JP6984846B2 - True azimuth measurement method - Google Patents

Description

The present invention relates to a true azimuth measuring method, and more particularly to a true azimuth measuring method using bias cancellation.

As a conventional true azimuth measuring method, for example, the true azimuth measuring method described in Patent Document 1 below is known. That is, in the conventional true azimuth measurement method shown in FIG. 3, the rotation angle speed of the earth is measured by the angular velocity sensor 3 mounted on the rotating member 2 of the true azimuth measurement device 1, and the true orientation is based on the rotation angle speed. Measure the angular velocity. After the first rotation angular velocity measurement is completed by the angular velocity sensor 3, the rotating member 2 is rotated by a rotation amount preset in the control table in order to remove the bias caused by the bias of the angular velocity sensor 3. Perform the second rotation angular velocity measurement. Then, the rate of change in the bias of the angular velocity sensor 3 between the first measurement and the second measurement is acquired from the rotation angle velocity obtained in the first measurement and the second measurement, and the rotation rate is used to obtain the rotation rate. Bias is removed from the measurement result of the angular velocity.

International Publication No. 2014/156288

In the conventional true azimuth measurement method as described above, the rotation angle velocity measured by the angular velocity sensor 3 and the rotation angle velocity in the direction orthogonal to the true azimuth are measured, and the measurement results of the respective rotation angle velocities are used. , A method of measuring the true azimuth is known.

However, in the conventional true azimuth measurement method, when an attempt is made to measure the true azimuth angle from the measurement result of the rotation angle speed and the rotation angle speed in a direction orthogonal to the azimuth angle, the rotation angle speed or the azimuth angle is orthogonal to the rotation angle speed or the azimuth angle. When any of the rotation azimuth angles in the direction is close to 0, the error in the measurement result of each rotation angle velocity measured greatly affects the error in the measurement result of the true azimuth, and the measurement accuracy of the true azimuth deteriorates. There was a problem of doing.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a true azimuth measurement method for improving the accuracy of true azimuth measurement.

In order to solve the above problems, the true azimuth measuring method according to the present invention is a true azimuth measuring method for an object to be measured, and has a first rotation angle speed which is the rotation angle speed of the earth and a first rotation angle speed. When the true azimuth angle of the object to be measured is measured by measuring the second rotation angle speed, which is the rotation angle speed of the earth in the orthogonal direction, and the first rotation angle speed or the second rotation angle speed is less than a predetermined threshold value. Is the true azimuth to which the offset value is added by measuring the first rotation angle speed and the second rotation angle speed with the predetermined offset value added to the true azimuth when the next true azimuth is measured. Is a method of measuring the true azimuth by subtracting the offset value from the true azimuth to which the offset value is added.

According to the true azimuth measurement method according to the present invention, the first rotation angle speed, which is the rotation angle speed of the earth, and the second rotation angle speed, which is the rotation angle speed of the earth in the direction orthogonal to the first rotation angle speed, are measured. When the true azimuth angle of the object to be measured is measured and the first rotation angle speed or the second rotation angle speed is less than a predetermined threshold value, the true azimuth angle is predetermined when the next true azimuth angle is measured. The true azimuth to which the offset value is added is measured by measuring the first rotation angle speed and the second rotation angle speed with the offset value added, and the offset value is subtracted from the true azimuth to which the offset value is added. Since the true azimuth is measured with, the accuracy of the true azimuth measurement can be improved.

It is a block diagram of the true azimuth angle measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the relationship of the rotation angular velocity when the offset is added to the measurement axis of the true azimuth measurement method which concerns on embodiment of this invention. It is a schematic diagram of the true azimuth measuring device of the conventional true azimuth measuring method.

Hereinafter, the true azimuth measurement method according to the embodiment of the present invention will be described with reference to the accompanying drawings.
First, FIG. 1 shows a configuration diagram of a true azimuth measuring device used in the true azimuth measuring method according to the embodiment of the present invention. Here, the true azimuth refers to the angle of the azimuth expressed with respect to true north. The true azimuth measuring device 10 mounted on the object to be measured includes an X-axis accelerometer 40, a Y-axis accelerometer 41, a Z-axis accelerometer 42, a gyro 50, a gyro turntable 51, and a well-known MPU 60. have. The gyro 50 has a measurement axis which is a reference axis for the measurement. The gyro 50 is rotatably installed on the gyro rotary table 51 with the measuring shaft. The gyro 50 is a medium-precision gyro such as an optical fiber gyro or a mechanical gyro. Further, as the gyro 50, a gyro with lower accuracy may be used as long as it has a resolution capable of detecting the rotation angular velocity of the earth.

The X-axis accelerometer 40, the Y-axis accelerometer 41, the Z-axis accelerometer 42, the gyro 50, and the gyro rotary table 51 are electrically connected to the MPU 60. The measurement results from the X-axis accelerometer 40, the Y-axis accelerometer 41, the Z-axis accelerometer 42, and the gyro 50 are input to the MPU 60. Further, a control signal for controlling the gyro rotary table 51 is output from the MPU 60.

The MPU 60 is connected to a recording unit 70, which is a personal computer installed outside the true azimuth measuring device 10, via a well-known RS-232C cable. The recording unit 70 communicates measurement information with the MPU 60 in both directions. The recording unit 70 may be an appropriate computer other than a personal computer, and the means for connecting to the MPU 60 may be another type of cable or wireless communication.

The true azimuth measuring device 10 is supplied with electric power from a device power source 80 installed outside.

ここで、Ωは地球の自転角速度（１５°／時）、λは計測地点の緯度である。
また、Ｈｅａｄに直交する方向の地球の自転角速度である第２自転角速度ωｙは式（２）で表される。

そして、式（１）及び式（２）から式（３）が導かれる。

Next, the principle of the true azimuth measurement method of this embodiment will be described.
When the measurement axis of the gyro 50 faces the true direction indicated by a certain true azimuth angle Head, the first rotation angular velocity ωx, which is the rotation angular velocity of the earth detected by the gyro 50, is represented by the equation (1). ..

Here, Ω is the rotation angular velocity of the earth (15 ° / hour), and λ is the latitude of the measurement point.
Further, the second rotation angular velocity ωy, which is the rotation angular velocity of the earth in the direction orthogonal to the head, is expressed by the equation (2).

Then, the equation (3) is derived from the equations (1) and (2).

As shown in the formulas (1) to (3), the true azimuth angle Head can be obtained by measuring the second rotation angular velocity ωy orthogonal to the measurement axis of the gyro 50. However, as can be understood from the equation (3), in this method, when either the value of the first rotation angular velocity ωx or the second rotation angle velocity ωy is close to 0, the first rotation angular velocity ωx and the first rotation angle velocity ωx are found. 2 The error of the rotation angular velocity ωy has a great influence as the error of the measurement result of the true azimuth angle Head.

Further, the medium-precision or low-precision gyro 50 used in this embodiment has a bias that greatly exceeds the first rotation angular velocity ωx and the second rotation angular velocity ωy of the earth. Therefore, in order to remove the bias from the measurement result, the gyro 50 is rotated by the gyro turntable 51 to rotate the measurement axis, and then the first rotation angular velocity ωx and the second rotation angular velocity ωy are measured again. Bias cancel.

Next, a specific method of this embodiment true azimuth measurement method will be described.
As shown in FIG. 2, the MPU 60 rotates the gyro rotary table 51 and directs the measurement axis of the gyro 50 to an angle α in an arbitrary direction. Here, the control zero point of the true azimuth measuring device 10 is set to an angle α = 0 °. The gyro 50 measures the measured value b0 of the angular velocity, and transmits the measured value b0 to the recording unit 70 via the MPU 60. The recording unit 70 records the measured value b0.

Next, in order to cancel the bias and obtain the measured value, the MPU 60 rotates the gyro rotary table 51 and directs the measuring axis of the gyro 50 to α + 90 °. The gyro 50 measures the measured value b1 of the angular velocity, and transmits the measured value b1 to the recording unit 70 via the MPU 60. The recording unit 70 records the measured value b1.

Next, in order to cancel the bias and obtain the measured value, the MPU 60 rotates the gyro rotary table 51 and directs the measuring axis of the gyro 50 to α + 180 °. The gyro 50 measures the measured value b2 of the angular velocity, and transmits the measured value b2 to the recording unit 70 via the MPU 60. The recording unit 70 records the measured value b2.

Next, in order to cancel the bias and obtain the measured value, the MPU 60 rotates the gyro rotary table 51 and directs the measuring axis of the gyro 50 to α + 270 °. The gyro 50 measures the measured value b3 of the angular velocity, and transmits the measured value b3 to the recording unit 70 via the MPU 60. The recording unit 70 records the measured value b3.

Next, the MPU 60 receives the measured values b1 to b4 from the recording unit 70. and,
ωx = b0-b2
ωy = b1-b3
Is calculated to obtain the first rotation angular velocity ωx and the second rotation angular velocity ωy.

When the first rotation angular velocity ωx or the second rotation angle ωy is less than the threshold value close to 0 set in advance, the error between the first rotation angular velocity ωx and the second rotation angle ωy as described above. However, it greatly affects the error of the measurement result of the true azimuth angle Head. Therefore, in the second and subsequent measurements, the gyro rotary table 51 is rotated so as to perform the above measurement in a state where β, which is a constant offset value, is added to α. That is, the gyro 50 sets the measurement axis b0', the measurement axis α + β + 90 ° measurement value b1', the measurement axis α + β + 180 ° measurement value b2', and the measurement axis α + β + 270 ° measurement value b3', respectively. The measurement is performed and the recording unit 70 records the measurement.

The MPU 60 receives measured values b1'to b4' from the recording unit 70. and,
ωx'= b0'-b2'
ωy'= b1'-b3'
Is calculated to obtain the first rotation angular velocity ωx'and the second rotation angular velocity ωy'.

In the second and subsequent measurements, since the values of the first rotation angular velocity ωx'and the second rotation angular velocity ωy' are measured with the offset value β added, the first rotation angular velocity ωx'and the said The second rotation angular velocity ωy'does not fall below the threshold value. Therefore, the error between the first rotation angular velocity ωx'and the second rotation angular velocity ωy'is less likely to affect as an error in the measurement result of the true azimuth angle Head.

Next, the MPU 60 calculates the true azimuth angle Head from the first rotation angular velocity ωx'and the second rotation angle velocity ωy'and the equation (3), and subtracts the offset value β from the value of the true azimuth angle Head. .. Next, the MPU 60 adds the difference between the zero point of the angle α for controlling the gyro turntable 51 and the zero point of the true azimuth measuring device 10 to the true azimuth head, and the true azimuth. Output as a measured value of the angle.

If the offset value β is 10 ° or less, the effect of offsetting the measurement result is small, so it is desirable that the offset value β exceeds 10 °. However, when the offset value β exceeds 45 °, for example, even if the offset value is added so as not to make the first rotation angular velocity ωx less than the threshold value close to 0, the second rotation angular velocity ωy is conversely close to 0. Therefore, there is no point in adding the offset value β. Therefore, the desirable value of the offset value β set in advance is more than 10 ° and 45 ° or less, and empirically, it is desirable that it is 30 ° or more and 45 ° or less.

As described above, in the method for measuring the true azimuth angle of the object to be measured, the first rotation angle velocity ωx which is the rotation angle velocity of the earth and the rotation angle velocity of the earth in the direction orthogonal to the first rotation angle velocity ωx. 2 The true azimuth angle Head of the object to be measured is measured by measuring the rotation angle velocity ωy, and if the first rotation angle velocity ωx or the second rotation angle velocity ωy is less than a predetermined threshold value, the next time. When measuring the true azimuth head, the offset is obtained by measuring the first rotation angle velocity ωx'and the second rotation angle velocity ωy'in a state where a predetermined offset value β is added to the true azimuth head. Since the true azimuth angle is measured by measuring the true azimuth head to which the value β is added and subtracting the offset value β from the true azimuth angle head to which the offset value β is added, the true azimuth angle is measured. The accuracy of measurement can be improved.

In this embodiment, the measurement was performed with the measurement axes of the gyro 50 oriented at α + 90 °, α + 180 °, and α + 270 ° for bias cancellation, but the angle applied to α was within the range of less than 360 °. It may be any angle.

The gist of the true azimuth measurement method according to the present invention is as follows. That is, it is a method for measuring the true azimuth of the object to be measured, and is the first rotation angular velocity ωx which is the rotation angular velocity of the earth and the second rotation angle velocity of the earth which is the direction orthogonal to the first rotation angular velocity ωx. The true azimuth angle Head of the object to be measured is measured by measuring the angular velocity ωy, and when the first rotation angle velocity ωx or the second rotation angle velocity ωy is less than a predetermined threshold value, the next true azimuth angle ωy is measured. When measuring the azimuth head, the offset value β is measured by measuring the first rotation angular velocity ωx'and the second rotation angular velocity ωy'in a state where a predetermined offset value β is added to the true azimuth head. This is a method of measuring the true azimuth angle by measuring the true azimuth angle Head to which the above is added and subtracting the offset value β from the true azimuth angle Head to which the offset value β is added.

The true azimuth measurement method according to the present invention is a true azimuth measurement method for an object to be measured, and is a first rotation angle speed which is the rotation angle speed of the earth and a rotation angle speed of the earth in a direction orthogonal to the first rotation angle speed. The true azimuth of the object to be measured is measured by measuring the second rotation angle speed, and when the first rotation angle speed or the second rotation angle speed is less than a predetermined threshold, the next true azimuth is measured. Occasionally, the true azimuth to which the offset value was added was measured by measuring the first rotation angle speed and the second rotation angle speed in a state where a predetermined offset value was added to the true azimuth, and the offset value was added. Since the true azimuth is measured by subtracting the offset value from the true azimuth, the accuracy of the true azimuth measurement can be improved.

β Offset value ωx 1st rotation angular velocity ωy 2nd rotation angular velocity Head True azimuth

Claims (1)

It is a method of measuring the true azimuth of the object to be measured.
The first rotation angular velocity, which is the rotation angular velocity of the earth,
The true azimuth angle of the object to be measured is measured by measuring the second rotation angular velocity, which is the rotation angular velocity of the earth in the direction orthogonal to the first rotation angular velocity.
When the first rotation angular velocity or the second rotation angular velocity is less than a predetermined threshold value, the predetermined offset value is added to the true azimuth when the next true azimuth is measured. By measuring the first rotation angular velocity and the second rotation angular velocity, the true azimuth to which the offset value is added is measured.
A true azimuth measuring method for measuring the true azimuth by subtracting the offset value from the true azimuth to which the offset value is added.

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