300, and includes the number of the block area to which the sign post 300 belongs, the X and Y coordinate positions, and the road direction as the contents of the transmitted radio wave. This transmitted radio wave is several hundred KH
It is modulated by z, its reach is less than 10 m, and the sign post is installed on the side of a straight road with straight lines in front and behind.

Before explaining the operation of this embodiment, the output circle of FIG. 5 will be used to help understanding of the present invention.

In the figure, the circle shown by the solid line is the output circle before magnetization,
That is, in the old output circle, its center is indicated by O ₀ . On the other hand, the circle indicated by the dotted line is the corrected output circle whose center is O _n.
Indicated by.

P is the coordinate position (Vx, V
y), and θ indicates the direction of the road R on which the sign post is installed.

Now, suppose that the vehicle is now traveling in a certain direction on the road R and the information on the road direction θ is obtained from the sign post, since the road R is a straight road, the solid line indicated by the road R is the coordinate position P. It can be easily understood that a straight line having an inclination θ passing through and the center of the output circle at the coordinate position P is on this straight line. However, when passing the sign post,
Since the traveling azimuth of the vehicle is reversed depending on which direction the vehicle comes from on the road R, there are two possible directions from the center of the output circle to the coordinate position P. Therefore, the center of the output circle is assumed to be two points on the straight line with the coordinate position P as the center.

That is, taking FIG. 5 (a) as an example, a point O _n (Xa, Ya) having a theoretical radius R of the output circle centered on the coordinate position P and a point
The centers of two points of O _n ′ (Xb, Yb) are assumed. Which of these two points is to be the center of the output circle for correction can be determined based on the old center O ₀ of the output circle. That is,
_Let la be the distance between the old center O ₀ and the new center O _n.
If the distance between O ₀ and the other center O _n ′ is lb, this distance l
By comparing a and lb, the shorter one is the new center. Output circles satisfying this relationship are shown in FIGS. 5 (a) and 5 (b). Further, as a limit of this relation, when the coordinate position P overlaps the old center O ₀ , that is, la = lb is theoretically considered, but at this time, la is set as the new center O _n (see FIG. 6C). ).

However, as shown in FIG. 5 (d), if the moved output circle having the true center (circle indicated by the chain line) does not include the old center O ₀ , the distances la and lb are reversed. For this reason, when a new center is found in the above relation, lb is shorter than la, so that O _n ′ is erroneously set as the center.

In this way, the center value is reset based on the radius R of the output circle in order not to select a point opposite to the true center point, that is, a point different by 180 °. The setting method will be further described based on FIG. 5 (e). The present value selected by moving the vehicle after the shorter center O'n of the distances la and lb in FIG. 4 is set to the true center value. 2. The distance from the center O'n of the coordinate position P'to the coordinate position P ', that is, the point where the point P has moved due to the movement of the vehicle is, for example, 2.
When it is 5 times or more, the previously selected center O'N is not centered but the previously selected point On is centered (theoretically, although the radius is R or more, the geomagnetic sensor The safety factor is set at 2.5 times, considering the accuracy of.

That is, the true center value of the output circle is finally determined from any of the points obtained at the positions distant by the radial distance of the output circle about the coordinate position in a straight line having the inclination of the road direction.

By the way, according to the knowledge of the present inventors, the correction amount corrected by the signal of the sign post is 90% or more within 10%. Therefore, most of FIGS. 5 (a) and 5 (b) are described above, and there is no practical problem when the la having a shorter distance is set as the new center. However, the present invention also includes the above-mentioned resetting means so that it can be applied to various situations as will be described later.

The operation of this embodiment will be described below with reference to the flowchart.

The flow chart of FIG. 6 is a general flow. First, as an initial process, the flag and the counter are cleared, and the center position of the geomagnetic direction sensor is set (step 600). Next, by operating the key input unit 205, the current traveling position of the vehicle is set (step 602),
A map to which a position serving as a reference for vehicle traveling guidance belongs is displayed, and the reference position is displayed on the map (step 604).

After that, when the interrupt calculation process (step 606), the radio wave reception position interrupt process (step 608) and the interval timer interrupt process (step 610) are performed to permit each interrupt (step 612), The presence or absence of movement is determined (step 614).

In this determination, if the movement of the vehicle is confirmed (YES in step 614), the update process accompanying the movement is performed on the screen (step 616). If the vehicle has not moved (NO in step 614), the update process is not performed.

FIG. 7 shows the integral calculation interrupt process (step 60 in FIG. 6).
6) is shown.

This processing is performed by reading the traveling direction θ of the vehicle by the geomagnetic direction sensor 203 (step 700) and then by the distance sensor 202 each time the vehicle travels a predetermined distance ΔD.
X direction component ΔX and Y direction component ΔY for distance data D
Is required (step 702).

Finally, these components are added to the X-direction integrated distances and the Y-direction integrated distances to update the integrated distances (step 704), and the updating process of step 616 in FIG. 6 is performed.

Next, interruption processing at the time of radio wave reception (step 608 in FIG. 6)
Is made.

This processing is shown in FIG. 8 and starts when the reception antenna 210 mounted on the vehicle starts receiving the transmission radio wave from the sign post 300.

In this process, when reception is first started, the reception data having the content shown in FIG. 4 is read (step 80).
0).

Then, the current position is rewritten with the received current position data, and the output values (Vx, Vy) of the geomagnetic direction sensor 203 and the road direction (θ) where the sign post 300 is installed are stored (steps 802, 804, 806). .

As a result, the coordinate position P (Vx, V described with reference to FIG.
y) and the road direction θ are obtained, the two points (O _n (Xa, Ya), 180 degrees different from each other around the coordinate position P by the output circle radius R theoretically obtained by the geomagnetic intensity are obtained. O
_n '(Xb, Yb)) is obtained in the next step 808.

That is, (Xa, Ya) and (Xb, Yb) are calculated by the following equation.

In step 810, the old centers O ₀ (CX, CY) and O _n (X
a, Ya) and the distance between O ₀ (CX, CY) and O _n ′ (Xb, Yb) la, lb
Is calculated by the following equation.

Then, in step 812, the la obtained in step 810 above is obtained.
And lb are compared to determine which of On and O′n is closer to the old center O ₀ . If la ≧ lb is satisfied in this determination (YES in step 360), the process proceeds to step 314, and (Xa, Yb) is set as a new center (CX, CY) (step 814), and a flag is set (step 816).

On the other hand, when la ≧ lb is not satisfied (NO in step 812)
Proceed to step 818 and set (Xa, Ya) to the new center (CX, C
Y) and set the flag to 0 (step 820 is 0).

When the above-described radio wave reception interrupt process is completed, a timing signal is given to the interval timer interrupt process (step 822) described in detail later, and this process is returned.

FIG. 9 shows the interval timer interrupt process, which is performed using the 1 sec interval timer after the above-described radio wave reception interrupt process, and starts 1 second after the above radio wave reception interrupt process. To be done.

First, in step 900, from the geomagnetic direction sensor 203 (Vx, V
y) is stored, and in the next step 902, the distance between the current center (CX, CY) of the output circle (the point selected as the true center last time) and the coordinate position (Vx, Vy) is theoretically calculated. Output circle radius R of 2.5
It is judged whether it is more than double. That is, in FIG. 5 (e), it is determined whether or not the distance between the coordinate position P'and the old center O'n is larger than 2.5R.

In this judgment, if the distance between the old center O'n and the coordinate position P'is within 2.5 times the output circle radius (NO in step 902), this process is terminated, and if it is 2.5 times or more. If (YES in step 902), the process proceeds to the next step 904. In this step 904, the flag state (steps 816 and 820 in FIG. 8) in the radio wave reception interrupt process is determined, and if the flag is set (YES in step 904).
8 shows step 816 in FIG. 8) sets (Xa, Ya) to the new center (CX, CY) (step 908), while if the flag is not set (step 904 is NO and FIG. 8 is shown in FIG. 8). Step 820 shows) (Xb, Yb) to the new center (CX, C
Y) is set again, and the processing is returned through the interval timer interrupt end processing (step 910).

As described above, according to the present embodiment, based on the road information from the sign post installed on the straight road, two centers are assumed at the output circle radius centering on the coordinate position having the inclination of the direction of the road. Then, output one of the two center points that is closer to the center coordinate position of the old output circle, or the point determined based on the distance from the assumed two center points to the bearing sensor output value. Since it is the center of, the traveling azimuth can be promptly corrected with only the information from one sign post.

<< Effect >> In the present invention, since the center coordinate position of the output circle moved by magnetization or the like can be obtained from the road information from one sign post installed on a straight road, the traveling direction can be corrected quickly.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram, FIG. 2 is a block diagram showing the constitution of the present invention, FIG. 3 is a constitution explanatory view of a sign post, and FIG.
FIG. 6 is a transmission guide diagram of a sign post, FIG. 5 is an explanatory diagram for explaining the operation principle of the present invention, and FIGS. 6 to 9 are flowcharts showing the processing procedure of the CPU. 200 …… Display unit 201 …… CPU 202 …… Vehicle speed sensor 203 …… Geomagnetic direction sensor 205 …… Key input unit 206 …… External storage 208 …… System ROM 209 …… RAM

Claims (1)

[Claims] 1. A geomagnetic component is decomposed and detected in two directions orthogonal to each other in a horizontal plane, and a coordinate position indicated by both detected geomagnetic components is detected in a direction from a center coordinate position of an output circle in which the position is to be included. In a vehicle traveling direction detection device for determining a traveling direction of a vehicle based on a roadside transmitting station traveling direction detecting means for detecting a current traveling direction based on direction information from a roadside transmitting station installed on a straight road, When the current traveling azimuth of the vehicle is detected by the roadside transmitting station traveling azimuth detecting means, on a straight line passing through the coordinate positions indicated by the current two geomagnetic components having the traveling azimuth as an inclination,
A center coordinate candidate extracting unit that extracts two points on the circumference corresponding to the radius of the output circle centered on the coordinate position as center coordinate candidates of the output circle, and two center coordinates by the center coordinate candidate extracting unit. When a candidate is extracted, a first center coordinate correction unit that uses a center coordinate candidate closer to the current center coordinate as a new center coordinate, and the center coordinate is corrected by the first center coordinate correction unit, and the center coordinate is corrected for a predetermined time. After a lapse of time, a distance calculation means for calculating the distance between the corrected center coordinates and the current coordinate position indicated by the two geomagnetic components, and the distance calculated by the distance calculation means is predetermined from the distance corresponding to the radius of the output circle. If larger than the above, the second center coordinate candidate which is not selected by the first center coordinate correcting means out of the two center coordinate candidates extracted by the center coordinate candidate extracting means is set as the new center coordinate. Vehicular running direction detecting apparatus comprising: the center coordinate correcting unit.