JP2002296037A - Gyrocompass device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gyrocompass device appropriately usable for laying a sewer pipe. SOLUTION: This gyrocompass device has; a cylindrical casing having a center axis line; a base disposed in the casing; a sensor part mounted on the base and comprising X, Y, and Z gyros, X, Y, and Z accelerometers, and a direction transmitter; a computation part for converting signals outputted from the sensor part into signals in a globe-surface coordinate system; and a drift/bias computation part for computing the direction of the base, the drift of the gyros, and a bias of acceleration, from the signals outputted from the sensor part in a survey mode, wherein the base has a plurality of turntables disposed along the center axis line and a drive for synchronously rotating the plurality of turntables, and the sensor part is mounted on the turntables so that its input axis line or measuring axis line is aligned with the center axis line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyro compass device for detecting the position of an object or a moving object, such as an object underground or underwater, to which a person has difficulty in approaching.
In particular, the present invention relates to a gyrocompass device and method suitable for use when laying a pipe having a relatively small diameter such as a sewer pipe by a propulsion method.

[0002]

2. Description of the Related Art When laying a pipe having a relatively small diameter, such as a sewer pipe, underground, a propulsion method is known in which the pipe is simultaneously arranged while digging underground. In this method, a vertical hole is excavated in the ground at the start point and the end point of the pipe. However, there is no need to dig the ground along the pipe, so that there is an advantage that traffic is not obstructed.

Referring to FIG. 9, an example of a propulsion method and an excavator used for the method will be described. The excavator includes a leading conduit 202 having a cutting blade 201 at a tip, and a leading conduit 202.
A guide member 203 attached to the rear end of the fume tubes 210A, 210B, 210C, 210D
And a main pushing device 220. The main pushing device 220 is arranged in a vertical hole at the starting point of the pipe. Inside the fume pipe, a sludge supply pipe 205, a sediment discharge pipe 206, and a sediment discharge pump 207 are arranged.

When a horizontal hole is excavated by the excavating blade, a mud material, for example, water is jetted from a mud material supply pipe 205 to the tip of the excavating blade 201. The excavated sediment is separated into water-blocking sediment and fluid sediment (slurry), and the fluid sediment is pumped up by a sediment discharge pump 207, and the sediment discharge pipe 2
06 to the outside.

FIG. 9A shows a dug to a predetermined position, where fume tube rows 210A, 210B, 21
This shows a state where 0C and 210D are arranged. At the start of excavation, only the leading conduit 202 is arranged in the main pushing device 220. FIG. 9B shows a state where the body is dug from this state by a dimension corresponding to the length of one fume tube. The fume tube rows 210A, 210 are
B, 210C, 210D while pushing forward,
Drill by 01. Thereby, the front conduit and the entire fume tube row are advanced. Next, as shown in FIG. 9C,
The piston of the main pushing device 220 is retracted, and the next fume tube 210E is arranged at the rear end of the last fume tube 210D.

[0006] This is repeated, and the front pipe 202 is inserted into the vertical hole at the end point.
Arrives, the front pipe 202, the sludge supply pipe 205, the sediment discharge pipe 206, and the discharge pump 207 are collected. Thereby, the pipe formed by the fume pipe from the start point to the end point is completed.

[0007] A gyrocompass device is provided in the leading conduit, and the current position is always detected. When the current position deviates from the expected position, the traveling direction is corrected. By changing the excavation direction, the traveling direction of the leading conduit can be adjusted. In this way, by excavating while adjusting the traveling direction of the leading conduit, an accurate pipe is laid from the start point to the end point.

In recent years, pipes are often laid over a relatively long distance by a propulsion method. In such a case, even a slight error in the traveling direction increases the error at the end point. For example, when digging 100 m with the traveling direction of the leading conduit deviated by one degree from the planned course, the end point is shifted by about 1.74 m from the planned course. Usually, it is desirable that the error is within several cm.

[0009]

Gyro-compass devices are used to detect the location of underground or underwater objects, such as excavator rigs. Various types of gyro compass devices, such as an electromagnetic wave type and a gyro, are used, but none of them are small, small in diameter, high in accuracy, and inexpensive. In particular, a small and small-diameter gyrocompass device that can be used in an environment of vibration, high temperature, and high humidity has a drawback that the price is high.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gyrocompass device which is small, small in diameter, high in measurement accuracy and inexpensive.

[0011]

According to the present invention, there is provided a gyrocompass apparatus comprising: a cylindrical casing having a center axis; a base disposed in the casing; and an XYZ gyro, XYZ mounted on the base. A sensor unit including an accelerometer and an azimuth transmitter, a computing unit that converts a signal output from the sensor unit in the compass mode to a signal of the earth surface coordinate system, and a signal output from the sensor unit in the surveying mode. And a drift / bias calculator for calculating the bias of the base, the drift of the gyro and the acceleration, and the base includes a plurality of turntables arranged along the center axis and the plurality of turntables. A driving device for rotating the sensor unit synchronously, and the sensor unit is mounted on the turntable such that an input axis or a measurement axis thereof is aligned with the center axis.

According to the present invention, the XYZ gyro is T
It is composed of DG (Tuned Dry Gyro).

According to the present invention, the calculation unit calculates a coordinate conversion matrix for converting a coordinate system provided on the base into a coordinate system of the earth's surface, and the earth using the coordinate conversion matrix. It has a local acceleration calculator for calculating the acceleration in the surface coordinate system and a local azimuth / posture calculator for calculating the azimuth and attitude in the earth surface coordinate system.

According to the present invention, the drift / bias calculation section includes a rotation control section for controlling the rotation of the turntable and data for storing the outputs of the XYZ gyro and the XYZ accelerometer using the azimuth of the turntable as a parameter. A measurement storage unit, a calculation unit for calculating the drift and bias of the output of the XYZ gyro and the XYZ accelerometer from the output from the data measurement storage unit, and an azimuth calculation unit for calculating the azimuth of the base; A bias and a drift of the sensor unit are detected from outputs of the sensor unit at a plurality of rotation angles of the table.

According to the present invention, the outer diameter of the cylindrical casing is 80 mm or less.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a gyro compass device of the present invention will be described with reference to FIGS. The gyrocompass device of the present example includes a casing 50 and a base 10 housed in the casing. The casing 50 has a cylindrical portion 51.
And disk portions 52 at both ends. According to this example, the cylindrical portion 51
Outer diameter of at least 80 mm or less, preferably 60 mm
It is as follows.

A coordinate system is set on the casing 50 or the base 10. X-axis along the central axis of the cylindrical part of the casing,
The y-axis is taken parallel to the base 10, and the z-axis is taken perpendicular to the base 10.
Since the coordinates set in this way can be regarded as the coordinates set for the moving body on which the gyrocompass device is mounted, the coordinates are hereinafter referred to as moving body coordinates. The reference direction of the base 10, that is, the direction of the moving body is the positive direction of the x-axis. On the other hand, the coordinates provided on the earth's surface are referred to as local coordinates or local coordinates. Local coordinates refer to the origin on a point on the earth's surface, the x-axis along the meridian along the horizontal plane, and the y-axis along the latitude.
This is a coordinate system in which the axis and the z-axis are vertically above.

The gyro compass device of this embodiment further includes an X accelerometer 11A and a Y accelerometer 12A mounted on the base 10.
And a Z accelerometer 13A, an X gyro 11G, a Y gyro 12G, a Z gyro 13G, and an azimuth transmitter 13Y, which constitute a sensor unit of the gyro compass device. The arrow attached to each sensor indicates the direction of the input axis or the measurement axis.

As the gyro, a TDG (Tuned Dry Gyro) may be used. TDG is 2 orthogonal to each other
It consists of a gyro with two input axes. Therefore, TD
When G is used, a first gyro composed of an XY gyro and a second gyro composed of a YZ gyro are used. The first gyro is used as the X gyro, and the second gyro is used as the Z gyro. The first as Y gyro
The second gyro may be used, or the first gyro is used here.

The base 10 is provided with a plurality of turntables. In the example of FIG. 1, two turntables 20A and 20B are provided, a first gyro, that is, an XY gyro is mounted on the first turntable 20A, and an X accelerometer and a Y accelerometer are mounted on a second turntable. 20B. In the example of FIG.
The first gyro, ie, the XY gyro, is mounted on the first turntable 20C, the X accelerometer is mounted on the second turntable 20D, and the Y acceleration is provided. The meter is mounted on the third turntable 20E. The azimuth transmitter 13Y (shown only in FIG. 1 and omitted in FIG. 2) is mounted on at least one of the plurality of turntables.

An azimuth servomotor is provided for rotating the plurality of turntables, and a suitable transmission, such as a backlashless gear transmission or backlash, is provided for transmitting the rotation of the azimuth servomotor to the plurality of turntables. A re-belt transmission is used. All turntables rotate synchronously, i.e. rotate in the same direction at the same relative angle and at the same rotational speed. Therefore, in order to detect the rotation angle of the turntable, as described above, the azimuth transmitter 13Y
It is only necessary to dispose it on one turntable, and it is not necessary to mount it on all turntables.

According to this example, the turntable has a constant rotation speed,
For example, it rotates at a rotation angle of ± 180 ° at 10 ° / sec. Since the rotation angle of the turntable is limited to ± 180 °, the cables or wires from the gyro, the accelerometer, and the azimuth transmitter mounted on the turntable are not entangled. As shown in FIG. 3, a circuit board constituting the operation units 2 and 3 is mounted on the base.

According to this embodiment, the X, Y, and Z accelerometers 11A, 11A,
2A, 13A, X, Y and Z gyros 11G, 12G,
13G and the azimuth transmitter 13Y are arranged on the central axis of the casing 50, that is, on the x-axis or in alignment with the x-axis. The rotation axes of the turntables 20A, 20B, 20C, 20D, and 20E are arranged on the x-axis.

The outline of the gyro compass device of this embodiment will be described with reference to FIG. The gyro compass device includes a sensor unit 1, a calculation unit 2, and a drift / bias calculation unit 3. The configuration of the sensor unit 1 has been described with reference to FIGS. Here, the input axis or the measurement axis (arrow) of each sensor will be described. The X accelerometer 11A and the X gyro 11G are arranged so that their input axes are aligned with the positive direction of the x-axis of the moving body coordinate system. It is arranged so as to match in the positive direction of the y-axis of the coordinate system. Z accelerometer 13A, Z gyro 13G and azimuth transmitter 13Y
Are arranged such that their input axes are aligned in the positive direction of the z-axis of the moving body coordinate system.

The X accelerometer 11A detects acceleration in the x-axis direction of the moving body coordinate system, and the X gyro detects an angular velocity ω _X about the x-axis of the moving body coordinate system. The Y accelerometer 12A detects acceleration in the y-axis direction of the moving body coordinate system, and
G detects the angular velocity ω _Y about the y-axis of the moving object coordinate system.
Z accelerometer 13A detects the acceleration in the z-axis direction of the moving body coordinate system, Z gyro 13G detects an angular velocity omega _Z around the z axis of the moving body coordinate system. The azimuth transmitter 13Y detects a rotation angle φ of the turntable 20 with respect to the azimuth (x-axis) of the moving body.

As described above, when TDG is used as the first and second gyros, the X gyro and the Y gyro are included in the first gyro, and the Y gyro and the Z gyro are included in the second gyro. Here, it is illustrated as a separate gyro.

The gyrocompass device of this embodiment functions as a strap-down gyrocompass when the moving body is moving, and functions as a surveying compass when the moving body is stationary. That is, the gyro compass device of the present example can operate in two modes: the compass mode and the survey mode.

The sensor section of the gyro compass device of this embodiment is directly mounted on a moving body whose position is to be measured. The moving body may be, for example, a leading conductor of a drilling rig. The sensor unit of the gyro compass device moves with the movement of the moving body, and takes the same direction and posture as the direction and posture of the moving body. Such a structure is generally called a strap down system.

When the gyro compass device of this embodiment is used as a strap-down compass mode, the arithmetic unit 2 receives the output signal of the moving body coordinate system from the sensor unit 1 and inputs the azimuth and azimuth of the local coordinate system. Calculate the attitude angle. In the compass mode, the rotary table is rotated by ± 180 ° in a sufficiently short time as compared with the compass cycle, so that the azimuth angle and the attitude angle from which the error components of the gyro and the accelerometer are removed can be obtained. Therefore, it is possible to reduce the azimuth error due to the temperature and aging of the sensor.
The gyro drift and the accelerometer bias obtained from the drift / bias calculator 3 may be used for the calculation of the azimuth and the attitude angle.

When the gyro compass device of this embodiment is used in the survey mode in a stationary state, the drift / bias calculator 3 calculates the drift of the gyro and the bias of the accelerometer, and further calculates the azimuth and the azimuth of the moving body. Calculate and output attitude angle.

Referring to FIG. 4, the configuration of the arithmetic unit 2 and the operation in the compass mode of the strap-down system will be described. The operation unit 2 is a coordinate conversion matrix operation unit (CTM operation unit)
201, a local azimuth / posture calculation unit 202, a local acceleration calculation unit 203, and a compass / correction calculation unit 204.
The CTM operation unit 201 inputs the angular velocity of the moving object coordinate system output from the X, Y, and Z gyros, and calculates and outputs a coordinate transformation matrix (CTM). As described above, the rotation of the turntable by ± 180 ° allows X and Y rotation.
The error in the gyro output has been removed.

A coordinate transformation matrix (CTM) is a 3 × 3 for transforming the coordinates of a moving object into local (local) coordinates.
It is a matrix. CTM is known and will not be described here.
For details, see, for example, Japanese Patent Application No. 5-779, filed on January 6, 1993 by the same applicant as the present application.

The local acceleration calculator 203 calculates the acceleration of the moving body coordinate system output from the X, Y and Z accelerometers 11A, 12A and 13A and a coordinate conversion matrix (CTM).
The coordinate transformation matrix (C
TM) and the rotation angle signal of the turntable output from the azimuth transmitter 13Y, and calculates the acceleration in the local coordinate system.

The compass correction calculation unit 204 inputs the local coordinate system acceleration output from the local acceleration calculation unit 203 and the rotation angle signal of the turntable output from the azimuth transmitter 13Y to control the compass and correct the azimuth. An arithmetic operation is performed to generate a torque signal, which is a control signal, which is output to a coordinate transformation matrix (CTM) operation unit 201.

The local azimuth / posture calculation unit 202 calculates the azimuth and the posture angle (roll angle and pitch angle) of the local coordinate system from the calculation result output from the coordinate conversion matrix (CTM) calculation unit 201. With respect to the azimuth and attitude angle of the local coordinate system calculated in this manner, the errors of the XY gyro and the XY accelerometer are removed by rotating the turntable by ± 180 °.

The operation in the survey mode will be described with reference to FIGS. 5, 6 and 7. As shown in FIG. 5, consider a point P at latitude λ in the northern hemisphere of the earth. Let O be the center of the earth,
The point at which the meridian passing through the point P intersects the equatorial plane is P _O , and the rotation axis of the earth is OP _N. Latitude λ of point P is ∠PO
Is a P _O. The horizontal plane H at the point P is a tangent plane to the earth surface.

The rotation angular velocity vector Ω _E of the earth is oriented in the direction of the rotation axis OP _N as shown in the figure. The rotation angular velocity vector Ω _E of the earth is a horizontal component HER (Horizontal Earth Rate) in the true north direction (arrow N) on the horizontal plane H, that is,
Ω _E cosλ and vertical component (Vertical Earth Rate)
That is, it can be decomposed into Ω _E sinλ.

As shown in FIG. 6, it is assumed that a gyrocompass device, that is, a moving body is arranged on a horizontal plane H at a point P. The azimuth of the moving object is aligned with the x-axis as described above. The azimuth ∠NPx of the moving body is Φ. X gyro input axis is PX _GS , Y gyro input axis is P
The input axes of Y _GS and Z gyro are PZ _GS .

It is assumed that the rotation angle of the input axis of the X gyro with respect to the azimuth Px of the moving body is φ. It is assumed that the rotation angle of the turntable is equal to the rotation angle φ of the input axis of the X gyro. The azimuth ∠NPX _GS of the input axis of the X gyro is Φ + φ. Y
Gyro input axis azimuth angle 入 力 NPY _GS is Φ + φ + 90
°.

X gyro is the rotation angular velocity vector Ω of the earth
Detecting an input axis PX _GS direction component of _E, Y gyro detects an input axis PY _GS direction component of the Earth's rotation angular velocity vector Omega _E, Z gyro input axis PZ _GS of the Earth's rotation angular velocity vector Omega _E The direction component is detected. Therefore,
The outputs ω _X , ω _Y , ω _z of the X, Y, Z gyros are expressed as follows.

[0041]

Ω _X = Ω _E cos λ cos (Φ + φ) + U _X ω _Y = Ω _E cos λ sin (Φ + φ) + U _Y ω _Z = −Ω _E sin λ + U _Z

Where Ω_EIs the rotational angular velocity of the earth, λ is latitude
Degrees. Φ is the azimuth of the moving object, that is,
Is the rotation angle of the gyro with respect to the azimuth of the moving object.
Turning angle, U_X, U_Y, U_ZAre gyro drifts
It is. Output ω of Z gyro _zHas a minus sign
Is such that the direction of the input axis is oriented in the negative direction of the z-axis.
This is because the gyro was attached. In this example, the circumference of the y axis is
The rotational angular velocity around the x axis and the rotational angular velocity
That is, dθ / dt = 0 and dσ / dt = 0.

The above example is a gyro compass device,
A case where the moving body is arranged on the horizontal plane H, and a case where the moving body is inclined will be considered. Consider a case where the moving body is rotationally biased around the input axis PX _GS of the X gyro by the rotation angle σ.

A description will be given with reference to FIG. FIG. 7 shows the plane formed by the input axis PX _GS of the X gyro and the input axis PY _{GS of the} Y gyro. The outputs ω _X , ω _Y , ω _Z of the X, Y, Z gyros are expressed as follows.

[0045]

Ω _X = Ω _E cos λ cos (Φ + φ) + U _X ω _Y = −Ω _E sin λ sin σ + Ω _E cos λ sin (Φ + φ) c
osσ + mg sinσ + qg cosσ + U Y ω Z = -Ω E sin λ cosσ-Ω E cos λ sin (Φ + φ) s
inσ-mg cosσ + qg sinσ + U _Z

Here, σ is the inclination angle of the moving body about the input axis PX _{GS with} respect to the horizontal plane H. The inclination angle σ is detected by the Y accelerometer. mg is a mass imbalance caused by the deviation of the center of gravity of the gyro rotor, and qg is a crosstalk amount caused by a change in the input angular velocity of the partner shaft. These are errors specific to TDG. X, Y, Z gyro output ω
_In order to determine the azimuth angle Φ of the moving object from _X , ω _Y , ω _Z , it is necessary to determine the gyro drifts U _X , U _Y , U _Z. The gyro drift U _X , U _Y , U _Z
A method for obtaining the following will be described.

The rotary table is stopped after being rotated at a constant rotation angle Δφ = 2π / n (for example, every 60 ° with n = 6) and output signals ω _X , ω _Y , ω _{Z of} three gyros And the output signal σ of the Y accelerometer is measured. By rotating the turntable once, n sets of measured values ω _Xi , ω _Yi , ω _Zi , σ _i
(I = 1 to n) are obtained. Among these measured values, attention is paid to data in which the rotation angles φ are different from each other by 180 °. For example, the output signals of the X, Y, Z gyro for the rotation angle φ are ω _X1 , ω _Y1 , ω _Z1 , and the output signals of the X, Y, Z gyro for the rotation angle φ + π are ω _X2 , ω _Y2 , ω _Assuming that _Z2 , these are expressed as follows.

[0048]

Ω _X1 = Ω _E cos λ cos (Φ + φ) + U _X ω _X2 = Ω _E cos λ cos (Φ + φ + π) + U _X

Ω _Y1 = −Ω _E sin λ sin σ ₁ + Ω _E cos λ
sin (Φ + φ) cosσ ₁ + mg sinσ ₁ + qg cosσ ₁ +
U _Y ω _Y2 = −Ω _E sin λ sin σ ₂ + Ω _E cos λ sin (Φ + φ
+ Π) cosσ ₂ + mg sinσ ₂ + qg cosσ ₂ + U _Y

Ω _Z1 = −Ω _E sin λ cos σ ₁ −Ω _E cos λ
sin (Φ + φ) sinσ ₁ −mg cosσ ₁ + qg sinσ ₁ +
U _Z ω _Z2 = −Ω _E sin λ cosσ ₂ −Ω _E cos λ sin (Φ +
φ) sinσ ₂ -mg cosσ ₂ + qg sinσ ₂ + U _Z

Here, σ ₁ and σ ₂ are the inclination angles of the movable body or the base 10 around the input axis of the X gyro with respect to the horizontal plane H when the rotation angles of the turntable are φ and φ + π, respectively. There is a geometrical relationship between the _two inclination angles σ ₁ and σ ₂ as follows.

[0052]

[Equation 4] σ ₁ = −σ ₂

The following relationship is obtained by substituting this into the equation (3) and transforming it.

[0054]

Ω _X1 = Ω _E cos λ cos (Φ + φ) + U _X ω _X2 = −Ω _E cos λ cos (Φ + φ) + U _X

Ω _Y1 = −Ω _E sin λ sin σ ₁ + Ω _E cos λ
sin (Φ + φ) cos σ ₁ + mg sin σ ₁ + qg cos σ ₁
+ U _Y ω _Y2 = Ω _E sin λ sinσ ₁ −Ω _E cos λ sin (Φ + φ)
_{cos σ 1 -mg sinσ 1 + qg} cosσ 1 + U Y

Ω _Z1 = −Ω _E sin λ cos σ ₁ −Ω _E cos λ
sin (Φ + φ) sin σ ₁ −mg cosσ ₁ + qg sinσ ₁
+ U _Z ω _Z2 = −Ω _E sin λ cosσ ₁ + Ω _E cos λ sin (Φ +
φ) sin σ ₁ −mg cosσ ₁ −qg sinσ ₁ + U _Z

From these six equations, six unknowns U _X , U _Y , U _Z , mg, qg, and Φ can be obtained. First, the following relational expressions are obtained from these expressions.

[0058]

Ω _X1 + ω _X2 = 2U _X ω _X1 −ω _X2 = 2Ω _E cos λ cos (Φ + φ) ω _Y1 + ω _Y2 = 2U _Y + 2qg cosσ ₁ ω _Y1 −ω _Y2 = 2Ω _E [−sin λ sin σ ₁ + cos λ sin (
Φ + φ) cos σ _{1] + 2mg sinσ 1 ω Z1 + ω} Z2 = -2Ω E sin λ cosσ 1 -2mg cosσ 1
+ 2U _Z ω _Z1 −ω _Z2 = -2Ω _E cos λ sin (Φ + φ) sin σ ₁ +
2qg sinσ ₁ + 2U _Z

Next, from these six equations, six unknowns U _X , U _Y , U _Z , mg, qg, and Φ can be obtained.

[0060]

U _X = (ω _X1 + ω _X2 ) / 2 U _Y = (ω _Y1 + ω _Y2 ) / 2-qg cosσ ₁ U _Z = (ω _Z1 + ω _Z2 ) / 2 + Ω _E sin λ cosσ ₁ + mg
cosσ ₁ Φ = cos ^-1 [(1 / 2Ω _E ) (ω _X1 −ω _X2 )] / (cos
λ)] − φ qg = [(ω _Y1 + ω _Y2 ) / 2−U _Y ] / cos σ ₁ mg = (Ω _E / sin σ ₁ ) [− sin λ sin σ ₁ + cos λ
sin (Φ + φ) cos σ ₁ ] − (ω _Y1 −ω _Y2 ) / ₂ sin σ ₁

The azimuth angle Φ of the moving object is the output ω _{X of the} X gyro.
(The second equation of Equation 6). If the inclination of the input axis of the X gyro is zero as in this example, it is sufficient.
However, when the inclination of the input axis of the X gyro is not zero, the output ω _{Y of the} Y gyro (fourth equation in Equation 6)
Equation).

[0062]

[Equation 8] Φ = sin ⁻¹ [｛(ω _Y1 −ω _Y2 ) −2 mg sin σ
₁ ｝ / 2Ω _E + sin λ sinσ ₁ ]] / cos λ cosσ ₁ ]
−φ

Here, for the sake of simplicity, if the mass unbalance mg and the crosstalk amount qg are known and ignored, the following relationship is obtained.

[0064]

U _X = (ω _X1 + ω _X2 ) / 2 U _Y = (ω _Y1 + ω _Y2 ) / 2 U _Z = (ω _Z1 + ω _Z2 ) / 2 + Ω _E sin λ cosσ ₁ Φ = sin ⁻¹ [｛( 1 / 2Ω _E ) (ω _Y1 −ω _Y2 ) + sin λ
sinσ ₁ ｝ / (cosλcosσ ₁ )] − φ

Next, a method of detecting the bias Δσ included in the output signal σ of the Y accelerometer and detecting the true tilt angle σ around the x-axis will be described. Similarly, the turntable is rotated at a constant rotation angle Δ
Every φ = 2π / n (for example, every 60 ° as n = 6)
The rotation is stopped, and the output signal σ _M of the Y accelerometer is measured. It is assumed that n sets of measured values σ _Mi (i = 1 to n) are obtained by rotating the turntable once. Among these measured values, attention is paid to data in which the rotation angles φ are different from each other by 180 °. For example, if the output signal of the Y accelerometer at the rotation angle φ is σ _M1 and the output signal of the Y accelerometer at the rotation angle φ + π is σ _M2 , the following expression is obtained.

[0066]

## EQU10 ## σ _M1 = σ ₁ + Δσ σ _M2 = σ ₂ + Δσ

Here, σ ₁ and σ ₂ are the inclination angles of the turntable 10 around the x-axis when the bias Δσ is zero and the rotation angle is φ and φ + π, as described above. There is a relationship of equation 4 between the _two inclination angles σ ₁ and σ ₂ around the x-axis. Therefore, the following relationship is obtained from the equation (9).

[0068]

Equation 11] _{σ M1 -σ M2 = σ 1 -σ} 2 = 2σ 1 σ M1 + σ M2 = σ 1 + σ 2 + 2Δσ = 2Δσ

Therefore, when the rotation angle of the turntable is φ, the true x
The tilt angle σ ₁ about the axis and the bias Δσ of the Y accelerometer are represented by the following equations.

[0070]

Σ ₁ = (σ _M1 −σ _M2 ) / 2 Δσ = (σ _M1 + σ _M2 ) / 2

When the rotation angle of the turntable is φ, the true tilt angle θ ₁ around the y-axis and the bias Δθ of the X accelerometer are obtained by the same method, and are given by the same expressions as in Expression 12, but are described in detail here. Not explained.

According to this example, n sets of measured values ω _Xi , ω _Yi , ω _Zi , σ _i , θ are obtained by rotating the turntable once.
_i (i = 1 to n) is obtained. Therefore, there are n / 2 sets of measurement values in which the rotation angles φ of the turntable differ from each other by 180 °. n
N / 2 sets of data Φ, U _X , U _Y ,
U _Z , σ ₁ , Δσ, Δθ are obtained. Therefore, more accurate values of Φ, U _X , U _Y , U _Z , σ ₁ , Δσ, θ ₁ , Δθ can be obtained by obtaining the average value or the least square approximation value.

Referring to FIG. 8, the configuration and operation of the drift / bias calculator 3 will be described. The drift / bias calculation unit 3 includes a rotation control unit 71, a sequencer unit 72, a data measurement storage unit 73, a direction calculation unit 74, and a calculation unit 75.

[0074] The rotation control unit 71 functions as the rotation angle of the turntable phi is equal to the set rotation angle phi _S. Rotation control unit 7
1 supplies the set rotation angle φ _S generated by the sequencer unit 72 to the azimuth servomotor 22. The azimuth servomotor 22 operates to rotate the turntable about the rotation axis.
The azimuth transmitter 13Y detects the rotation angle φ of the turntable and outputs it to the rotation control unit 71. When the output signal phi azimuth transmitter 13Y is equal to the set rotation angle phi _S, data measurement storage unit 73 and stores measured turntable data.

The data measurement storage unit 73 stores X, Y, Z
Iro output signal ω_X, Ω_Y, Ω_Z, Set rotation angle φ_S= Φ
And the inclination angles θ and σ output from the XY accelerometer (clockwise
The direction is set to +. ). Next, the sequencer section 72
Is the new set rotation angle φ_S= Φ _S+ Δφ to generate rotation control
It is supplied to the control unit 71. The rotation control unit 71 includes the direction transmitter 13
Y output signal φ is the new set rotation angle φ_SWill be equal to
Operate the azimuth servo motor as shown.

Thus, the output signal φ of the azimuth transmitter 13Y
Is equal to the new set rotation angle φ _S , the data measurement storage unit 73 measures and stores the gyro data. Therefore, data measurement storage unit 73 stores the data for each set rotational angle phi _S.

The data measurement storage unit 73 stores the set azimuth angle φ_S
= Φ_iData ω for each_Xi, Ω_Yi, Ω_{Z i}, Σ_i, Θ_i(I
= 1 to n) are sequentially stored. Recorded in the data measurement storage unit 73
Many data φ remembered_i, Ω_Xi, Ω_Yi, Ω_Zi, Σ_i,
θ_i(I = 1 to n) are the direction calculation unit 74 and the calculation unit sequentially
75. The arithmetic unit is calculated by the equations of Equations 7 to
75 is gyro drift U_X, U_Y, U_ZAnd accelerometer
Compute bias Δσ, Δθ and attitude angle σ, θ to calculate azimuth
The unit 74 calculates the direction Φ of the turntable.

Referring again to FIGS. 1 and 2, the second embodiment of the present invention will be described.
Will be described. The above example is a gyrocompass device of a strap-down type, but the example described below is a gyrocompass device of a semi-strap-down type.

The roll shafts 53 are mounted on both ends of the base 10. The roll shaft 53 is rotatably mounted on the disk 52 of the casing. A non-contact DST (direct servo torquer) may be used to rotate the base 10 around the roll axis 53. In addition, a rotary transformer may be used for power supply to the sensor mounted on the turntable and transmission and reception of signals. Further, the gyro compass device is provided with a mechanism for controlling the base 10 around the roll axis 53, whereby the base 10 is always held at a predetermined roll position (horizontal position). Therefore, the sensor unit of the gyro compass device moves together with the movement of the moving body while being held at the predetermined roll position, and assumes the same posture as the moving body. This is referred to herein as a semi-strap down system.

[0080] In the semi-strapdown system, the base and the gyro compass device is always predetermined rotational position in the input axis PX _GS around the X gyro. Therefore, in the above discussion, the rotation angle σ may be set to zero.

Although the embodiments of the present invention have been described above, it will be understood by those skilled in the art that the present invention can be variously modified within the scope of the invention described in the claims.

[0082]

According to the present invention, there is an advantage that it is possible to provide a small-sized, small-diameter, high-accuracy and low-cost gyrocompass device for measuring the position of an object underground or underwater.

According to the present invention, there is an advantage that the position of a relatively small-diameter pipe underground or underwater, such as a sewer pipe, can be measured accurately and without excavating the ground.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a main part of a gyro compass device of the present invention.

FIG. 2 is a diagram showing an example of a main part of another example of the gyro compass device of the present invention.

FIG. 3 is a diagram illustrating an example of the overall configuration of a gyrocompass device according to the present invention.

FIG. 4 is a diagram illustrating a configuration example of an arithmetic unit of the gyro compass device of the present invention.

FIG. 5 is an explanatory diagram for explaining a rotation angular velocity vector of the earth.

FIG. 6 is an explanatory diagram for describing components of a rotation angular velocity vector of the earth detected by an XYZ gyro.

FIG. 7 shows XYZ when the gyro compass device is inclined.
FIG. 4 is an explanatory diagram for explaining components of a rotation angular velocity vector of the earth detected by a gyro.

FIG. 8 is a diagram showing a configuration example of a drift / bias calculation unit of the gyro compass device of the present invention.

FIG. 9 is an explanatory diagram for explaining an example of a conventional excavator.

[Explanation of symbols]

10 Base, 11A, 12A, 13A Accelerometer, 11G, 12G, 13G Gyro, 13Y
... azimuth transmitter, 20 ... turntable, 50 ... casing, 51 ... cylindrical part, 52 ... disk part, 53 ...
・ Roll shaft, 201: excavating blade, 202: leading pipe, 203: guide member, 210A, 210B, 2
10C, 210D, 210E ... Hume tube, 220
... Main push pipe, 205 ... Supply pipe, 206 ... Drain pipe, 207 ... Pump

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masaru Ebihara 2-16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Co., Ltd. (72) Inventor Yasuo Takada 2--16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Corporation (72) Inventor Takeshi Hojo 2-16-46 Minami Kamata, Ota-ku, Tokyo F-term in Tokimec Corporation (Reference) 2F029 AA08 AB03 AC03 AD01 2F105 AA10 BB13

Claims (5)

[Claims] 1. A cylindrical casing having a central axis, a base disposed in the casing, a sensor unit mounted on the base and including an XYZ gyro, an XYZ accelerometer and an azimuth transmitter, and a compass mode. In the calculation section, a signal output from the sensor section is converted into a signal of the earth surface coordinate system, and in the surveying mode, a azimuth of the base, a gyro drift, and a bias of acceleration are calculated from the signal output from the sensor section. A drift / bias calculation unit, and the base has a plurality of turntables arranged along the central axis and a driving device for synchronously rotating the plurality of turntables, The gyro compass device, wherein the sensor unit is mounted on the turntable such that an input axis or a measurement axis thereof is aligned with the center axis. 2. The gyro compass device according to claim 1, wherein said XYZ gyro is constituted by a TDG (Tuned Dry Gyro). 3. The operation unit includes: a coordinate conversion matrix operation unit that calculates a coordinate conversion matrix for converting a coordinate system provided on the base into an earth surface coordinate system; and an earth surface coordinate system using the coordinate conversion matrix. 2. The gyro compass device according to claim 1, further comprising: a local acceleration calculator for calculating the acceleration of the gyro and a local azimuth and orientation calculator for calculating the azimuth and orientation of the earth surface coordinate system. 4. The drift / bias calculation unit includes a rotation control unit that controls rotation of the turntable and a data measurement storage unit that stores outputs of the XYZ gyro and the XYZ accelerometer using the azimuth of the turntable as a parameter. XYZ gyro and XYZ from the output from the data measurement storage unit
A calculating unit for calculating the drift and bias of the output of the accelerometer; and an azimuth calculating unit for calculating the azimuth of the base, wherein the bias of the sensor unit is calculated based on the output of the sensor unit at a plurality of rotation angles of the turntable. The gyro compass device according to claim 1, wherein the gyro compass device is configured to detect a drift and a drift. 5. The outer diameter of the cylindrical casing is 80 m.
The gyro compass device according to claim 1, wherein m is equal to or less than m.