• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.2
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• pp.166-171
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• 1995

Recently, various navigational instruments are being composed into a total navigational system. This system requires accurate ship's heading in digital form. The authors have been studying about an electromagnetic compass with a three - axis magnetic sensor in order to provide an accurate ship's magnetic heading which the compass deviations can automatically compensated in the compass itself. In this pater describe on the theory how to derive the poisson's coefficients from ship's magnetism measured with three axis magnetic sensor and the results obtained by the simulation using deviascope, and that results practically coincident with the value observed by bearing on a distant object with magnetic compass.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.309-317
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• 2010

This paper proposes an efficient measurement system for the velocity and direction of the wind using the dual rotor wind power generator in vessel. Conventional digital measurement system recognizes the direction and the velocity of the wind using the electric compass or synchronous motor and Vane probe method using hall sensors. But each system has its own short-comings: the synchronous motor has a larger measurement error than the magnetic compass and magnetic compass is weak for the external disturbances such as fluctuation of the vessel. To compensate these short-comings, this paper proposes a new compensation algorithm for the fluctuation errors according to the external interference and the unexpected movement of the vessel along the roll and pitch directions. The proposed system is implemented with the dual compasses and a synchronous motor. The proposed independent power generation system can be operated by itself and can raise the efficiency of the wind power generation systems of 30 ~ 400 W installed along the vertical and horizontal axes. The proposed system also realizes the efficient and reliable power production system by the MPPT algorithm for the real-time recognition of the wind direction and velocity. An advanced switching algorithm for the battery charging system has been also proposed. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.177-180
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• 2002

In this paper, we has been studied self controlled mobile robot system with CCD camera. This system consists of TMS320F240 digital signal processor, step motor, RF module and CCD camera. 2-axis compass and magnetic sensor, we used wireless RF module for movable command transmiting between robot and host PC. This robot go straight until 95 percent filled screen with white color both side from input image. And the robot recognizes obstacle about 95 percent filled something, so it could turn for avoid the obstacle and conclude new path plan. it could get turning angle from 2-axis compass and magnetic sensor.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.851-859
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• 2004

This paper describes a new method for the acquisition of deviation coefficients, B and C, using a single observed deviation at a fixed compass heading. At first it discusses some problems in the synthesis of two coefficients, B and C, from various observed deviation values in the four USS warships. Then, new theories and procedures for optimal coefficients, $\^{B}\;and\;\^{C},$ are dealt with and then the validity of the proposed method are evaluated. The result of findings indicates that the approximated coefficients, $\^{B}\;and\;\^{C},$ can give optimal approximation to an single observed deviation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.87-90
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• 2006

The Earth's spherical harmonic model of the main field and of the secular variation, of the geomagnetic field gives the intensity and geomagnetic structure at any location around the earth, assuming an undistorted, steady state field that no external sources or localized earth anamalies. To consider the practical use of a ship's digital compass in earth's magnetic field, Earth's spherical harmonic model is searched for the related practical methods and procedures as a basic study in this work.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.23-32
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• 2004

This paper describes a new estimation method for deviation coefficients, B and C. using only measured single deviation at a fixed compass bearing. At first, some problems in the deviation synthesis with only two coefficients, B and C, are discussed using observed deviation values measured in the four USS warships. Then, acquisition theories and procedures to obtain optimal coefficients, B and C, are expanded and then the efficiencies of the proposed prediction method are evaluated. As results from evaluations, it is shown that the approximated coefficients, B and C, can give optimal approximation to observed single deviation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.133-139
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• 2005

Resonant-Type Magnetometer(RM) using high permeability isotropic magnetic material is designed to implement Smart Digital Compass. Theoretically, the inductance L of a coil, winding on the magnetic core, is proportion to the change of permeability $\mu(H)$ and, the change values of L can be obtain as the change of frequency by simple Schmitt Trigger circuit. By the use of integrated circuit switch, the RM can be designed with simple circuit and it can provide overcoming the drift by temperature and the variation of operating points in $\mu(H)$ curve. The facts that Metglas 2705M is an optimum magnetic material and ship's permanent magnetism can be obtain from measured values of RM are also known in this study.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.131-135
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• 2006

The objective of the project is to model and study the geomagnetic field structure and its secular variation in space and in time due to sources in the dynamic fluid outer core. the Earth's spherical harmonic model of the main field and of the secular variation gives the intensity and geomagnetic structure at any location around the Earth, assuming an undistorted, steady state field that no external sources or localized earth anomalies. To consider the practical use of a ship's digital compass in Earth's magnetic field, Earth's spherical harmonic model is searched for the related practical methods and procedures as a basic study in this work.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.219-228
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• 2013

The surveillance imaging equipments are functioning to observe the shape of the target in real time or to measure its location precisely. The roles of such equipments are becoming more important in today's weapon systems.The aforementioned imaging equipments can be classified based on the modes of operations such as fixed, installed on cars, or composite of those. Also, according to different concepts of sensor operation, a separate type uses independent housing for each sensor whereas in a composite type a set of multiple sensors are housed into a unit altogether. The sensors in general have magnetism, thereby introducing the possible negative effects, particularly in the composite types, in locating the reference position, which is carried out by the digital compass. The use of shielding material/housing could be an option but results in increased weight and reduced portability, restricting its use in composite type equipments. As such, the objective of this paper is to study on how to reduce such magnetic effects on the position location. To do so, in the absence of magnetic shielding, a variety of sensor positions were first modeled. By combing the result with the fact that the functions of PAN & Tilt are used in the equipments, a new position location algorithm is proposed. The use of the new algorithm can automate the position location process as compared to the manual process of the existing approach. In the algorithm developed, twelve locations are measured in connection with both the azimuth and elevation angles in comparison to the six locations alone around the azimuth angle. As a result, it turns out that the measurement range has been widened but the measurement time reduced. Also, note that the effect of errors the operators may make during measurement could be reduced.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.16-23
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• 2020

This paper describes an alignment algorithm that estimates the initial heading angle of AUVs (Autonomous Underwater Vehicle) for starting navigation in a sea area. In the basic dead reckoning system, the initial orientation of the vehicle is very important. In particular, the initial heading value is an essential factor in determining the performance of the entire navigation system. However, the heading angle of AUVs cannot be measured accurately because the DCS (Digital Compass) corrupted by surrounding magnetic field in pointing true north direction of the absolute global coordinate system (not the same to magnetic north direction). Therefore, we constructed an experimental constraint and designed an algorithm based on extended Kalman filter using only inertial navigation sensors and a GPS (Global Positioning System) receiver basically. The value of sensor covariance was selected by comparing the navigation results with the reference data. The proposed filter estimates the initial heading angle of AUVs for navigation in a sea area and reflects sampling characteristics of each sensor. Finally, we verify the performance of the filter through experiments.