• Title/Summary/Keyword: Motion rate of spin axis

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An Algorithmic Study on Free-gyro Positioning System( I ) - Measuring Nadir Angle by using the Motion Rate of a Spin Axis -

  • Jeong, Tae-Gweon;Park, Sok-Chu
    • Journal of Navigation and Port Research
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    • v.31 no.9
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    • pp.751-757
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    • 2007
  • The authors aim to establish the theory necessary for developing free gyro positioning system and focus on measuring the nadir angle by using the motion rate of a free gyro. The azimuth of a gyro vector from the North can be given by using the property of the free gyro. The motion rate of the spin axis in the gyro frame is transformed into the platform frame and again into the NED (north-east-down) navigation frame. The nadir angle of a gyro vector is obtained by using the North components of the motion rate of the spin axis in the NED frame. The component has to be transformed into the horizontal component of the gyro by using the azimuth of the gyro vector and then has to be integrated over the sampling interval.

A Theoretical Study on Free Gyroscopic Compass

  • Jeong, Tae-Gweon;Park, Sok-Chu
    • Journal of Navigation and Port Research
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    • v.30 no.9
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    • pp.729-734
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    • 2006
  • The authors aim to establish the theory necessary for developing the free gyroscopic compass and focus on mainly two points. One is to suggest north-finding principle by the angular velocity of the earth's rotation, and the other is to suggest orthogonal coordinate transformations of the motion rate of the spin axis, which transforms the components of motion rate in the free gyro frame into those in the platform frame and that this transformed rate is, in turn, transformed into the NED(north-east-down) navigation frame. Subsequently, ship's heading is obtained by using the fore-aft and athwartship components of the motion rate of the spin axis in the NED frame. In addition it was found how to solve the transformation matrix necessary for transforming each frame.

A Theoretical Study on Free Gyrocompass

  • Park, Sok-Chu;Jeong, Tae-Gweon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.9-14
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    • 2006
  • The authors aim to establish the theory necessary for developing the free gyrocompass. The following considerations are taken. One is to suggest north-finding principle by the angular velocity of the earth's rotation, and the other is to suggest that the motion rate of the spin axis in the free gyro frame is transformed into the platform fame and this transformed rate is again transformed into the NED navigation frame. After transformation ship's heading is obtained using the fore-aft and athwartship components of the motion rate of the spin axis in the NED frame In addition it was suggested how to solve the transformation matrix necessary for transforming each frame.

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Dynamic Analysis of Tuning-Fork Gyroscope (음차자이로의 동적특성 연구)

  • 곽문규;한상보
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.247-252
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    • 2002
  • A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The tuning-fork gyroscope has been developed to avoid this problem, which utilizes a coriolis coupling term and vibration about one axis. Because of the coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study, we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.

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Dynamic Analysis of Toning-fork Gyroscope (음차자이로의 동적특성 연구)

  • 곽문규;송명호
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.2
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    • pp.92-98
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    • 2003
  • A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The toning-fork gyroscope has been developed to avoid this problem, which utilizes a Coriolis coupling term and vibration about one axis. Due to the Coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study. we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.

A Study on the Errors in the Free-Gyro Positioning and Directional System (자유자이로 위치 및 방위시스템의 오차에 관한 연구)

  • Jeong, Tae-Gweon
    • Journal of Navigation and Port Research
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    • v.37 no.4
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    • pp.329-335
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    • 2013
  • This paper is to develop the position error equations including the attitude errors, the errors of nadir and ship's heading, and the errors of ship's position in the free-gyro positioning and directional system. In doing so, the determination of ship's position by two free gyro vectors was discussed and the algorithmic design of the free-gyro positioning and directional system was introduced briefly. Next, the errors of transformation matrices of the gyro and body frames, i.e. attitude errors, were examined and the attitude equations were also derived. The perturbations of the errors of the nadir angle including ship's heading were investigated in each stage from the sensor of rate of motion of the spin axis to the nadir angle obtained. Finally, the perturbation error equations of ship's position used the nadir angles were derived in the form of a linear error model and the concept of FDOP was also suggested by using covariance of position error.