JPH0763561A - Azimuth measuring device and method for correcting its drift - Google Patents

Abstract

PURPOSE:To improve azimuth measuring precision without enlarging a device by regarding the time change of a measurement result as the drift change of an azimuth gauge, and calculating this time change. CONSTITUTION:A control part 23 transfers the instruction of reset of an operation panel 22 to an azimuth gauge 23, and also outputs the measurement result of the azimuth gauge 23 to a panel 22 when the instruction of measurement is received from a remote switch 40. The panel 22 receives the instruction from the switch 40, transfers the instruction to an arithmetic part 10, and also transfers the measurement result of azimuth outputted from the control part 25 from the panel 22 to the arithmetic part 10. In the arithmetic part 10, a microprocessor (MPU) 22 calculates, as a first information processing means, the drift change of the azimuth gauge 23 from the measurement data in a standard position and its measuring time. The MPU 11 also determines, as a second information processing means, the drift quantity of the azimuth gauge 23 at the point of time when a subject to be measured is measured to determine the true angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth measuring device for measuring azimuth using a gyro-type azimuth meter and a drift correction method thereof.

[0002]

2. Description of the Related Art Among azimuth measuring devices, it is well known that the azimuth measuring device using a gyro azimuth has a simple preparation process for measurement and high measurement accuracy. Conventionally, the only drawback of this type of direction measuring device is the influence of the rotation of the earth,
The gyro cannot maintain a certain posture due to the influence of an earthquake or the manufacturing viscosity of gyro parts, and the gyro is slightly deviated (the amount of the deviation is called a drift amount). Therefore, an error occurs in the measurement result of the azimuth. Therefore, JP-A-60-123715 proposes the following drift correction method for measurement results.

The proposed correction method will be described with reference to FIG. The gyro azimuth meter is reciprocated between the starting point X and the target point Y, and the azimuth is measured during this period. It is assumed that a curve such as CC in FIG. 11 is obtained as the measurement result of the azimuth measuring device from the start time t0 to the time tn when the vehicle returns to the start point. The difference between the measured azimuth at time t0 and the measured azimuth at time tn at the same point (in this case, in the same direction) is the drift amount D. In this proposal, it is considered that the drift amount changes from the time t0 like a straight line AA, and, for example,
The difference d between the measured azimuth at time ti on the curve CC and the azimuth at time ti on the straight line AA is determined as the true azimuth. With this proposal, it has become possible to eliminate the effects of gyro excursion, which changes linearly with the passage of time, such as the effects of the rotation of the earth.

[0004]

However, when an azimuth measuring device is installed in a building, mechanical equipment, etc. and the azimuth is measured for centering, the influence of an earthquake or vibration is added to the gyro to cause drift. The amount also changes as shown by the curve BB in FIG. The amount of such vibration influence varies depending on the measurement location, and it is difficult to measure the vibration itself, and even if the vibration is measured by an accelerometer, the azimuth measuring device becomes large. . Even if the effects of earthquakes and vibrations are removed, the amount of drift does not necessarily change linearly with the passage of time like the straight line AA,
It may show a quadratic curve change.

Therefore, in view of the above points, an object of the present invention is to provide an azimuth measuring device and a drift correction method therefor capable of further improving the azimuth measuring accuracy without increasing the size of the device. .

[0006]

In order to achieve such an object, the invention of claim 1 detects a drift amount of a gyro-type azimuth meter and corrects a drift of a measurement result of the gyro-type azimuth meter. In an azimuth measuring apparatus for performing, a first time measuring means for measuring a first measurement time of a plurality of azimuth measurements performed at different times with respect to a specific direction, and a second time measuring means for measuring an azimuth of an object to be measured. The second time measuring means for measuring the measurement time and the time change of the measurement result in the specific direction are regarded as the drift change of the gyro azimuth meter, and the mathematical expression expressing the time change with a curve is specified. A first information processing unit that obtains by statistical processing using the measurement result about the direction and the first measurement time, and the gyro-type azimuth meter driver at the second measurement time based on the obtained mathematical formula. Characterized by comprising a second information processing means for detecting the bets amount.

According to a second aspect of the present invention, there is provided a drift correction method for an azimuth measuring device which detects a drift amount of a gyro azimuth meter and corrects a drift for a measurement result of the gyro azimuth meter, which is different for a specific direction. The first measurement time of a plurality of azimuth measurements performed at that time is measured, the second measurement time when the azimuth of the measurement target is measured, and the time of the measurement result in the specific direction is measured. The change is regarded as a drift change of the gyro-type azimuth meter, a mathematical expression expressing the temporal change with a curve is obtained by statistical processing using the measurement result and the first measurement time for the specific direction, and the obtained value is obtained. The drift amount of the gyro-type azimuth meter at the second measurement time is detected by the calculated mathematical expression.

[0008]

The inventor of the present application has noticed that, when the measurement results of the azimuth in the same direction are obtained a plurality of times and the times thereof are known, it is possible to approximate the drift change affected by the vibration by a curve. In the second aspect of the invention, measurement is performed a plurality of times in a specific direction such as the reference direction, and the drift change of the gyro compass is acquired from the measurement result and the measurement time. Since the obtained drift change is represented by a mathematical expression relating to time, the drift amount at the time when the measurement target is measured can be obtained from the measured time (second measurement time).

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, the measuring method of the azimuth measuring apparatus of this embodiment will be described with reference to FIG. FIG. 1 shows the relationship between the measurement azimuth angle of the azimuth measuring device with respect to the reference direction (corresponding to the specific direction of the present invention) at the reference position and the measurement azimuth angle with respect to the measurement target at an arbitrary time.

The azimuth measuring device measures a specific direction at a reference position a plurality of times at regular intervals, and in the example of FIG.
-Measure 4 times at T4. Measurement results at this time SMP1 to SMP
The MP4 and the measurement times T1 to T4 are stored in the azimuth measuring device. After that, the time TTn is measured every time the direction of the measurement target is measured. The azimuth measurement results M1 to Mn and the time measurement results TT1 to TTn are stored in the azimuth measuring device. When the measurement for the object to be measured is completed, the azimuth measuring device is returned to the reference position, and the azimuth measurement in a specific direction is performed. Further, the time T6 is measured. The azimuth measurement result at this time, SMP5 and the time measurement result T6 are stored in the azimuth measuring device.

The relationship between the measurement result thus obtained and the time is as shown in FIG. In the present embodiment, the azimuths indicated by the measurement results of a plurality of points at the reference positions obtained before and after the measurement of the measurement target, in other words, the draft amount is considered to change on the curve A of FIG. A function representing the curve A is acquired by statistical processing based on the result and the measurement time. The distance (Δ1 to Δn in FIG. 1) between the curve indicated by the function thus obtained and the azimuth measurement results M1 to Mn of the measurement target is calculated in the azimuth measuring device, and the calculation result is the true measurement. Determined as azimuth.

FIG. 2 shows the external appearance of an embodiment of an azimuth measuring apparatus for measuring the azimuth by the above measuring method, and FIG. 3 shows the main circuit configuration. 2 and 3, the gyro unit 20 incorporates a gyro compass 23 and outputs the angle formed by the installation direction of the gyro unit 20 and the reference direction in the form of an electric variable, in the present embodiment, an analog voltage. This output is transferred to the arithmetic unit 10 by the cable 30. Further, the gyro unit 20 uses the battery 21 as a power source and gives an instruction to execute measurement from the operation panel 22. The arithmetic unit 10 has a keyboard 12 and a display device 13 described later, and performs processing such as input of operation instructions and display of azimuth measurement results.

The gyro unit 20 will be described. As the azimuth meter 23, a well-known gyro-type azimuth meter can be used.
In this embodiment, an azimuth meter having the following functions, that is, when the azimuth meter is installed at a specific position and the installation direction of the azimuth meter is the reference position, that is, when a so-called zero point adjustment is instructed from the operation panel 22 (hereinafter This instruction is called a reset instruction.) When the direction of the azimuth meter coincides with this direction, the offset level voltage is output as the measurement result of the azimuth, and when the azimuth meter is pointed in another direction, the reference direction is output. An azimuth meter is used to add a voltage proportional to the angle formed by the voltage to the offset level voltage.

The control unit 24 transfers an instruction for resetting the operation panel 22 to the azimuth meter 23, and when a measurement instruction is given from the remote switch 40 via the operation panel 22, the measurement result of the azimuth meter 23 is displayed on the operation panel 22. Output to. The operation panel 22 receives a measurement instruction from the remote switch 40, transfers the instruction to the calculation unit 10, and outputs the measurement result of the azimuth output from the control unit 24 to the operation panel 22.
To the calculation unit 10. In this embodiment, the remote switch 40 issues an instruction to start measurement at a reference position for drift correction and an instruction to measure a measurement target.

Next, the arithmetic unit 10 will be described. Microprocessor (MPU) 11 is ROM, RAM, CPU
4 and 7, which will be described later, are executed to perform drift correction on the measurement result of the azimuth meter 23. It also controls the entire arithmetic unit 10. MPU
A clock 11A (first and second clocking means of the invention of claim 1) is connected to 11. As will be described later, the MPU 11 operates as the first and second information processing means of the invention of claim 1.

From the keyboard 12, various operation instructions and data relating to measurement are input to the MPU 11. The display 13 displays guide information (hereinafter referred to as menu information) for inputting operation instructions, measurement results, and the like under the control of the MPU 11.

Floppy disk storage device (FDD) 1
4 reads / writes data from / in the mounted floppy disk 14A. In this embodiment, the measurement result is stored in the floppy disk 14A.

The input / output interface (I / O) 15 receives the measurement result of the gyro unit 20 after A / D conversion from the MPU 11
And the instruction issued from the MPU 11 to the gyro unit 10. A / D (analog / digital)
The converter 16 converts the measurement result in analog voltage form into a digital signal indicating a voltage value.

The measurement operation executed in such a system configuration will be described. When the system is powered on, the main routine shown in FIG. 4 is started. MPU1
1 displays the menu screen of FIG. 8 on the display screen of the display 13 by this main routine (S10), and waits for the user's mode instruction. The user looks at the display screen and indicates a desired mode from the keyboard 12. In this embodiment, the following modes are prepared.

1) Setting mode --- Calendar, time,
A mode for inputting an identification name of measurement data and a file name for storing the measurement data 2) Measurement mode --- mode for executing azimuth measurement 3) Disk management mode --- floppy disk 14
Mode for reading, displaying, or printing the file list stored in A. 4) Power-off mode --- Mode for ending the control procedure of FIG. 4 Hereinafter, the control processing contents of the MPU 11 will be described in the order of user operation. . The user looks at the display screen and indicates the setting mode with the keyboard 12 (S20). This instruction is detected in step S30 of FIG. 4, and the execution procedure of the MPU 11 shifts to the setting process of step S35.

The detailed procedure of this setting process is shown in FIG. In FIG. 5, the MPU 11 displays the menu screen shown in FIG. 9 and receives the input of data to be set. At this time, the user sequentially inputs data such as a calendar from the keyboard 12. Input data is RAM in MPU11
Is temporarily stored in (S100 to S130). When the processing procedure of FIG. 5 is completed, the execution procedure of the MPU 11 is S1 of FIG.
Since it returns to 0, the display screen of FIG. 8 is again displayed on the display unit 13. Since the setting process is completed, the user next selects the measurement mode. When this mode selection is detected in S40 of FIG. 4, the MPU 11 shifts to the measurement process of S45.

The detailed procedure of the measurement process is shown in FIG. In FIG. 6, the MPU 11 displays the menu screen shown in FIG. 10 on the display screen (S200). The measurement data group B is not displayed at this point. The user looks at this display screen and gives an instruction on the processing content. In this embodiment, the following processing is prepared.

I) Process of receiving the measurement result from the gyro unit 10, performing drift correction on the measurement result, and displaying the correction result ii) Process of editing setting data such as file name iii) Measurement data, correction Processing to save the measured data afterwards to a floppy disk iv) Processing to end the measurement mode.

The user selects the measurement execution process of i) (S210). When it is detected that the measurement processing is instructed by the instruction input from the keyboard 12 (S2
20), the MPU 11 shifts the execution procedure to the angle measurement process of step S225 of FIG. The detailed procedure of the angle measurement process is shown in FIG. Next, the user installs the gyro unit 20 in the reference direction P of FIG. 2 and gives a reset instruction from the operation panel 22. As a result, the output level of the azimuth meter 23 is set to the offset level. Next, the user selects the remote switch 4
0 is used to instruct the start of the initial processing. In response to this instruction, the MPU 11 starts the timekeeping by the clock 11 and the I / O of the first measurement result of the azimuth meter 23 at this time point.
15 and stores it in the internal memory (S300
→ S310).

Hereinafter, the MPU 11 acquires the measurement result of the azimuth meter for a total of four times and the measurement result of the clock 14A (the first measurement time of the invention of claim 1) every time a fixed time (10 seconds in this example) elapses. Yes (loop processing of S320 to S340).
After that, the MPU 11 waits for a measurement instruction from the user regarding the measurement target (loop processing of S350). After the above-described initial processing, the user sets the analog unit 20 in the direction Q of the measurement target.
(See FIG. 2) and operate the remote switch 40. By this operation, the measurement instruction is given on the operation panel 2
2, transferred to the MPU 11 via the I / O 15. MP
Upon receiving this instruction, U11 reads the measurement result of the azimuth at this time from the I / O 15 and stores it in the internal memory.
Further, the elapsed time after the start of the initial process (the second measurement time of the invention of claim 1) is read from the clock 11A and stored in the internal memory in association with the measurement result (S35).
0 → S360). Hereinafter, each time the MPU 11 operates the remote switch 40, the MPU 11 stores the measurement result of the specified number of times (total 5 times) and the elapsed time thereof in the internal memory (S350 to S3).
70 loop processing). After performing the measurement for the specified number of times, the user returns the gyro unit 20 to the reference direction P (see FIG. 2) again and operates the remote switch 40 (S380). In response to this instruction, the MPU 11 stores the azimuth measurement result and measurement time (the second measurement time of the invention of claim 2) at this time in the internal memory (S390).

By performing the above-described processing five times at the reference position and five times at any position, the MPU 11
Calculates the drift change of the azimuth meter 23 (function indicating the curve A in FIG. 1) from the measurement data at the reference position and the measurement time as the first information processing means of the invention of claim 1 (S).
400). This function is f (t) that represents the azimuth y as a function of time t using a conventionally known statistical method, for example, a statistical method such as a least square method, regression analysis, or Fourier analysis.
To get. For example, when f (t) is represented by a quadratic function such as ax ² + bx + c, the coefficients a, b, and c that minimize the distance between the measurement data of the reference point and the function f (t) are obtained.

When the function f (t) is obtained, the MPU 11 as the second information processing means of the invention of claim 1 sets the drift amount of the azimuth meter 23 at the time when the measurement target is measured as the function f (t) and the measurement time. By substituting, the true angle d _i (d in FIG. 11) is obtained by the following equation (S410).

[0029]

D _i = D _i (t _i ) −f (t _i ) where D _i (t _i ) is the actual measurement angle at time t _i , and is the actual measurement output (unit is Volt). , Is obtained by multiplying by a conversion factor for converting the angle or by integration. The corrected azimuth is displayed as shown in FIG. 10 together with other data, for example, the measurement result before correction, the measurement time, etc., and the execution procedure returns to the mode input processing (S420 in FIG. 7).
→ S200 in FIG. 6). When the user wants to store the measurement result in the floppy disk, the user instructs the save mode using the keyboard 12, and the MPU 11 stores the measurement data acquired up to now and the corrected measurement data in the floppy disk 14A via the FDD 14 ( S210-S2
40 → S245).

The data floppy disk 14A
If it is necessary to modify the setting data before storing it in the, the user can modify the setting data and make new settings using the edit processing mode.

As described above, in this embodiment, the change in the drift of the compass is not approximated by a straight line as in the conventional case.
Approximate with a curve. Therefore, the measurement time is acquired while performing the measurement a plurality of times at the reference position. Therefore,
The correction accuracy for the measurement result is improved, and a more accurate azimuth angle can be obtained.

In addition to this embodiment, the following example can be implemented.

1) Since the number of measurement points at the reference position is determined by a mathematical expression representing a curve, it may be determined in consideration of correction accuracy and processing time. When the function is expressed by a polynomial, the number of measurement points at the reference position must be at least 3 in the second order and at least 4 in the third order.

2) In this embodiment, the measurement at the reference position is performed before and after the measurement of the measurement target, but the measurement at the reference position may be performed between the measurement of the measurement target. In this case, the remote switch 40 instructs which measurement is to be performed.

3) In the present embodiment, the arithmetic unit 10 and the gyro unit 20 are constructed separately, but they may be integrated. Furthermore, it is also possible to store actual measurement data in a non-volatile storage medium such as a floppy disk and use a personal computer or the like to perform drift correction of the measurement data at a later date.

[0036]

As described above, according to the present invention,
Since the drift change of the gyro-type azimuth meter can be approximated by a curve, non-linear effects such as vibration applied during measurement (effects not proportional to time) can also be detected from the azimuth measurement result. For this reason, not only can the apparatus structure be simplified, but the measurement accuracy can be improved as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a characteristic diagram for explaining a method of the present invention.

FIG. 2 is a perspective view showing an appearance of an embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit configuration of an embodiment of the present invention.

4 is a flowchart showing a control procedure executed by the MPU 11 of FIG.

5 is a flowchart showing a control procedure executed by the MPU 11 of FIG.

6 is a flowchart showing a control procedure executed by the MPU 11 of FIG.

7 is a flowchart showing a control procedure executed by the MPU 11 of FIG.

FIG. 8 is an explanatory diagram showing a display example of the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a display example of the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a display example of the embodiment of the present invention.

FIG. 11 is a characteristic diagram for explaining a conventional azimuth measuring method.

[Explanation of symbols]

 10 Computational Section 11 MPU 12 Keyboard 13 Display 14 FDD 15 I / O 16 A / D 20 Gyro Section 22 Operation Panel 23 (Gyro Type) Compass 24 Control Section 40 Remote Switch

Claims (2)

[Claims] 1. An azimuth measuring device for detecting a drift amount of a gyro azimuth meter and performing drift correction for a measurement result of the gyro azimuth meter, comprising: a plurality of azimuths performed at different times with respect to a specific direction. A first time measuring means for measuring a first measurement time of measurement, a second time measuring means for measuring a second measurement time when the azimuth of the measurement target is measured, and a measurement result in the specific direction The time change of is regarded as the drift change of the gyro azimuth meter, and the mathematical expression expressing the time change by a curve is obtained by the statistical processing using the measurement result for the specific direction and the first measurement time. One including a first information processing means and a second information processing means for detecting a drift amount of the gyro compass at the second measurement time by the obtained mathematical expression. Measuring device. 2. A drift correction method for an azimuth measuring device for detecting a drift amount of a gyro azimuth meter and performing drift correction for a measurement result of the gyro azimuth meter, the method being performed at different times for a specific direction. The first measurement time of a plurality of azimuth measurements is timed, the second measurement time is measured when the azimuth of the measurement target is measured, and the time change of the measurement result in the specific direction is calculated by the gyro formula. It is regarded as a drift change of the azimuth meter, a mathematical expression expressing the temporal change with a curve is acquired by statistical processing using the measurement result for the specific direction and the first measurement time, and the mathematical expression obtained above is used to obtain the mathematical expression. A drift correction method for an azimuth measuring device, comprising detecting a drift amount of the gyro azimuth meter at a second measurement time.