JP2010197123A - Electronic azimuth meter and azimuth correction control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform easily and precisely a calibration treatment such as two point correction in an electronic azimuth meter. <P>SOLUTION: The electronic azimuth meter includes a first memory control means which stores a first and a second data output from a geomagnetism detection means when a first switch is input (step S24), an azimuth memory control means which calculates and stores an azimuth indicated by an azimuth display means at inputting the first switch (step S25), and a specific azimuth indication control means which controls an azimuth display means to indicate the stored azimuth even when an instrument body is rotated during waiting a second switch input after the first switch input (S27, S28). A correction data is obtained from the data taken during the first and the second switch inputs (S31). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electronic azimuth meter having a correction function and an azimuth correction control method thereof.

  2. Description of the Related Art There has been known an electronic compass that detects a direction by a magnetic sensor that electrically detects geomagnetism, and indicates a direction by electrically driving a pointer or performing display output (for example, Patent Document 1). ).

  In addition, in such an electronic azimuth meter, a measurement error occurs due to the magnetic environment at the place of use or the magnetization of the electronic azimuth meter itself. Therefore, there is a technique for correcting such a measurement error by a calibration method called two-point correction. It has been proposed (for example, Patent Document 2).

  In the two-point correction, first, the output of the first magnetic sensor is taken in a state where the main body of the electronic compass is oriented in a certain direction on the horizontal plane, and then the main body of the electronic compass is 180 ° from the above direction on the horizontal plane. In the rotated state, the second output of the magnetic sensor is taken in, and the output offset of the magnetic sensor that generates a measurement error is obtained from these two outputs. And it becomes possible to correct | amend the measurement error of a magnetic sensor using the value of this output offset.

Japanese Patent No. 3316689 Japanese Patent No. 3476797

  In order to perform the two-point correction as described above, the user rotates the device body by 180 ° after capturing the output of the first magnetic sensor with the device body directed in a certain direction and before capturing the second output. There must be.

  The operation of rotating the device main body by 180 ° is difficult to perform accurately unless the device main body is placed on a horizontal place and a mark line or the like as a reference for the rotation angle is provided. . For this reason, for example, when the user holds the device main body in his / her hand or is worn on his / her arm, there is a problem that an accurate two-point correction operation cannot be easily performed.

  An object of the present invention is to enable calibration processing such as two-point correction to be performed relatively easily and accurately in an electronic compass.

In order to achieve the above object, the invention according to claim 1
A geomagnetism detecting means for outputting first and second data corresponding to the strength of the first direction component of the geomagnetism and the second direction component intersecting the first direction;
Azimuth display means for pointing and displaying the azimuth;
First storage control means for storing the first and second data output from the geomagnetism detection means when there is a first switch input;
An azimuth storage control means for calculating and storing the azimuth indicated by the azimuth display means at the time of the first switch input based on the first and second data output from the geomagnetism detection means;
Second storage control means for storing the first and second data output from the geomagnetism detecting means when there is a second switch input;
Even if the device main body is rotated after waiting for the second switch input after the first switch input, the specific direction determined from the direction stored by the direction storage control means is the direction. A specific orientation instruction control means for controlling the orientation display means, as indicated by the display means;
Correction value calculation means for obtaining correction data based on the data stored by the first and second storage control means;
After the correction data is obtained by the correction value calculation means, the first and second data output from the geomagnetism detection means are corrected based on the correction data, and the corrected first and second data are corrected. Azimuth calculating means for obtaining the azimuth based on the data of
It is an electronic azimuth meter provided with.

The invention according to claim 2 is the electronic azimuth meter according to claim 1,
The specific orientation indicated by the orientation display means during standby for the second switch input is the same orientation as the orientation indicated by the orientation display means at the time of the first switch input. Yes.

The invention according to claim 3 is the electronic azimuth meter according to claim 1,
The specific orientation indicated by the orientation display means during standby for the second switch input is an orientation rotated 180 ° from the orientation indicated by the orientation display means at the time of the first switch input. It is a feature.

The invention according to claim 4 is the electronic azimuth meter according to claim 1,
Reference position instruction control for controlling the azimuth display means so that the azimuth display means points to a predetermined reference position on the apparatus main body from the standby of the first switch input to the time of the first switch input. Means
Furthermore, it is characterized by having.

The invention according to claim 5 is the electronic azimuth meter according to claim 1,
Correction start control means for shifting to the correction mode by a predetermined operation input;
The first switch that waits for the first switch input to be performed by giving a notification for instructing the first switch input in a state where the device main body is directed in a certain direction when the correction mode is entered. Input waiting means;
When the first switch input is made, a second switch that waits for the second switch input to be issued by giving a notification to instruct to rotate the device main body by 180 ° to perform the second switch input Input waiting means;
Correction end control means for releasing the correction mode when the correction data is obtained by the correction value calculation means when the second switch is input;
It is characterized by having.

The invention according to claim 6 is the electronic azimuth meter according to claim 1,
The azimuth display means is configured to point and display the azimuth with a rotatable pointer.

The invention according to claim 7 is the electronic azimuth meter according to claim 1,
The azimuth display means is configured to point and display the azimuth by segment display or dot display.

The invention according to claim 8 provides:
A geomagnetism detecting means for outputting first and second data corresponding to the strength of the first direction component of the geomagnetism and the second direction component intersecting the first direction, and a first output from the geomagnetism detecting means. The correction data is obtained by being executed by a control unit of an electronic azimuth meter having an azimuth calculating means for calculating an azimuth based on the first and second data and the correction data, and an azimuth display means for indicating and displaying the azimuth. An azimuth correction control method for an electronic compass,
A correction start control step for shifting to a correction mode when a predetermined operation input is received;
The first switch that waits for the first switch input to be performed by giving a notification for instructing the first switch input in a state where the device main body is directed in a certain direction when the correction mode is entered. An input waiting step;
A reference position instruction control step for controlling the azimuth display means so that a predetermined reference position on the device body is pointed to by the azimuth display means during standby for the first switch input;
A first storage control step of storing the first and second data output from the geomagnetism detection means in a storage unit when the first switch input is made;
An azimuth storage control step of calculating the azimuth indicated by the azimuth display means at the time of the first switch input based on the first and second data output from the geomagnetism detection means and storing it in a storage unit;
When the first switch input is made, a second switch that waits for the second switch input to be issued by giving a notification to instruct to rotate the device main body by 180 ° to perform the second switch input An input waiting step;
Even when the device main body is rotated while waiting for the second switch input, the direction display means is controlled so that the specific direction stored by the direction storage control step is indicated by the direction display means. A specific orientation instruction control step;
A second storage control step of storing the first and second data output from the geomagnetism detection means in the storage unit when the second switch is input;
A correction value calculating step for obtaining the correction data based on the data stored by the first and second storage control steps;
A correction end control step of canceling the correction mode after input of the second switch;
It is characterized by having.

  According to the present invention, when the device main body is rotated while waiting for the second switch input, control is performed so that the specific direction is indicated by the direction display means. By rotating the device body reliably, the device body can be accurately rotated at a predetermined rotation angle from when the first switch is input to when the second switch is input. Thereby, there is an effect that an accurate correction process can be easily realized.

It is a top view which shows the external appearance of the electronic direction meter of embodiment of this invention. It is a block diagram showing the whole electronic azimuth meter composition of an embodiment. It is the block diagram which showed the detail of the magnetic sensor. It is a graph showing the relationship between the detection data calculated | required from the output of a magnetic sensor, and an azimuth | direction, (a) is a graph when there is no output offset, (b) is a graph when it has an output offset. It is the flowchart which showed the control procedure of the direction measurement process performed by CPU. It is explanatory drawing which showed the outline | summary of the flow of a 2 point | piece correction process. It is the first half part of the figure explaining the state change of the electronic azimuth meter along the flow of the two-point correction process. It is the latter half part of the figure explaining the state change of the electronic azimuth meter along the flow of a two-point correction process. It is the flowchart which showed the control procedure of the 2 point | piece correction mode process performed by CPU. It is a top view which shows the other example of an electronic azimuth meter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view showing the external appearance of an electronic compass according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the overall configuration of the electronic compass.

  The electronic azimuth meter 100 according to this embodiment has two functions of a clock function and an azimuth meter function, and is a device that is used by being worn on an arm, for example. As shown in FIG. 1, the electronic azimuth meter 100 has an hour hand 102 and a minute hand 103 for indicating an hour and a minute, and a second hand 104 for indicating and displaying a second and an azimuth on a dial 101. It is provided in the state. A part of the dial plate 101 is provided with a digital display unit 106 such as a liquid crystal display. Further, around the electronic azimuth meter 100, a plurality of operation buttons b1 to b6 for inputting operation commands from the user are provided.

  As shown in FIG. 2, the electronic azimuth meter 100 includes a magnetic sensor 1 that detects geomagnetism, an amplifier circuit 5 that amplifies the difference between the two output voltages PS1 and PS2 of the magnetic sensor 1, and an amplifier circuit 5 A / D conversion circuit 6 that converts the output voltage Vs of the A / D converter into a digital value, a register 7 that temporarily stores the output of the A / D conversion circuit 6, and a CPU (Central Processing Unit) that performs overall control of the device ) 11, a ROM (Read Only Memory) 12 that stores a control program and control data, a RAM (Random Access Memory) 13 that provides a working memory space to the CPU 11, and a switch input having the operation buttons b1 to b6 Unit 15, a counting circuit 14 c that counts time and date, an oscillation circuit 14 a and a frequency dividing circuit 14 b that supply signals of a constant period to the counting circuit 14 c, and a bias magnetic field to the magnetic sensor 1. It includes a bias coil CL1, CL2 for antibody, and a coil driving circuit 9 and the waveform synthesizing circuit 10 for driving the bias coil CL1, CL2.

  Further, the electronic compass 100 has a gear train mechanism 23 which is a combination of a plurality of gears and rotates the minute hand 103 and the hour hand 102 in conjunction with each other, a step motor 22 which rotationally drives the train wheel mechanism 23, and A motor drive circuit 21, a gear train mechanism 26 for independently rotating the second hand 104, a step motor 25, a motor drive circuit 24, a display drive circuit 28 for driving the digital display unit 106, and the like are provided. Yes.

  Among the above-described configurations, the azimuth display means is configured by rotating the second hand 104 on the dial 101, and the geomagnetic detection means is configured by the magnetic sensor 1, the amplifier circuit 5, and the bias coils CL1 and CL2.

  FIG. 3 shows a detailed configuration diagram of the magnetic sensor.

  The magnetic sensor 1 includes four magnetoresistive elements MR1, MR2, MR3, and MR4 and four pads Pd1, Pd2, Pd3, and Pd4 formed on a substrate 1a. The magnetoresistive elements MR1, MR2, MR3, MR4 are arranged at angles orthogonal to the respective magnetic detection directions of the other magnetoresistive elements MR1, MR2, MR3, MR4 adjacent to each other. Further, each detection direction is formed so as to have an inclination of 45 degrees with respect to the vertical direction of the magnetic sensor 1 in FIG. Each of these magnetoresistive elements MR1, MR2, MR3, MR4 forms a bridge circuit via pads Pd1, Pd2, Pd3, Pd4, and a predetermined DC voltage is applied between a pair of opposed pads Pd1, Pd3. V is applied. Since each magnetoresistive element MR1, MR2, MR3, MR4 changes its resistance value due to the action of a magnetic field, each magnetoresistive element is applied with a predetermined DC voltage V applied between the pads Pd1, Pd3. When a magnetic field acts, the resistance value changes, and voltages PS1 and PS2 corresponding to the magnetic field are generated at the pads Pd2 and Pd4. The azimuth is detected based on the differential amplification output Vs representing the difference between the voltages PS1 and PS2 output from the amplifier circuit 5.

  Further, as shown in FIGS. 3 and 2, two bias coils CL <b> 1 and CL <b> 2 that are orthogonal to each other are wound around the magnetic sensor 1. The bias coil CL1 generates bias magnetic fields B1 and B2 that are phase-inverted in the front-rear direction of the magnetic sensor 1 (the direction that forms 45 ° with the magnetic detection direction of each magnetoresistive element) depending on the direction of the current that flows. The other bias coil CL2 generates bias magnetic fields B3 and B4 that are phase-inverted in the left-right direction of the magnetic sensor 1 (a direction that forms 45 ° with the magnetic detection direction of each magnetoresistive element) depending on the direction of the current that flows.

  FIG. 4 shows a graph showing the relationship between the detection data X, Y obtained from the output of the magnetic sensor and the direction. FIG. 4A is a graph when there is no output offset, and FIG. 4B is a graph when there is an output offset.

  In the graph of FIG. 4, “detection data” on the vertical axis is detection data obtained from the differential amplification output Vs of the magnetic sensor 1, and “angle” on the horizontal axis is when the magnetic sensor 1 is rotated 360 ° on the horizontal plane. The rotation angle is shown. One graph line (X) indicates detection data X obtained by generating bias magnetic fields B3 and B4 orthogonal to the measurement direction by energization of the bias coil CL2, and the other graph line (Y) indicates the bias coil CL1. Detection data Y obtained by generating bias magnetic fields B1 and B2 parallel to the measurement direction by energization is shown.

  Here, the detection data X corresponds to the first data, and the differential amplification output Vs when the bias magnetic field B4 is generated is subtracted from the differential amplification output Vs when the bias magnetic field B3 is generated. It is a voltage value, and shows a value corresponding to the strength of the measurement direction component of geomagnetism. The detection data Y corresponds to the second data, and is a voltage obtained by subtracting the differential amplification output Vs when the bias magnetic field B2 is generated from the differential amplification output Vs when the bias magnetic field B1 is generated. This value is a value corresponding to the strength of the direction component orthogonal to the geomagnetic measurement direction.

  When the magnetic sensor 1 has no offset, the detection data X and Y obtained from the output of the magnetic sensor 1 change sinusoidally according to the measurement direction (angle) as shown in FIG. The detection data X has a maximum value at an azimuth angle of 0 °, while the detection data Y has a maximum value at an azimuth angle of 90 °. Further, the amplitude of the detection data X and the amplitude of the detection data Y can be made substantially equal.

Therefore, by obtaining the two detection data X1 and Y1 based on the output of the magnetic sensor 1 at an arbitrary measurement orientation θ1, the measurement orientation θ1 can be obtained as in the following equation (1).
θ1 = tan ⁻¹ (Y1 / X1) (1)

  However, in reality, since an offset occurs in the magnetic sensor 1, the detection data X and Y obtained from the output of the magnetic sensor 1 are as shown in FIG. That is, the detection data X and Y are values obtained by adding the offset values HX and HY to values that change sinusoidally.

  The offset values HX and HY can be obtained as follows. That is, two detection data HY1 and HY2 are obtained from an arbitrary angle θ2 and an angle θ3 rotated 180 ° therefrom. And the offset value HY is obtained by calculating these arithmetic mean. The offset value HX for the detection data X can be obtained similarly. As described above, the output of the magnetic sensor 1 is acquired at two points of the arbitrary angle θ2 and the angle θ3 rotated by 180 ° therefrom, and the offset values HX and HY are obtained from these outputs by two-point correction. It is processing.

Since the offset values HX and HY are already known, the offset values HX and HY are subtracted from the detection data X and Y obtained from the output of the magnetic sensor 1, so that the offset as shown in FIG. The corrected detection data after correction can be obtained. Therefore, even when an offset occurs in the magnetic sensor 1, the measurement direction θ1 can be obtained as in the following equation (2).
^{θ1 = tan -1 [(Y1a-} HY) / (X1a-HX)] ··· (2)

  Next, the operation of the electronic azimuth meter 100 configured as described above will be described.

  The electronic azimuth meter 100 has a time display mode for displaying time and an azimuth measurement mode for measuring and displaying the azimuth as a plurality of operation modes. In addition to these operation modes, various setting modes are provided. Among the setting modes, there is a two-point correction mode for performing azimuth measurement calibration processing. These operation modes and setting modes are switched by a switch input process performed by the CPU 11 when a predetermined operation command is input from the user via the switch input unit 15 (operation buttons b1 to b6). When the mode is shifted to the time display mode, the CPU 11 executes a time display process, and when the mode is shifted to the direction measurement mode, the direction measurement process and the direction display process are performed. If the mode is shifted to the two-point correction mode, the two-point correction mode process is executed. The switch input process, time display process, azimuth measurement process, azimuth display process, and two-point correction mode process are included in the control program stored in the ROM 12.

[Time display mode]
In the time display mode, the CPU 11 outputs a predetermined pulse to the motor drive circuits 21 and 24 based on the count data and the count operation of the count circuit 14c by the time display process. Accordingly, the hour / minute hands 102 and 103 and the second hand 104 are rotationally driven as time passes, and the time is displayed on the dial 101.

[Direction measurement mode]
In the direction measurement mode, the CPU 11 repeatedly executes the direction measurement process and the direction display process at short time intervals. The azimuth measurement process is a process for obtaining the azimuth from the output of the magnetic sensor 1, and the azimuth display process is a process for rotationally driving the second hand 104 to always indicate a predetermined direction based on the azimuth measurement result. First, the direction measurement process will be described.

  FIG. 5 shows a flowchart of the azimuth measurement process executed by the CPU 11.

  When the azimuth measurement process is started, the CPU 11 sequentially applies currents in the forward direction and the reverse direction to the bias coils CL1 and CL2 to generate the bias magnetic fields B1 to B4 (steps S1, S3, S5, and S7). When these bias magnetic fields B1 to B4 are generated, the value of the differential amplification output Vs of the magnetic sensor 1 is stored in the detection data memories V1 to V4 of the register 7 (steps S2, S4, S6, S8).

  When the four differential amplification outputs Vs are taken from the magnetic sensor 1 as described above, the detection data X and Y shown in FIG. 4 are calculated from these. That is, the difference between the values of the detection data memories V1 and V2 is calculated as the detection data Y (step S9). Further, the difference between the values of the detection data memories V3 and V4 is calculated as the detection data X (step S10). Here, the calculated detection data X and Y are the detection data shown in the graph of FIG.

  When the detection data X and Y are calculated, the detection data X and Y are substituted into the equation (Equation (2)) including the correction term based on the offset values HX and HY in the above-described equation for obtaining the azimuth, and the azimuth D is obtained. Is calculated (step S11: orientation calculation means). Here, the offset values HX and HY are previously obtained by two-point correction processing described later and stored in the register 7 or the RAM 13.

Next, in order to compensate for the uncertainty of the constant (π) of tan ⁻¹ , according to the sign of “X−HX” and the sign of “Y−HY” (steps S12 and S13), in step S11 The calculated D value is determined deterministically. That is, if both are positive values, the D value calculated in step S11 is directly used as a measurement result, and if X−HX is a negative value, 180 ° is added to the D value (step S14). Is the measurement result. If X-HX is a positive value and Y-HY is a negative value, 360 ° is added to the D value (step S15), and this is taken as the measurement result. By such processing, a measurement result of 0 ° to 360 ° as the azimuth angle D is obtained.

  The value of the azimuth angle D calculated in this way indicates the azimuth angle in which the measurement direction of the magnetic sensor 1 is oriented with respect to the north. Then, when the D value is calculated in this way, this azimuth measurement processing is terminated. The value of the azimuth angle D is stored in a predetermined area of the register 7 or RAM 13, and this azimuth measurement process is terminated.

  In the azimuth measurement mode, when the azimuth measurement process ends, the CPU 11 executes the azimuth display process. First, based on the azimuth angle D obtained by the azimuth measurement process, the number of steps from the current position of the second hand 104 to the predetermined direction so that the second hand 104 points in a predetermined direction (for example, the north direction or a user-specified direction). Is calculated. Next, the CPU 11 outputs a pulse for the number of steps to the motor drive circuit 24. Thereby, the second hand 104 is step-driven and moves to a position indicating a predetermined direction. In addition to these, the value of the azimuth angle D is displayed on the digital display unit 106. And this azimuth | direction display process is complete | finished.

  In the azimuth measurement mode, the azimuth measurement process and the azimuth display process are repeatedly performed at short time intervals, so that the second hand 104 always indicates a predetermined direction.

[2-point correction mode]
The two-point correction mode is shifted by a user operation input via the operation buttons b1 to b6. First, the outline of the two-point correction mode process will be described.

  FIG. 6 is an explanatory diagram showing an outline of the two-point correction mode processing, and FIGS. 7 and 8 are explanatory diagrams showing state changes of the electronic azimuth meter along the flow of the two-point correction mode processing. .

  The two-point correction mode can be shifted from the azimuth measurement mode. Therefore, the user performs a predetermined operation input and enters the azimuth measurement mode (step J1). When the azimuth measurement mode is entered, azimuth measurement is started. For example, if the electronic azimuth meter 100 is at an azimuth angle of 315 °, it is measured, and display output is performed according to the measurement result. For example, as shown in FIG. 7A, an azimuth angle of 315 ° is displayed on the digital display unit 106, and the north direction is indicated by the second hand 104. The hour hand 102 and the minute hand 103 remain at the current time (8 o'clock).

  In this state, when the user performs a predetermined operation input, the mode shifts to the two-point correction mode (step J3: correction start control means). When the processing in the two-point correction mode is started, as shown in FIG. 7B, the first button is pressed on the digital display unit 106 with the electronic azimuth meter 100 pointing in an arbitrary direction. A notification display of “−1−” representing the instruction content is performed (step J4). At the same time, the second hand 104 moves to a reference position (for example, a 00 second position) of the electronic azimuth meter 100.

  In accordance with this notification display, the user presses the operation button b1 with the electronic azimuth meter 100 oriented in a certain direction. Thus, the first output of the magnetic sensor 1 is acquired by the CPU 11 in a state where the electronic azimuth meter 100 faces an arbitrary azimuth angle.

  When the first output is acquired, subsequently, as shown in FIG. 7C, the digital display unit 106 is instructed to rotate the electronic compass 100 by 180 degrees and press the second button. A notification “-2-” is displayed (step J5).

  When the notification is displayed, the direction of the reference position pointed to by the second hand 104 when the first button input is performed by measuring the direction and driving the second hand 104 inside the electronic compass 100. The (specific direction) is controlled so that the second hand 104 continues to point even if the direction of the electronic compass 100 changes. Therefore, when the user displays the “-2-” notification, when the user rotates the electronic azimuth meter 100 by 90 ° on a horizontal plane (step J6), as shown in FIG. When the first operation button b1 is input, the user continues to point in a specific direction.

  Accordingly, as shown in FIG. 8 (e), the user rotates the electronic compass 100 until the second hand 104 overlaps the 6 o'clock position of the dial 101, depending on the direction indicated by the second hand 104. The electronic azimuth meter 100 can be rotated exactly 180 °. And if it rotates in this way, a user will input the operation button b1 for the 2nd time (step J7).

  When the second operation button b <b> 1 is pressed, the CPU 11 acquires the second output of the magnetic sensor 1. Then, predetermined calculation processing is performed internally, and offset values HX and HY of the magnetic sensor 1 are obtained. When the offset values HX and HY are obtained, the two-point correction mode processing is terminated and the normal azimuth measurement mode is resumed (step J8). And as shown in FIG.8 (f), it returns to the drive control and display output of the second hand 104 of azimuth | direction measurement mode.

  FIG. 9 shows a flowchart of the two-point correction mode process executed by the CPU 11.

  During the above two-point correction mode process, the following control process is executed inside the electronic azimuth meter 100. That is, when a predetermined operation input is made and the process proceeds to the two-point correction mode process, first, the CPU 11 performs control to move the second hand 104 to a reference position (for example, 12 o'clock position) on the dial 101 (step S21: reference). Position instruction control means). Specifically, the number of steps from the current position of the second hand 104 to the standard position (for example, 12 o'clock position) of the electronic azimuth meter 100 is calculated, and pulses corresponding to the number of steps are output to the motor drive circuit 24 to output the second hand. 104 is moved to the reference position.

  Next, the CPU 11 outputs to the display drive circuit 28 and displays the above-mentioned “−1−” on the digital display unit 106 (step S22). When this notification display is performed, the CPU 11 waits until the first operation button b1 is input (step S23: first switch input standby means).

  Here, when the operation button b1 is pressed by the user, the CPU 11 proceeds to the next step S24 and acquires the output of the magnetic sensor 1. That is, currents in the forward and reverse directions are passed through the bias coils CL1 and CL2 to sequentially generate the bias magnetic fields B1 to B4, and when the bias magnetic fields B1 to B4 are generated, the differential amplification output Vs of the magnetic sensor 1 is acquired. Detection data X and Y are calculated from these. This is the same processing as steps S1 to S10 in FIG. Then, the detected data X and Y are substituted into the correction data calculation variables HX1 and HY1 and stored in the register 7 or the RAM 13 (step S24: first storage control means).

  Subsequently, the CPU 11 calculates the value of the azimuth angle D in the 12 o'clock direction based on the detection data X and Y calculated in step S24 and stores the value in the register 7 or the memory unit Z in the RAM 13 (step S25: azimuth storage control). means). The calculation process of the azimuth angle D is performed by the same process as steps S11 to S15 in FIG.

  Next, the CPU 11 outputs to the display driving circuit 28 and displays the above-mentioned “-2-” on the digital display unit 106 (step S26). Then, when this notification display is performed, the process proceeds to a loop process of steps S27 to S29, and a process of waiting for input of the second operation button b1 while performing azimuth measurement and drive control of the second hand 104 is performed (second process). Switch input standby means).

  That is, when the process proceeds to the loop process of steps S27 to S29, first, an azimuth measurement process is performed to obtain the azimuth angle indicated by the 12 o'clock position of the dial 101 (step S27). This azimuth measurement process is the same as that described in FIG. Next, the number of steps for moving the second hand 104 is calculated from the obtained azimuth angle and the azimuth angle D stored in the memory unit Z in step S25, and the position of the azimuth angle D stored in the memory Z is calculated. (Step S28: specific direction instruction control means). Subsequently, it is determined whether or not the second operation button b1 is input (step S29). If there is no input, the process returns to step S27.

  By the loop processing of steps S27 to S29, the second hand 104 always points in the direction of the reference position when the first operation button b1 is input while waiting for the input of the second operation button b1, and the user designates the second hand 104. Depending on the direction, the electronic compass 100 can be rotated 180 ° accurately and easily.

  If the second operation button b1 is input during the loop process, the process exits the loop process and proceeds to the next step S30. After shifting to step S30, the CPU 11 first acquires the output of the magnetic sensor 1 in a state rotated by 180 °. That is, the same processing as steps S1 to S10 in FIG. 5 is performed. Then, the calculated detection data X and Y are substituted into the correction data calculation variables HX2 and HY2 and stored in the register 7 or the RAM 13 (step S30: second storage control means).

  At this stage, the values of the respective detection data X and Y at the arbitrary azimuth angle θ2 shown in the graph of FIG. 4B and the azimuth angle θ3 rotated 180 ° therefrom are acquired, and the variables HX1, HX2, HY1, The state is stored in HY2.

Therefore, offset values (correction data) HX, HY appearing in the azimuth angle calculation equation (formula (2)) are calculated from the values of these variables HX1, HX2, HY1, HY2 as follows.
HX = (HX1 + HX2) / 2 (3)
HY = (HY1 + HY2) / 2 (4)
Then, the obtained offset values HX and HY are stored in the register 7 or the RAM 13 (step S31: correction value calculation means). Then, the two-point correction mode process is ended (correction end control means).

  When the two-point correction mode process is completed, the azimuth is calculated from the next azimuth measurement process using the offset values HX and HY stored in step S31 of the two-point correction mode process.

  As described above, according to the electronic azimuth meter 100 and the control method of the two-point correction mode of this embodiment, during the two-point correction mode process, the direction indicated by the second hand 104 when the first operation button b1 is input. Since the angle is stored and the second hand 104 is always controlled to point to the stored azimuth angle while waiting for the input of the second operation button b1, the user can rely on the indication direction of the second hand 104 to make an electronic operation. The compass 100 can be rotated exactly 180 °. For example, even when the electronic azimuth meter 100 is held in the hand or worn on the arm, the electronic azimuth meter 100 can be accurately rotated 180 ° by adjusting the second hand 104 so as to overlap the 6 o'clock position. it can.

  Then, the second operation button b1 is input in a state where the electronic azimuth meter 100 is accurately rotated by 180 ° by such control, whereby the correction data (offset value HX) is accurately obtained by the two-point correction mode process. , HY). Such correction data enables highly accurate azimuth measurement.

  Further, according to the electronic azimuth meter 100 of this embodiment, the specific direction pointed to by the second hand 104 while waiting for the input of the second operation button b1 indicates that the second hand 104 points to the input of the first operation button b1. Therefore, the user can intuitively recognize the state in which the electronic azimuth meter 100 is rotated 180 ° with reference to the position when the first operation button b1 is input.

  Note that the specific direction indicated by the second hand 104 during the second input standby of the operation button b1 is not limited to the above-described direction. For example, a direction rotated 180 ° from the direction indicated by the second hand 104 when the first operation button b1 is input may be employed as the specific direction. In this case, by rotating the electronic azimuth meter 100 so that the second hand 104 is aligned with the 12 o'clock position of the dial 101, the user can accurately rotate 180 ° from when the first operation button b1 is input. In addition, a direction rotated 90 ° or 270 ° from the direction indicated by the second hand 104 when the first operation button b1 is input is adopted as the specific direction described above, and the 3 o'clock position of the dial 101 is indicated to the user. It is also possible to control so that the 9 o'clock position and the second hand 104 are aligned.

  Further, according to the electronic azimuth meter 100 of this embodiment, the second hand 104 is moved to the reference position (12 o'clock position) on the dial 101 until the first operation button b1 is pressed after shifting to the two-point correction mode. ), The position of the second hand 104 is always constant during the two-point correction mode process, and a two-point correction process that is easy for the user to understand can be realized.

  Also, during the two-point correction mode process, the operation button b1 is pressed on the digital display unit 106 or electronically while the first operation button b1 is waiting for input or the second operation button b1 is waiting for input. Since the notification display indicating the rotation of the type compass meter 100 is performed, the user only has to operate the electronic compass 100 according to the notification display, and an easy-to-understand two-point correction process can be realized.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above-described embodiment, as a form in which the azimuth is pointed and displayed, a form in which the azimuth is indicated using the pointer (second hand 104) is shown. For example, in the plan view of the other electronic azimuth meter 100A in FIG. As shown, it is possible to adopt a mode in which the direction is indicated by dot display or segment display.

  In the example of FIG. 10, a circumferential belt-shaped azimuth indicator 112 is provided on the outer peripheral portion of the display unit 111, and the designated azimuth indicator of the azimuth indicator 112 is highlighted to indicate the designated azimuth. Has been made possible. In the example of FIG. 10, the north is indicated by the point N <b> 1 where three points are displayed in the direction indicator 112. In addition, the display unit 111 displays an azimuth angle display N2 in the measurement direction and a symbol display N3 in the east, west, south, and north directions. In addition, a mode in which an arrow is displayed on the display unit by dot display or the like to indicate the direction may be employed.

  In the above embodiment, in the two-point correction mode process, the second hand 104 is controlled to move to the reference position while waiting for the input of the first operation button b1, but this process may be omitted. good. In addition, the detailed structure and method specifically shown in the embodiments can be appropriately changed without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 5 Amplifying circuit 6 AD conversion circuit 7 Register CL1, CL2 Coil 9 Coil drive circuit 11 CPU
12 ROM
13 RAM
15 switch input unit b1 to b6 operation button 24 motor drive circuit 25 step motor 26 train wheel mechanism 104 second hand 106 digital display unit X, Y detection data (first and second data)
HX, HY offset value (correction data)

Claims (8)

A geomagnetism detecting means for outputting first and second data corresponding to the strength of the first direction component of the geomagnetism and the second direction component intersecting the first direction;
Azimuth display means for pointing and displaying the azimuth;
First storage control means for storing the first and second data output from the geomagnetism detection means when there is a first switch input;
An azimuth storage control means for calculating and storing the azimuth indicated by the azimuth display means at the time of the first switch input based on the first and second data output from the geomagnetism detection means;
Second storage control means for storing the first and second data output from the geomagnetism detecting means when there is a second switch input;
Even if the device main body is rotated after waiting for the second switch input after the first switch input, the specific direction determined from the direction stored by the direction storage control means is the direction. A specific orientation instruction control means for controlling the orientation display means, as indicated by the display means;
Correction value calculation means for obtaining correction data based on the data stored by the first and second storage control means;
After the correction data is obtained by the correction value calculation means, the first and second data output from the geomagnetism detection means are corrected based on the correction data, and the corrected first and second data are corrected. Azimuth calculating means for obtaining the azimuth based on the data of
An electronic azimuth meter characterized by comprising:   The specific orientation indicated by the orientation display means during standby for the second switch input is the same orientation as the orientation indicated by the orientation display means at the time of the first switch input. The electronic azimuth meter according to claim 1.   The specific orientation indicated by the orientation display means during standby for the second switch input is an orientation rotated by 180 ° from the orientation indicated by the orientation display means at the time of the first switch input. The electronic azimuth meter according to claim 1, wherein: Reference position instruction control for controlling the azimuth display means so that the azimuth display means points to a predetermined reference position on the apparatus main body from the standby of the first switch input to the time of the first switch input. Means
The electronic azimuth meter according to claim 1, further comprising: Correction start control means for shifting to the correction mode by a predetermined operation input;
The first switch that waits for the first switch input to be performed by giving a notification for instructing the first switch input in a state where the device main body is directed in a certain direction when the correction mode is entered. Input waiting means;
When the first switch input is made, a second switch that waits for the second switch input to be issued by giving a notification to instruct to rotate the device main body by 180 ° to perform the second switch input Input waiting means;
Correction end control means for releasing the correction mode when the correction data is obtained by the correction value calculation means when the second switch is input;
The electronic azimuth meter according to claim 1, comprising:   The electronic azimuth meter according to claim 1, wherein the azimuth display means is configured to point and display the azimuth with a rotatable pointer.   2. The electronic azimuth meter according to claim 1, wherein the azimuth display means is configured to point and display the azimuth by segment display or dot display. A geomagnetism detecting means for outputting first and second data corresponding to the strength of the first direction component of the geomagnetism and the second direction component intersecting the first direction, and a first output from the geomagnetism detecting means. The correction data is obtained by being executed by a control unit of an electronic azimuth meter having an azimuth calculating means for calculating an azimuth based on the first and second data and the correction data, and an azimuth display means for indicating and displaying the azimuth. An azimuth correction control method for an electronic compass,
A correction start control step for shifting to a correction mode when a predetermined operation input is received;
The first switch that waits for the first switch input to be performed by giving a notification for instructing the first switch input in a state where the device main body is directed in a certain direction when the correction mode is entered. An input waiting step;
A reference position instruction control step for controlling the azimuth display means so that a predetermined reference position on the device body is pointed to by the azimuth display means during standby for the first switch input;
A first storage control step of storing the first and second data output from the geomagnetism detection means in a storage unit when the first switch input is made;
An azimuth storage control step of calculating the azimuth indicated by the azimuth display means at the time of the first switch input based on the first and second data output from the geomagnetism detection means and storing it in a storage unit;
When the first switch input is made, a second switch that waits for the second switch input to be issued by giving a notification to instruct to rotate the device main body by 180 ° to perform the second switch input An input waiting step;
Even when the device main body is rotated while waiting for the second switch input, the direction display means is controlled so that the specific direction stored by the direction storage control step is indicated by the direction display means. A specific orientation instruction control step;
A second storage control step of storing the first and second data output from the geomagnetism detection means in the storage unit when the second switch is input;
A correction value calculating step for obtaining the correction data based on the data stored by the first and second storage control steps;
A correction end control step of canceling the correction mode after input of the second switch;
An azimuth correction control method for an electronic azimuth meter characterized by comprising:

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