JP3668855B2 - Gyro compass - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a gyrocompass, and more particularly to a surveying gyrocompass for measuring the azimuth angle of a stationary object with respect to the meridian or a gyrocompass for detecting the traveling direction of an underground excavator.
[0002]
[Prior art]
  FIG. 8 shows an example of use of a gyrocompass for surveying. A transit 301 is mounted on a horizontal base 302-1 at the upper end of a tripod 302, and a gyrocompass 303 is attached to the upper end of the transit 301. Yes. A fine adjustment screw 301A is mounted on the lower surface of the transit 301. By adjusting the screw 301A, the transit 301 is arranged on a horizontal plane.
[0003]
  The direction and inclination angle of the object are measured by the transit 301, and the azimuth angle of the base line of the transit 301 with respect to the meridian is measured by the gyrocompass 303.
[0004]
  With reference to FIG. 9, an example of a gyrocompass for surveying disclosed in Japanese Patent Application No. Hei 4-168953 filed on June 26, 1992 by the same applicant as the present applicant will be described. The gyrocompass includes a base 310, a pair of azimuth bearings 312A and 312B disposed in the center hole 310a of the base 310, and an azimuth shaft 314 fitted to the inner ring of the azimuth bearings 312A and 312B. An azimuth gear 316 attached to the top of the azimuth axis 314 and a turntable 318 attached to the upper end of the azimuth axis 314 are provided.
[0005]
  The assembly composed of the azimuth axis 314, the azimuth gear 316, the turntable 318, and the gyro 320 can integrally rotate around the center line of the azimuth axis 314, that is, the azimuth axis ZZ.
[0006]
  The base 310 has an upper flange portion 310b and a lower flange portion 310c, and a step motor 322 and a zero cross pickup 326 are attached to the upper flange portion 310b. A pinion 324 is mounted on the rotation shaft of the step motor 322, and the pinion 324 is meshed with the bearing gear 316 attached to the bearing shaft 314. Thus, the rotation of the step motor 322 passes through the pinion 324 and the bearing gear 316. And transmitted to the azimuth axis 314.
[0007]
  The zero-cross pickup 326 may be configured optically, for example, and the optical zero-cross pickup 326 may be, for example, a pin 326A mounted on the lower surface of the bearing gear 316 and the upper surface of the upper flange portion 310b. The light-emitting element 326B and the light-receiving element 326C attached to the sensor may be included.
[0008]
  When the pin 326A passes between the light emitting element 326B and the light receiving element 326C, it is detected as a change in the amount of light emitted by the light emitting element 326B and received by the light receiving element 326C. Thus, the turntable 31 with respect to the base 310.8Can be detected.
[0009]
  The base 310 is mounted on the corresponding reference surface of the transit 301 so that the lower surface 310d of the lower flange portion 310c thereof is horizontal, and thus the azimuth axis ZZ is arranged in alignment with the vertical direction, that is, the Z axis. Will be.
[0010]
  The principle of measuring the azimuth angle Φ of the base 310 (baseline of the transit 301) with a gyrocompass will be described with reference to FIGS. Consider a point P in the northern hemisphere of the earth. The point where the meridian passing through point P intersects the equator plane is P_O And the rotation axis of the earth is OP_NAnd Latitude λ of point P is ∠POP_OIt is. The horizontal plane H at the point P is a tangential plane with respect to the earth surface.
[0011]
  Earth rotation angular velocity Ω_E Is the rotation axis OP as shown_NFacing the direction. Such a vector Ω_E Is the horizontal component HER (Horizontal Earth Rate) on the horizontal plane H (arrow N), that is, Ω_EIt can be decomposed into cos λ and a vertical component VER (Vertical Earth Rate), that is, Ω E sin λ.
[0012]
  As shown in FIG. 11, a two-dimensional coordinate is taken on a horizontal plane H with a point P as an origin, a true east direction as an E axis, and a true north direction as an N axis. Base3The azimuth angle of 10 is the base for the meridian ON310 is the rotation angle ＲNOR of the reference line OR, and the azimuth angle Φ + φ of the turntable 318 is the rotation angle ∠NOQ of the reference line OQ of the turntable 318 with respect to the meridian ON.
[0013]
  Since the gyro 320 is mounted on the turntable 318 and rotates therewith, the input axis of the gyro 320 is in the direction of the reference line OQ of the turntable 318.
[0014]
  At point P, the gyrocompass has its azimuth axis ZZleadIt is assumed that they are arranged in a straight direction. In such a case, even if the turntable 318 rotates, the input axis OQ of the gyro 320 is always in the horizontal plane H.
[0015]
  Therefore, rotation angular velocity Ω_EThe vertical component VER of the vector is not detected by the gyro 320, but only the horizontal component HER is detected.
[0016]
  Rotational angular velocity Ω_EThe horizontal component HER of the vector is changed to the input axis OQ direction (reference line OQ direction) of the gyro 320 and the OQ perpendicular thereto._T Disassemble in the direction. The component of horizontal component HER in the input axis OQ direction is Ω_Ecos λ cos (Φ + φ) and O−Q perpendicular to it_TDirectional component is Ω_Ecos λ sin (Φ + φ).
[0017]
  What is detected by the gyro 320 is the rotational angular velocity Ω._E Of the horizontal component HER of the vector, the component Ω in the input axis OQ direction of the gyro 320_Ecos λ cos (Φ + φ).
[0018]
  The angular velocity Ω actually output by the gyro 320 is expressed by the following equation (1).
[0019]
[Expression 1]
  Ω = (1 + ΔF) Ω_Ecosλcos (Φ + φ) + ΔU
[0020]
  Where Ω_EIs the rotational angular velocity of the earth, λ is the latitude, Φ is the azimuth angle of the base 310, and φ is the rotation angle of the turntable 318 relative to the base 310. ΔF is a scale factor error, and ΔU is a drift of the gyro 320.
[0021]
  In order to obtain the azimuth angle Φ of the base 310 using the equation (1), the scale factor error ΔF and the drift ΔU must be eliminated from this equation. A method for obtaining the azimuth angle Φ of the base 310 by eliminating the scale factor error ΔF and the drift ΔU is known.
[0022]
  The turntable 318 is stopped by rotating at a constant angle of 2π / n (for example, every 60 ° with n = 6), and the output angular velocity Ω of the gyro 320 is measured. When the turntable 318 is rotated once, n measurement values Ωi (i = 1 to n) are obtained. Such a measured value Ωi is given by
[0023]
[Expression 2]
  φ = (2π / n) (i−1)
[0024]
  As required. Therefore, the following equation (3) is obtained by substituting the equation (2) into the equation (1).
[0025]
[Equation 3]
  Ωi = (1 + ΔF) Ω_Ecos λ cos [Φ + (2π / n) (i−1)] + ΔU
[0026]
  From these n angular velocities Ωi, the azimuth angle Φ of the base 310 can be obtained by the method of least squares. Since the azimuth angle Φ thus obtained does not include the scale factor error ΔF and the drift ΔU, the azimuth angle Φ of the base 310 is obtained even if the scale factor error ΔF and the drift ΔU exist.
[0027]
  A description will be given with reference to FIG. 9 again. The control loop connected to the gyro 320 includes a rotation control unit 340, a sequencer unit 342, a measurement storage unit 344, and a calculation output unit 346.
[0028]
  The rotation control unit 340 uses the reference signal supplied from the zero-cross pickup 326 and the command signal supplied from the sequencer unit 342, for example, to send a command signal to rotate the turntable 318 by a rotation angle 2π / n and stop the command signal. 322 is supplied. The measurement storage unit 344 stores n angular velocity Ωi signals supplied from the gyro 320 one after another.
[0029]
  The calculation output unit 346 uses the n angular velocity Ωi signals supplied from the measurement storage unit 344 to calculate3The azimuth angle Φ of the base 310 is calculated by the following formula and is output.
[0030]
[Problems to be solved by the invention]
  The conventional gyrocompass 303 isSince the azimuth angle Φ is calculated using the formula of Formula 3 on the assumption that the azimuth axis ZZ is arranged in the vertical direction,Before measuring the azimuth angle, it was necessary to adjust the fine adjustment screw 301A on the lower surface of the transit 301 and arrange the transit 301 horizontally.
[0031]
  When the conventional gyrocompass 303 is used for an underground excavator, the course of the underground excavator is inclined with respect to the horizontal plane.WhenAs the underground drilling rig progresses, the gyrocompass attached to it will tilt.For this reason, it is necessary to keep the gyrocompass base 310 mounted horizontally even if the attitude of the underground excavator itself tilts during excavation so that the azimuth axis ZZ always faces the vertical direction.Similar problems arise.
[0032]
  Even when the base 310 is tilted in this way,Gyro 320ByoutputBe doneThe angular velocity Ω is expressed by the equation (1). However, if the horizontal table 302-1 is inclined, the value of the output angular velocity Ω of the gyro 320 includes an error due to the inclination.(See Figure 8).
[0033]
  Thus, the output angular velocity Ω of the gyro 320 includes the error ΔΩ due to the inclination of the horizontal base 302-1, and an accurate value of the azimuth angle Φ of the base 310 cannot be obtained.
[0034]
  In view of this point, the present invention is to propose a gyrocompass capable of accurately obtaining the azimuth angle Φ of the base even when the input axis of the gyro is inclined with respect to the horizontal plane during surveying.
[0035]
[Means for Solving the Problems]
  The gyrocompass of the present invention isA gyro having a spin axis in the X-axis direction;thisA support device that rotatably supports the gyroscope around the Y-axis and the Z-axis, and a support device that rotatably supports the support device around the Y-axis and has a follow-up shaft that is perpendicular to the base,thisIn a gyro compass that has a tracking ring that can rotate around a vertical axis that passes through the tracking axis and a finger north device that applies finger north force to the gyro, and that measures the azimuth angle Φ of the base relative to the meridian A rotation control unit for sequentially rotating the shaft at every predetermined rotation angle, and an angular velocity ω around the Y axis detected by the gyro_Y And angular velocity ω around the Z axis_Z And the rotation angle φ of the tracking ringDetected by east-west inclinometer or east-west accelerometerA data measurement storage unit for inputting and storing the inclination angle σ of the Y axis with respect to the horizontal plane;thisdatameasurementA base azimuth calculating unit that calculates the azimuth angle Φ of the base with respect to the meridian from the data stored in the storage unit.Is a thing.
[0036]
  Further, the present invention provides the gyrocompass described above,datameasurementIt is configured to have a gyro drift calculation unit that calculates the gyro drift from the data stored in the storage unitIs a thing.
[0037]
  Further, the present invention provides the gyrocompass described above,The gyro drift calculatorFrom the data stored in the data measurement storage unitFurthermore, it is configured to calculate the bias of the east-west inclinometer or east-west accelerometer.Is a thing.
[0038]
  Further, the present invention provides the gyrocompass described above,The rotation controller detects the azimuth angle Φ of the base with respect to the meridian and then rotates the tracking axis in the opposite direction.ΦIt is configured so that the base line of the tracking axis is oriented in the meridian direction by rotating onlyIs a thing.
[0039]
  Further, in the gyrocompass described above, the present invention is based on the tilt angle σ of the Y axis determined by the gyro drift calculation unit based on the data of the east-west inclinometer or the east-west accelerometer,The base azimuth calculation unit is configured to measure the azimuth angle Φ of the base with respect to the meridian even when the base is inclined.
[0040]
  Further, in the gyrocompass described above, the present invention provides the gyro drift from the gyro drift calculation unit and the bias of the east-west inclinometer or east-west accelerometer before the normal gyro compass operation.Automatic correctionAndDriving the gyrocompassDuring ~Is also configured to point in the measured true north direction.
[0041]
  Furthermore, in the gyrocompass described above, the present invention detects the azimuth angle Φ of the base with respect to the meridian, and rotates the tracking axis in the opposite direction by the rotation angle Φ so that the baseline of the tracking axis directs the meridian direction.Before the normal gyro compass operation, the gyro compass is oriented to true north in advance, and the gyro drift,East-west inclinometer or east-west accelerometer biasCan be used immediately as a gyro compassIt is what.
[0042]
  The gyrocompass according to the present invention isRotate the gyro support device around the Y axisLevel (horizontal) control system andRotate the following axisIt has an azimuth control system, and by level (horizontal) control systemGyro spin axisIs controlled to be horizontal, and the azimuth angle φ of the tracking ring is set to the set azimuth angle φ by the azimuth control system._S Is controlled to be equal to.
[0043]
  Therefore, the angular velocity ω around the Y axis detected by the gyro_Y And angular velocity ω around the Z axis_Z In addition to the base orientation Φ to be obtained, the rotation angle φ of the tracking ring and the tilt angle σ of the Y axis with respect to the horizontal planeInformationIncludingIt will be.
[0044]
  The output signal ω of such a gyro_Y , Ω_Z In order to obtain the base orientation Φ more,FirstA plurality of different azimuth angles φ by sequentially rotating the tracking ring by a predetermined angle_iData for ω_Yi, Ω_Zi, Σ_i SeekingRu.AndSuch multiple data ω_Yi, Ω_Zi, Σ_iMore variable φ_i , Σ_i The base orientation Φ is obtained by deleting.
[0045]
  In accordance with the present invention, an alignment mode is incorporated that operates prior to the normal compass mode. According to such an alignment mode, the base orientation Φ is obtained, and the follower ring is rotated in the opposite direction by the rotation angle Φ. As a result, the north end of the gyro compass points to true north.
[0046]
  According to the present invention, the gyro drift is measured and corrected by the alignment mode. Accordingly, the finger north end of the gyrocompass directed in the alignment mode is directed to true north, and the subsequent gyrocompass operation is performed in a state of being directed to true north with high accuracy.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
  First, an outline of the gyrocompass of the present invention will be described with reference to FIG. The gyrocompass in this example is configured for surveying.
[0048]
  The gyro compass of this example is a flex gyro or TDG (Tuned Dry Gyro) as shown on the right side of FIG.Is a gyroTDG 11, block 13, follow ring 15 and base 10 are provided. Following ring 15 is relative to base 10Erected verticallyThe TDG 11 is attached to the follower ring 15 so as to be rotatable around the horizontal axes 13A and 13B. In this way, the TDG 11 can rotate around two axes, horizontal axes 13A and 13B parallel to the attachment surface and a follow-up shaft 17 perpendicular to the attachment surface.
[0049]
  For the following explanation, when the spin axis of the TDG 11 is oriented horizontally,The Z axis is taken along the follow axis 17, the Y axis is taken along the horizontal axes 13A and 13B, and the X axis is taken perpendicularly to both.At this time,The spin axis of TDG 11 is the X-axis direction.
[0050]
  As shown on the left side of FIG. 1, an azimuth servomotor 29 and an azimuth transmitter 31 are mounted on the follower shaft 17, and the TDG 11 is rotated around the follower shaft 17 by the azimuth servomotor 29 and is followed by the azimuth transmitter 31. A rotation angle φ around the axis 17 is detected.
[0051]
  The TDG 11 has a Y gyro and a Z gyro, and the Y gyro has a rotational angular velocity ω around the Y axis._Y The Z gyro detects the angular velocity ω around the Z axis._Z Is detected.
[0052]
  The block 13 is equipped with a north-south inclinometer or north-south accelerometer and an east-west inclinometer or east-west accelerometer. The north-south inclinometer detects the rotational inclination angle θ around the Y axis of the spin axis of the TDG 11 relative to the horizontal plane, and the east-west inclinometer detects the rotational inclination angle σ around the X axis of the spin axis of the TDG 11 relative to the horizontal plane. The inclination angle σ around the X axis output by the east-west inclinometer represents the inclination angle σ around the X axis of the base 10 or the mounting surface with respect to the horizontal plane.
[0053]
  The gyro compass of this example further has a level control system and an azimuth control system.Detects the rotation angle θ around the Y axisNorth and southSlopeThe output signal of the meter acts so that the output signal becomes zero, and the direction control system outputs the output signal φ of the direction transmitter 31 to the set direction φ._S Acts to be equal to
[0054]
  The gyro compass of this example further includes a rotation control unit 71, a sequencer unit 72, a data measurement storage unit 73, a base direction calculation unit 74, and a drift calculation unit 75, which will be described later.
[0055]
  The gyrocompass of this example is used for surveying, the tilting motion of the mounting surface or base of the gyrocompass is extremely slow, and the rotational angular velocity around the Y axis and the rotational angular velocity around the X axis are zero, that is, dθ / dt. = 0 and dσ / dt = 0.
[0056]
  First,The principle of measuring the base orientation Φ with the gyrocompass of this example will be described with reference to FIGS. 10, 12, and 13. As described with reference to FIG. 10, a horizontal plane H is considered at a point P of latitude λ, and the horizontal axis is an east-west axis (EW axis) and the vertical axis is a north-south axis (NS axis) on the horizontal plane H. Take coordinates.
[0057]
  FIG. 12 shows a case where the gyrocompass of this example is arranged on the horizontal plane H, that is, a case where the rotational inclination angle σ around the X axis of the base 10 is zero and σ = 0. The azimuth angle Φ of the base 10 is the rotation angle ∠ NOR of the reference line OR of the base 10 with respect to the meridian ON, and the azimuth angle φ + Φ of the gyro spin axis OX1 is the spin axis OX with respect to the meridian ON₁Rotation angle ∠ NOX₁It is.
[0058]
  The TDG 11 has an X axis, a Y axis, and a Z axis, and includes a Y gyro having an input axis in the Y axis direction and a Z gyro having an input axis in the Z axis direction.
[0059]
  Therefore,Y gyro input axis OY₁ Is perpendicular to the gyro spin axis OX1 as shown, and the Z gyro input axis OZ₁ Is the gyro spin axis OX₁And Y gyro input axis OY₁ Are perpendicular to both sides and perpendicular to the paper surface.
[0060]
  As described with reference to FIG. 10, the earth rotation angular velocity Ω at the point P_EIs the horizontal component Ω_E cos λ and vertical component Ω_E can be decomposed into sin λ. Therefore, the angular velocity ω detected by the Y gyro and the Z gyro_Y, Ω_Z Is expressed as: U_Y , U_Z Is the gyro drift respectively.
[0061]
[Expression 4]
  ω_Y = -Ω_Ecosλsin (Φ + φ) + U_Y
  ω_Z = -Ω_Esinλ + U_Z
[0062]
  FIG. 13 shows a YZ plane when the gyrocompass of this example is rotated and inclined about the X axis with respect to the horizontal plane H. FIG. The base 10 is inclined around the X axis by an inclination angle σ, and the input axis OY of the Y gyro₂ And Z gyro input axis OZ₂ Are horizontal OY₁And vertical direction OZ₁ Is inclined by an angle σ. The tilt angle θ around the Y axis is zero by the operation of the level control system. Therefore, the angular velocity ω detected by the Y gyro and the Z gyro_Y, Ω_Z Is expressed as:
[0063]
[Equation 5]
  ω_Y = Ω_Esinλsinσ−Ω_E cosλsin (Φ + φ) cosσ
        + Mgsinσ + qgcosσ + U_Y
  ω_Z = -Ω_Esinλcosσ-Ω_E cosλsin (Φ + φ) sinσ
        -Mgcosσ + qgsinσ + U_Y
[0064]
  Where Ω_EIs the rotational angular velocity of the earth, λ is the latitude, σ is the inclination angle around the X axis of the base 10 with respect to the horizontal plane H, Φ is the base orientation, that is, the azimuth angle of the reference line OR of the base 10 with respect to the meridian, and φ is the gyro Compass direction, that is, rotation angle of gyrocompass relative to base 10, U_Y , U_Z Is the gyro drift respectively. Furthermore, mg is a mass unbalance 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 counterpart shaft. These are errors specific to TDG. Here, it is assumed that the mass unbalance mg is known and the crosstalk amount qg is unknown.
[0065]
  The inclination angle σ around the X axis with respect to the horizontal plane H is expressed as follows by the pitch angle α and the roll angle β of the base 10. Note that the pitch angle α is a rotation angle around an axis perpendicular to the reference line OR of the base 10 with respect to the horizontal plane H, and the roll angle β is a rotation angle around the reference line OR of the base 10 with respect to the horizontal plane H.
[0066]
[Formula 6]
  sinσ = sinβcosφ + sinαsinφ
[0067]
  In order to obtain the azimuth angle Φ of the base 10 from the equation (5), the gyro drift U_Y , U_Z It is necessary to ask. The tracking ring 15 is moved at a constant rotation angle Δφ = 2π / n (n is an even number.For example, the output signal ω of the two gyros of the TDG 11 is stopped after being rotated by rotating every 60 ° (n = 6)._Y, Ω_Z Measure the output signal σ of the east-west inclinometer. By rotating the tracking ring 15 once, n sets of measured values ω_Yi, Ω_Zi, Σ_i(I = 1 to n) shall be obtained. Among these measured values, attention is paid to data whose azimuth angles φ are different from each other by 180 °. For example, the output signal of a Y gyro with an azimuth angle φ is ω_Y1, Output signal of Y gyro for azimuth angle φ + π is ω_Y2Then, it is expressed as follows.
[0068]
[Expression 7]
  ω_Y1= Ω_E sinλ sinσ₀ −Ω_Ecosλsin (Φ + φ) cosσ₀
        + Mgsinσ₀ + Qgcosσ₀+ U_Y
  ω_Y2= Ω_E sinλ sinσ_{0 '}−Ω_Ecosλsin (Φ + φ + π) cosσ_{0 '}
        + Mgsinσ₀'+ Qgcosσ₀'+ U_Y
[0069]
  Where σ₀ , Σ₀'Is an inclination angle around the X axis of the base 10 with respect to the horizontal plane H in the case of azimuth angles φ and φ + π, respectively. These two east-west inclination angles σ₀ , Σ₀There is a geometric relationship between '
[0070]
[Equation 8]
  σ₀ = −σ₀'
[0071]
  This relationship can also be obtained from the equation (6). Substituting this into the equation (7) gives the following relationship.
[0072]
[Equation 9]
  ω_Y1= Ω_E sinλsinσ₀ −Ω_Ecosλsin (Φ + φ) cosσ₀
        + Mgsinσ₀ + Qgcosσ₀+ U_Y
  ω_Y2= -Ω_E sinλsinσ₀ + Ω_Ecosλsin (Φ + φ) cosσ₀
        -Mgsinσ₀ + Qgcosσ₀ + U_Y
[0073]
  A similar formula is used for the output signal ω of the Z gyro._Z Can also be obtained. Output signal of Z gyro with azimuth φ is ω_Z1, The output signal of Z gyro for azimuth angle φ + π is ω_Z2And
[0074]
[Expression 10]
  ω_Z1= -Ω_E sinλcosσ₀ −Ω_Ecosλsin (Φ + φ) sinσ₀
        -Mgcosσ0 + qgsinσ0 + U_Z
  ω_Z2= -Ω_E sinλcosσ₀ −Ω_Ecosλsin (Φ + φ) sinσ₀
        −mgcosσ₀ −qgsinσ₀+ U_Z
[0075]
  Here, for simplification, the mass unbalance mg and the crosstalk amount qg are ignored. The following relationship is obtained from the formulas (9) and (10).
[0076]
## EQU11 ##
  ω_Y1+ Ω_Y2= 2U_Y
  ω_Y1−ω_Y2= 2Ω_E[Sinλsinσ₀ −cosλsin (Φ + φ) cosσ₀ ]
  ω_Z1+ Ω_Z2= -2Ω_E[Sinλcosσ₀ + Cosλsin (Φ + φ) sinσ₀ ] + 2U_Z
[0077]
  From the three equations of Equation 11, the azimuth angle Φ, Y gyro and Z gyro drift U of the base 10_Y , U_Z Is obtained by the following equation.
[0078]
[Expression 12]
  Φ = sin-1 [{sinλsinσ₀ -(1 / 2Ω_E) (Ω_Y1−ω_Y2)} / (Cosλcosσ₀)]-Φ
  U_Y = (Ω_Y1+ Ω_Y2) / 2
  U_Z = (Ω_Z1+ Ω_Z2) / 2 + Ω_E[Sinλcosσ₀+ Cosλsin (Φ + φ) sinσ₀ ]
[0079]
  next,Detect the bias Δσ included in the output signal of the east-west inclinometer or east-west accelerometer,In the inclined base 10A method for detecting the inclination angle σ around the X axis will be described. Similarly, the follower ring 15 is moved at every constant rotation angle Δφ = 2π / n (n is an even number.(For example, n = 6 every 60 °) and stop, and the output signal σ of the east-west inclinometer_M Measure. By rotating the tracking ring 15 once, n sets of measured values σ_Mi(I = 1 to n) shall be obtained. Among these measured values, attention is paid to data whose azimuth angles φ are different from each other by 180 °. For example, the output signal of the east-west inclinometer when the azimuth is φ is σ_M1, The output signal of the east-west inclinometer when the azimuth is φ + π is σ_M2Then, it is expressed as follows.
[0080]
[Formula 13]
  σ_M1= Σ₀ + Δσ
  σ_M2= Σ₀'+ Δσ
[0081]
  Where σ₀ , Σ₀'Is the tilt angle around the X axis of the base 10 in the case of azimuth angle φ and φ + π when the bias Δσ is zero as described above. This 2OneTilt angle σ around the X axis₀, Σ₀There is an equation of the formula 8 between '. Therefore, the following relationship is obtained from the equation (13).
[0082]
[Expression 14]
  σ_M1−σ_M2= Σ₀ −σ₀'= 2σ₀
  σ_M1+ Σ_M2= Σ₀ + Σ₀'+ 2Δσ = 2Δσ
[0083]
  Therefore, when the azimuth angle of the base 10 is φ, the inclination angle σ around the true X axis₀ And the bias Δσ of the east-west inclinometer is expressed by the following equation.
[0084]
[Expression 15]
  σ₀ = (Σ_M1−σ_M2) / 2
  Δσ = (σ_M1+ Σ_M2) / 2
[0085]
  According to this example, n sets of measured values ω are obtained by rotating the tracking ring 15 once._Yi, Ω_Zi, Σ_i (I = 1 to n) are obtained, and n / 2 sets of measurement values are obtained in which the azimuth angles φ of the base 10 are different from each other by 180 °.Therefore,n / 2 sets of data Φ, U from n / 2 sets of measured values_Y, U_Z , Σ₀ , Δσ is obtained, and by obtaining the average value or the least square approximation of these values,More likelyΦ, U_Y, U_Z , Σ₀ , Δσ values are obtained.
[0086]
  Again referring to FIG.Level control system and direction control systemexplain. The rotation control unit 71 determines that the azimuth angle φ of the TDG 11 is the set azimuth angle φ._S Functions to be equal to The rotation control unit 71 sets the set azimuth angle φ generated by the sequencer unit 72._SIs supplied to the azimuth servo motor 29. The follow-up ring that supports the TDG 11 by operating the azimuth servo motor 29 rotates around the follow-up axis (azimuth axis). The azimuth transmitter 31 detects the azimuth angle φ of the TDG 11 and outputs it to the rotation control unit 71. The output signal φ of the bearing transmitter 31 is the set bearing angle φ_SThe data measurement storage unit 73 measures and stores the data of the TDG 11.
[0087]
  The data measurement storage unit 73 outputs the output signal ω of the Y gyro and Z gyro._Y , Ω_Z Enter. Output signal ω of Y gyro and Z gyro_Y , Ω_Z Is supplied to the data measurement storage unit 73 via an integrator. Output signal S from the integrator_Y, S_Z Is expressed as:
[0088]
[Expression 16]
  S_Y = -Ω_Y
  S_Z = -Ω_Z
[0089]
  The data measurement storage unit 73 further has a set azimuth angle φ_S = Φ, tilt angle σ, east-west inclinometer or east-west acceleration output signal σ _M Enter (Westward rise is +). Next, the sequencer unit 72 sets a new set azimuth angle φ_S= Φ_S−Δφ is generated and supplied to the rotation control unit 71. In the rotation control unit 71, the output signal φ of the direction transmitter 31 is changed to a new set direction angle φ._S The azimuth servo motor 29 is operated so as to be equal to.
[0090]
  Thus, the output signal φ of the azimuth transmitter 31 becomes a new set azimuth angle φ._S The data measurement storage unit 73 measures and stores gyrocompass data. Thus, the data measurement storage unit 73 sets the set azimuth angle φ_SStore every data.
[0091]
  FIG. 2 shows a configuration example of the data measurement storage unit 73. The data measurement storage unit 73 includes a number of storage units, and the set azimuth angle φ_S = Φ_i Data S every time_Yi, S_Zi, Σ_i(I = 1 to n) are sequentially stored.
[0092]
  AndA large number of data φ stored in the data measurement storage unit 73_i , S_Yi, S_Zi, Σ_i (I = 1 to n) are sequentially supplied to the base orientation calculation unit 74 and the drift calculation unit 75. The drift calculation unit 75 calculates the drift U by the equation_Y, U_Z The base direction calculator 74 calculates the base direction Φ using the equation (4).
[0093]
  next,An alignment mode in the gyrocompass of the present invention will be described with reference to FIG. According to this example, the alignment mode is activated prior to the normal compass mode. The alignment mode functions to calculate the base direction Φ and to direct the direction of the gyro compass in the true north direction. FIG. 3 shows the procedure of such an alignment mode.
[0094]
  In step 201, the alignment mode is started. The direction transmitter 31 at the start of the alignment modeDirectionOutput signal φ = φ₁The default orientation φ_S= φ₁ And Next, in step 202, the level control system and the azimuth control system described above are activated, the inclination angle θ around the Y axis becomes zero, and the output signal φ of the azimuth transmitter 31 is set to the set azimuth φ._S= Φ₁Restrained by Next, proceed to step 203 and set direction φ_S = Φ₁ Data S in the case of_Yi, S_Zi, Σ_iIs stored in the data measurement storage unit 73. In the above example, φ_i= Φ₁ , S_Yi= S_Y1, S_Zi= S_Z1, Σ_i= Σ₁ It is.
[0095]
  Next, proceed to step 204 and set orientation φ_S Is equal to 360 °. φ_S If ≠ 360 °, go to step 205 and φ_S + Δφ = φ₁+ Δφ is the new setting direction φ_S Replace with
[0096]
  Therefore, the new setting direction φ_SIs φ_S = Φ₂ = Φ₁ + Δφ. Proceeding to step 202, the level control system and the azimuth control system are activated again, the inclination angle θ around the Y axis becomes zero, and the output signal φ of the azimuth transmitter 31 is set to the set azimuth φ._S= Φ₂ = Φ₁ It becomes equal to + Δφ. That is, φ = φ₂ = Φ₁ + Δφ. Next, proceed to step 203 and set direction φ_S= Φ₂ Data S in case of_Yi, S_Zi, Φ_i , Σ_iIs stored in the data measurement storage unit 101. In the above example, φ_i = Φ₂ , S_Yi= S_Y2, S_Zi= S_Z2, Σ_i= Σ₂ It is.
[0097]
  Next, proceed to step 204 and set orientation φ_S Is equal to 360 °. φ_S If ≠ 360 °, go to step 205 and φ_S + Δφ is the new setting direction φ_SReplace with New setting direction is φ_S = Φ_Three = Φ₂ + Δφ.
[0098]
  In this way, steps 202, 203, 204, and 205 are repeated, and the set orientation φ_S Is increased by Δφ. Φ in step 204_S If it is = 360 °, the process proceeds to step 206, and the data stored in the data measurement storage unit 73 is extracted. Drift U from such data_Y, U_Z And the base orientation Φ.
[0099]
  Finally, go to step 207, before starting compass modeGyro compassSet initial orientation. Initial orientation is φ_S0= −Φ. That is, the gyrocompass in the opposite directionOnly calculated base azimuth ΦRotate. Thereby,Gyro compassThe reference line faces true north. At this time, gyro drift and east-west accelerometer bias correction are performed.
  Thus, when the alignment mode according to this example is completed, the normal compass mode is started. Gyro drift in advance in alignment modeU _Y , U _Z And east-west accelerometer biasΔσSubsequent compass because it has been correctedIn modeIn operation, the north end of the gyrocompass can be oriented in the true north direction.
[0100]
  FIG. 4 shows a gyrocompass according to the present invention.Configuration overviewThe figure is shown. The gyro compass of this example has a flex gyro or TDG (Tuned Dry Gyro) 11, and the TDG 11 is attached to a block 13.
[0101]
  As shown here, block 13Set the center of as the originConsidering the XYZ coordinate system, the Z-axis is taken in the vertical direction, and the X-axis and the Y-axis are taken perpendicular to each other in the horizontal plane.
[0102]
  The spin axis of the gyro is arranged along the X axis, and when the finger north end of the gyro is taken in the positive direction of the X axis as shown, the Y axis is arranged along the east-west direction. The block 13 is supported by a follower ring 15 so as to be rotatable around the Y axis. The follower ring 15 has a follower shaft 17 along the Z axis, and the follower shaft 17 is rotatable around the Z axis. It is mounted on the base 10. Thus, the block 13 is supported so as to be rotatable around two axes of the Y axis and the Z axis.
[0103]
  In block 13,North-south inclination, that is, rotation inclination around the Y axisCornerA north-south inclinometer or north-south accelerometer 21 that detects θ;,Tilt in the east-west direction, that is, rotation around the X axisCornerAn east-west inclinometer or east-west accelerometer 23 for detecting σ is attached.
[0104]
  Further, a horizontal servo motor or horizontal DST (direct servo torquer) 27 is mounted along the Y axis of the tracking ring 15, and an azimuth servo motor or bearing DST (direct servo torquer) 29 is mounted along the tracking axis 17. It is installed. Below the tracking shaft 17 is a direction transmitter.(Azimuth encoder)31 is mounted, such orientationOscillator31 detects the rotation angle of the follow-up shaft 17 around the Z-axis.
[0105]
  The TDG 11 is equipped with a pickup (not shown) that detects the displacement of the gyro rotor with respect to the gyro case, and the pickup is arranged to detect the angular displacement around the Y axis and the angular displacement around the Z axis of the gyro rotor. Has been. The pickup that detects the angular displacement around the Y axis of the gyro rotor is called a horizontal pickup, and the pickup that detects the angular displacement around the Z axis of the gyro rotor is called an orientation pickup. The TDG 11 is provided with a Y torquer and a Z torquer (not shown) that torque the gyro rotor around the Y axis and the Z axis.
[0106]
  When an angular displacement about the vertical axis (Z axis) occurs between the gyro case and the gyro rotor, the angular displacement is detected by the azimuth pickup, and the angular displacement signal is supplied to the azimuth servo calculation unit 61. A driving signal is supplied from the azimuth servo calculation unit 61 to the azimuth servo motor 29 via the commutator control circuit 63. Accordingly, the TDG 11 is driven to rotate around the Z axis, and the angular displacement about the vertical axis (Z axis) between the gyro case and the gyro rotor is controlled to be zero.
[0107]
  Similarly, when an angular displacement around the horizontal axis (Y axis) occurs between the gyro case and the gyro rotor, the angular displacement is detected by the horizontal pickup, and the angular displacement signal is supplied to the horizontal servo calculation unit 65. The A drive signal is supplied from the horizontal servo calculation unit 65 to the horizontal servo motor 27. Thereby, the TDG 11 is driven to rotate around the Y axis, and the angular displacement about the horizontal axis (Y axis) between the gyro case and the gyro rotor is controlled to be zero.
[0108]
  As a result, no disturbance torque around the horizontal axis (Y axis) and the vertical axis (Z axis) is applied to the gyro.
[0109]
  next,The finger north action of the gyrocompass of this example will be described. When the gyrocompass mounting surface is on a horizontal plane, the torque Kθ (K is a ballast constant or fingertip constant) around the Y axis, that is, around the horizontal axis, to the gyro rotor by the Y torquer of TDG11. Is obtained).
[0110]
  However, when the mounting surface of the gyrocompass is inclined in the east-west direction, the support mechanism of the gyrocompass in this example has no east-west freedom (freedom around the X axis).And Z ToruCaThus, it is necessary to divide and apply the torque Kθ to be applied to the gyro rotor.
[0111]
  Torking signal to torque the gyro rotor around the Y axis by Y torquerDrive torque byT_Y0Torking signal to torque the gyro rotor around the Z axis by Z torquerDrive torque byT_Z0And Such Torking signalDrive torque byT_Y0, T_Z0Is represented by the following equation.
[0112]
[Expression 17]
  T_Y0= Kθcosσ
  T_Z0= -Kθsinσ
[0113]
  Where θ is the output signal of the north-south accelerometer 21 (NorthSet the side rise to +. ), Σ is an output signal of the east-west accelerometer 23 (westward rise is defined as +). K is a finger north constant.
[0114]
  Torking signalDrive torque byT_Y0, T_Z0 ButSupplied to Y and Z torquers of TDG 11, whereby the gyro rotor is torqued around the Y axis, ie around the horizontal axis. This torque amount is “applying a torque proportional to the inclination of the spin axis relative to the horizontal plane around the horizontal axis of the gyro”. In this way, finger north force is applied to the gyro, and a gyro compass is formed.
[0115]
  next,An example of the gyrocompass of the present invention will be described with reference to FIGS. FIG. 5 shows a front configuration of the gyrocompass of this example, and FIG. 6 shows a plan configuration of the gyrocompass of this example.
  In the following description of FIGS. 5 and 6, portions corresponding to those in FIGS. 1 and 4 are denoted by the same reference numerals.The gyrocompass of this example has a board 41 and a cylindrical cover 43 attached to the board 41. Within the cover 43, the TDG 11 is attached to the block 13, and the block 13 isAround the horizontal axes 13A, 13B, ieIt is supported so as to be rotatable around the Y axis.Here, the board 41 corresponds to the base 10 described above.
[0116]
  As shown in FIG. 5, the block 13 has horizontal shafts 13A and 13B on both sides, and the horizontal shafts 13A and 13B are fitted to the inner rings of the bearings 19A and 19B of the follower ring 15 arranged correspondingly. Yes. In such a block 13,As shown in FIG. 4 and FIG.A north-south inclinometer or north-south accelerometer 21 is mounted along the X-axis. The tracking ring 15 includesAs shown in FIG. 4, FIG. 5 and FIG.An east-west inclinometer or east-west accelerometer 23 and a horizontal servo motor 27 are mounted along the Y axis.
[0117]
  The horizontal servomotor 27 may be a pancake type direct acting type that does not use gears and pinions, and the horizontal shafts 13A and 13B of the block 13 are used.InIt includes an inner rotor 27-1 attached and an outer stator 27-2 attached to the follower ring 15 correspondingly.
[0118]
  A platform 49 is mounted on the lower side of the tracking ring 15, and an azimuth axis, that is, a tracking shaft 17 is mounted on the platform 49.
[0119]
  Below the platform 49 is a rotary transformer 45, an azimuth servo motor 29, and an azimuth encoder.(Azimuth oscillator)31 is arranged. The rotary transformer 45 includes a lower stator 45-1 attached to the board 41 and an upper rotor 45-2 attached to the platform 49. According to this example, the disadvantage of the slip ring is eliminated by using the rotary transformer 45 instead of the slip ring.
[0120]
  The azimuth servo motor 29 has an outer stator 29-1 attached to the board 41 and an inner rotor 29-2 attached to the platform 49. The azimuth encoder 31 is attached to the board 41 corresponding to the inner shaft portion 31-1 attached to the coupling 47 attached to the lower end portion of the follow-up shaft 17.Not shownIncluding the outer stator.
[0121]
  The follower ring 15, the platform 49, the follower shaft 17, the rotor 45-2 of the rotary transformer 45, the rotor 29-1 of the azimuth servomotor 29, and the shaft part 31-1 of the azimuth encoder 31 constitute a rotating part. The rotating portion is rotatably supported by a bearing 53A attached to the platform 49 and a bearing 51 attached to the follower shaft 17.
[0122]
  In FIG.Mounted on the block 13TDG11TheFlex gyroWasA configuration example is shown. For details of the flex gyroscope, see, for example, Japanese Patent Application No. 60-103083 (Japanese Patent Laid-Open No. 61-260117) filed on May 15, 1985 by the same applicant as the present applicant.
[0123]
  As shown in FIG.TDG11InTake the XYZ axes. Gyro rotor159The X axis is taken along the spin axis, and the Y axis and Z axis perpendicular to each other are taken. Such a coordinate system is aligned with the X, Y, and Z axes of the XYZ axes taken in the block 13 in FIG.
[0124]
  The flex gyro has a housing 151, an upper cap 153 mounted on the upper side of the housing 151, and a lower cap 155 mounted on the lower side. The housing 151 and the upper and lower caps 153 and 155 constitute a gyro case. An upper chamber is formed between the upper surface of the housing 151 and the upper cap 153, and a lower chamber is formed between the lower surface of the housing 151 and the lower cap 155.
[0125]
  A gyro rotor 159 is disposed in the upper chamber, and the gyro rotor 159 is elastically supported by a flex hinge 161. A shaft 165 is mounted on the flex hinge 161, and the shaft 165 is supported by a center hole of the inner cylindrical protrusion 151 </ b> A of the housing 151 via a ball bearing 157.
[0126]
  A motor 167 is disposed in the lower chamber, and the motor 167 has a stator 167-1 and a corresponding rotor 167-2. The stator 167-1 is mounted on the inner wall of the outer cylindrical protrusion 151B of the housing 151, and the rotor 167-2 is mounted on the lower end of the shaft 165 so as to be surrounded by the stator 167-1.
[0127]
  The gyro rotor 159, the flex hinge 161, the shaft 165, and the rotor 167-2 constitute an integral assembly, and are configured to be able to rotate at high speed around the central axis of the shaft 165. The central axis of shaft 165, i.e., the rotational axis of such an assembly, is the spin axis of the gyro rotor.
[0128]
  When an AC voltage is applied to the windings of the stator 167-1 of the motor, the rotating magnetic field generated thereby acts on the rotor 167-2 of the motor. Thereby, torque is generated and the rotor 167-2 of the motor rotates with respect to the stator 167-1. Thus, the assemblies 159, 161, 165, and 167-2 rotate around the X axis, and the gyro rotor 159 rotates at high speed around the spin axis.
[0129]
  In the upper chamber, torque around the Y axis and Z axis is applied to the gyro rotor 159.For multipleA ToruCa 171 is provided. This ToruCa 171 corresponds to the Y ToruCa and Z ToruCa of the TDG 11 described with reference to FIG. Such a torquer 171 includes an annular permanent magnet 171-1 mounted on the gyro rotor 159 and a torquer coil 171-2 mounted on the upper surface of the housing 151 correspondingly. The ToruCa coil 171-2 is disposed in the annular groove 159A of the gyro rotor 159 and spaced from it.
[0130]
  A magnetic circuit Ψ is formed along the annular groove 159A of the gyro rotor 159 through the permanent magnet 171-1 as shown by the arrow in the figure. Torque is generated by the cooperation of the magnetic circuit and the magnetic field generated by the torquer coil 171-2.
[0131]
  In the upper chamber,pluralA pickup 173 is arranged. The pickup 173 corresponds to the horizontal pickup and the azimuth pickup of the TDG 11 described with reference to FIG. The pickup 173 is mounted on the upper surface of the housing 151 adjacent to the torquer 171.
[0132]
  Consider a case where an angular velocity around the Y axis or Z axis perpendicular to the spin axis acts on the housing 151 while the gyro rotor 159 rotates at a high speed. The gyro rotor 159 keeps its position with respect to the inertial space by the gyro orientation retention. Accordingly, the gyro rotor 159 is rotationally displaced about the Y axis or the Z axis relative to the housing 151. The amount of rotational deviation around the Y axis or the amount of rotational deviation around the Z axis of the gyro rotor 159 is detected by the pickup 173.
[0133]
  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and it is easily understood by those skilled in the art that other various configurations can be adopted without departing from the gist of the present invention. Let's be done.
[0134]
【The invention's effect】
  According to the present invention, when the gyrocompass is used in the normal compass mode, there is an advantage that the gyrocompass can be used immediately since the finger north end of the gyrocompass is directed to true north in advance.
[0135]
  According to the present invention, there is an advantage that the azimuth angle of the base relative to the meridian can be measured with high accuracy even when the base is inclined.
[0136]
  According to the present invention,In advanceMeasure the azimuth angle with respect to the meridian and measure the bias of the gyro drift and east-west inclinometer or east-west accelerometer, and automatically correct it.ButChange,Accordingly, even if an azimuth error occurs, it can be corrected. Therefore, there is an advantage that the true north azimuth can be oriented with high accuracy in the subsequent gyrocompass operation.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of a gyrocompass according to the present invention.
FIG. 2 is a diagram showing a configuration example of a data measurement storage unit of the present invention.
FIG. 3 is a flowchart illustrating an alignment mode according to the present invention.
FIG. 4 shows the gyrocompass of the present invention.ExampleIt is.
FIG. 5 is a cross-sectional view showing a front configuration of an example of a gyrocompass according to the present invention.
FIG. 6 is a cross-sectional view showing a planar configuration of an example of a gyrocompass according to the present invention.
FIG. 7 is a cross-sectional view of an example of TDG.
FIG. 8 is an explanatory diagram for explaining an example of use of a conventional surveying gyrocompass.
FIG. 9 is an explanatory diagram illustrating a configuration example of a conventional surveying gyrocompass.
FIG. 10 is an explanatory diagram for explaining the principle of detecting an orientation with respect to the meridian by a conventional surveying gyrocompass;
FIG. 11 is an explanatory diagram for explaining the principle of detecting an orientation with respect to the meridian by a conventional surveying gyrocompass;
FIG. 12 is an explanatory diagram for explaining the detected angular velocity of each gyro when the rotation angle σ around the X axis of the base is zero.
FIG. 13 is an explanatory diagram for explaining a detected angular velocity of each gyro when a rotation angle σ around the X axis of the base is not zero.
[Explanation of symbols]
10 base
11 TGD
13 blocks
13A, 13B Horizontal axis
15 Tracking ring
17 Tracking axis
19 Bearing
21 North-south inclinometer or north-south accelerometer
23 East-West inclinometer or East-West accelerometer
27 Horizontal servo motor
27-1 Rotor
27-2 Stator
29 direction servo motor
31 Direction transmitter, direction encoder
35 Compass calculator
36 Horizontal Torking Circuit
37 Directional Torking Circuit
41 board
43 Cover
45 Rotary transformer
47 coupling
49 platform
51, 53A Bearing
61 Azimuth Servo Calculation Unit
63 Commutator control circuit
65 Horizontal servo calculator
71 Rotation control unit
72 Sequencer
73 Data measurement storage
74 Base orientation calculation unit
75 Drift calculator
110 Gyro rotor
111 Gyro case
113 Suspension line
147 Azimuth encoder
151 Housing
153 Upper cap
155 Lower cap
157 Ball bearing
159 Gyro rotor
159A  groove
161 Flex Hinge
161A Center hole
165 axis
167 motor
167-1 Stator
167-2 Rotor
171-1 Permanent magnet
171-2 ToruCa Coil
173 Pickup
301 Transit
301A Screw
302 Tripod
302-1 horizontal platform
303 Gyrocompass
310 base
310a hole
310b, 310c Flange
310d bottom
312A, 312B bearing
314 Azimuth axis
316 bearing gear
318 turntable
320 Gyro
322 step motor
324 Pinion
326 Zero cross pickup
326A pin
326B Light emitting element
326C light receiving element
340 Rotation control unit
342 Sequencer
344 Measurement storage unit
346 Calculation output section

Claims (7)

A gyro having a spin axis in the X-axis direction, a support device that supports the gyro so as to be rotatable about the Y axis and the Z axis, and a follow-up axis that supports the support device rotatably about the Y axis and is perpendicular to the base A tracking ring that is rotatable about a vertical axis passing through the tracking axis, and a finger north device for applying finger north force to the gyro, and having an azimuth angle Φ of the base with respect to the meridian In the gyro compass to be measured, a rotation control unit for sequentially rotating the following axis for each predetermined rotation angle, the angular velocity ω _Y around the Y axis and the angular velocity ω _Z around the Z axis detected by the gyro and the following A data measurement storage unit for inputting and storing the rotation angle φ of the ring and the inclination angle σ of the Y axis with respect to the horizontal plane detected by the east-west inclinometer or the east-west accelerometer, and a meridian from the data stored in the data measurement storage unit Against the above base Gyrocompass, characterized in that it is configured to have a base azimuth calculation section which calculates a position angle [Phi, the.   2. The gyro compass according to claim 1, further comprising a gyro drift computing unit that computes a gyro drift from the data stored in the data measurement storage unit.   3. The gyro compass according to claim 2, wherein the gyro drift calculation unit is configured to calculate a bias of an east-west inclinometer or an east-west accelerometer further than the data stored in the data measurement storage unit. Gyro compass to do. In the gyrocompass according to claim 1, 2, or 3,
The rotation control unit is configured to detect the azimuth angle Φ of the base with respect to the meridian and then rotate the tracking axis in the opposite direction by the azimuth angle Φ so that the baseline of the tracking axis is directed in the meridian direction. Gyrocompass characterized by that. In the gyrocompass according to claim 3 ,
From the tilt angle σ of the Y-axis obtained by the gyro drift calculation unit based on the data of the east-west inclinometer or the east-west accelerometer, the base direction calculation unit is configured to support the base with respect to the meridian even when the base is inclined. The gyrocompass is characterized by being configured to measure the azimuth angle Φ. The gyro compass according to claim 3, 4 or 5,
The gyro drift from the gyro drift calculation unit and the bias of the east-west inclinometer or the east-west accelerometer are automatically corrected before normal gyro compass operation, and the true north direction measured even during operation of the gyro compass is obtained. A gyro compass characterized by being oriented. The gyro compass according to claim 6,
After detecting the azimuth angle Φ of the base with respect to the meridian, the tracking axis is rotated in the opposite direction by the azimuth angle Φ so that the base line of the following axis is oriented in the meridian direction. The gyrocompass is directed to true north, and the bias of the gyro drift, the east-west inclinometer or the east-west accelerometer is corrected, so that it can be used immediately as a gyrocompass. .

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