JPS58135412A - Direction arithmetic device - Google Patents

Abstract

PURPOSE:To display the correct traveling direction, the present position, etc. of a traveling object regardless of the difference of magnetization and declination, by correcting the declination shift that is produced when a traveling object containing a direction arithmetic device having an earth magnetism sensor is shifted toward a region having a different declination. CONSTITUTION:A computer executes a prescribed program when a vehicle containing an earth magnetism sensor 30 is traveling, and an exciting circuit 60 applies the exciting signal to an exciting winding 32 of the sensor 30 on the basis of the constant voltage supplied from a constant voltage circuit 80. The signals corresponding to the angle formed by the winding direction of the output winding and the horizontal component of the earth magnetism are fed to a microcomputer 110 from the 1st and 2nd output windings 33 and 34 of the sensor 30 via an output circuit 70 and an A/D converter 100. A correction switch 90a feeds a signal to the computer 110 to correct an error caused by the magnetization of the car; while a correction switch 90b feeds the declination correcting signal produced with a change of the traveling region to the computer 110. Then the corrected traveling direction of the car is displayed to a direction display 140.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an azimuth calculation device, and more particularly to a azimuth calculation device suitable for calculating the direction in which a moving object such as a vehicle is traveling.

Conventionally, this type of direction calculation device uses a ring-shaped magnetic D
K. A geomagnetic sensor formed by winding an excitation winding and winding first and second output windings orthogonally to each other so as to surround mutually opposing portions of the magnetic core is installed, for example, on the body of a vehicle. When fixed to a part of the roof and applying an excitation voltage to the excitation winding, under the excitation state of the magnet 1b, the direction of the horizontal component of the earth's magnetic field and the first and second
The first and second output voltages are generated in accordance with each angular difference with each winding direction of the output winding, and the direction in which the vehicle is traveling is calculated based on the relationship between these two output voltages. There is something configured.

However, in the azimuth calculation device 1t configured in this way, when the vehicle is magnetized, the magnetic field based on the magnetization effect and the horizontal component of the geomagnetism are combined so that the [j component field acts on the geomagnetic sensor. As a result, errors occur in each of the angular differences, resulting in a problem that the heading direction of the vehicle cannot be calculated properly. Furthermore, even if the vehicle is not magnetized, if the vehicle is driven in an area where the declination angle with respect to the horizontal component of the earth's magnetic field is different, the geomagnetic sensor may be fixed to the roof of the vehicle in advance. Therefore, the deviation of the declination angle causes an error in each of the above-mentioned angular differences, resulting in a problem that the traveling direction of the vehicle cannot be properly calculated.

The present invention has been made with this in mind, and its first object is to provide an azimuth calculation device equipped with a geomagnetic sensor that detects the angular difference between a predetermined reference direction and the direction of geomagnetism. An azimuth calculation device configured to correct a deviation in declination caused by a moving object mounted thereon when it moves to an area with a different declination angle by driving a geomagnetic sensor according to declination information regarding the moving area. Our goal is to provide the following.

A second object of the present invention is to reduce the detection error from the geomagnetic sensor caused by the magnetization when the moving object is magnetized once by combining the resultant magnetic field between the geomagnetism and the magnetism caused by the magnetization. Corrected to appropriate values in relation to 1. Another object of the present invention is to provide an azimuth calculation device that corrects deviations in declination angles in the same way as in the case described above.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
6 to 6 show an example in which the present invention is applied to an orientation display device, and in FIG. 1, reference numeral 10 indicates a casing fixed to a part of the roof of a vehicle body. Inside the casing 10 is a support body 20 in which a geomagnetic sensor 60 and a large-diameter spur gear 40a are integrally assembled.
A rotating shaft 21 that passes through an annular magnetic core 61 of the geomagnetic sensor 60 and extends vertically is rotatably supported horizontally between the top and bottom walls of the casing 10 by a pair of bearings 11 and 12. A support plate 22 made of a circular printed circuit board is fitted into the support plate 21 at its center 0 part, perpendicularly to the support plate 21 . The support plate 22 includes a plurality of support arms 26a,
..., 26e supports the magnetic core 31 of the geomagnetic sensor 60 in a water 1F shape relatively immovably, and a plurality of slip rings 24al..., 24θ are provided on the upper surface of the support plate 22.
is formed as shown in FIG.

The k-holding arms 26a, -'-, and 26e are all made of a conductive material having appropriate mechanical strength, and each inserts the printed circuit board 22 into the slip ring 24 at its upper end.
a, ..., 24e (in Fig. 2, the support arm 23c, the slip ring 24C of 25θ
, 24e). Also, a slip ring 24a.

, 24e, brushes 16a, . ing.

As shown in FIGS. 1 and 6, the geomagnetic sensor 60 includes the above-mentioned annular magnetic core 31, an excitation winding 62 that is wound around the magnetic core and excites the magnetic core 31, and the magnetic cores 61 facing each other. The magnetic core 61 generates a first output signal having a level corresponding to a first angular difference between the winding direction and the direction of the horizontal component of the earth's magnetic field. The first output winding 66 is wound so as to surround the mutually opposing portions of the magnetic core 31 perpendicular to the first output winding 63, and the winding direction and the direction of the water/F component force of the geomagnetic field are The second output winding 34 generates a second output signal having a level corresponding to the second angular difference between the magnetic core 31 and the magnetic core 31. The spur gear 40a is pivotally supported by the rotating shaft 21 of the support body 20, and a small diameter spur gear 401) pivotally supported by the output shaft of a four-phase pulse motor 50 meshes with this spur gear 402. The pulse motor 50 is housed in a recess in the bottom wall of the casing 10, and is horizontally rotatable with its output shaft. Note that the excitation winding 32 has both terminals connected to support arms 26a.

23b'. Also, the first and second
The common terminal of the output windings 35, 54 is connected to the lower end of the support arm 23d, and the remaining terminals of each output winding 36, 34 are connected to the respective lower ends of the support arm 23C923θ.

As shown in FIG. 3, the excitation circuit 60 is connected at its Okayama terminal to the brushes 15a and 13b extending outward through the insulator 13 and the L wall of the casing 10, and is connected to the constant voltage circuit 80. An excitation signal (for example, an AC signal) necessary to excite the magnetic core 31 of the geomagnetic sensor 30 is generated based on the constant voltage applied to the slip ring 2.
4a and 24b to the excitation winding 32. The output processing circuit 70 outputs the brush 16a at its x3 input terminal.
.

Brush 130 + 1 extending outward similarly to 151)
5 d+138, and form a timing signal of a predetermined period in response to an excitation signal from the excitation circuit 60 under a constant voltage from the constant voltage circuit 80.
The first output signal from the output winding 33 is transferred to the slip ring 23.
d, 23e and the brushes 13d, 13e, and receives the second output signal from the second output winding 54 through the slip rings 23c, 25d and the brushes 13c, 13d, and receives these Okayama power signals. After each amplification, sampling and holding is performed in response to the timing signal, and both sampling and holding results are set to levels corresponding to the above-mentioned same angle difference! , 7 (hereinafter referred to as the first level x and the second level /L/y). Note that the constant voltage circuit 80 is supplied with power from the vehicle battery B when the main switch SW is closed, and generates a constant voltage.

The microcomputer 110, as shown in FIG.
Constant voltage circuit 801 calibration calibration switch a.

90b and the A-D converter 100, and when the calibration switch 90a is closed, the calibration switch 90a sends a magnetization calibration command signal necessary to correct the output error of the geomagnetic sensor 60 caused by the magnetization of the vehicle. occurs, while the calibration switch 901
) is a declination calibration command signal necessary to correct the output error of the geomagnetic sensor 30 caused by the deviation of the declination with respect to the horizontal component force direction of the earth's magnetism when the driving area of the vehicle changes. occurs. A/D converter 100 converts the first and second analog signals from output processing circuit 70 into sequential first and second digital signals.

In addition, in this embodiment, each calibration switch 90a.

90b is provided at a suitable location within the vehicle interior.

The microcomputer 110 is formed by an LSI and becomes activated in response to a constant voltage from the constant voltage circuit 80, and is a central processing unit (hereinafter referred to as CPU).
, input/output device (hereinafter referred to as), read-only
It includes a memory (hereinafter referred to as ROM), a random access memory (hereinafter referred to as RAM), and a clock circuit.

% applies both calibration command signals from the calibration switches 9oa and 90b to cptr, and also applies each digital signal from the AD converter 100 to the RAM. Also, ROM
Predetermined computer programs necessary for the CPU to execute according to the flowcharts shown in FIGS. 4 to 6 are stored in advance.

The CPU executes a computer program in response to a series of clock signals generated from the clock circuit in cooperation with a crystal oscillator, and during the execution performs various arithmetic processes as described in the operation explanation below, It generates an azimuth display signal necessary to display the traveling direction of the vehicle, and also generates a vehicle rotation command signal and a magnetization calibration completion signal during magnetization calibration. In addition, when calibrating the declination, the CPU also calculates the azimuth setting command signal necessary to set the vehicle to true north, the first motor rotation command signal necessary to rotate the geomagnetic sensor 30 by a predetermined angle, and the deviation of the declination. A second motor rotation command signal and a declination angle calibration completion display signal necessary to rotate the geomagnetic sensor 60 by an angle necessary for correction are generated.

The drive circuit 120 responds to the direction display signal from the CPU, generates the content of the direction display signal as a drive signal, and applies it to the direction display 140. The direction indicator 140 is provided in the cabin of the vehicle, and on the inside of the display surface,
As shown in FIG. 3, eight light emitting diodes are arranged radially at equal angular intervals to display eight directions.

In this case, one direction of each of these light emitting diodes coincides with true north (hereinafter referred to as north) and coincides with the forward direction of the vehicle. Thus, the direction indicator 140 configured as described above responds to the drive signal from the drive circuit 120 and causes the light emitting diode corresponding to the content of the drive signal to emit light by conduction, thereby displaying the traveling direction of the vehicle.

The message display 150 is not a dot matrix display, but its drive unit decodes the content of this signal in response to a vehicle rotation command signal (or magnetization calibration completion display signal) from the CPU, and displays the decoding result. , a command message to the effect of ``rotating the vehicle'' (or a message of ``magnetization calibration completed'') is displayed in a dot matrix by an electroluminescent effect. In addition, the message display 150 uses its drive unit to decode the content of this signal in response to the direction setting command signal (or declination calibration completion signal) from the CPU, and interprets the decoding result as "the forward direction of the vehicle". A command message to the effect of ``set the declination to true north'' (or a message to the effect that ``declination calibration has been completed'')
Displayed as a dot matrix by electroluminescence. The drive circuit 130 responds to the first motor rotation command signal (or the second motor rotation command signal) from the CPU and converts the contents of the first motor rotation command signal (or the contents of the second motor rotation command signal) into the first drive. It is generated as a signal (or a second drive signal) and applied to the pulse motor 50.

In this embodiment configured as described above, when mounting the direction display device on the vehicle, the vehicle is demagnetized in advance, and the geomagnetic sensor 30 assembled inside the casing 10 is mounted on the heavy vehicle. It is fixed parallel to the horizontal part of the roof of the car body. In addition, geomagnetic sensor 3
It is assumed that the winding direction of the first output winding 32 of 0 coincides with the direction of the horizontal component of earth's magnetism at the current position of the vehicle. In this case, since the brushes 156 to ISe are slidably and securely in contact with the slip rings 24a to 24e of the support plate 22, the winding direction of the first output winding 62 is caused by mechanical vibration etc. It does not deviate from the direction of the component force.

In this state, when the vehicle is driven forward and the direction display device is activated, the excitation winding 32 of the geomagnetic sensor 30 is activated by the magnetic core 3 in response to an excitation signal from the excitation circuit 60.
1 is maintained in the excited state, the Tomoni microcomputer 110 activates the patch IJ with the main switch SW closed.
The CPU operates in response to the constant voltage from the constant voltage circuit 8'0 generated in cooperation with the constant voltage circuit 8'0, and starts executing the computer program at step 200 according to the flowchart of FIG.

When the computer program proceeds to step 210, 0
The PTT initializes the contents of the microcomputer 110, and then the computer program is transferred to the calibration switch 9.
The process advances to step 220 in which it is determined whether or not a magnetization calibration command signal is generated from 0a. At this stage, if calibration switch 9 (M remains open, CP
Step 24 in which U determines "NO" in step 220, and the computer program determines whether or not a declination calibration command signal is generated from the calibration switch 90t).
Advance to 0. At this stage, the calibration switch 901)
is open, (!PU is in step 240
If the answer is NO, the computer program proceeds to step 260. Then, the first
The first and second analog signals generated from the output processing circuit 70 corresponding to the first and second output signals from the second output windings 33 and 34 are sequentially converted into the first and second analog signals by the A/D converter 100. It is converted into a second digital signal and then R
Stored in AM.

When the computer program proceeds to step 270, C
PU converts the first digital signal value X to the first correction value X0F
F8F! T (currently zero due to initialization) is subtracted to obtain the first subtraction value X, and the second correction value yoFFsET is obtained from the second digital signal irMy.
(At this stage, it is zero due to initialization) is subtracted by 7 times to obtain the second subtraction value Y. Then, in step 280, the CPU calculates the traveling direction of the coasting vehicle from the ratio of the second subtraction value f[Y to the first subtraction value X in step 270, and this calculation result is used as a direction display signal in step 290. Amount of drive generated:? Granted to % 120. Then, at W, the dynamic circuit 120 decodes the azimuth display signal in response to the azimuth display signal from the CPU, and applies this V4R result to the azimuth display 140 as a drive signal. As a result, the direction indicator 140! In response to the drive signal from the 114 motion circuit 120, the light emitting diode corresponding to this signal is connected]1@
This signal is transmitted to allow the driver to visually confirm the direction in which the vehicle is traveling.

If the driver discovers that there is an error between the current heading and the content displayed on the heading indicator 140 while the above-described driving conditions continue, the driver should first rotate the vehicle. At the same time, a magnetization calibration command signal is generated from the calibration switch 90a. Thereafter, when the computer program proceeds to step 220, the CPU determines that "yEsJ" based on the generation of the magnetization calibration command signal from the calibration switch 90a, and executes the magnetization calibration shown in the flowchart of FIG. Proceed to routine 230.The CPU then proceeds to step 26.
At step 1, the execution of the magnetization calibration routine 230 is started, and at this stage, the first and @2 signals are sequentially generated from the A-D converter 100 in response to the first and second analog signals from the output processing circuit 70. In step 232, the value X of the first digital signal is set as the second level maximum value XMAXx, and is also set as the first level XYMAX corresponding to the second level maximum value YMAX.

When the computer program proceeds to step 262a,
The CPU sets fly of the second digital signal in step 231a as the second level maximum value YMAX and also sets it as the second level YXMAX corresponding to the second level maximum value XMAX, and in the next step 233,
A rotation command pattern (previously stored in the ROM) corresponding to the command message to make the vehicle rotate once is generated as a vehicle rotation command signal, and the message display 150
granted to.

Then, the message display device 150 uses its driving section to display CP.
The content of the vehicle rotation command signal from U is decoded, and the decoding result is displayed in a dot matrix as a command message to ``make the vehicle rotate once'' by means of an electroluminescent effect. This causes the driver to start rotating the vehicle.

When the computer program proceeds to step 234 with the start of rotation of the vehicle, the CPU stores the first and d32 digital numbers 1d generated from the A-D converter 100 at this stage in the RAM, and executes the computer program. , Xu*x < x Step 23
Proceed to 5. Then, if the set result XMAX in step 232 is not smaller than the value X of the first digital signal in step 234, the determination result in step 235 becomes "NO". On the other hand, if the set result XMAX in step 232 is smaller than the value X of the first digital signal in step 234, the cPU determines "YBsJ" in step 235, and
5a, the value X of the first digital signal in step 234 is updated as the maximum rubel value xIJAX, and the value y of the second digital signal in step 234 is updated.
is the second level YXM corresponding to the second rubel maximum value XMAX
Update as AX.

The computer program performs step 235 or 235a.
Step 266 to determine if YMAX < y from
Proceeding to step 262a, the second level maximum value YMA! is not smaller than the value y of the second digital signal in step 234, the determination result in step 236 becomes "NO". On the other hand, step 7” 232a
If the second level maximum value YMAX at is smaller than the value y of the second digital signal at step 234,
In step 266, the CPU determines that the value y of the second digital signal in step 434 is "I'ygs", and updates the value y of the second digital signal in step 434 as the second level maximum iYMAX, and updates the value It is updated as the second level XYIjAX corresponding to the 2nd level maximum ti YMAX.

Therefore, when the computer program proceeds from step 266 or 236a to step 267 in which it is determined whether the rotation of the vehicle has ended, it is determined that the vehicle is currently rotating and a magnetization calibration command signal is generated from the calibration switch 902. Therefore, the CPU determines "NO" and returns the computer program to step 234. After that, the CPU repeats the calculations through steps 234 to 237 of the computer program during the rotation of the vehicle,
``!3 Calibration switch 90a upon completion of rotation of the vehicle
When the Jw magnetic calibration command li from
The latest XYMAX in step 266a is set as the first
It is updated as a correction value X0FIF81CT and stored in the RAM, and in step 268a, the latest YXMAI in step 235a is updated as a second correction value YOFPSET and stored in the RAM. This means that the magnetization calibration has been properly performed.

When the computer program proceeds to step 239, C
The PU generates a magnetization calibration completion display pattern (previously stored in the ROM) corresponding to the message indicating "Magnetization calibration completion" as a magnetization calibration completion display signal, and applies it to the message display 150. . Therefore, the message display 150 uses its drive unit to decode the contents of the magnetization calibration completion display signal from the CPU, and sends this decoding result as a message that means "magnetization calibration complete" by electroluminescent action. Display dot matrix. As a result, the driver visually confirms the completion of the magnetization calibration based on the content displayed on the message display 150.

After completing the magnetization calibration routine 250 at each step 239a, the computer program proceeds to step 260, where the CPU currently outputs the first and second digital ICs originating from the A-D converter 100. In the next step 270, the first correction value X0FFSICT in step 238 is subtracted from the value X of the first digital signal in step 260 to obtain the first subtraction value X, and the second correction value in step 238 is Y
OFFSET is subtracted from the value y of the second digital signal at step 260 to obtain a second subtracted value Y. Next, in step 280, the CPU calculates each subtraction value X obtained in step 270 in the same manner as described above.
Calculate the traveling direction of the vehicle from Y and display this as direction display 1
, occurs as No. As a result, the direction indicator 140
A drive circuit 120 that responds to an orientation display signal from the CPU.
The light emitting diode emits light by the cooperative action with the light emitting diode. As a result, the driver can confirm the traveling direction of the vehicle and the direction display 140.
It is possible to check whether there are any errors between the displayed content and the displayed content.

If it is determined that the above-mentioned error exists at this stage, the driver determines that the error is due to the yaw angle, drives the vehicle directly to an appropriate nearby service station, and switches the calibration switch. 901) to generate a declination calibration command signal. Thereafter, when the computer program proceeds to step 240, the CPU turns on the calibration switch 90.
Based on the generation of the declination angle calibration command signal from b, it is determined that it is YE8J, and the computer program proceeds to the declination angle calibration routine 250 shown in the flowchart of FIG.

When the computer program proceeds to step 251a,
An azimuth setting command pattern (preliminarily stored in the ROM) corresponding to the command message to align the traveling direction of the vehicle with true north is generated from the CPU as an azimuth setting command signal and is applied to the message display 150. Then, the message display device 150 uses its drive unit to decode the content of the direction setting command signal from the CPU, and electrically outputs the decoding result as a command message to "align the traveling direction of the vehicle with true north." A dot matrix display is created by the luminescence effect. Therefore, the driver can use the message display 150
The user visually confirms the displayed content, sets the vehicle to the true north setting equipment of the service station so that the traveling direction of the vehicle coincides with true north, and eliminates the declination calibration command signal from the calibration switch 901).

Therefore, when the computer program proceeds to step 252 where it determines whether the declination calibration command signal disappears, C
Based on the disappearance of the declination calibration command signal from the calibration switch 90b as described above, the PU
1, and in the next step 252a, the geomagnetic sensor 3
0, that is, the initial rotation angle value θ of the pulse motor 50. (In this example, θ.=0) is the rotation angle θ, and then,
The computer program proceeds to step 253. Then, the second output from the second output winding 34 of the geomagnetic sensor 60
The second signal generated from the output processing circuit 70 corresponding to the output No. 1d
The analog digital signal d is converted into a second digital signal by the A/D converter 100 and stored in the RAM under the control of the cPU.

When the computer program proceeds to step 2530,
The CPU sets the value y of the second digital signal in step 253 to the second level maximum value YMAX, and sets the rotation angle θ in step 252a to the rotation angle maximum value θ &
[Set AX, and in the next step 254, the first rotation command necessary to rotate the pulse motor 50 in the forward rotation direction (or reverse rotation direction) by a predetermined angle Δθ (previously stored in the ROM) Generates a signal and drives the drive circuit 130
granted to. Then, the drive circuit 160 generates a first drive signal and applies it to the pulse motor 50 in response to the first motor rotation command signal from the CPU. Next, pulse motor 5
0 rotates to a predetermined angle in the normal rotation direction (or reverse rotation direction) by θ in response to the first drive signal from the drive circuit 160, and along with this, the spur gear 4Qa is rotated under the rotational action of the spur gear 401). rotates in the reverse direction (or forward direction), and the support plate 2
2 rotates integrally with the spur gear 40a' under the sliding action of the brushes 13a to 13e against the slip rings 24a to 24e. This means that the magnetic core 61 of the geomagnetic sensor 30 rotates integrally with the support plate 22 by a predetermined angle Δθ in the reverse direction (or 11 millimeter rotation direction).

When the computer program proceeds to step 254a,
The CPU adds a predetermined angle Δθ to the rotation f(1θ) obtained in step 252a and renews it as a new rotation angle θ.
The computer program proceeds to step 255 where it determines for 360°<0.

However, at this stage, as understood from the above, 660°>θ, so the CPU determines "NO" at step 255, and at step 256, the A-D converter 100 at this stage The second digital signal generated from the YM is stored in the RAMK, and the computer program is
The process advances to step 257 where it is determined whether Ax<y. In this case, the second level maximum value Y in step 256a
If IllAx is not smaller than the value y of the second digital signal in step 256, the determination result in step 257 becomes "No". On the other hand, the second level maximum III in step 253a! YMAX is step 25
If it is smaller than the value y of the second digital signal at 6, then
(!The PU determines [YESJ in step 257, and then in step 257a, the value y of the second digital signal in step 256 is set to the new second level maximum IF
fMAX is set, and the rotation angle θ in step 25411 is newly set to the rotation angle maximum value θMAI.

After the calculation in step 257 or 257a is completed, the CPU repeats the calculation in steps 254 to 257a of the computer program, and
When the rotation angle θ repeatedly updated in step 4a becomes 360° or more, it is determined in step 255 that “Y Ei SJ”, and in step 258 the step motor 5 is rotated until the latest rotation angle maximum value θMAI obtained in step 257a.
A second motor rotation command signal necessary to rotate the motor 0 is generated and applied to the drive circuit 160. Then, step motor 5
0 is C! The latest rotation angle maximum value θ is determined by the action of the drive circuit 160 in response to the second motor rotation command signal from the PU.
The support plate 22 rotates to MAX, and the support plate 22 rotates under the rotational action of the spur gears 406, 401) as in the case described above. This means that 6a and 51 of the geomagnetic sensor 30 rotate to the maximum value θMAX of the Jl new rotation angle in the same way as the step motor 50, and as a result, the first output winding 32 of the geomagnetic sensor 30 rotates The winding direction corresponds to the direction of the horizontal component of the geomagnetic force at the current position of the vehicle.

When the computer program proceeds to step 259, O
'PU gives a declination calibration completion display pattern (previously stored in the ROM) corresponding to the message indicating completion of declination calibration to the message display 150 as a declination calibration completion display signal. For this reason, the message display device 150
The drive section decodes the content of the declination calibration completion display signal from the CPU, and displays the decoding result in a dot matrix by electroluminescence as a message meaning "Declination calibration complete." When the computer program proceeds to step 260 after the declination calibration routine 250 ends in step 259a, the CPU at this stage
The first and second digital signals originating from the converter 100 are stored in RAM, and in the next step 270, the first and second digital signals are stored in step 26.
The first and second correction values xOFFS at 8 and 238a
ET m Calculate the first and second subtraction values X and Y based on the YOIPF81CT and the values X and 7 of the first and second digital words in step 260, and based on these calculation results X and Y. The traveling direction of the vehicle is determined in step 280.
This is calculated in step 290, and is generated as a direction indicating signal in step 290. As a result, the direction indicator 140 causes the light emitting diode to emit light in substantially the same manner as in the case described above to indicate that the traveling direction of the vehicle is due north. As a result, the driver can confirm that the display error of the direction display device has been completely eliminated.

Next, a modification of the above embodiment will be described with reference to FIGS. 7 to 9. In this modification, the position detector 65 is assembled inside the casing 10, and the amplifier circuit 35 (l
is connected between the position detector 35 and the microcomputer 110: and a card reader 111 is connected to the microcomputer 110. The position detector 65 is
It is composed of a photocoupler 35a and a disc 35b, and the disc 35b is horizontally fitted to the rotating shaft 21 of the support 2o at its center, and radially and horizontally at its circumference. The first output winding 35c of the geomagnetic sensor 60 is perforated so as to be perpendicular to the winding direction of the first output winding 3°3. Therefore, in the position detector 35, if the disc 35b rotates and moves horizontally between the light emitting part and the light receiving part of the photocoupler 35a at its circumference, light from the light emitting part of the photocoupler 35a is emitted. passes through the slit 55c of the disc 35b and passes through the photocoupler 35. When the light is received by the light receiving section of the geomagnetic sensor 30, a light reception signal is generated from the photocoupler 35a as a reference signal representing the reference position of the geomagnetic sensor 30. Note that the photocoupler 556 is fixed to the end of the bottom wall of the casing 10 with the screw 14 at its mounting portion.

The amplifier circuit 55d generates a light emission signal necessary to cause the light emitting part of the photocoupler 35a to emit light based on the constant voltage from the constant voltage circuit 8o, and applies it to the photocoupler 35a, and also outputs an ant quasi signal from the photocoupler 35a. The signal is amplified and applied to the microcomputer 110 as an amplified reference signal. When the card reader 111 receives a magnetic card 111a in which a proper declination angle is magnetically stored as a pattern corresponding thereto, the card reader 111 sends the contents of the magnetic card 111a as a declination signal to the microcomputer 110.

In the microcomputer 110, the declination calibration routine 300 shown in the flowchart of FIG. 9 is the declination calibration routine 2 shown in the flowchart of FIG.
50 is stored in advance in the ROM. Also, C.P.
U is used to rotate the geomagnetic sensor 30 by a predetermined angle during execution of the declination calibration routine 600, in place of the above-mentioned azimuth setting command signal, first and second motor rotation command signals, and declination calibration completion display signal. A necessary third motor rotation command signal and a fourth motor rotation command signal necessary to rotate the geomagnetic sensor 30 by an angle corresponding to the contents of the declination signal are generated. The other configurations are substantially the same as those of the previous embodiment.

In this modified example configured as above, if the determination result in step 24o (see FIG. 4) of the computer program is "yEsJ", the CPU executes the argument calibration routine 300 according to the flowchart in FIG. The process starts in step 301, and in step 302, a sixth motor rotation command signal necessary to rotate the geomagnetic sensor 30 by a predetermined angle is generated and applied to the drive circuit 130.Then, the drive circuit 130 starts the rotation of the sixth motor from the CPU. A sixth drive signal is generated in response to the rotation command signal to drive the pulse motor 5.
Assigned to 0. As a result, the pulse motor 50 rotates by a predetermined angle, and the support body 20 is rotated in conjunction with the spur gears 40a and 40b. This means that the geomagnetic sensor 30 and the disk 55b rotate by the predetermined angle described above.

However, at this stage, assuming that the amplification reference signal is not generated from the amplifier circuit 55d, the CPU determines "No" in step 303 and returns the computer program to step 302. After that, both steps 502.30
5, the disk 35b and the geomagnetic sensor 60 continue to rotate as the rotation angle of the pulse motor 50 increases, and the slit 55c of the disk 35b connects to the photocoupler 352.
When detected, a reference signal is generated from the photocoupler 35a and is applied to the amplified reference signal and the city microcomputer 110 under the control of the amplification circuit 55d.

Next, in step 303, the cpU determines "yII!sJ" based on the amplification reference signal, and in step 304, reads the argument signal from the card reader 111.

However, it is assumed that the magnetic card 111a has been inserted into the card reader 111 in advance. Then, in the next step 305, the CPU generates the contents of the declination signal based on the declination signal in step 304 as a fourth motor rotation command signal. Then, the pulse motor 50 rotates by an angle corresponding to the contents of the argument signal under the control of the drive circuit 160 responsive to the fourth motor rotation command signal. In other words, the geomagnetic sensor 60 rotates by an appropriate declination angle from the reference position defined by the reference signal from the position detector 35. Note that if the computer program proceeds to step 280 as in the previous embodiment, it can be confirmed that the display contents of the direction indicator 140 are correct.

In the above embodiments and modifications, the other magnetic V sensor 60 is connected to a pair of spur gears 4Qa, 4Qb and a pulse motor 5.
Although the example in which the geomagnetic sensor 60 is rotated by 0 has been described, instead of this, for example, the geomagnetic sensor 60 may be rotated by a pair of bevel gears and a DC motor.

In addition, in the above-mentioned embodiments and modifications, an example in which the present invention is adopted as a direction display device has been described, but instead of this, for example, the present invention may be adopted and implemented as a current position display device of the vehicle. Good too. In this case, a distance sensor i is used to detect the traveling distance of the vehicle, and the microcomputer 110 determines the current traveling position of the vehicle based on the value of the detection signal from the distance sensor and the traveling direction determined in step 280. The current traveling position may be displayed by an appropriate electrical display means in response to the calculation result. In this case, a circular winding installed vertically so as to interlink with the lines of magnetic force caused by the earth's magnetism is rotated horizontally to detect a sine wave voltage induced in the circular winding in relation to the earth's magnetic field, and the vehicle Another geomagnetic sensor that detects the rotational position of the annular winding may be used in place of the geomagnetic sensor 60, and the traveling direction of the vehicle may be calculated from the rain detection results from the geomagnetic sensor. . Note that the present invention is of course applicable not only to vehicles but also to various types of moving bodies such as ships.

In addition, in the above embodiment, when magnetization calibration and declination calibration are performed together, it is necessary to perform the calculation in the declination calibration routine 250 after the calculation in the magnetization calibration routine 230 is completed. , since the magnetic card 111a is used, the magnetization calibration Lunitine 23
0 and the declination calibration routine 300 may be performed first.

As explained above, in the azimuth calculation device according to the present invention, as exemplified in the above embodiments and modified examples, the azimuth calculation device is provided in a part of a moving body to detect the angular difference between a predetermined reference direction and the direction of geomagnetism. A driving means is connected to a geomagnetic sensor that generates this as a detection signal, and a driving means is connected to a geomagnetic sensor that generates this as a detection signal, and a ru A feature of the configuration is that an output signal necessary for driving the geomagnetic movement sensor is generated and applied to the driving means to correct the reference direction in accordance with the declination information regarding the moving area. As a result, even if the moving body enters a movement area with a different declination angle, the reference is adjusted according to the declination determined in the movement area described above under the drive of the geomagnetic sensor 11 by the driving means. The direction can be stopped, and therefore the heading which is the calculation result of the calculation means can always be correctly obtained.

As a result, when the device of the present invention is adopted and implemented as an azimuth display device, current position display device, etc. of various moving objects, the moving direction, current traveling position, etc. of the moving object can be displayed regardless of the difference in declination. It can always be displayed correctly.

Furthermore, in the azimuth calculation device according to the present invention described above,
When the movable body is magnetized, the calculation means calculates the value of the detection signal generated from the geomagnetic sensor during the rotation of the movable body according to 11. , generating an output signal necessary for driving the geomagnetic sensor so that the value is corrected as a value necessary for calculating the heading, and the reference position is corrected according to the declination information, and the driving means Therefore, even if the movable object enters a movement area with a different declination angle in a magnetized state, it will be determined in that movement area regardless of the magnetized state, in the same way as in the case described above. The reference direction can be corrected in accordance with the declination angle, and therefore,
The heading which is the calculation result of the calculation means can always be obtained correctly. As a result, when the device of the present invention is adopted and implemented as an azimuth display device, current position display device, etc. of various moving objects,
The moving direction, current position, etc. of the moving body can always be displayed correctly regardless of differences in its magnetization and declination.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a main part of the device of the present invention, Fig. 2 is a perspective view showing the state of sliding contact between the slip ring and the brush, Fig. 3 is a block diagram of the device of the present invention, and Figs. 4 to 6 3 is a flowchart showing the operation of the microcomputer in FIG. 3, FIG. 7 is a sectional view showing a modification of the device of the present invention in FIG. 1, and FIG. 8 is a block diagram for the modification of FIG. 7.
and FIG. 9 is a flowchart showing the operation of the microcomputer in FIG. 8. Explanation of symbols 20... Prong body, 60... Geomagnetic sensor, 35...
・Position detector, 40a, 40b... Spur gear, 50...
・Pulse motor, 70...Output processing circuit, 100...
・A-D converter, 110... microcomputer,
111... Card reader, 130... Drive circuit. Applicant Nippondenso Co., Ltd. Agent Patent Attorney Teru Hase - 1st Prisoner 2N

Claims (1)

[Claims] m. A geomagnetic sensor that is installed in a part of a moving object and generates a signal by detecting and transmitting an angular difference between a predetermined reference direction and the direction of the ground -°C, and this geomagnetic sensor. In the azimuth calculation device I'l, the azimuth calculation device I'l is equipped with a calculation means for calculating the progress and position of the mobile object according to the value of the detection signal from the azimuth sensor, and a drive connected to the geomagnetic sensor to drive the geomagnetic sensor. and means for providing declination information regarding the moving area of the moving body described in +iif above in said calculation means, and said calculation means corrects the rail reference position in accordance with said declination information. An azimuth calculating device characterized in that the g/c is applied to generate an output signal necessary for driving the geomagnetic sensor according to 011 and apply it to the driving means. (2) A geomagnetic sensor that is installed on a part of the moving body and detects the angular difference between a predetermined reference direction and the direction of geomagnetism and generates a detection signal based on the detection signal from this geomagnetic sensor. The azimuth calculation device includes a calculation means for calculating the traveling direction of the mobile object, and the azimuth calculation device includes a driving means connected to the geomagnetic sensor to drive the geomagnetic sensor, and also provides declination information regarding the moving area of the mobile object. When the moving body is magnetized, the computing means is configured to calculate the value of the detection signal generated from the geomagnetic sensor during the rotation of the moving body from the geomagnetism and the magnetism of the moving body. Driving the geomagnetic sensor so that the value is corrected as a value necessary for calculating the heading in relation to a composite magnetic field between the magnets, and the reference position is corrected in accordance with the declination information. An azimuth calculation device characterized in that it generates a necessary output signal and applies it to the driving means.