Tae-Gweon Jeong

A Theoretical Study on Free Gyroscopic Compass

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 earths 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, ships 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 Basic Study on Position Fixing by Free Gyros

The authors aim to design further an upgraded and self-contained position fixing system to meet the future commercial requirements. As a first step this paper is to investigate the theoretical structure of position fixing based on the nature of free gyro, in which the tilt angles of the two spin axes at an arbitrary position are measured respectively and the elapsed time with respect to a reference position or starting point is observed And it illustrates some limitations to be expected in this system.

A New Approach to the Evaluation of Collision Risk using Sech Function

Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study analysed the existing methods of appraising the collision risk, examined the problem that are intrinsic to them, and developed a new approach to its evaluation by using the sech function as an alternative to them. This paper applied the new method in appraising the collision risk and suggested how to decide the safe range of ownship`s action

Comparison of Goal-line and In-length Analyses in the Proximity Measures of Simulated Maneuvers

우리나라의 경우 선박조종시뮬레이션을 이용한 선박 통항의 안전성 평가는 흔히 목표선 분석으로 이뤄지고 있다. 이 논문에서는 목표선 분석만으로 이뤄지는 통항 안전성 평가의 위험성을 경고할 목적으로 하나의 예로서 한국해양수산연수원의 선박조종시뮬레이터를 이용하여 15,000 TEU급 컨테이너 선박이 풍속 26노트 풍...

A Study on Development of Multipurpose Ship`s Interface Unit

Each on-board equipment providing navigational and engine information has different signals. These signals should be analyze, be transformed to the standard digital form and be transmitted to each client on board through the earlier developed ILU (integrated LAN unit). Therefore this paper was to analyze the signals of each equipment for navigation and engine and was to use the serial technology necessary for the equipment and IDU (information display unit). And this paper was then to develop an SIU (ship`s interface unit) and to test it onboard.

A Study on Development of Integrated System of Ship`s Information

As a method to improve the present operational and safe function in navigation this paper developed an efficient and economical integrated system of ship`s information. This system is, systematically and comprehensively, to monitor, save, analyse, and display information on navigation and environment around own ship in real time by connecting one user to another through an on-board LAN or data communication via satellite so that many users on board can obtain simultaneously and easily the information in real time not only in the wheelhouse and engine room but also in many robins and ship`s offices. And it consists of four(5) components; data distribution program, database of navigational and engine-related information, multi-functional monitoring program, ship management program and other application program.

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

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 Study on the Performance Comparison of Three Optimal Alpha-Beta-Gamma Filters and Alpha-Beta-Gamma-Eta Filter for a High Dynamic Target

The α‐β‐γ tracking filter is useful for tracking a constant acceleration target with zero lag error in the steady state. It, however, depicts a constant lag error for a maneuvering target. Various algorithms of the α‐ β‐γ tracking filter exist in literature and each one of them presents its own unique challenges and advantages depending on the design requirement. This study investigates the operation of three α‐β‐γ tracking filter design methods which include Benedict‐ Bordner also known as the Simpson filter, Gray‐Murray filter and the fading memory constant acceleration filter. These filters are then compared based on the ability to reduce noise and follow a maneuvering target with minimum lag error, against the jerky model α‐β‐γ‐η. Results obtained from simulations of the input model of the target dynamics under consideration indicate an improvement in performance of the jerky model in comparison with the constant acceleration models. http://www.transnav.eu the International Journal on Marine Navigation and Safety of Sea Transportation Volume 11

Optimization of the Gain Parameters in a Tracking Module for ARPA system on Board High Dynamic Warships

The purpose of this paper is to determine the optimal values of the gain parameters used in the tracking module for a highly dynamic warship. The algorithm of the tracking module uses the -- filter to compute accurate estimates and update the state variables, that is, positions, velocity and acceleration. The filtering coefficients ,  and  are determined from set values of the damping parameter, . Optimization is achieved by plotting a range of the damping parameter  against the corresponding residual error and then selecting the best value of ξ with the minimum residual error. Optimal values of the smoothing coefficients are subsequently computed from the selected damping parameter, . Key word : Tracking module, -- filter, optimization, smoothing, prediction, state variables, residual error †Corresponding Author: tgjeong@kmou.ac.kr 051)410-4246 * Representing Author: pbf9527@gmail.com ** njonjoann@gmail.com

A Basic Study on Development of a Tracking Module for ARPA system for Use on High Dynamic Warships

The maritime industry is expanding at an alarming rate hence there is a perpetual need to improve situation awareness in the maritime environment...