JPH08313260A - Vehicle direction detector - Google Patents

Abstract

(57) [Summary] [Objective] The disturbance magnetic field is detected by grasping the magnetic field three-dimensionally with respect to the geomagnetism, and when the disturbance magnetic field is detected, the orientation data by the geomagnetic sensor is excluded. [Structure] Sensor case provided at the rear of the vehicle roof
A geomagnetic sensor 11 is arranged substantially horizontally in the magnet 50, and a magnetic field Z component sensor 13 for detecting the Z direction component of the magnetic field is arranged substantially vertically. When the voltage generated in the coil of the magnetic field Z component sensor 13 exceeds a predetermined threshold value, it is determined that a disturbance magnetic field exists, and based on the determination result, the vehicle azimuth data obtained by the geomagnetic sensor 11 is excluded, and the magnetic field depends on the geomagnetism. Detects the direction of the vehicle with another sensor. That is, a single magnetic field Z component sensor
The disturbance magnetic field can be detected only by 13, and it is not necessary to dispose a plurality of sensors at a distance. Therefore, the size of the device can be reduced. Further, when the disturbance magnetic field is detected, the azimuth data obtained by the geomagnetic sensor 11 is eliminated, so that the reliability of the vehicle azimuth detection is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle azimuth detecting device, and more particularly to a device for preventing an abnormal detection of a traveling azimuth of a vehicle due to a disturbance magnetic field.

[0002]

2. Description of the Related Art As a conventional vehicle azimuth detecting device, for example, a device disclosed in Japanese Patent Laid-Open No. 63-85312 is known. FIG. 5 is a block diagram of the device disclosed in this publication.
Will be described.

As shown in FIG. 5, a pair of magnetic sensors 70 and 71 for detecting the traveling direction of the vehicle based on the geomagnetism are
It is connected to a pair of AD converters 73 and 74 for AD-converting each azimuth detection output through an adjustment circuit 72 that adjusts the obtained azimuth detection output in preparation for AD conversion. However, the magnetic sensors 70 and 71 are mounted at a fixed distance when mounted on a vehicle. The AD converters 73 and 74 are connected to a comparator 75 which compares the respective azimuth data obtained by the magnetic sensors 70 and 71. The AD converter 73 and
When the difference between the azimuth data obtained by the magnetic sensor 70 and the azimuth data obtained by the magnetic sensor 71 in the comparator 75 exceeds a predetermined value, a disturbance magnetic field (high-voltage line, line, etc. (Disturbed magnetic field) is present,
It is connected to a disturbance magnetic field detection circuit 76 which detects a disturbance magnetic field. Further, the AD converters 73 and 74 are respectively connected to a storage circuit 77 which stores the azimuth data detected before and after the AD converters 73 and 74.

Then, the disturbance magnetic field detection circuit 76 and the storage circuit 77 eliminate the azimuth data during the influence of the disturbance magnetic field, and estimate the azimuth data during that time from the azimuth data detected before and after the azimuth data. Is connected to a calculation processing circuit 78 for performing calculation for complementing, and is connected to a display device 79 for displaying the complemented direction.

The operation of this vehicle azimuth detecting device will be described. The direction data obtained from the magnetic sensors 70 and 71 are the direction data D1 of the magnetic sensor 70 and the direction data D2 of the magnetic sensor 71. In the disturbance magnetic field detection circuit, when the difference between D1 and D2 exceeds the disturbance magnetic field detection reference value Dn, the disturbance magnetic field exists and it is determined that the obtained data is affected by the disturbance magnetic field.

The difference between the direction data D1 and the direction data D2 does not exceed Dn before and after the vehicle has entered the region affected by the disturbance magnetic field, and the D1 and D2 are stored in the storage circuit 77. In addition, the arithmetic processing circuit 78
The azimuth is calculated by. When the vehicle passes through the region affected by the disturbance magnetic field, the difference between the direction data D1 and the direction data D2 exceeds Dn, so the disturbance magnetic field detection circuit detects the disturbance magnetic field, and the arithmetic processing circuit detects the magnetic field. The orientation data obtained from the sensors 70 and 71 are excluded. For the azimuth data during this period, the azimuth data immediately before entering the area affected by the disturbance magnetic field and the azimuth data immediately after passing through the area are read from the memory circuit 77, and the arithmetic processing circuit 78 interpolates based on these data. Will be complemented. The vehicle azimuth detecting device displays the azimuth thus obtained on the display device 79.

[0007]

However, in the above-described vehicle azimuth detecting device, since the azimuth data from the two geomagnetic sensors are compared to detect the disturbance magnetic field, a difference between the azimuth data of the two sensors is required. To be done. Therefore, there is a problem that a certain horizontal distance is required between both sensors in order to obtain orientation data that is not affected by the same disturbance magnetic field before and after entering the area affected by the disturbance magnetic field. Therefore, the vehicle azimuth detecting device of the present invention detects the disturbance magnetic field by grasping the magnetic field three-dimensionally with respect to the geomagnetism, and the detected vehicle traveling azimuth is abnormal due to the influence of the disturbance magnetic field. The purpose is to judge.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a vehicle azimuth detecting device mounted on a vehicle for detecting a traveling azimuth of the vehicle, and a horizontal component detecting means for detecting a horizontal component of a magnetic field. And a direction detection means for detecting the traveling direction of the vehicle based on the detection result of the horizontal component detection means, a vertical component detection means for detecting the vertical component of the magnetic field, and a disturbance based on the detection result of the vertical component detection means. A disturbance magnetic field detecting means for detecting a magnetic field, and an abnormality judging means for judging that the detection result of the azimuth detecting means is abnormal based on the detection result of the disturbance magnetic field detecting means.

[0009]

According to the above means, the horizontal component of the magnetic field is detected by the horizontal component detecting means, and based on the detection result, the heading detecting means detects the traveling direction of the vehicle. At the same time, the vertical component of the magnetic field is detected by the vertical component detecting means, and the disturbance magnetic field is detected by the disturbance magnetic field detecting means based on the detection result. Then, based on the detection result of the disturbance detection means, the abnormality determination means determines that the detection result of the azimuth detection means is abnormal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described with reference to FIGS. 1 is a block diagram of the present embodiment, FIG. 2A is a geomagnetic sensor, FIG. 2B is a schematic diagram of a magnetic field Z component sensor, and FIG. 3 is a schematic diagram of a geomagnetic sensor attached to a vehicle. Is. However, arrow F indicates the front of the vehicle and arrow R indicates the rear of the vehicle.

As shown in FIG. 1, the geomagnetic sensor 11, which is the horizontal component detecting means, uses the horizontal components of the geomagnetism as the X and Y components in the three-dimensional X, Y and Z directions, and the voltage generated by the X component of the geomagnetism. Is a sensor for detecting the azimuth angle with respect to the earth's magnetism, which is the azimuth data of the vehicle, based on the voltage generated by the Y component. That is, the geomagnetic sensor 11
Is a sensor for detecting the absolute direction on the earth.
The geomagnetic sensor 11 is connected to an azimuth data detector 12 which is azimuth detecting means for detecting azimuth data of the vehicle. The magnetic field Z component sensor 13, which is a vertical component detecting means, uses the vertical component of the magnetic field with respect to the earth magnetism as the Z component in the X, Y, and Z directions of the three-dimensional system, and detects the disturbance magnetic field based on the voltage generated by the Z component. It is a sensor. And
The magnetic field Z component sensor 13 is connected to an output voltage determination unit 14 which is a disturbance magnetic field detecting means for detecting a disturbance magnetic field.

The azimuth data detector 12 and the output voltage determiner 14 are based on the determination result of the output voltage determiner 14.
The azimuth data from the azimuth data detection unit 12 is connected to the azimuth data output unit 15 which is an abnormality judging means for judging that the azimuth data is abnormal due to the influence of the disturbance magnetic field. The azimuth data output unit 15 is connected to the current position detection unit 16 that detects the current position of the vehicle.

A GPS positioning device 17 for detecting an absolute position (latitude, longitude and altitude) on the earth from a signal from a satellite is provided in the current position detecting section 16 to detect a rotation angle of a vehicle such as a vibration gyro or an optical fiber gyro. A gyro sensor 18 for detecting the relative azimuth of the vehicle is connected thereto.
Further, the current position detector 16 is connected to a vehicle speed signal output device 19 for outputting vehicle speed information, a map information device 20 such as a CD-ROM, and a display 21 for displaying the position of the vehicle.

As shown in FIG. 2A, in the geomagnetic sensor 11, the exciting coil 31 is wound around the annular permalloy core 30, and the X-direction coil 32 and the Y-direction coil 33 intersect in a cross shape. It is a structure wound so as to straddle the outer diameter of the annular permalloy core 30.

As shown in FIG. 2 (b), the magnetic field Z
The component sensor 13 includes an annular permalloy core 40, an excitation coil 41, and an excitation coil 41.
Is wound, and the Z-direction coil 42 is wound so as to straddle the outer diameter of the annular permalloy core 40.

As shown in FIG. 3, the geomagnetic sensor 11 is substantially horizontal in a box-shaped sensor case 50 attached to the rear portion of the roof of the vehicle, and the magnetic field Z component sensor is provided.
Reference numerals 13 are substantially vertical and are arranged with a slight distance from the bottom surface of the sensor case 50.

The operation of this embodiment will be described. In the geomagnetic sensor 11, an AC voltage is applied to the exciting coil 31, and the azimuth data detector 12 measures a voltage V1 generated in the X-direction coil 32 and a voltage V2 generated in the Y-direction coil 33, and the azimuth data is obtained. The detector 12 detects the azimuth angle I, which is the azimuth data of the vehicle with respect to the geomagnetism, by the formula I = tan ⁻¹ (V1 / V2).

At the same time, in the magnetic field Z component sensor 13, an AC voltage is applied to the exciting coil 41, and the output voltage determination unit 14 measures the voltage V3 generated in the Z direction coil 42 to detect the disturbance magnetic field. This is because the geomagnetism has a small component in the Z direction (vertical direction) on the ground plane,
Since it is very weak, normally, the voltage V3 generated in the Z-direction coil 42 is substantially constant. However, since the disturbance magnetic field has a clear three-dimensional magnetic field with respect to the earth's magnetism, the voltage V3 changes due to the vertical component of the disturbance magnetic field. Therefore, the disturbance magnetic field can be detected by detecting the change in the voltage V3. However, in reality, the voltage value of the Z-direction coil 42 is not always constant due to the traveling of the vehicle, the inclination of the road surface, etc., so that the voltage V3 is the predetermined threshold voltage value Vt.
When it exceeds, the existence of the disturbance magnetic field is judged and the disturbance magnetic field is detected.

Then, in the azimuth data output unit 15, depending on the presence or absence of the disturbance magnetic field determined by the output voltage determination unit 14,
It is determined whether or not the azimuth data of the vehicle obtained by the azimuth detecting unit 12 is abnormal.

FIG. 4 shows a flow chart of the detection of the disturbance magnetic field and the abnormality judgment of the azimuth data, which will be described in detail with reference to the components shown in FIGS. First, step 60
Then, the presence or absence of the disturbance magnetic field is determined by the output voltage determination unit 14 depending on whether the voltage V3 generated in the Z-direction coil 42 is equal to or less than the predetermined threshold voltage value Vt.

If NO, that is, if it is determined that there is a disturbance magnetic field, the process proceeds to step 61, and the azimuth data output unit 15 determines that the azimuth data detected by the azimuth data detection unit 12 is abnormal. If it is determined, the acquisition of the azimuth data is stopped, and the process ends. If YES, that is, if it is determined that there is no disturbance magnetic field, proceed to step 62,
In the azimuth data output unit 15, it is determined that the azimuth data detected by the azimuth data detection unit 12 is normal,
Import azimuth data. Then, the process proceeds to step 63, and the azimuth data is output to the current position detection unit 16.

Here, the criterion of the disturbance magnetic field in step 60 is the predetermined threshold voltage value Vt.
The rate of change of the voltage V3 generated in the directional coil 42 and the like are not limited to the examples.

The current position detecting unit 16 detects the current position of the vehicle based on the information from the azimuth data output unit 15, the GPS positioning device 17, the gyro sensor 18, and the vehicle speed signal output device 19, and the map The current position of the vehicle is displayed on the display 21 on the map read from the information device 20.
To be displayed. When the azimuth data output unit 15 determines that the azimuth data detected by the azimuth data detection unit 12 is abnormal based on the detection result of the output voltage determination unit 14 (step 61 in FIG. 4). Detects the traveling direction of the vehicle only by the relative direction obtained by the gyro sensor 18.

According to this embodiment, the magnetic field Z component sensor
The disturbance magnetic field can be detected only by 13. That is, in order to compare the direction detection results of a plurality of sensors, it is not necessary to provide a predetermined distance between the sensors, so that the sensor case 50 can be integrated and the device can be downsized.
Further, the azimuth data detection unit 12 is affected by the disturbance magnetic field.
Since it is possible to determine that the detection result of is abnormal, it is possible to improve the reliability in the direction detection.

[0025]

According to the present invention, the disturbance magnetic field can be detected by a single sensor by grasping the magnetic field three-dimensionally with respect to the geomagnetism and detecting the disturbance magnetic field. Therefore,
Since it is not necessary to provide a predetermined distance between the sensors for comparing the detection results of a plurality of sensors, the device can be downsized. Further, since it is possible to determine that the azimuth detection result is abnormal due to the influence of the disturbance magnetic field, the reliability in the azimuth detection can be improved.

[Brief description of drawings]

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

FIG. 2A is a schematic diagram of a geomagnetic sensor for detecting X and Y components according to an embodiment of the present invention. FIG. 2B is a schematic diagram of the geomagnetic sensor for detecting the Z component in the embodiment of the present invention.

FIG. 3 is a schematic diagram of a geomagnetic sensor mounted on a vehicle according to an embodiment of the present invention.

FIG. 4 is a flowchart of a disturbance magnetic field detection and orientation data abnormality determination according to the embodiment of the present invention.

FIG. 5 is a block diagram of a conventional vehicle azimuth detecting device.

[Explanation of symbols]

 10 ... Geomagnetic sensor 11 ... Geomagnetic sensor for X and Y component detection 12 ... Direction data detection unit 13 ... Geomagnetic sensor for Z component detection 14 ... Output voltage determination unit 15・ ・ ・ ・ Direction data output unit 16 ・ ・ ・ Current position detection unit 17 ・ ・ ・ ・ GPS positioning device 18 ・ ・ ・ ・ Gyro sensor 19 ・ ・ ・ ・ ・ ・ Vehicle speed signal output device 20 ・ ・ ・ ・ ・ ・ Map information device 21 ····display

Claims (1)

[Claims] 1. A horizontal component detecting means mounted on a vehicle for detecting a horizontal component of a magnetic field, an azimuth detecting means for detecting a traveling azimuth of a vehicle based on a detection result of the horizontal component detecting means, and a vertical component of a magnetic field. A vertical component detecting means for detecting a disturbance magnetic field, a disturbance magnetic field detecting means for detecting a disturbance magnetic field based on the detection result of the vertical component detecting means, and a detection result of the azimuth detecting means based on the detection result of the disturbance detecting means. A vehicle azimuth detecting device, comprising: