JPS63284410A - Traveling azimuth detector for vehicle - Google Patents

Abstract

PURPOSE:To correct the center coordinate position of a coordinate position output circle easily and speedily by calculating the deviation in the center of the coordinate position output circle indicated by earth magnetism components due to magnetization according to road information from a sign post. CONSTITUTION:An earth magnetism component detecting means (a) detects orthogonal earth magnetism components corresponding to a vehicle direction and a traveling azimuth arithmetic means (b) calculates and determines the traveling azimuth of the vehicle according to the direction from the center coordinate position Co of the output circle to the coordinate position indicated by the detected earth magnetism components. The azimuth theta of azimuth information on a road R from the roadside transmitting station (d) of the sign post and coordinates (Vx, Vy) of a point P indicated by the earth magnetism components corresponding to the azimuth theta are extracted and a center value setting means (e) selects one of two points corresponding to the radius of the output circle on the road R which is closer to the coordinate Co from the point P as the center of the output circle corrected for an output circle which deviates in center, thereby calculating the quantity of the center deviation. Therefore, the coordinate position of the center of the output circle is corrected easily and speedily and the corrected output circle due to magnetization, etc., is used to accurately correct the traveling azimuth of the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device that detects the running direction of a vehicle using earth's magnetism.

(Prior art) This type of device disclosed in Japanese Patent Application Laid-Open No. 59-100812 is mounted on a vehicle in a horizontal position with a pair of windings, and these windings provide windings in two directions perpendicular to each other in the horizontal plane. When a geomagnetic sensor detects geomagnetism resolved into its components and a vehicle equipped with this geomagnetic sensor travels around in a uniform geomagnetism, the coordinates indicated by the detected voltages of these windings form a circle ( The output circle is drawn, and during normal driving of the vehicle, the direction from the central coordinate position of the output circle to the coordinate position indicated by both geomagnetic components is determined as the running direction of the vehicle.

However, when the vehicle body is magnetized while the vehicle is running, the circle moves relative to its center coordinates, and as a result, both geomagnetic components shift from the center coordinate position when not magnetized or when the magnetization was previously corrected. The direction toward the coordinate position indicated by is determined as the running direction of the vehicle, and an error occurs in the measurement of the running direction.

Therefore, conventionally, when a vehicle is magnetized, it runs in a circle, and the coordinate position indicating the normal center of the circle, which has been corrected for magnetization, is determined based on a plurality of geomagnetic component pairs detected during that time. Ta.

In addition, roadside transmitting stations (hereinafter referred to as "sign posts") indicate the location and road direction of each point at specified intervals on the road.
It has also been proposed that when a vehicle passes a sign post, a straight line is drawn according to the direction of the road, and the center coordinate position of the output circle is corrected using the intersection points of the multiple straight lines.

(Problem to be Solved by the Invention) However, in the former conventional method, it is necessary to drive the vehicle around each time the vehicle body is magnetized to determine the center coordinate position of the output circle, so it is possible to run the vehicle around the circle. It is necessary to search for a place that has a large area and is free from anything that disturbs the earth's magnetic field when driving in circles, and therefore, there is a problem that the correction causes a large burden on the driver when driving. Ta.

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 a plurality of sign posts.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to quickly and easily correct the center coordinate position of the output circle that has moved due to the sloping of the field. The object of the present invention is to provide a vehicle running direction detecting device that is capable of detecting a running direction of a vehicle.

(Configuration of the Invention) In order to achieve the above object, an apparatus according to the present invention is configured as shown in FIG.

In the geomagnetic component detecting means a shown in the figure, the geomagnetic field is separated into components in two directions perpendicular to each other in a horizontal plane and detected.

Then, the running azimuth calculating means calculates the running azimuth of the vehicle based on the direction from the center coordinate position of the output circle to the coordinate position indicated by the detected geomagnetic components.

Roughly speaking, the driving direction extracting means C extracts information indicating the road direction in which the vehicle is currently traveling from the radio waves transmitted by the roadside transmitting station d.

The center value setting means e sets the coordinate position on a straight line that includes the coordinate positions indicated by both geomagnetic components detected at the time of receiving the transmitted radio wave and has the slope of the road direction indicated by the information extracted from the transmitted radio wave. Either one of the two points determined based on the radius of the output circle as the center is set as the true center value of the output circle.

Then, the output circle center correction means f corrects the center coordinate position of the output circle based on the center value determined by the center value setting means e.

(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.

(Embodiments) Hereinafter, preferred embodiments of the vehicle position detection device according to the present invention will be described based on the drawings.

FIG. 2 shows a block diagram of the present invention, in which the current travel position and travel trajectory of the vehicle are displayed on a map to provide travel guidance.

These displays are performed on a display section 200 composed of a CRT or the like, and the current traveling position of the vehicle is determined by a CPU 201. In this CPU 201, the distance sensor 2
02 and the detection signals from the geomagnetic direction sensor 203 are input via the sensor interface 204, and are integrated and processed to determine the current position of the vehicle relative to the reference position. Note that the reference position can be given to the CPU 201 from a key input unit 205 that includes a keyboard or the like.

Note that the map data displayed on the display unit 200 is stored in an external storage device 20 such as a compact disk device or ROM.
6 and displayed on the display unit 200 via a VRAM (VIDEORAM) 207.

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

In the figure, 210 is a receiving antenna for receiving radio waves transmitted from a sign post, which will be described later.The signal received by this receiving antenna 210 is processed by a receiving circuit 211 such as amplification, and then sent via a receiving interface 212. It is designed to be input to the CPU 201.

FIG. 3 shows the configuration of the sign post 300,
This sign post 300 has a storage circuit 301 that stores transmission data. An omnidirectional transmitting antenna 302 that transmits radio waves containing the transmitted data, and this transmitting antenna 3
It is composed of a transmitting circuit 303 for transmitting from 02.

Fig. 4 roughly shows the contents of the transmission from the sign post 300, and the contents of the transmitted radio wave include the number of the block area to which the sign post 1-300 belongs, the X and Y coordinate position, and the road direction. There is. This transmitted radio wave is
It is modulated with H2 in the hundreds, and its reach is less than 10 meters, and the sign post is installed on the roadside of a straight road that continues in a straight line in front and behind.

Hereinafter, before explaining the operation of this embodiment, the output circle in FIG. 5 will be used for explanation in order to help the understanding of the present invention.

In the figure, the circle indicated by a solid line is the output circle before magnetization, that is, the old output circle, and its center is indicated by Oo. On the other hand, the circle indicated by the dotted line is the correction output circle whose center is On.
is shown.

P is the coordinate position (VX,
Vy), and θ indicates the direction of the road R where the sign post is installed.

Now, if a vehicle is currently traveling on road R in a certain direction and we obtain information about the road direction θ from the sign post, this road R is a straight road, so the solid line indicated by this road R is the coordinate position P. It is easy to understand that the center of the output circle at the coordinate position P lies on this straight line.

However, when passing the sign post, the traveling direction of the vehicle is reversed depending on which direction on the road R it comes from, so there are two possible directions from the center of the output circle toward the coordinate position P. Therefore, the center of the output circle is at the coordinate position P
Two points are assumed to be on a straight line with .

In other words, if we take FIG.
The centers of the two points On-(Xb, Yb) are assumed.

Which of these two points should be set as the center of the output circle for correction can be determined based on the old center Oo of the output circle. In other words, let the distance between the old center Oo and the new center On be la, and the distance between the old center Oo and the other center On''!
When b is this distance 1a, i! ,b compared,
The shorter one is the new center. Output circles that satisfy this relationship are shown in FIGS. 5(a) and 5(b). In addition, as a limit of this relationship, it is theoretically conceivable that when the coordinate position P is connected to the old center O8, that is, ga=, gb, but in this case, la is taken as the new center On (Fig.
reference).

However, as shown in FIG. 5(d), when the output circle (circle indicated by a chain line) with the moved real center no longer includes the old center Oo, the pressure 11. With ea! b is reversed. Therefore, when finding a new center using the above relationship, I
! From a! Since b is shorter, On- is mistakenly centered.

In this way, in order to avoid selecting a point opposite to the point that should be the true center, that is, a point that differs by 180 degrees, the center value is reset based on the radius R of the output circle. The setting method will be briefly explained based on Fig. 5(e).In Fig. 4, the distance 1a! After taking the shorter one of b - n as the true center value, from the current center O'n selected by the movement of the vehicle to the coordinate position P', that is, the point where point P has moved due to the movement of the vehicle. For example, if the distance is 2 of radius R
．． If the radius is 5 times or more, the center is not centered at the previously selected center 0"N, but is instead centered at the previously unselected point On (theoretically, the radius is greater than or equal to R, but the geomagnetic sensor (The safety factor is assumed to be 2.5 times based on the accuracy etc.)

In other words, the true center value of the output circle is finally determined from any of the points found on a straight line having the inclination of the road direction and located at a radial distance away from the coordinate position of the output circle.

By the way, according to the findings of the present inventors, more than 90% of the correction amount corrected by the sign post signal is within 10%. Therefore, most of the areas shown in FIG. In order to be able to respond to any situation, the above-mentioned resetting means are also included.

The operation of this embodiment will be explained below using a flowchart.

The flowchart in FIG. 6 is a general 70-
First, as initial processing, flags and counters are cleared and the center position of the geomagnetic azimuth sensor is set (step 600). Next, the current traveling position of the vehicle is set by operating the key human power section 205 (step 602).
), a map to which a position serving as a reference for vehicle travel guidance belongs is displayed, and the reference position is displayed on the map (step 604).

Thereafter, when each interrupt permission process for the integral calculation interrupt process (step 606), the radio wave reception position interrupt process (step 608), and the interval timer interrupt process (step 610) is performed (step 612>, the vehicle It is determined whether there is movement (step 614).

In this judgment, if it is confirmed that the vehicle has moved (YES in step 614), an update process is performed on the screen in accordance with the movement (step 616).If the vehicle has not moved (NO in step 614), the update process is performed on the screen (step 616). No processing takes place.

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

In this process, the geomagnetic direction sensor 203 first reads the driving direction θ of the vehicle (step 700), and then the distance sensor 202 reads the X direction component ΔX and Y A directional component ΔY is determined (step 702).

Finally, these components are added to the cumulative distance in the X direction and the cumulative distance in the Y direction, and these cumulative distances are updated (step 704), and the updating process of step 616 in FIG. 6 described above is performed.

Next, interrupt processing when receiving radio waves (step 608 in Figure 6)
will be done.

This process is shown in FIG. 8, and starts when the receiving antenna 210 mounted on the vehicle starts receiving the radio waves transmitted from the sign post 300.

In this process, when reception is first started, the received data shown in FIG. 4 is read (step 800).
).

Next, the current position is rewritten with the received current position data, and the output values (VX, Vy
) The direction (θ) of the road where Tosono Sign Post T-300 (7) is installed is stored (steps 802 and 804).
．． 806>.

As a result, the coordinate position P(Vx,
Vy) and the road direction θ have been determined, so with the output circle radius R, which is theoretically determined from the geomagnetic strength,
Two points (071(
Xa, Ya), On” (Xb, Yb)) are determined in the next step 808.

That is, (Xa, Ya) and (Xb, Yb) are determined by the following formula.

Also, in step 810, the old center Oo (CX.

CY) and On (xa, Ya) and Oo (CX, C
The distances ga, , gb between Y) and On-(Xb, Yb) are determined by the following equation.

Then, in step 812, the ! obtained in step 810 above is obtained! a and J2. By comparing the size of b, it is determined whether the dots between Qn and O'n are close to the old center Oo.

With this judgment la≧! If b is satisfied (YES in step 360), the process proceeds to step 314, sets (Xb, Yb) as the new center (CX, CY) (step 814), and sets a flag (step 816).

On the other hand, la≧j2. If b is not satisfied (step 81
2 is NO), proceed to step 818 (Xa, Ya)
is the new center (CX, CY) and the flag is set to O (step 820 is O).

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

FIG. 9 shows interval timer interrupt processing, which is performed using the I SeC interval timer after the above-mentioned radio wave reception interrupt processing, and one second after the radio wave reception interrupt processing. will be started.

First, in step 900, the geomagnetic direction sensor 203 (
VX, vy> is memorized, 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 above coordinate position (VX, VV) is calculated theoretically. It is determined whether the radius R of the output circle above is 2.5 times or more.

That is, in FIG. 5(e), it is determined whether the distance between the coordinate position P- and the old center O'n is greater than 2.5R.

In this judgment, if the distance between the old center Q''n and the coordinate position P' is within 2.5 times the output circle radius (No in step 902), this process is terminated;
If it is twice or more (YES in step 902), the process advances to the next step 904.

In this step 904, the flag status in the radio wave reception interrupt process (steps 816 and 820 in FIG. 8) is determined, and if the flag is set (step 904
is YES and indicates step 816 in FIG. 8), (Xa
, Ya) to the new center (CX, CY) Step 9
08), on the other hand, if the flag is not set (step 904 is No and step 820 in FIG. This process is returned through the input end process (step 910).

As described above, according to this embodiment, two centers are assumed at the output circle radius position based on the road information from the signposts placed on the straight road kjQ, centered on the coordinate position having the slope of the direction of the road. Then, the point that is closer to the center coordinate position of the old output circle among the two center points, or the point determined based on the distance from the assumed two center points to the orientation sensor output value, is set as the output circle. Since the center of the signpost is set at the center of the signpost, the driving direction can be quickly corrected using only information from one sign post.

(Effects) According to the present invention, the center coordinate position of the output circle moved by @magnetic means can be determined based on road information from one sign post installed on a straight road, so the driving direction can be quickly corrected.

[Brief explanation of the drawing]

Figure 1 is a diagram corresponding to claims, Figure 2 is a block diagram showing the configuration of the present invention, Figure 3 is an explanatory diagram of the configuration of the sign post, and Figure 4 is a diagram showing the configuration of the sign post.
The figure is a transmission guide diagram of the sign post, Figure 5 is an explanatory diagram for explaining the operating principle of the present invention, and Figures 6 to 9 are CPLJ
This is a 70-day diagram showing the processing procedure. 200...Display device 201...CPU 202...Vehicle speed sensor 203...Geomagnetic direction sensor 205...Key human power section 206...External storage device 208...System ROM 209...RAM No. Figure 3 Figure 4 4 bytes 4 bytes 4 bytes 2 bytes Figure 5 (c) (d) Figure 6 Figure 9

Claims (1)

[Claims] (1) Geomagnetic component detection means that separates and detects geomagnetism into components in two directions orthogonal to each other in a horizontal plane, and a coordinate position indicated by both detected geomagnetic components from the center coordinate position of the output circle where the above position should be included. A driving direction calculation means for calculating the driving direction of the vehicle based on the direction; and a driving direction extraction means for extracting information indicating the road direction in which the vehicle is currently traveling from radio waves transmitted from a roadside transmitting station installed on a straight road. and, the output circle is centered at the coordinate position on a straight line that includes the coordinate positions indicated by both geomagnetic components detected at the time of receiving the transmitted radio wave and has the slope of the road direction indicated by the information extracted from the transmitted radio wave. center value setting means for setting either one of the points found at positions radially apart from each other as the true center value of the output circle; and an output circle for correcting the center coordinate position of the output circle based on the new center value. A vehicle running direction measuring device, comprising: center correction means.