JPH06174863A - Electronic compass - Google Patents

Abstract

PURPOSE:To provide an electronic compass which can easily detect accurate bearings with respect to either direction determined when correcting bearings detected by detection of geomagnetism. CONSTITUTION:An electronic compass is controlled by a microcomputer 10 and the longitude and latitude of the point where the electronic compass is placed are entered by operation of a switch. A predetermined address in a ROM 18 is designated according to the longitude and latitude and to the date and time of the point which are sent from a time measuring circuit 14, and the correct bearings of the sun at that point and at that time, which are prestored in the storage portion, are read out. An error in measurement using a method of detecting geomagnetism is calculated from the correct bearings of the sun and from the bearings of the sun calculated from a signal from a magnetism detecting circuit 11, i.e., the bearings of the sun determined by detection of geomagnetism, and is used as a correction value in measuring other bearings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic azimuth meter for detecting a geomagnetism to obtain a desired azimuth.

[0002]

2. Description of the Related Art Conventionally, a small electronic azimuth meter which detects the terrestrial magnetism by a magnetic detection element such as a magnetoresistive element or a Hall element to obtain a desired azimuth and displays the azimuth in a desired direction is convenient for carrying. It is widely used for practical purposes.

[0003]

By the way, as described above, the azimuth measured by the conventional electronic azimuth meter generally contains an error due to various causes. Even when measured, the measured azimuth angle is more uniform than the actual azimuth angle (for example, 5 °).
However, this is relatively large among various errors and cannot be ignored. In order to correct the error as described above, an accurate azimuth for any direction is obtained, and the difference between this and the azimuth measured by the electronic azimuth meter is calculated in advance, and for other directions. Even when the azimuth is measured, it may be corrected based on the difference, but at present there is no method for simply obtaining the accurate azimuth for any direction. The present invention has been made in view of the above circumstances, and provides an electronic azimuth meter capable of easily obtaining an accurate azimuth with respect to any of the orientations used for correction of the azimuth obtained by detecting the geomagnetism. With the goal.

[0004]

According to the present invention, the direction of the sun from the point at that time is determined based on the time, date and longitude and latitude of the point input in order to achieve the above object. It is equipped with a means for generating an accurate azimuth.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on an embodiment shown in the drawings. The present embodiment is an electronic wristwatch to which the present invention is applied. FIG. 1 shows the appearance of this embodiment. On the upper part of the upper surface of the watch case 1 to which the watch band 4 is attached, an azimuth arrow 2 for printing the azimuth is printed and displayed (this azimuth arrow 2 is at the 6 o'clock position, the center of the pointer). It is provided on a straight line connecting the 12:00 and the 12 o'clock position), and the mode switch S1 and the adjustment switch S are provided on the side surface of the watch case 1.
2. A longitude correction switch S3 and a latitude correction switch S4 are provided. A liquid crystal display panel for displaying the time or direction is provided below the watch glass 3 mounted on the upper surface of the watch case 1.

FIG. 2 shows a circuit configuration of this embodiment. That is, the present embodiment has a configuration in which the CPU 10 is mainly connected to other circuit units. CPU
Reference numeral 10 denotes a circuit unit that sends signals to each circuit, controls them, processes and processes the sent data, and sends the processed data.

The magnetic detection circuit section 11 includes a magnetic sensor section 11
a, a differential amplifier 11b that amplifies the voltage difference between the connection points P2 and P4 of the magnetic sensor unit 11a, and a differential amplifier 11b.
11c that further amplifies the output of A / D, and A / D that digitally converts the output from the amplifier 11c and gives it to the CPU 10.
And a conversion circuit 11d. The magnetic sensor unit 11a is formed on a substrate (for example, an alumina substrate) (not shown).
The magnetoresistive elements MR1, MR2, MR3, and MR4 form a bridge circuit. And the connection points P1 and P3
A constant voltage is applied by the DC power supply E between them, and the potentials of the connection points P2 and P4 are applied to the differential amplifier 11b. As shown in the upper right part of the portion showing the magnetic sensor portion 11a, the direction of the straight line connecting the connection points P1 and P3 is the Y-axis direction, and the direction perpendicular to this is the X-axis direction. Facing in a positive direction. Further, coils L1 and L2 that are orthogonal to each other and generate bias magnetic fields in the X-axis and Y-axis directions are wound around the magnetic sensor unit 11a. The power supplies Px and Py reverse the outflow direction according to the signals sequentially given from the CPU 10, respectively, and the coils L1 and Py.
It is a power supply that applies a current to L2 and sequentially applies four types of bias magnetic fields to the magnetoresistive elements MR1 to MR4. Thus, from the magnetic detection circuit section 11 to the CPU 10, the connection point P2 when the above-mentioned four types of bias magnetic fields are sequentially applied,
A digital signal corresponding to the potential difference of P4 is transmitted. The CPU 10 calculates the azimuth in the direction indicated by the azimuth arrow 2 (indicating how many times it has rotated clockwise from the north direction) from the given digital signal.

The oscillating circuit 12 is a circuit which constantly sends a signal of a constant frequency. The frequency divider circuit 13 is the oscillator circuit 1.
It is a circuit that divides the signal from 2 to a predetermined frequency and sends it to the time counting circuit 14. The time counting circuit 14 is a circuit that counts the signals sent from the frequency dividing circuit 13 to obtain the current time (including the date), and sends this to the CPU 10.

The display unit 15 is a circuit unit which includes the above-mentioned liquid crystal display panel and displays the current time data or direction data sent from the CPU 10 on the liquid crystal display panel. RAM16
Includes various registers described below, stores data from the CPU 10 in the corresponding registers under the control of the CPU 10, and stores the data stored in these registers in the CP.
It is a circuit unit for sending to U10. The switch unit 17 is a circuit unit that includes the mode switch S1, the adjustment switch S2, the longitude correction switch S3, and the latitude correction switch S4, and sends a corresponding switch input signal to the CPU 10 when any one of them is operated.

The ROM 18 fixedly stores the direction of the sun's direction at each time (including date) for each area designated by longitude and latitude, and the CPU 10 designates the address corresponding to the area and time. It is a circuit unit that sends to the receiving CPU 10 the azimuth of the direction of the sun at that point at that time.

FIG. 3 shows a partial configuration of the RAM 16 described above. The mode register M is a register for designating a mode. When 0 is set, the mode register M designates a clock mode in which the current time data from the time counting circuit 14 is displayed on the liquid crystal display panel of the display unit 15, and 1 is set. When set, specifies the compass mode when using it as a compass. The state register N is a register for designating the state in the above azimuth meter mode, and when 1 is set, it designates a preset state when presetting the longitude and latitude of the point whose azimuth is to be measured, When 0 is set, the normal state when actually measuring the azimuth is designated. The longitude register K and the latitude register I are registers for storing the longitude and latitude set in the preset state, respectively.

The measurement value register D includes a magnetic detection circuit section 11
This is a register for storing the azimuth obtained based on the signal from (that is, the azimuth in the direction indicated by the azimuth arrow 2). The correction value register C is a register in which a correction value for adding to the azimuth stored in the measurement value register D to obtain a true azimuth in the direction indicated by the azimuth arrow 2 is set. The sun azimuth register SD is a register for storing the azimuth of the direction of the sun at the point designated by the longitude / latitude of the longitude register K and the latitude register I.

Next, the operation of this embodiment configured as described above will be described. FIG. 4 is a general flow chart showing an outline of the operation of this embodiment, and FIG. 5 is a flow chart showing in detail the switch processing of step S2 of FIG. In step S1 of the general flow chart of FIG. 4, it is determined whether or not there is a switch input signal from the switch unit 17, and when there is such a signal, the process proceeds to the switch process of step S2 to execute the switch process corresponding to the signal. After that, the process proceeds to step S3, but if it is determined in step S1 that there is no switch input signal, the process directly proceeds to step S3. In step S3, it is determined whether the value of the mode register M is 1, that is, the azimuth meter mode is set. If the azimuth meter mode is set,
In step S4, the value of the status register N is 0, and it is determined whether the status is normal. If it is in the normal state, the process proceeds to step S5, and the magnetic detection circuit unit 1
1 is executed, and the azimuth measuring process of calculating the azimuth in the direction of the azimuth arrow 2 and setting it in the measurement value register D is executed based on the digital signal from the A / D conversion circuit 11d of the magnetic detection circuit unit 11. . Next, in step S6, the correction value of the correction value register C is added to the azimuth calculated in step S5 to obtain the true azimuth of the azimuth arrow 2, and the azimuth of the measurement value register D is updated with this true azimuth. To do. When the process of step S6 is completed, or when it is determined that the value of the state register N is 1 instead of 0 in step S4, or the preset state is set in step S3, the value of the mode register M is not 1 If it is 0 and it is determined to be the clock mode, the process proceeds to the display processing of step S7, and the data designated to be displayed at that time is displayed on the display unit 1.
No. 5 is displayed on the liquid crystal display panel, and after that, the process returns to step S1.

The operation in various states will be described in detail below. (A) Operation at the time of switching to the compass mode For example, it is assumed that the value of the mode register M is 0 and the watch mode is set. To switch the mode from the clock mode to the compass mode, the mode switch S1 is operated. At this time, the operation is detected in step S1 of FIG. 4, the process proceeds to the next step S2, that is, the switch process of FIG. 5, and it is determined that the mode switch S1 is operated in step S10. In step S11, the value of the mode register M is inverted from 0 to 1 to set the compass mode.

After the azimuth meter mode is set as described above, it is determined in step S3 of FIG. 4 that the value of the mode register M is already 1 and the azimuth meter mode is set. In S4, the value of the state register N is 0, and it is judged that the state is in the measuring state, and the process proceeds to step S5. In step S5, a signal is sent to the magnetic detection circuit unit 11 to sequentially invert the currents from the power supplies Px and Py, and the current is sequentially sent from the magnetic detection circuit unit 11, that is, from the A / D conversion circuit 11d. The direction of the direction indicated by the direction arrow 2 is obtained from the street digital signal,
The azimuth measurement process of setting this in the measurement value register D is executed. Then, in step S6, the correction value already set in the correction value register C (correction value obtained at the time of the previously performed adjustment operation) is set to the direction of the measurement value register D obtained in the above measurement process. The added azimuth is obtained, and the measurement value register D is updated accordingly, and the next step S7
Then, the direction of the measurement value register D is displayed on the display unit 15.

(B) Operation at the time of adjusting operation The value in the direction displayed on the display unit 15 measured as described above is different from the expected value, and a new value is displayed in the displayed direction. When it is suspected that an error is included, an adjustment operation is performed to update the correction value in the correction value register C.

In the adjusting operation, first, the switch S2 is operated to bring it into a preset state. In this case, the operation is detected in step S13 of FIG.
Then, the value of the state register N is inverted from 0 to 1 to be in the preset state. In the next step S15, the value of the state register N is already 1 instead of 0, and it is judged that the state is in the preset state. After this switching process is completed, the process proceeds to the display process of step S7 through steps S3 and S4 of FIG. 4, and the longitude and latitude already set in the longitude register K and the latitude register I are displayed on the display unit 15.

When the longitude displayed on the display unit 15 as described above is different from the longitude of the point, that is, the azimuth measuring point, the correct longitude of the point is displayed while looking at the display unit 15. Until the longitude correction switch S3 is operated. At this time, each time the longitude correction switch S3 is operated, it is detected in step S20 of FIG. 5, and the longitude of the longitude register K is corrected to be larger by a predetermined value in step S21 (note that In this case, the longitude of the longitude register K becomes 0 ° after reaching 180 ° east longitude, and thereafter, the longitude in the west longitude is made larger, and then returns to 0 ° after reaching 180 ° west longitude, and thereafter. Greater longitude in the east longitude).

When the latitude displayed on the display unit 15 is different from that of the point as described above, the latitude correction switch is displayed while looking at the display unit 15 until the correct latitude of the point is displayed. Operate S4. At this time, each time the latitude correction switch S4 is operated, it is detected in step S22 of FIG. 5, and in step S23 the latitude of the latitude register I is corrected to be larger by a predetermined value (note that In this case, after the latitude of the latitude register I reaches 90 ° north latitude, it returns to 0 °, and after that, the latitude in the south latitude is increased, and 0 ° after reaching 90 ° south latitude.
Return to and increase the latitude in the north latitude.

After setting the longitude and latitude of the point in the longitude register K and the latitude register I as described above, the azimuth arrow 2 is directed to the direction of the sun from the point, and the adjustment switch is then set. Operate S2. In this case, the operation is detected in step S13 of FIG. 5, and the value of the state register N is inverted from 1 to 0 in the next step S14 to switch from the preset state to the measurement state. Then, in step S15, the value of the status register N is already 0.
In step S16, it is determined that it is in the measurement state, and the combination of the longitude of the longitude register K, the latitude of the latitude register I and the time from the time counting circuit 14 (including the date as described above) is dealt with. ROM address
The direction designated by No. 18 and stored in the storage unit of that address, that is, the azimuth of the direction of the sun from this point at this time point is read out and set in the sun direction register SD.
Next, in step S17, step S5 of FIG.
In the same manner as the azimuth measurement processing in the above, signals are sequentially sent to the magnetic detection circuit unit 11, and the azimuth arrow 2 is obtained from the digital signals sequentially sent from the magnetic detection circuit unit 11 accordingly.
The direction of the direction pointed to by, ie, the direction of the direction of the sun from that point is obtained, and this is set in the measurement value register D. Thereafter, in step S18, the azimuth set in the sun azimuth register SD from the azimuth set in the measurement value register D (that is, the azimuth of the sun direction measured by geomagnetism) (the point and time point are designated and the ROM 18 is designated).
The correct azimuth of the direction of the sun read from) is subtracted, and the difference is set as a correction value in the correction value register C.

(C) Operation in other cases After setting a new correction value in the correction value register C by the adjusting operation as described above, when the azimuth arrow 2 is directed in an arbitrary direction to be measured, In the same manner as described above, the steps S1, S3 and S4 of FIG.
In step S5, the direction indicated by the direction arrow 2 is obtained by the magnetic method in step S5 and set in the measurement value register D. In step S6, the correction value is set in the direction set in the measurement value register D. The new correction value set in the register C is added and corrected, and the direction of the measurement value register D is updated with the corrected direction. Then, in step S7, the orientation of the measurement value register D corrected as described above is displayed on the display unit 15.

Further, after the azimuth is measured as described above, to switch from the azimuth meter mode to the clock mode,
The mode switch S1 is operated. In this case, the operation is detected in step S10 of FIG. 5, and the value of the mode register M is inverted from 1 to 0 to set the clock mode. Then, after that, the process proceeds to step S7 through step S3 of FIG. 4, and the current time from the time counting circuit 14 is displayed on the display unit 15.

The present invention is not limited to the above embodiment, and various modifications and applications are possible without departing from the scope of the present invention.

For example, in the present embodiment, in the adjusting operation, the direction of the sun at the current time (including the date as described above) at the designated point (that is, the point designated by the longitude and latitude) is read from the ROM 18. Although it was obtained by reading it directly, it is calculated and obtained each time based on a predetermined calculation formula stored in advance in the ROM 18 and the above-mentioned longitude, latitude and time (including date). Of course, it is also good.

Further, in this embodiment, in the adjusting operation, the azimuth arrow 2 is directed toward the sun, and the azimuth arrow 2 is aimed directly at the sun between the sun and the operator's eyes. However, as shown in FIG. 6 as an external view and a cross section (a cross section taken at the 12 o'clock position, the center of the pointer, and the line passing through the 6 o'clock position) (the same figure (a) is an external view, (B) is a cross-sectional view), a part of the bezel 5 is a sun aiming piece 5a pivotally supported at the 12 o'clock position, and the end of the sun aiming piece 5a that is not pivotally supported is lifted. The sun aiming piece 5a may be perpendicular to the upper surface of the watch glass 3 at the pivot point so that the sun can be aimed at. In this case, simply adjust the position of the electronic azimuth meter so that the shadow of the sun aiming piece 5a overlaps the straight line connecting the 12 o'clock position, the center of the pointer and the 6 o'clock position. 5a
Will face the direction of the sun, which is the target of direction measurement. Therefore, the dazzling is not felt unlike when the azimuth arrow 2 is aimed directly at the sun and the direction of the azimuth 2 is directed to the sun, and the adjusting operation becomes easier.

[0026]

As described in detail above, the present invention provides an accurate azimuth of the direction of the sun from a point at that point in time, based on the time, date and the longitude and latitude of the point entered. Since the present invention relates to an electronic azimuth meter equipped with a means for generating, an electronic azimuth capable of easily obtaining an accurate azimuth for any of the orientations used for correction of the azimuth obtained by detecting the geomagnetism. It is possible to provide the total.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a circuit configuration of the embodiment.

FIG. 3 is a diagram showing a partial configuration of a RAM shown in FIG.

FIG. 4 is a general flowchart showing an outline of the operation of the above embodiment.

FIG. 5 is a flowchart showing in detail the switch processing in FIG.

FIG. 6 is a diagram for explaining a configuration of an application modification example of the present invention.

[Explanation of symbols]

 2 azimuth arrow 5 bezel 5a sun sighting piece 11 magnetic detection circuit section 18 ROM S1 mode switch S2 adjustment switch S3 longitude correction switch S4 latitude correction switch M mode register N status register K longitude register I latitude register D measurement value register C correction value register SD sun direction register

Claims (1)

[Claims] 1. A device for identifying an apparatus based on a time measuring means for counting time and date, a longitude / latitude setting means for setting longitude and latitude, a geomagnetism detecting means for detecting geomagnetism, and a geomagnetism detected by the geomagnetism detecting means. Azimuth detecting means for detecting the azimuth of one direction of the direction, in a state where the one direction of the specific direction is directed to the sun,
The azimuth obtained by the azimuth detecting means, the time, date,
Azimuth difference calculating means for finding the azimuth difference from the azimuth of the sun determined from the longitude and latitude, and after the azimuth difference is calculated by the azimuth difference calculating means, the azimuth detected by the azimuth detecting means is corrected by the azimuth difference. And an azimuth display means for displaying the azimuth corrected by the correction means.