JPS63284413A - Traveling azimuth detector for vehicle - Google Patents

Abstract

PURPOSE:To accurately detect the traveling azimuth of a vehicle by calculating the traveling direction of the vehicle from received data from a roadside transmission station and intersection information which is stored previously. CONSTITUTION:The center position of an earth magnetism azimuth sensor is set under the control of a CPU 201, the current traveling position of the vehicle is set from a key input part 205, and a guide map and a reference position are displayed on a CRT 20. Then when the movement of the vehicle is confirmed, integral calculation interruption processing is started to read the traveling azimuth of the vehicle out of a sensor 203, and X- and Y- directional components of distance data are found every time the vehicle travels by a specific distance and added to each directional integral distances. Further, the current value is rewritten with the received data from an antenna 210, information on principal intersections is read out of an external storage device 206, and the distance between a last coordinate value to each intersection is calculated to find the road azimuth. Then the center of a new output circle is obtained from the radius of the output circle of earth magnetism intensity and the road azimuth.

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 center coordinate position of the outgoing circle to the coordinate position indicated by both geomagnetic components is determined as the running direction of the vehicle.

When the vehicle body is magnetized while the vehicle is running, the above-mentioned components move relative to the 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 indicated coordinate position is determined as the running direction of the vehicle, and an error occurs in the measurement of the running direction.

Conventionally, when the vehicle is magnetized, the vehicle travels in a circle, and the coordinate position indicating the correct center of the magnetization is determined based on a plurality of pairs of geomagnetic components detected during that time. Ta.

In addition, a roadside transmitting station (hereinafter referred to as a "sign post") is installed at each predetermined interval point on the passageway, and the transmitter station (hereinafter referred to as a "sign post") is installed to indicate the position, path, power level, etc. of that point. It has also been proposed to correct the center coordinate position of the output circle using the intersection points of a plurality of straight lines.

(Problem to be Solved by the Invention) However, in the former conventional method, it is necessary to make the vehicle go around and find the center coordinate position of the output circle every time the vehicle body is magnetized. It is necessary to search for a place that is as spacious as possible and where there is nothing that disturbs the geomagnetic field in order to perform a circular drive, and therefore, there is a problem in that the correction imposes a large burden on the driver while driving. Ta.

Furthermore, in the latter conventional method, there was an inconvenience in that the intersection of straight lines could not be found unless there were 1q of information on a plurality of sign posts.

(Objective of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a vehicle running direction detection device that can accurately detect the running direction of a vehicle.

(Configuration of the Invention) In order to achieve the above object, a vehicle position detection device according to the present invention is configured as shown in FIG.

The receiving/holding means a receives and stores the traveling direction of the vehicle from one intersection to another intersection and the coordinate position data of the roadside transmitting station from the radio waves transmitted by the roadside transmitting station a.

The intersection information storage means C stores coordinate positions of major intersections.

Further, the position successive unit d stores the position of the roadside transmitting station immediately before the roadside transmitting station and the intersection information storage unit C.
The positions of two intersections sandwiching the roadside transmitting station are read from .

Further, the vehicle direction calculating means e calculates the vehicle direction based on the distance from the previous roadside transmitting station position read by the position successive means and the two respective intersection positions, and the road direction taught by the roadside transmitting station. Calculate.

(Operation) In the present invention, the traveling direction of the vehicle is calculated from received data from the roadside transmitting station and pre-stored intersection information.

(Description of 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.
The map stored in the VRAM 207 and displayed on the display section 200 is displayed via the VRAM 207.

Furthermore, the processing of the CPU 201 is carried out 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 as a roadside transmitting station, which will be described later.The signal received by this receiving antenna 210 is subjected to processing such as amplification in a receiving circuit 211, and then received. The information is input to the CPU 201 via the interface 212.

FIG. 3 shows the contents of the map data stored in the external storage device 206, which includes the ID codes of each sign post, major intersections, and X, Y of major intersections.
Contains coordinates.

FIG. 4 shows the configuration of the sign post 400,
This sign post 400 has a storage circuit 401. which stores transmission data. An omnidirectional transmitting antenna 402 that transmits radio waves containing the transmitted data, and this transmitting antenna 4
It is configured by a transmitting circuit 403 for transmitting from 02.

FIG. 5 roughly shows the transmission contents of the sign post 400, and the ID code, X and Y coordinate position, and road direction (θ) of the sign post 400 are included as the contents of the transmitted radio wave. .

Note that the transmitted radio wave with this content is modulated at several hundred Hz, and its range is said to be 10 meters or less. Additionally, sign posts are installed near major intersections.

Hereinafter, before explaining the operation of this embodiment, a description will be given based on FIG. 6.7 in order to make the present invention easier to understand.

FIG. 6 is a similar map displayed on the display unit 200, and it is assumed that the vehicle is now heading north from intersection A toward intersection B, as shown by the dotted line. Note that the 0 mark on the map indicates the location where the sign post 400 is installed, and the information for each intersection on this map has already been stored in the external storage device 206 as shown in FIG. There is. Further, each sign post (400-a-c) teaches the information shown in FIG. 5 above. Among this information, the road direction indicates the road direction when the vehicle is traveling from one of the two intersections that sandwich the sign post to the other. Therefore, in Figure 6, intersection A
The road direction θ based on due east when the vehicle heads toward intersection B is taught. Therefore, when a vehicle is heading from intersection A to 8, the road direction θ can be accepted as the vehicle direction, but on the other hand, when a vehicle is heading from intersection B to A, θ is 180 It can be understood that the direction in which the angle is added is the direction in which the vehicle is traveling.

Therefore, in the present invention, the external storage device 206 stores information about which intersection the vehicle is traveling between two major intersections.
The judgment is made based on the intersection information stored in the . In other words, to determine the direction of travel, measure the distance between the two intersections that sandwich the sign post you passed this time and the sign post you passed last time (R new), and move from the intersection with the shorter distance to the intersection with the longer distance. It is determined that the vehicle is moving.

Taking this as an example in Fig. 6, the distance LA from the sign post 40O-a to the intersection A is compared with the distance B to the intersection B, and the vehicle moves from the shorter distance to the longer intersection. It is determined that this is progressing.

Conversely, when a vehicle is heading south, i.e. from intersection B to intersection A, it should stop at sign post 400.
- This is done by comparing the distance from G to the intersection BSA.

Note that map information such as intersections is stored in advance in the external storage device 206 as shown in FIG. 3 described above, so the above determination can be easily made.

As described above, the direction of travel of the vehicle can be determined based on the intersection information and data received from the sign post. Furthermore, since the direction (θ) of the road from the sign post is determined, the output point P (VX, VY) of the geomagnetic direction sensor 203 at the time of passing the sign post is determined. You can find the radius length of the output circle (On) on the line and use it as the center value of the output circle after correction (
(See Figure 7).

Now, the operation of this embodiment will be explained using a flowchart.

The flowchart of FIG. 8 is a general 70-
First, as an initial step 9a, flags and counters are cleared, and the center position of the geomagnetic azimuth sensor is set (step 800). Next, the current traveling position of the vehicle is set by operating the key human power section 205 (step 80).
2) 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 804).

At that time, when each interrupt permission process for the integral calculation interrupt process (step 806) and the radio wave reception interrupt process (step 808) is performed (step 810L), it is determined whether or not the vehicle is moving (step 812). .

In this judgment, if the movement of the vehicle is confirmed (YES in step 812), an update process is performed on the screen in accordance with the movement (step 814). Further, if the vehicle does not move (No in step 812), the update process is not performed.

FIG. 9 shows the integral calculation interrupt processing (step 80 in FIG. 6).
6) is shown.

In this process, the geomagnetic direction sensor 203 first reads the running direction θ of the vehicle (step 900), and then the distance sensor 202 reads the X direction component ΔX and Y A directional component ΔY is determined (step 902).

Finally, these components are added to the cumulative distance in the X direction and the cumulative distance in the Y direction, and the cumulative distances are updated (step 904), and the updating process of step 814 in FIG. 8 described above is performed.

Next, interrupt processing when receiving radio waves (step 808 in Figure 8)
will be explained based on FIG.

This process starts when the receiving antenna 210 mounted on the vehicle starts receiving the radio waves transmitted from the sign post 400.

In this process, when reception is first started, the received data shown in FIG. 5 is read (step 100).
0).

Next, the current value is rewritten based on the received data (step 1010), and it is determined whether the received data was written in the stack area when the vehicle previously passed another sign post (step 1010). 102
0>. If it is not stated in this judgment (
Step 1020 is NO), the data received this time is pushed to the stack area and the interrupt returns (Step 1
030).

Further, when the received data is bushed (YES in step 1020), the coordinate position (XT) of the sign post previously received from the stack area.

YT) is read out (step 1040), and the received data received this time is stored in the stack area for the next interrupt processing when receiving radio waves (step 10).
50).

In step 1060, information about the received ID code of the sign post and major intersections that sandwich this sign post,
That is, in FIG. 6, when the sign post 400-b receives the information, the ID code of the sign post 400-b and the coordinate positions (XA, YA), (XB,
YB) is read from the external storage device 206, and in the next step 1070, the distance between the coordinate position (XT, YT) read out in step 1040 and each intersection ASB is calculated using the following equation.

In step 1080, L calculated in step 1070
The size of A and LB is judged, and if LA is 18 or more (
If LA is smaller than 18 (NO in step 1080), add 180 degrees to the road direction θ taught from the sign post to determine the vehicle direction. Set the direction as the vehicle direction (step 1100)
.

Next, in step 1110, the value of the radius of the output circle from the geomagnetic strength is set as the orientation vector length A, and the orientation vector is calculated from this vector length A and the road orientation (step 1120>. The starting point of the orientation vector is the corrected Since this is the center value (CX, CY) of the output circle, this is set as the center of the new output circle (step 1130), and the process returns.

As described above, according to this embodiment, the direction of travel of the vehicle can be determined from the previously received data from the sign post and the intersection information. Also, more signposts]
By being taught the road direction from ・, the center value of the output circle can be easily determined. Therefore, the center coordinate position of the output circle can be accurately corrected every time the sign post passes.

(Effects) According to the present invention, the previously received radio wave data is stacked, and the traveling direction of the vehicle can be detected from the stacked reception data based on the intersection information, so that the vehicle's traveling direction can be accurately determined every time it passes a roadside transmitting station. You can get your bearings.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to claims, Fig. 2 is a block diagram showing the configuration of the present invention, Fig. 3 is a front view showing the format of the external storage device, Fig. 4 is an explanatory diagram of the structure of the sign post, and Fig. 5 is a block diagram showing the configuration of the present invention. The transmission guide map of the sign post, Figures 6 and 7 are explanatory diagrams for explaining the present invention in detail, and Figures 8 to 10 are C
It is a flowchart which shows the processing procedure of PU. 2...Receiving and holding means b...Roadside transmitting station C...Intersection information storage means d...Position reading means e...Vehicle heading calculation means Fig. 1 Section 3 Fig. 4 Fig. 4 / in 1t 4t 2t 97Fig. 8

Claims (1)

[Claims] (1) Receiving and holding means for receiving and storing data on the coordinate position of a roadside transmitting station and the road direction when a vehicle moves from one intersection to another, and storing data on the coordinate position of major intersections. an intersection information storage means for extracting the coordinate positions of two intersections that sandwich the roadside transmission station from the intersection information storage means when transmitting radio waves from the roadside transmission station; a position reading means for extracting the coordinate position of the roadside transmitting station immediately before the roadside transmitting station; a distance between the extracted position of the immediately preceding roadside transmitting station and the two extracted intersection positions; A vehicle running direction detection device comprising: vehicle direction calculation means for calculating the vehicle direction based on the road direction indicated by .