JPH08201059A - Azimuth detector - Google Patents

Abstract

PURPOSE: To detect the azimuth correctly even in a place where the field is disturbed instantaneously by an arrangement wherein a turning correction means extracts such X and Y signals as a rectangle touching the inner circle of an azimuth circle is formed when the points on X-Y coordinates are connected and then sets the intersection of diagonals of the rectangle at the center of the azimuth circle. CONSTITUTION: An advancing azimuth detection means 44 detects the azimuth of geomagnetic by subtracting the bias component at the center of an azimuth circle from X and Y signals outputted from a geomagnetic sensor 2 and determines the advancing direction of a vehicle by subtracting the offset from a signal generated from a gyro 3. A turning correction means 45 calculates the center of azimuth circle formed on the X-Y coordinates by the X and Y signals and corrects the center of azimuth circle depending on the variation in the amount of magnetization of the car body. X and Y signals are then extracted such that a rectangle touching the inner circle of the azimuth circle is formed when four points on the X-Y coordinates are connected and the intersection of the diagonals of the rectangle is set at the center of the azimuth circle so that the center of azimuth angle can be determined based on the X and Y signals at four points. With such arrangement, extraction of noisy X and Y signals can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth detecting device for detecting a traveling azimuth of a vehicle.

[0002]

2. Description of the Related Art As is well known, when a vehicle makes one revolution, FIG.
And {(X−Kx Bsx) ² / (Kx Beh) ² } + {(Y−Ky Bsy) ² / (Ky Beh) ² } = 1 as shown in the formula, the azimuth center is the origin of the XY coordinates. It becomes a locus to draw the ellipse moved from the point to the point (Kx Bsx, Ky Bsy) on the XY coordinates.

Here, Beh is the horizontal component of the magnetic field density in the air due to the earth's magnetic field, and Kx and Ky are the outputs of the first magnetic detection element and the second magnetic detection element, X and Y.
Bsx, Bsy are coefficients that depend on each output gain of the signal.
Is an extra magnetic flux density existing at the place where the geomagnetic sensor is attached and caused by the magnetization of the steel sheet of the vehicle body due to the magnetic flux other than the earth's magnetic field.

Therefore, in order to detect the traveling direction of the vehicle by the geomagnetic sensor, it is necessary to correct the vehicle body magnetization components KxBsx and KyBsy so as to be removed from the X and Y signals. There are two types of correction, one is performed by the driver's intention and the other is automatically performed. In the text, the former is called "turning correction" and the latter is called "automatic correction".

Further, since the locus drawn by the X and Y signals on the XY coordinates, that is, the azimuth circle has an elliptical shape, an error occurs in the detected traveling azimuth as it is.

Therefore, in order to detect the traveling direction of the vehicle with high accuracy, it is desired that the azimuth circle has a perfect circular shape, so that the output gains of the X and Y signals are equivalently k = Kx = Ky.
As shown in FIG. 8, the azimuth circle is corrected to be a perfect circle so that This correction is described in the text as "Ellipse correction".
Is called.

That is, the locus of the circle at this time is as shown by {X ² / (KBeh) ² } + {Y ² / (KBeh) ² } = 1.

Next, conventional turning correction will be described.
FIG. 9 is a block diagram showing a conventional azimuth detecting device disclosed in, for example, Japanese Patent Publication No. 62-30364.

In the figure, reference numeral 2 is a geomagnetic sensor which outputs X and Y signals corresponding to the traveling direction of the vehicle.
The signal is inputted to the maximum / minimum value detecting means 8 as a digital value through the multiplexer 6 and the A / D converter 7.

Then, the maximum value Xmax and minimum value Xmin and Y of the X signal detected by the maximum / minimum value detecting means 8 are detected.
The maximum value Ymax and the minimum value Ymin of the signal are stored in the storage means 5.

A push button switch 9 is operated by the driver when obtaining the maximum and minimum values of the X and Y signals, and the signal is the correction signal generating means 1.
0, the maximum / minimum value detecting means 8 and the storing means are arranged so that the maximum value and the minimum value as described above are respectively obtained and stored from the X and Y signals while the push button switch 9 is in the ON state. Control the operation of 5.

The X and Y signals are also input to the calculating means 4, and using the maximum and minimum values stored in the storage means 5, the X and Y signals at the center of the azimuth circle, which is the vehicle body magnetization amount. Biases Xd and Yd of Xd = (Xmax + Xmin) / 2 = Kx Bsx Yd = (Ymax + Ymin) / 2 = Ky Bsy, and corrected output signals X'and Y '
Is obtained from X '= X-Xd Y' = Y-Yd and output.

Next, the operation of turning correction will be described. FIG. 10 is a flow chart for explaining the operation procedure of the azimuth detecting apparatus shown in FIG. First, in step ST1, it is determined whether or not the push button switch 9 is in the on state. If it is in the on state, steps ST2 to ST4 are executed next, otherwise step ST5 and step ST6.
To execute.

Then, in step ST2, the X and Y signals are read from the geomagnetic sensor 2, and in step ST3, the maximum / minimum value detecting means 8 obtains the maximum and minimum values of the X and Y signals. Subsequently, in step ST4, the maximum value and the minimum value thus obtained are newly stored in the storage means 5.

On the other hand, steps ST5 and ST6
Is a process performed when the push button switch 9 is off, that is, when the vehicle is traveling normally.

First, in step ST5, the X and Y signals are read, and in step ST6, the correction output values X'and Y'as described above are calculated by the calculation means 4 using the maximum and minimum values stored in the storage means 5. Is calculated and output. Although not shown in FIG. 9, the traveling direction of the vehicle is obtained from the corrected output values X'and Y '.

Next, the conventional ellipse correction will be described. For example, the part of the conventional azimuth detecting device disclosed in Japanese Patent Publication No. 62-30569, which performs elliptic correction, is partly the same as the block diagram used in the description of the turning correction, and therefore the description of the same part is omitted. Will be omitted and different parts will be described.

The difference in processing contents from the calculation means 4 at the time of turning correction is that the output gain coefficients kx and ky of the X and Y signals are kx = (1 / Beh) {(Xmax-Xmin) / 2} ∝, respectively.
{(Xmax-Xmin) / 2} ky = (1 / Beh) {(Ymax-Ymin) / 2} ∝
In the case of {(Ymax-Ymin) / 2} and kx ≠ ky, X and Y signals are respectively X ″ = {2A / (Xmax−Xmin)} X′Y ″ = {2A / (Ymax−Ymin)} The correction is performed as shown by Y ', and the correction is arithmetically performed so that the output becomes equivalent when kx = ky = k.

Similarly, only the different steps will be described in the flowchart for explaining the operation of the ellipse correction. In FIG. 11, in step ST7, the maximum value and the minimum value stored in the storage means 5 are used to perform the above X ',
Corrected output values X ″ and Y ″ are output from Y ′ by calculation.

Next, the conventional automatic correction will be described. For example, in the conventional azimuth detecting device disclosed in Japanese Patent Laid-Open No. 5-215553, as shown in FIG. 12, an intersection of vertical bisectors of two strings connecting three points S1, S2, S3 on the azimuth circle. O is taken as the center of the azimuth circle.

FIG. 13 is a block diagram showing only a portion necessary for explaining the automatic correction. In the figure, reference numeral 4 is a calculation means for performing various calculations, which has a function of automatic correction. A geomagnetic sensor 2, a distance sensor 1, and a storage means 5 for holding the X and Y signals of the geomagnetic sensor 2 are connected to the computing means 4.

Next, the operation of automatic correction will be described. FIG. 14 is a flow chart for explaining the operation of the azimuth detecting apparatus shown in FIG. In the figure, step ST11
Then, every time it moves πm (about 3.14 m), the geomagnetic sensor 2
The X and Y signals are read, and a total of 30 sets of X and Y signals are stored in the storage means 5.

Next, in step ST12, it is judged whether or not a total of 30 sets of X and Y signals have been stored. If a total of 30 sets are stored, the process proceeds to step ST13 and the first set and the 31st set. It is determined whether the orientation difference of the geomagnetic orientation detected from the X and Y signals of the eye is within 3 degrees. If the azimuth difference is within 3 degrees, the process proceeds to step ST14.

Further, in step ST14, it is determined whether the azimuth difference of all 30 sets is within 5 degrees. If there is no azimuth change exceeding 5 degrees, it is determined that necessary stable data has been detected on a certain straight road, and the process proceeds to step ST15.

In this step ST15, 30 sets of X and Y are set.
Regarding the signals, the data on the maximum side and the minimum side with large variations are discarded, and the average of the X and Y signals for the middle 20 sets is obtained.

Next, in step ST16, if all three points on the azimuth circle have not been set, the average of the X and Y signals is held as the first point S1. In step ST17, if the point S1 has already been set and the heading difference between the point S1 and the heading is 80 degrees or more and 135 degrees or less, the average of the X and Y signals is set as the second point S2. Hold.

Further, in step ST18, the average of the X and Y signals is held as point S3 when the heading difference between each of the heading directions of point S1 and point S2 is 80 degrees or more.

Next, in step ST19, the 3
If it is determined that the points have been set, and if it is determined that the points have been set, then in step ST20, three points on the azimuth circle, that is, point S1.
(X1, Y1), point S2 (X2, Y2), point S3 (X
3, Y3), a candidate point O (Xo, Yo) at the center of the azimuth circle is calculated.

Here, Xo = {a (X2 + X3) -b (X1 + X2)-(Y1
-Y3) (Y3-Y2) (Y2-Y1)} / {2 (a-
b)} Yo = {a (Y1 + Y2) -b (Y2 + Y3)-(X1
-X3) (X3-X2) (X2-X1)} / {2 (a-
b)} a = (X3-X2) (Y2-Y1) b = (X2-X1) (Y3-Y2).

In step ST21, finally 3
Candidate points of the center of each azimuth circle, that is, points O1 and O2,
When it is determined that the points O3 are aligned, the difference between the candidate points is calculated in step ST22.

When it is determined in step ST23 that the difference between the candidate points is within the allowable value D, step S
At T24, the average of the three candidate points is updated as the center of the azimuth circle.

Next, a conventional method for determining the occurrence of vehicle body magnetization will be described. For example, in a conventional azimuth detecting device disclosed in Japanese Patent Laid-Open No. 5-71964, FIG. 15 is a block diagram of this azimuth detecting device.

In FIG. 15, reference numeral 2 denotes a geomagnetic sensor which outputs X and Y signals corresponding to the traveling direction of the vehicle. The geomagnetic direction calculating means 11 calculates the geomagnetic direction from the X and Y signals. Reference numeral 3 denotes an angular velocity sensor that outputs an angular velocity signal according to a change in the traveling direction of the vehicle. The integrator 12 integrates the angular velocity signal to calculate the second direction.

Numeral 13 is a subtractor for calculating the azimuth difference between the geomagnetic azimuth and the second azimuth. The azimuth difference is low-pass filter 14
The geomagnetic disturbance component is removed at and is connected to the calculating means 48 via the absolute value calculating means 15.

Then, the calculating means 48 compares the absolute value of the azimuth difference and its differential value with a predetermined value, or judges whether the X and Y signals are within a predetermined range to determine whether or not the vehicle body has arrived. The presence or absence of magnetism is determined.

Next, the operation of the conventional vehicle body magnetization detection method will be described. FIG. 16 is a flow chart for explaining the operation of the calculating means 48 shown in FIG. In the figure, in step ST31, the absolute value of the azimuth difference is read in every predetermined cycle, and in step ST32, it is determined whether or not the absolute value is larger than the first predetermined value.

In step ST33, the differential value of the absolute value is calculated, and in step ST34, it is determined whether or not the differential value is larger than the second predetermined value. Furthermore, step ST
At 35, X, outside the radius R1 and R2 range from the azimuth center,
It is determined whether there is a Y signal point.

As a result, step ST32 and step S
When the absolute value is larger than the first and second predetermined values in both T34 and it is determined in step ST35 that the X and Y signals are out of the above range, it is determined that the vehicle body is magnetized. The center of the azimuth circle is corrected in step ST36.

[0039]

Since the conventional azimuth detecting device is constructed as described above, the turn correction requires a plaza where the vehicle can swivel and the magnetic field is less disturbed, and the plaza is secured. If it is not possible, turn correction must be carried out in the place where there is an instantaneous disturbance of the magnetic field, and the X and Y signals containing noise are used as the maximum or minimum values,
There was a problem that the center of the azimuth was erroneously calculated.

Further, in the conventional elliptic correction, the correction is fixed based on the azimuth circle drawn by the magnetic field density of the place where the turning correction is carried out. The magnetic field is distorted depending on the installation direction and the buried amount of
The magnetic field density changes, which causes the size of the azimuth circle to change, which causes a problem that the X and Y signals cannot be accurately corrected.

In the conventional automatic correction, the accuracy of detecting the center of the azimuth circle is determined by the three points on the azimuth circle extracted during traveling of the vehicle. As described above, the size of the azimuth circle depends on the traveling location. However, even if stable X and Y signals are extracted in the same straight path, they may not be X and Y signals on the same azimuth circle, and as a result, the detected azimuth circle center There was a problem such as an error.

Further, in the conventional method for determining the occurrence of body magnetization,
When a point on the XY coordinates due to the X and Y signals after the vehicle body is magnetized moves to a different position on the azimuth circle, the azimuth circle radius falls within the predetermined range, so it is erroneous that the vehicle body is not magnetized. There was a problem such as judgment.

Further, the magnetic field is greatly distorted depending on the place of travel,
When a point caused by the X and Y signals moves inside or outside the azimuth circle, there is a problem that it is erroneously determined that the vehicle body is magnetized. As a result, there is a problem that the geomagnetic direction cannot be used accurately for the calculation of the traveling direction.

The present invention provides an azimuth detecting device capable of avoiding the extraction of noisy X and Y signals and accurately detecting the center of the azimuth circle even in the case of turning correction in the presence of an instantaneous magnetic field disturbance. The purpose is to get.

Further, according to the present invention, when the momentary disturbance of the magnetic field is out of the allowable range, the detection of the center of the azimuth circle is automatically stopped, and the turning correction is carried out at the place where the momentary disturbance of the magnetic field is present. Even so, it is an object of the present invention to obtain an azimuth detecting device capable of preventing erroneous detection of the azimuth center.

Further, according to the present invention, by calculating the azimuth circle center from a point on an arc suitable for detecting the azimuth circle center, an azimuth detecting device which can improve the detection accuracy of the azimuth circle center and the reliability of the traveling azimuth is obtained. The purpose is to

Another object of the present invention is to obtain an azimuth detecting device capable of accurately detecting the center of the azimuth circle for each right turn or left turn of the vehicle.

Another object of the present invention is to obtain an azimuth detecting device capable of calculating a plurality of candidate points for the azimuth center in order to detect the best azimuth center from a limited arc.

Another object of the present invention is to provide an azimuth detecting device capable of preventing erroneous detection of the azimuth circle center deviated from an arc of only one direction.

Another object of the present invention is to obtain an azimuth detecting device capable of stably detecting the center of the azimuth circle.

Another object of the present invention is to obtain an azimuth detecting device which can detect the traveling azimuth satisfactorily even in a place where there is magnetic field distortion.

Another object of the present invention is to obtain an azimuth detecting device which can correct the X and Y signals in response to the magnetic field distortion which fluctuates depending on the traveling place, and can detect the advancing azimuth satisfactorily.

It is another object of the present invention to obtain an azimuth detecting device which can detect the traveling azimuth satisfactorily even when there is magnetic field distortion.

Another object of the present invention is to obtain an azimuth detecting device which can detect the advancing azimuth satisfactorily even if the magnetic field is momentarily disturbed.

Another object of the present invention is to provide an azimuth detecting device which can accurately determine whether or not the vehicle body is magnetized immediately after the vehicle body is magnetized.

It is another object of the present invention to provide an azimuth detecting device capable of accurately determining that the vehicle body is magnetized when an azimuth error occurs in the geomagnetic direction after the vehicle body is magnetized.

Another object of the present invention is to provide an azimuth detecting device capable of satisfactorily detecting the traveling azimuth after the occurrence of magnetization of the vehicle body.

Another object of the present invention is to provide an azimuth detecting device capable of accurately determining whether or not the vehicle body is magnetized even in a place where there is a large magnetic field distortion.

It is another object of the present invention to provide an azimuth detecting device capable of accurately determining that the vehicle body is magnetized when an azimuth change angle error occurs in the geomagnetic direction after the vehicle body is magnetized.

Another object of the present invention is to provide an azimuth detecting device capable of preventing erroneous determination that the vehicle body is magnetized in a place where there is magnetic field distortion in the running place.

[0061]

According to a first aspect of the present invention, there is provided an azimuth detecting device, wherein an absolute azimuth X, which corresponds to a traveling azimuth of a vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
Turning correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the turning correction means comprising:
The X and Y signals are extracted so that a rectangle which is in contact with the inner circle of the azimuth circle when the points on the Y coordinate are connected is extracted, and after the extraction of the X and Y signals, the intersection of the diagonal lines of the rectangle is set as the azimuth circle center. It is a thing.

In the azimuth detecting device according to the second aspect of the present invention, the turning correction means extracts the X and Y signals such that when the points on the XY coordinates are connected, a rectangle is formed which is in contact with the inner circle of the azimuth circle. After the extraction of the X and Y signals, the intersection of the vertical bisectors of the long side and the short side of the rectangle is set as the center of the azimuth circle.

In the azimuth detecting apparatus according to the third aspect of the present invention, the turning correction means sets the large and small ranges centering on the point by the X and Y signals at the start of correction, and then the vehicle turns. When the arc of the azimuth circle becomes larger than a predetermined value and the point by the X and Y signals returns to the small range again, it is determined that the correction can be normally completed.
Further, when the vehicle passes through the large range without entering the small range, it is determined that the correction is abnormally completed.

In the azimuth detecting apparatus according to the fourth aspect of the present invention, the turning correction means sets a range around the point by the X and Y signals at the start of correction, and then the turning angle detected from the angular velocity signal has a predetermined value. When the size of the arc of the azimuth circle is less than a predetermined value or the point by the X and Y signals does not return to the set range again when the above, it is considered that the correction is abnormally ended. It was decided to judge.

In the azimuth detecting apparatus according to a fifth aspect of the present invention, the automatic correcting means extracts an arc after forming the azimuth circle on the XY coordinates into an image, and forms the arc.
The azimuth circle center is calculated from one or more pixels, and the azimuth circle is imaged when the azimuth circle radius and the fluctuations of the X and Y signals are each less than a predetermined value.

In the azimuth detecting apparatus according to the sixth aspect of the present invention, the automatic correction means forms an arc by extracting the arc after the azimuth circle on the XY coordinates is imaged, and at least 3 is formed.
The center of the azimuth circle is calculated from two or more pixels, and when extracting the circular arc, only the pixels in the middle of the thickness are left for the portion where the thickness of the circular arc imaged above becomes large, and it is determined that it is noise. Then, it is designed to be removed.

In the azimuth detecting apparatus according to the invention of claim 7, the automatic correcting means forms an arc by extracting an arc after image-forming the azimuth circle on the XY coordinates and forming at least 3 arcs.
When the center of the azimuth circle is calculated from two or more pixels, and when the above-mentioned image-shaped arc is beyond the predetermined angle range, the center of the azimuth circle is calculated using the pixels located at equal parts of the arc. It was done like this.

In the azimuth detecting apparatus according to the invention of claim 8, the automatic correcting means extracts an arc after forming the azimuth circle on the XY coordinates into an image, and forms at least 3 arcs.
The azimuth circle center is calculated from three or more pixels, and an average of a plurality of azimuth circle center candidate points calculated by a combination of a plurality of pixels on the circular arc imaged as described above is used as the azimuth circle center for correction. It is the one.

In the azimuth detecting apparatus according to the invention of claim 9, the automatic correcting means extracts an arc after forming the azimuth circle on the XY coordinates into an image, and forms at least 3 arcs.
The azimuth circle center is calculated from three or more pixels, and the azimuth circle center is updated by weighting according to the size of the arc imaged.

The azimuth detecting device according to the invention of claim 10 is
The automatic correction means extracts an arc after image-forming the azimuth circle on the XY coordinates, calculates the azimuth circle center from at least three or more pixels forming the arc, and calculates the calculated azimuth circle center. If the distance of each pixel is not within the predetermined range, it is determined that the pixel is noise and the noise is removed.

The azimuth detecting apparatus according to the invention of claim 11 is
The ellipse correcting means calculates the azimuth circle ellipticity from the average value of the X and Y signals stored for each predetermined azimuth, and corrects the X and Y signals.

The azimuth detecting device according to the invention of claim 12 is
The ellipse correction means has four quadrants from the first quadrant to the fourth quadrant of the bearing circle.
In one quadrant, one or two quadrants are convoluted with the X and Y signals of the other quadrant, and the azimuth ellipticity is calculated from the average value of the X and Y signals stored for each predetermined azimuth. ,
The X and Y signals are corrected.

The azimuth detecting device according to the invention of claim 13 is
The ellipse correction means divides the XY coordinates into a plurality of areas, calculates the azimuth ellipticity from the average value of the X and Y signals stored for each area, and corrects the X and Y signals. It is the one.

The azimuth detecting device according to the invention of claim 14 is
The ellipse correction means corrects the X and Y signals based on the azimuth circle radius detected when the turning correction is performed.

The azimuth detecting device according to the invention of claim 15 is
The vehicle body magnetization occurrence determination means determines whether or not vehicle body magnetization occurs by detecting that a point on the arc of the XY coordinates remains at another position when it is returned after being shaken in one direction. It is something that is done.

The azimuth detecting device according to the invention of claim 16 is
The vehicle body magnetization occurrence determining means obtains an average azimuth difference between the geomagnetic azimuth and the second azimuth for each unit time, unit distance, and unit angle, and determines the average azimuth difference to be a predetermined value or more. It is determined that the vehicle body is not magnetized when traveling for a distance or more, and it is determined that the vehicle body is not magnetized when the vehicle turns more than a predetermined distance or more than a predetermined angle with all the average bearing differences being less than a predetermined value. It is the one.

The azimuth detecting device according to the invention of claim 17 is
When it is determined that the vehicle body is magnetized, the traveling azimuth detecting means does not use the geomagnetic azimuth for calculating the traveling azimuth, but calculates the traveling azimuth only by the output of the second azimuth sensor.

The azimuth detecting device according to the invention of claim 18 is
The automatic correction means starts the correction of the azimuth center immediately when it is determined that the vehicle body is magnetized.

The azimuth detecting device according to the invention of claim 19 is
The vehicle body magnetization occurrence determination means obtains an average azimuth change angle difference between the geomagnetic azimuth change angle and the second azimuth change angle for each unit time, unit distance and unit angle, and one of the average azimuth change angle differences is calculated. It is determined that the vehicle body is magnetized when the vehicle has traveled for a predetermined distance or more in a state of being a predetermined value or more, and has turned a predetermined distance or more or a predetermined angle or more while all the average azimuth change angle differences are less than the predetermined value. Sometimes, it is determined that the vehicle body is not magnetized.

The azimuth detecting apparatus according to the invention of claim 20 is
The vehicle body magnetization occurrence determination means sets a predetermined value to be compared with the average azimuth difference or the azimuth change angle difference using the ratio of the azimuth circle radius during traveling of the vehicle to the azimuth circle radius detected at the time of turning correction. It is the one.

[0081]

The azimuth detecting device according to the invention of claim 1 is X-
By connecting the four points of the Y coordinate with a line to extract the X and Y signals that form a rectangle in contact with the inner circle of the azimuth circle,
By making it possible to extract each point by checking the X and Y signals, and by detecting the intersection of the diagonal lines of the rectangle as the center of the azimuth circle, four points of X, which are more than the conventional two points (maximum value / minimum value), can be obtained. , It is possible to calculate the azimuth center from the Y signal.

The azimuth detecting apparatus according to the invention of claim 2 is
By connecting four points of XY coordinates with a line, by extracting the X and Y signals that form a rectangle in contact with the inner circle of the azimuth circle, it is possible to extract while checking each point by the X and Y signals. Further, by detecting the intersection of the vertical bisectors of the long side and the short side of the rectangle as the azimuth circle center, four candidate points for the azimuth circle center can be detected.

The azimuth detecting device according to the invention of claim 3 is
At the start of correction, after setting two large and small ranges centered on the point on the XY coordinates, when the arc on the XY coordinates becomes larger than a predetermined size, the point by the X and Y signals is re-established. When returning to the small range, it is judged that the correction can be completed normally, and when passing through the large range without entering the small range, it is considered that the instantaneous magnetic field disturbance is outside the allowable range. The center detection is automatically stopped so that the driver does not have to consider whether it is better to keep turning the vehicle.

The azimuth detecting device according to the invention of claim 4 is
When the range around the point on the XY coordinates is set at the start of correction and the turning angle detected from the angular velocity signal exceeds a predetermined value, the size of the arc of the azimuth circle is below a predetermined value. Alternatively, if the points by the X and Y signals do not return to the set range again, it is determined that the momentary disturbance of the magnetic field is outside the allowable range, and the detection of the center of the azimuth circle is automatically stopped. This saves the driver from having to consider whether it is better to keep turning the vehicle.

The azimuth detecting device according to the invention of claim 5 is
By imaging the azimuth circle on the XY coordinates as an image, data suitable for calculating the azimuth center can be selected from the pixel group forming the arc, and the azimuth radius and the fluctuations of the X and Y signals can be changed. In the case of a predetermined value or less, the azimuth circle is imaged to eliminate the pixels of the X and Y signals when the magnetic field is instantaneously disturbed in the imaged pixel group.

The azimuth detecting device according to the invention of claim 6 is
It is possible to prevent the arc from being buried in noise by leaving only the pixels in the middle of the portion where the thickness of the arc that has been converted into an image becomes large and removing the pixels other than that pixel as noise.

The azimuth detecting device according to the invention of claim 7 is
When the imaged arc is in the range of 80 degrees or more, the azimuth circle center is calculated by using the pixels in the equally divided parts of the arc, which enables the azimuth circle center to be calculated for each turn. To do.

The azimuth detecting device according to the invention of claim 8 is
It is possible to calculate a plurality of candidate points for the center of the azimuth circle from the same arc by making several combinations of pixels used for the calculation of the center of the azimuth circle from the pixel group of the imaged arc.

The azimuth detecting device according to the invention of claim 9 is
The reliability of the calculated center of the azimuth circle is ensured by setting the weighting coefficient according to the size of the arc imaged.

In the azimuth detecting apparatus according to the tenth aspect of the present invention, after the azimuth circle center is calculated from the image-shaped arc-shaped pixel group and the calculated distance between the azimuth circle center and each pixel is not within a predetermined range, By determining that the pixel is noise and removing the noise, unnecessary pixels are eliminated and subsequent arc extraction is facilitated.

According to the eleventh aspect of the invention, the azimuth detecting device calculates the azimuth ellipticity from the average value of the X and Y signals stored for each predetermined angle, so that the X and Y signals are generated according to the magnetic field distortion at the traveling place. Makes the signal correctable.

According to the twelfth aspect of the present invention, the azimuth detecting device calculates the azimuth ellipticity from the average value of the X and Y signals stored for each predetermined angle, so that the X and Y signals are generated in accordance with the magnetic field distortion at the traveling place. The signal can be corrected, and the X and Y signals can be corrected according to the magnetic field distortion at the traveling place. In addition, by convoluting the X and Y signals of the other quadrants into one or two quadrants among the four quadrants of the azimuth circle from the first quadrant to the fourth quadrant, the X and Y signals can be quickly obtained at each predetermined angle. To be able to store.

The azimuth detecting apparatus according to the invention of claim 13 divides the XY coordinates into a plurality of areas, and calculates the azimuth circular ellipticity from the average value of the X and Y signals stored for each area. , X and Y signals can be corrected according to the magnetic field distortion at the traveling place.

The azimuth detecting device according to the invention of claim 14 is based on the azimuth circle radius detected when the turning correction is performed,
By correcting the X and Y signals, it is possible to easily correct the X and Y signals according to the instantaneous magnetic field disturbance at the traveling place.

According to the fifteenth aspect of the present invention, in the azimuth detecting device, the behavior of the points on the XY coordinates seen when the vehicle body is magnetized, that is, the points on the arc of the XY coordinates are swung in one direction. It is possible to determine whether or not the vehicle body is magnetized without detecting the error in the geomagnetic direction by detecting that the vehicle remains at another position when returning from the vehicle.

According to the sixteenth aspect of the present invention, in the azimuth detecting apparatus, the average azimuth difference between the geomagnetic azimuth and the second azimuth, which is azimuth information other than geomagnetism, is calculated for each unit time, unit distance and unit angle, and compared with a predetermined value. By doing so, it is possible to accurately detect whether or not the orientation error of the geomagnetic orientation has expanded.

According to the seventeenth aspect of the present invention, in the case where it is determined that the vehicle body is magnetized by determining whether the vehicle body is magnetized by comparing the geomagnetic direction with the second direction or the traveling direction. , The geomagnetic azimuth is not used for the calculation of the traveling azimuth, and whether or not the azimuth error of the geomagnetic azimuth has expanded can be accurately detected.

In the azimuth detecting apparatus according to the eighteenth aspect of the invention, when it is determined that the vehicle body is magnetized, the azimuth circle center is corrected immediately, and the azimuth circle center is not unnecessarily corrected. By doing so, it is possible to avoid accidentally erroneously correcting the center of the azimuth circle in a place where the magnetic field distortion is large.

According to the nineteenth aspect of the present invention, in the azimuth detecting device, the average azimuth change angle difference between the azimuth change angle of the geomagnetic azimuth and the azimuth change angle of the second azimuth is obtained for each unit time, unit distance and unit angle, and the predetermined azimuth change angle is determined. By comparing with the value, it is possible to accurately detect whether or not the error in the azimuth change angle of the geomagnetic azimuth has expanded.

In the azimuth detecting device according to the twentieth aspect of the present invention, a predetermined value for respectively comparing the average azimuth difference or the azimuth change angle difference between the geomagnetic azimuth and the second azimuth with respect to the azimuth circle radius detected when the turning correction is performed is performed with respect to the vehicle. By setting using the ratio of the azimuth circle radius during traveling, it is possible to determine whether or not the vehicle body is magnetized depending on the degree of magnetic field distortion.

[0101]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a distance sensor that outputs a pulse signal according to the traveling distance of the vehicle, 2 is a geomagnetic sensor that outputs X and Y signals according to the traveling direction of the vehicle, and 3 is a signal that corresponds to the yaw rate of the vehicle. It is a gyro as an angular velocity sensor that outputs.

Reference numeral 4A is a signal processor to which the outputs of the distance sensor 1, the geomagnetic sensor 2 and the gyro 3 are input. In the signal processor 4A, reference numerals 41 and 42 are a traveling distance detecting means and a traveling state detecting means for detecting a traveling distance and a traveling state from the output of the distance sensor 1.

Further, 43 is an offset detecting means for detecting offset data from the running state and the output of the gyro 3, 44 is a traveling direction detecting means, and 45 is a bias component of the X and Y signals based on the output of the geomagnetic sensor 2. Turning correction means, 46 automatic correction means, 47 ellipse correction means,
Reference numeral 48 denotes a vehicle body magnetization occurrence determining means, which outputs the traveling direction and traveling distance of the vehicle from the traveling direction detecting means 44 and the traveling distance detecting means 41. Reference numeral 5 is a storage means for storing the data calculated by the signal processor 4A.

Next, the operation will be described. Signal processor 4
A detects the traveling direction of the vehicle at each processing timing determined at constant time intervals. In the signal processor 4A, the traveling distance detecting means 41 is arranged so that the distance sensor 1 is provided every predetermined time.
The traveling distance is detected from the count number of the pulse signal generated by the.

When the traveling state detecting means 42 detects the pulse signal generated by the distance sensor 1 within a predetermined time, the traveling state is determined to be traveling, and otherwise, the traveling state is determined to be stopped. If the traveling state is stopped, the offset detecting means 4
3 averages the signals emitted by the gyro 3 and uses it as an offset.

On the other hand, when the traveling state is traveling, the traveling direction detecting means 44 detects the geomagnetic direction by subtracting the bias of the direction circle center from the X and Y signals emitted by the geomagnetic sensor 2. The offset is subtracted from the signal generated by the gyro 3 to obtain the turning angle.

Then, after the azimuth change angle is obtained from the difference between the previous detected value and the present detected value of the geomagnetic azimuth, if the difference between the azimuth change angle of the geomagnetic azimuth and the turning angle of the gyro 3 is a predetermined value or more, it is instantaneous. If there is magnetic field disturbance, it is determined that there is no instantaneous magnetic field disturbance.

Further, the gyro azimuth is obtained by cumulatively adding the turning angle to the geomagnetic azimuth when there is no momentary magnetic field disturbance.
Then, the traveling direction is detected by weighted averaging the geomagnetic direction and the gyro direction with a weighting coefficient according to the disturbance of the magnetic field.

Next, the operation of the turning correction means 45 will be described with reference to FIG. First, at the start of turning correction, a point based on the X and Y signals corresponding to the traveling direction of the vehicle is extracted as a first point S1 (X1, Y1) contacting the inner circle of the arc, and as shown in FIG. 2 (a). , And two ranges P and Q of large and small are set on the XY coordinate centering on that point.

Further, when the point by the X and Y signals starts to draw a circular arc on the XY coordinates due to the turning of the vehicle, the maximum value (Xmax, Ymax) and the minimum value (Xmin, Ymin) of the X and Y signals are obtained.
) Is updated while the X or Y signal is the first point S1.
When there is a difference within a predetermined value with respect to the X1 or Y1 signal value of, the point by the X, Y signal is set as the second point S2.

Similarly, for the third point S3 and the fourth point S4, the X and Y signals which are within a predetermined value from the X or Y signals set as the points at the four corners of the rectangle.
Set points by signal.

Then, the points at the four corners of the rectangle have been extracted, the size of the circular arc, that is, the difference between the maximum value and the minimum value is equal to or greater than a predetermined value, and the points based on the latest X and Y signals are detected. When it enters the small range set at the start of turning, Fig. 2 (b)
As shown in, the calculation is performed so that the intersection point 0 of the two diagonal lines of the rectangle is the center of the azimuth circle.

Further, when the size of the arc exceeds a predetermined value, the point S5 by the latest X, Y signals passes through the large range without entering the small range set at the start of turning, or If the points at the four corners of the rectangle are not extracted, the center of the azimuth circle cannot be detected normally, and the correction is stopped.

Next, the operation of the automatic correction means 46 will be described with reference to FIG. First, when the azimuth circle radius which is the distance between the point and the center of the azimuth circle due to the X and Y signals and the fluctuations of the X and Y signals are equal to or less than the predetermined values, respectively, as shown in FIG.
The azimuth circle based on the Y signal is quantized to form an image, and a drawing plane as shown in FIG. 3B is created.

Then, in the pixel group on the drawing plane, in the portion where the thickness of the arc is large, only the pixel in the middle is left, and the other pixels are removed as noise to extract the arc.

Further, when the turning angle detected by the traveling azimuth detecting means 44 from the angular velocity signal of the gyro 3 is in the range of 80 degrees or more, the circular arc is divided into three equal parts, FIG. 3 (c).
Calculation of the coordinates (xo, yo) of the azimuth center q is performed using three pixels (m1 to m3) as shown in FIG.

That is, c ₁ = y ₂ −y ₁ c ₂ = x ₂ −x ₁ c ₃ = (y ₁ ² −y ₂ ² + x ₁ ² −x ₂ ² ) / 2 d ₁ = y ₃ −y ₁ If d ₂ = x ₃ −x ₁ d ₃ = (y ₁ ² −y ₃ ² + x ₁ ² −x ₃ ² ) / 2, then y ₀ = (d ₁ c ₃ −d ₃ c ₁ ) / (d ₂ c ₁ -d ₁ c
_{2) x 0 = - (c} 2 y 0 + c 3) / c 1 become. After the calculation of the center of the azimuth circle, if the distance between the center of the azimuth circle and each pixel is not within the predetermined range, the pixel is removed as noise.

Next, the operation of the ellipse correction means 47 will be described with reference to FIG. First, after subtracting the bias component (Xo, Yo) at the center of the azimuth circle as shown in FIG. 4A from the X and Y signals, the absolute value is obtained, and the fourth quadrant from the second quadrant of the azimuth circle is obtained. The X and Y signals in the quadrant are convoluted into the first quadrant as shown in FIG.

Then, the first quadrant is divided into, for example, four regions for each predetermined azimuth, m pieces of X and Y signals are stored for each corresponding region, and the X and Y signals stored for each region are stored. Are averaged by the following formula, and the representative point Pi (vi, u
i) In this embodiment, the representative points P ₁ , P ₂ , P ₃ and P ₄ are obtained.

[0120]

[Equation 1]

[0121]

[Equation 2]

Further, when all the representative points Pi for each area are obtained, the azimuth ellipticity k = b / a is calculated by the following equation using the representative points Pi, and the azimuth circular shape (ellipse) is calculated. Only the X signal is corrected by X ′ = X × k so that it becomes a perfect circle.

[0123]

(Equation 3)

[0124]

[Equation 4]

[0125]

(Equation 5)

[0126]

(Equation 6)

Next, the operation of the vehicle body magnetization occurrence determination means 48 will be described with reference to FIG. FIG. 5 shows an example of the shake of the X and Y signals generated when the vehicle body is magnetized. Here, the X and Y signals before the vehicle body is magnetized are on a point P6 on one circumference. On the other hand, it shows that the X and Y signals have moved to another position P7 on the circumference after the occurrence of the magnetization of the vehicle body.

Here, first, the traveling azimuth detecting means 44 determines whether or not the vehicle is traveling straight ahead based on the turning angle detected from the angular velocity signal of the gyro 3 as the second azimuth sensor.

The vehicle body magnetization occurrence judging means 48 calculates an average geomagnetic direction θ ₁ while traveling straight ahead, and after that, the X and Y signals have fluctuated by a predetermined value or more as shown by a dotted line W in a few seconds. The average geomagnetic azimuth θ immediately after
_{When 2} has an azimuth difference between θ ₁ and a predetermined value (constant C) or more, it is determined that the vehicle body is magnetized.

Further, the average azimuth difference between the geomagnetic azimuth and the gyro azimuth is obtained for each unit time, unit distance, and unit angle, and is compared with each predetermined value (constant C). When the vehicle has continuously run for a predetermined distance or more in the above state, it is determined that the vehicle body is magnetized.

After it is determined that the vehicle body has magnetized, the center of the azimuth circle is corrected by the automatic correction means 46 so that the geomagnetic azimuth is correct and all the azimuth differences are less than the respective predetermined values. It is determined that the vehicle body is not magnetized when the vehicle continuously travels or turns more than a predetermined angle.

When it is determined that the vehicle body is magnetized, the traveling direction detecting means 44 does not use the geomagnetic direction but calculates the traveling direction only by the turning angle detected from the gyro 3.

Example 2. In the first embodiment, the turning correction means 45 sets the four corners so that the intersection of the two diagonal lines of the rectangle becomes the center of the azimuth circle when the point by the X and Y signals enters the small range Q set at the start of turning. However, as shown in FIG. 6, the intersection 0'of the vertical bisectors of the long side and the short side of the rectangle may be calculated as the center of the azimuth circle, which is similar to the above embodiment. You can expect an effect.

Example 3. In the above-described first embodiment, when the size of the circular arc becomes equal to or larger than the predetermined value, the turning correction means 45 does not cause the point by the latest X and Y signals to fall within the small range Q set at the start of turning, and to make a large value. It is explained that the correction is stopped when the vehicle passes through the range P. However, when the turning angle of the vehicle being corrected is detected by the gyro 3 and the turning angle becomes a predetermined value or more, the size of the arc is a predetermined value. If it is less than the above, the correction may be stopped, and the same effect as that of the above embodiment can be expected.

Example 4. In the first embodiment, the automatic correction means 46 calculates the azimuth center q by extracting three pixels from the noise-removed pixel group forming the arc on the drawing plane as shown in FIG. 3B. As described above, if the azimuth circle center is calculated using the pixels extracted from the pixel group, the number of pixels used for the calculation and the calculation formula may be changed,
The same effect as that of the above embodiment can be expected.

Example 5. In the first embodiment described above, the automatic correction means 46 has been described to extract three pixels from the pixel group forming the arc on the drawing plane as shown in FIG. 3A to calculate the azimuth center q. A plurality of combinations of three pixels extracted from the pixel group may be created, a plurality of candidate points at the center of the azimuth circle may be calculated, and an average of them may be set as the center of the azimuth circle. You can expect an effect.

Example 6. In the first embodiment described above, the automatic correction means 46 has been described to extract three pixels from the pixel group forming the arc on the drawing plane as shown in FIG. 3A to calculate the azimuth center q. The calculated candidate points of the azimuth circle center q may be set according to the size of the circular arc, and the azimuth circle centers may be weighted and averaged to be updated, and the same effect as the above embodiment can be expected.

Example 7. In the first embodiment, the ellipse correction means 47 convolves the X and Y signals of the second quadrant to the fourth quadrant of the azimuth circle into the first quadrant, divides the area for each predetermined azimuth, and then stores the X and Y signals. However, the ellipticity may be calculated by setting a region for storing the X and Y signals in all directions of 360 degrees, or calculating the ellipticity by another calculation formula.
The same correction effect as in the above embodiment can be expected.

Example 8. In the first embodiment described above, the ellipse correction means 47 has been described as setting an area for storing the X and Y signals for each predetermined azimuth. However, the XY coordinates are divided into a plurality of areas and stored for each area. The azimuth circle ellipticity may be calculated from the average value of the X and Y signals, and the same effect as in the above embodiment can be expected.

Example 9. In the above-described first embodiment, the ellipse correction means 47 has been described as being divided into regions for each predetermined azimuth and then storing the X and Y signals. However, the instantaneous azimuth radius r r = √ {(X−X X ′ = X × R / r may be obtained by correcting the X signal so that _o ) ² + (Y−Y _o ) ² } becomes equal to the azimuth circle radius R detected during the turning correction. The same effect as that of the above-mentioned embodiment can be expected.

Example 10. In the first embodiment described above, the automatic correction means 46 has always been described to calculate and correct the azimuth circle center q, but only when the vehicle body magnetization occurrence determination means 48 determines that the vehicle body magnetization occurs. The calculation and correction of the center may be performed, and the same effect as the above embodiment can be expected.

Example 11. In the first embodiment, the vehicle body magnetization occurrence determination means 48 uses the gyro 3 as the geomagnetic direction and the second direction sensor for each unit time, unit distance and unit angle.
Detected the average heading difference of the gyro heading detected in the above, and explained that it was supposed that the car body was magnetized when running continuously for a predetermined distance or more with this being above a predetermined value. The average difference in azimuth change angle may be detected and compared with the respective predetermined values, and the same effect as in the above embodiment can be expected.

Example 12. In the above-described first and eleventh embodiments, the vehicle body magnetization occurrence determining means 48 has been described as the constant C, which is a predetermined value to be compared with the average azimuth difference or the azimuth change angle difference between the geomagnetic azimuth and the gyro azimuth, respectively. The predetermined value S is set to S = C (| r / R− by using the ratio of the azimuth circle radius r during traveling of the vehicle to the azimuth circle radius R detected during the correction.
1 | +1) may be set, and the same effect as the above embodiment can be expected.

[0144]

As described above, according to the invention of claim 1, the geomagnetic sensor for outputting the X and Y signals of the absolute direction corresponding to the traveling direction of the vehicle, and the progress of the vehicle from the X and Y signals. Advancing azimuth detecting means for obtaining the azimuth, and turning correction means for calculating the azimuth circle center on the XY coordinates by the X and Y signals and correcting the azimuth circle center according to the change in the magnetization amount of the vehicle body. The turning correction means extracts X and Y signals such that when the points on the XY coordinates are connected to form a rectangle that is in contact with the inner circle of the azimuth circle, and after the X and Y signals are extracted, the rectangular shape is extracted. Since it is configured so that the intersection of the diagonal lines is the center of the azimuth circle,
While avoiding the extraction of noisy X and Y signals,
Even if it is a turning correction in a place where there is an instantaneous magnetic field disturbance,
There is an effect that the one that can accurately detect the center of the azimuth circle is obtained.

According to the second aspect of the present invention, the turning correction means extracts the X and Y signals which form a rectangle which is tangent to the inner circle of the azimuth circle when the points on the XY coordinates are connected, and the X and Y signals are extracted. Since the intersection of the vertical bisectors of the long side and the short side of the rectangle is set as the center of the azimuth circle after the Y signal is extracted, the extraction of noisy X and Y signals can be avoided and the Even if the turning correction is performed in a place where there is a large disturbance in the magnetic field, there is an effect that the center of the azimuth circle can be accurately detected.

According to the third aspect of the present invention, the turning correction means sets two large and small ranges centered on the point by the X and Y signals at the start of correction, and then the azimuth circle obtained by turning the vehicle. When the arc of is larger than a predetermined value and the point by the X and Y signals returns to the small range again, it is determined that the correction can be normally completed, and the range does not fall within the small range. Since it is configured to judge that the correction is abnormally terminated when it passes through a large range, the detection of the center of the azimuth circle is automatically stopped when the instantaneous magnetic field disturbance is outside the allowable range. Even if the turning correction is performed in a place where there is an instantaneous magnetic field disturbance, there is an effect that it is possible to prevent erroneous detection of the azimuth center.

According to the fourth aspect of the present invention, the turning correction means sets the range around the point by the X and Y signals at the start of correction, and then the turning angle detected from the angular velocity signal becomes a predetermined value or more. If the size of the arc of the azimuth circle is less than a predetermined value, or if the points by the X and Y signals do not return to the set range again, it is determined that the correction is abnormally completed. Since it is configured to, when the instantaneous magnetic field turbulence is out of the allowable range, the detection of the center of the azimuth circle is automatically stopped and the turning correction is performed at the momentary magnetic field turbulence. There is an effect that it is possible to obtain what can prevent erroneous detection of the azimuth center.

According to the fifth aspect of the present invention, the automatic correction means extracts an arc after image-forming the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. Since the center is calculated and the azimuth circle radius and the fluctuations of the X and Y signals are each less than or equal to a predetermined value, the azimuth circle is imaged so that a pixel suitable for detecting the azimuth circle center can be obtained. Is extracted, there is an effect that the detection accuracy of the azimuth circle center and the reliability of the traveling azimuth can be improved.

According to the sixth aspect of the invention, the automatic correction means extracts an arc after forming the image of the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. The center is calculated, and when extracting the circular arc, only the pixels in the middle of the thickness are left in the portion where the thickness of the circular arc imaged above becomes large, and the rest are judged to be noise and removed. Therefore, by extracting the pixels suitable for detecting the center of the azimuth circle, there is an effect that the detection accuracy of the center of the azimuth circle and the reliability of the traveling direction can be improved.

According to the invention of claim 7, the automatic correction means extracts an arc after forming the image of the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. When the center is calculated and the above-mentioned image-shaped arc is within a predetermined angle range or more, the azimuth center is calculated using the pixels located at equal parts of the arc. There is an effect that it is possible to improve the detection accuracy of the azimuth circle center and the reliability of the traveling azimuth from the arcs obtained for each right turn and left turn.

According to the eighth aspect of the present invention, the automatic correction means extracts an arc after image-forming the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. Since the center is calculated and an average of a plurality of azimuth circle center candidate points calculated by combining a plurality of pixels on the above-mentioned image-shaped arc is used as the azimuth circle center, the arc is limited. Therefore, the best azimuth center can be detected, and as a result, the one that can improve the reliability of the traveling azimuth is obtained.

According to the ninth aspect of the present invention, the automatic correction means extracts an arc after forming the image of the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. Since the center is calculated and the azimuth circle center is updated by weighting according to the size of the arc imaged, the azimuth circle center can be stably detected and the reliability of the traveling azimuth can be improved. There is an effect that can be improved.

According to the tenth aspect of the invention, the automatic correction means extracts an arc after forming the image of the azimuth circle on the XY coordinates, and extracts the azimuth circle from at least three or more pixels forming the arc. If the distance between the calculated azimuth circle center and each pixel is not within the predetermined range by calculating the center, the pixel is determined to be noise and removed. It is possible to obtain a pixel capable of stably detecting the circular arc and the center of the azimuth circle from the pixels.

According to the eleventh aspect of the present invention, the ellipse correction means calculates the azimuth circle ellipticity from the average value of the X and Y signals stored for each predetermined azimuth, and corrects the X and Y signals. Since it is configured as described above, by correcting the azimuth circle (ellipse) while the vehicle is traveling so as to be a perfect circle, there is an effect that the traveling azimuth can be satisfactorily detected even in a place where there is magnetic field distortion.

According to the twelfth aspect of the present invention, the ellipse correction means has one or two quadrants among the four quadrants of the azimuth circle, the X and Y signals of the other quadrants. Is convoluted and the azimuth ellipticity is calculated from the average value of the X and Y signals stored for each predetermined azimuth, and the X and Y signals are corrected. There is an effect that the Y signals can be quickly aligned, the azimuth ellipticity can be calculated in response to the magnetic field distortion, and the X and Y signals can be corrected.

According to the thirteenth aspect of the present invention, the ellipse correction means divides the XY coordinates into a plurality of areas, and calculates the azimuth ellipticity from the average value of the X and Y signals stored for each area. Since the calculation is performed and the X and Y signals are corrected, the X and Y signals are corrected so that the azimuth circular shape (ellipse) during traveling of the vehicle becomes a perfect circle, so that even when there is magnetic field distortion. In addition, it is possible to obtain the one that can detect the traveling direction satisfactorily.

According to the fourteenth aspect of the present invention, the ellipse correction means is configured to correct the X and Y signals so that the azimuth circle radius detected at the time of turning correction becomes equal to the instantaneous azimuth circle radius. Therefore, even if there is an instantaneous disturbance of the magnetic field,
There is an effect that it is possible to obtain the one that can detect the traveling direction satisfactorily.

According to the fifteenth aspect of the present invention, the vehicle body magnetization occurrence determining means determines that the point on the arc of the XY coordinates remains at another position when it is returned after being shaken in one direction. Since the presence / absence of magnetization of the vehicle body is determined by the detection, the presence / absence of magnetization of the vehicle body can be accurately determined immediately after the occurrence of magnetization of the vehicle body.

According to the sixteenth aspect of the present invention, the vehicle body magnetization occurrence determining means obtains an average heading difference between the geomagnetic heading and the second heading for each unit time, unit distance and unit angle. It is determined that the vehicle body is magnetized when the vehicle travels for a predetermined distance or more in a state in which the bearing difference is a predetermined value or more.
Since it is configured to judge that the vehicle body is not magnetized when the vehicle turns more than a certain distance or more than a certain angle in a state where all the average heading differences are less than a predetermined value, the vehicle body is not magnetized when an orientation error occurs in the geomagnetic direction. There is an effect that it is possible to accurately determine the presence of magnetism.

According to the seventeenth aspect of the present invention, when the traveling azimuth detecting means determines that the vehicle body is magnetized, the geomagnetic azimuth is not used for calculating the traveling azimuth, and only the output of the second azimuth sensor is used. Since it is configured to calculate the heading,
There is an effect that the one that can improve the reliability of the traveling direction is obtained.

According to the eighteenth aspect of the invention, the automatic correction means is configured to immediately start the correction of the center of the azimuth circle when it is determined that the vehicle body is magnetized. There is an effect that the one that can improve the reliability of the traveling direction is obtained.

According to the nineteenth aspect of the present invention, the vehicle body magnetization occurrence determining means obtains an average azimuth change angle difference between the geomagnetic azimuth change angle and the second azimuth change angle for each unit time, unit distance and unit angle. , When any one of the average azimuth change angle differences is equal to or greater than the predetermined value, it is determined that the vehicle body is magnetized when the vehicle travels a predetermined distance or more, and all the average azimuth change angle differences are less than the predetermined value. Since it is determined that the vehicle body is not magnetized when the vehicle turns more than a certain distance or more than a certain angle in a certain state, it is possible to accurately determine that the vehicle body is magnetized when an azimuth change angle error occurs in the geomagnetic direction. There is an effect that the one that can improve the reliability of the azimuth is obtained.

According to the twentieth aspect of the present invention, the vehicle body magnetization occurrence determination means is running the vehicle with respect to the azimuth circle radius detected at the time of turning correction with a predetermined value to be compared with the average azimuth difference or the azimuth change angle difference, respectively. Since it is configured to use the ratio of the azimuth circle radius of, the vehicle body magnetization is erroneously determined when the point caused by the X and Y signals moves inside or outside the azimuth circle due to the ground distortion of the traveling place. There is an effect that what can be prevented is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an azimuth detecting apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of the turning correction means in the present invention.

FIG. 3 is an explanatory diagram showing the operation of the automatic correction means according to the present invention.

FIG. 4 is an explanatory diagram showing the operation of the ellipse correction means in the present invention.

FIG. 5 is an explanatory view showing the operation of the vehicle body magnetization occurrence determination means according to the present invention.

FIG. 6 is an explanatory view showing another turning correction operation by the turning correction means in the present invention.

FIG. 7: X of direction detection output by a conventional direction detection device
-It is explanatory drawing which shows the azimuth circle drawn on a Y coordinate.

FIG. 8 is an explanatory diagram showing a method of correcting an azimuth circle of XY coordinates from an elliptical shape to a perfect circular shape in a conventional azimuth detecting apparatus.

FIG. 9 is a block diagram showing a conventional azimuth detecting device.

10 is a flowchart showing an operation of the azimuth detecting apparatus in FIG.

FIG. 11 is a flowchart showing the operation of ellipse correction by the conventional azimuth detecting device.

FIG. 12 is an explanatory diagram showing an operation of automatic correction by a conventional azimuth detecting device.

FIG. 13 is a block diagram showing another conventional direction detecting device.

14 is a flowchart showing the operation of automatic correction in the azimuth detecting apparatus of FIG.

FIG. 15 is a block diagram showing another conventional azimuth detecting device.

FIG. 16 is a flow chart showing a vehicle body magnetization occurrence determination operation in a conventional azimuth detecting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 distance sensor, 2 geomagnetic sensor, 3 gyro (angular velocity sensor), 5 storage means, 44 traveling direction detection means, 45 turning correction means, 46 automatic correction means, 47
Ellipse correction means, 48 Body magnetization occurrence determination means.

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[Procedure amendment]

[Submission date] August 4, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 11

[Correction method] Change

[Correction content]

FIG. 11

Claims (20)

[Claims] 1. An absolute azimuth X according to a traveling azimuth of a vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with a turning correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the turning correction means, when the points on the XY coordinates are connected, Extract the X and Y signals that form a rectangle that touches the circle,
An azimuth detecting device, characterized in that, after the extraction of the X and Y signals, the intersection of the diagonal lines of the rectangle is the center of the azimuth circle. 2. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with a turning correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the turning correction means, when the points on the XY coordinates are connected, Extract the X and Y signals that form a rectangle that touches the circle,
An azimuth detecting apparatus, characterized in that, after the extraction of the X and Y signals, the intersection of the vertical bisectors of the long side and the short side of the rectangle is the center of the azimuth circle. 3. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device having a turning correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the turning correction means has a large or small size centered on a point based on the X and Y signals at the start of correction. After setting the two ranges, when the arc of the azimuth circle obtained by turning the vehicle becomes larger than a predetermined value, the point by the X and Y signals returns to the small range again. The azimuth detecting apparatus is characterized in that it is judged that the correction can be normally completed when the above condition is satisfied, and that the correction is abnormally ended when the condition has passed through the large range without entering the above small range. 4. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, an angular velocity sensor that outputs an angular velocity signal according to a change in the traveling direction of the vehicle, a traveling direction detecting means that obtains a traveling direction of the vehicle from the X and Y signals and the angular velocity signal, and X by X, Y signal
In the azimuth detecting device including a turning correction means for calculating the center of the azimuth circle on the Y coordinate and correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the turning correction means is provided when the correction is started. The size of the arc of the azimuth circle is less than or equal to a predetermined value when the turning angle detected from the angular velocity signal is greater than or equal to a predetermined value after setting the range centered on the point by the X and Y signals, or The azimuth detecting device is characterized in that when the point by the X and Y signals does not return to the set range again, it is judged that the correction is abnormally ended. 5. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with an automatic correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the automatic correction means after the azimuth circle on the XY coordinates is imaged. An arc is extracted, the azimuth circle center is calculated from at least three or more pixels forming the arc, and the azimuth circle image is obtained when the azimuth circle radius and the fluctuations of the X and Y signals are each less than or equal to a predetermined value. An azimuth detecting device characterized by being imaged. 6. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with an automatic correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the automatic correction means after the azimuth circle on the XY coordinates is imaged. A circular arc is extracted, the center of the azimuth circle is calculated from at least three or more pixels forming the circular arc, and the portion in which the thickness of the circular arc imaged during the circular arc extraction is in the middle of the thickness is a pixel. The azimuth detecting device is characterized in that only the noise is left and the others are judged to be noise and removed. 7. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with an automatic correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the automatic correction means after the azimuth circle on the XY coordinates is imaged. An arc is extracted, the azimuth circle center is calculated from at least three or more pixels forming the arc, and when the arc imaged is within a predetermined angle range or more, the arc is divided into equal parts. An azimuth detecting device, characterized in that an azimuth circle center is calculated using a certain pixel. 8. An absolute azimuth X according to a traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with an automatic correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the automatic correction means after the azimuth circle on the XY coordinates is imaged. An arc is extracted, an azimuth circle center is calculated from at least three or more pixels forming the arc, and a plurality of azimuth circle center candidate points calculated by a combination of a plurality of pixels on the arc imaged above are calculated. An azimuth detecting device, characterized in that an averaged one is used as a center of an azimuth circle for correction. 9. An absolute azimuth X according to the traveling azimuth of the vehicle,
A geomagnetic sensor that outputs a Y signal, a traveling direction detection unit that obtains a traveling direction of the vehicle from the X and Y signals, and a azimuth circle center on the XY coordinates based on the X and Y signals,
In an azimuth detecting device provided with an automatic correction means for correcting the center of the azimuth circle in response to a change in the amount of magnetization of the vehicle body, the automatic correction means after the azimuth circle on the XY coordinates is imaged. A circular arc is extracted, the azimuth circle center is calculated from at least three or more pixels forming the circular arc, and the azimuth circle center is updated by weighting according to the size of the circular arc imaged. Direction detection device. 10. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
An azimuth detecting device comprising an automatic correction means for calculating the azimuth circle center on the XY coordinates based on the X and Y signals and correcting the azimuth circle center in accordance with a change in the magnetization amount of the vehicle body,
The automatic correction means extracts an arc after imaging the azimuth circle on the XY coordinates as an image, calculates the azimuth circle center from at least three or more pixels forming the arc, and calculates the calculated azimuth circle center. And the distance between each pixel is not within the specified range,
An azimuth detecting device characterized in that the pixel is determined to be noise and removed. 11. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
Turning correction means for calculating the center of the azimuth circle on the XY coordinates based on the X and Y signals and correcting the center of the azimuth circle in accordance with the change in the amount of magnetization of the vehicle body, and the azimuth circle while the vehicle is traveling. In an azimuth detecting device provided with an ellipse correcting means for correcting the shape into a perfect circle, the ellipse correcting means calculates an azimuth circle ellipticity from an average value of the X and Y signals stored for each predetermined azimuth,
An azimuth detecting device characterized by correcting the X and Y signals. 12. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
Turning correction means for calculating the center of the azimuth circle on the XY coordinates based on the X and Y signals and correcting the center of the azimuth circle in accordance with the change in the amount of magnetization of the vehicle body, and the azimuth circle while the vehicle is traveling. In the azimuth detecting device having an ellipse correcting means for correcting the shape into a perfect circle, the ellipse correcting means is provided in one or two quadrants of four quadrants of the azimuth circle from the first quadrant to the fourth quadrant. The X and Y signals of other quadrants are convoluted, and the azimuth circle ellipticity is calculated from the average value of the X and Y signals stored for each predetermined azimuth to correct the X and Y signals. Azimuth detecting device. 13. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to the traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
Turning correction means for calculating the center of the azimuth circle on the XY coordinates based on the X and Y signals and correcting the center of the azimuth circle in accordance with the change in the amount of magnetization of the vehicle body, and the azimuth circle while the vehicle is traveling. In an azimuth detecting device having an ellipse correcting means for correcting the shape into a perfect circle, the ellipse correcting means divides the XY coordinates into a plurality of areas, and stores the X, Y coordinates stored in each area.
The azimuth ellipticity is calculated from the average value of the Y signals, and the above X, Y
An azimuth detecting device characterized by correcting a signal. 14. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
Turning correction means for calculating the center of the azimuth circle on the XY coordinates based on the X and Y signals and correcting the center of the azimuth circle in accordance with the change in the amount of magnetization of the vehicle body, and the azimuth circle while the vehicle is traveling. In the azimuth detecting device having an ellipse correcting means for correcting the shape into a perfect circle, the ellipse correcting means corrects the X and Y signals based on the azimuth circle radius detected at the time of performing the turning correction. Characteristic direction detection device. 15. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to the traveling azimuth of the vehicle, and a traveling azimuth detecting unit that obtains the traveling azimuth of the vehicle from the X and Y signals.
A vehicle body magnetization occurrence determination means for determining the presence or absence of vehicle body magnetization from the locus of points on the XY coordinates by the X and Y signals, and an azimuth circle center on the XY coordinates by the X and Y signals. In an azimuth detecting device having an automatic correction means for calculating and correcting the azimuth circle center in accordance with a change in the magnetization amount of the vehicle body, the vehicle body magnetization occurrence determining means is located on the arc of the XY coordinates. An azimuth detecting device for determining whether or not a vehicle body is magnetized by detecting that a certain point is shaken in one direction and then returned to another position. 16. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of a vehicle, a second azimuth sensor that detects azimuth information of the vehicle from other than geomagnetism, the geomagnetic sensor and the second. Whether or not the vehicle body is magnetized is determined by comparing the geomagnetic orientation and the second orientation with a traveling orientation detection unit that obtains the traveling orientation of the vehicle using the geomagnetic orientation and the second orientation detected by the orientation sensor. In the azimuth detecting device including the vehicle body magnetization occurrence determining means, the vehicle body magnetization occurrence determining means obtains an average bearing difference between the geomagnetic bearing and the second bearing for each unit time, unit distance and unit angle, When any one of the average heading differences is equal to or greater than a predetermined value, it is determined that the vehicle body is magnetized when traveling for a predetermined distance or more, and all the average heading differences are less than the predetermined value. The azimuth detecting apparatus is characterized in that it is determined that the vehicle body is not magnetized when the vehicle turns by a predetermined distance or more or a predetermined angle or more in a state of being turned on. 17. A geomagnetic sensor that outputs an X and Y signal of an absolute azimuth according to a traveling azimuth of a vehicle, a second azimuth sensor that detects azimuth information of the vehicle from other than the geomagnetism, the geomagnetic sensor and the second. Whether the vehicle body is magnetized by comparing the geomagnetic direction and the second direction or the advancing direction with the advancing direction detecting means for obtaining the advancing direction of the vehicle using the geomagnetic direction and the second direction detected by the direction sensor, respectively. In the azimuth detecting device provided with the vehicle body magnetization occurrence determining means, the traveling azimuth detecting means does not use the geomagnetic azimuth for calculating the traveling azimuth when it is determined that the vehicle body magnetization occurs. An azimuth detecting apparatus, which calculates a traveling azimuth based only on outputs of two azimuth sensors. 18. A geomagnetic sensor that outputs X and Y signals of an absolute azimuth according to a traveling azimuth of a vehicle, a second azimuth sensor that detects azimuth information of the vehicle from other than geomagnetism, the geomagnetic sensor and the second Whether or not the vehicle body is magnetized is determined by comparing the geomagnetic orientation and the second orientation with a traveling orientation detection unit that obtains the traveling orientation of the vehicle using the geomagnetic orientation and the second orientation detected by the orientation sensor. A vehicle body magnetization occurrence determination means and an automatic correction means for calculating the azimuth circle center on the XY coordinates by the X and Y signals and correcting the azimuth circle center according to the change of the magnetization amount of the vehicle body. In the azimuth detecting device, the azimuth detecting device is characterized in that the automatic correction means immediately starts correction of the center of the azimuth circle when it is determined that the vehicle body is magnetized. 19. A geomagnetic sensor that outputs X and Y signals of an absolute azimuth according to a traveling azimuth of a vehicle, a second azimuth sensor that detects azimuth information of the vehicle from other than geomagnetism, the geomagnetic sensor and the second Car body magnetization is generated by comparing the azimuth change angles of the geomagnetic azimuth and the second azimuth with the advancing azimuth detecting means for obtaining the azimuth of the vehicle using the geomagnetic azimuth and the second azimuth detected by the azimuth sensor, respectively. In the azimuth detecting device including a vehicle body magnetization occurrence determining means for determining the presence or absence of the magnetic field, the vehicle body magnetization occurrence determining means determines the geomagnetic azimuth change angle and the second azimuth change angle for each unit time, unit distance and unit angle. The average difference in azimuth change angle is calculated, and it is determined that the vehicle body is magnetized when the vehicle has run for a predetermined distance or more with any of the average azimuth change angle differences being equal to or larger than the predetermined value. Further, the azimuth detecting device is characterized in that it is determined that the vehicle body is not magnetized when the vehicle turns by a predetermined distance or more or a predetermined angle or more in a state where all the average azimuth change angle differences are less than a predetermined value. 20. The vehicle body magnetization occurrence determining means uses a predetermined value to be compared with an average azimuth difference or azimuth change angle difference, respectively, using a ratio of the azimuth circle radius during traveling of the vehicle to the azimuth circle radius detected during turning correction. The azimuth detecting device according to any one of claims 16 to 19, wherein the azimuth detecting device is set as follows.