• 한국항해학회지
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• 제4권1호
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• pp.1-18
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• 1980

As the NNSS system calculates ship's position by the doppler shift of the NNSS radio waves caused by the change of the distance between Transit Satellite and the ship, ship's speed error inevitably results in the position error, and moreover this kind of erroris most dominant compared with other errors especially in high speed ships and airplanes. Most NNSS receivers now in use have adoptedsuccessive short doppler counts as positioning data and by investigating the dispersion of serval successive positions calculated and by neglecting the mean position having dispersion of over certain threshold level, more accurate adn safe position is to be achieved. This paper proposes the method of finding ship's true speed by selecting a speed having least position dispersion for given successive doppler counts. And by computer simulation it was verified that the method proposed here is reasonable in finding the ship's desired correct speed together with the correct ship's position.

• 한국항해항만학회지
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• 제38권2호
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• pp.89-96
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• 2014

This paper presents an improvement for calculating method of astronomical ship position based on circle of equal altitude equation. In addition, to enhance the accuracy of ship position achieved from solving equation system, the authors used singular value decomposition (SVD) in least square method instead of normal decomposition. In maths, the SVD was proved more numerically stable than normal decomposition. Therefore, the solution of equation system will be more efficient and the result would be more accurate than previous methods. By proposal algorithm, a computer program have been developed to help the navigators in calculating directly ship position when the modern equipment has failure. Finally, some of experiments are carried out to verify effectiveness of proposed algorithm, the results show that the accuracy of ship position based on new method is better than the intercept method.

• 수산해양기술연구
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• 제54권2호
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• pp.181-187
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• 2018

In order for the probe to perform ocean exploration and survey research, it is necessary to adjust the position of the ship as desired by dynamic positioning system. The dynamic positioning system of T/S NARA is applied to K-POS dynamic positioning system of Kongsberg, which makes maintaining the ship's position, changing position and heading control possible. T/S NARA is not capable of dynamic positioning if one or more propulsive forces are lost with DP Level One. However, it is predicted that dynamic positioning can be achieved even at the time of missing one thrust in a good sea condition. Therefore, we want to analyze the effect of each propulsion on the performance of dynamic position system. When one of the bow thruster and azimuth thrusters lost their propulsion, maintaining the ship's position, changing position and heading control performance were compared and analyzed. If the situation occurred disable from using the bow thruster, they can not maintain ship's position. Azimuth thruster was influential for the ship's position control and bow thruster was influential in heading control. The excellent dynamic positioning performance can be achieved, considering the propulsion power that will have a impact on each situation in the future.

• 한국항해항만학회지
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• 제37권4호
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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.

• 한국통신학회논문지
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• 제35권9B호
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• pp.1314-1321
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• 2010

선박 접안 유도시스템은 선박 내에 장착된 위치 기반 UWB(Ultra WideBand)와 해안에 설치된 리더기를 통해 받은 접안 지점 내의 선박 정박 유무 정보를 바탕으로 관제시스템이 접안을 요청한 선박에 대해 선박의 크기와 종류를 판별하여 그 결과에 따라 접안이 가능한 지점의 위치 정보를 해당 선박에 무선 송출하여 선박의 접안을 유도한다. 이는 선박의 정박시간 대기로 발생하는 불필요한 연료의 낭비와 접안 과정 중 발생하는 충돌 사고를 예방하여 안전성을 제시할 수 있다. 본 연구에서는 위치기반 UWB를 이용한 선박 접안 유도시스템의 테스트베드를 구현하였다. 또한 java 기반의 사용자 인터페이스를 구현하여 모바일 기기 등을 통해 실시간으로 동종의 선박들 가운데에서 사용자의 선박의 위치를 쉽게 인지할 수 있도록 정박 위치 정보를 제공하는 편의성을 제공한다.

• Journal of Advanced Marine Engineering and Technology
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• 제25권1호
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• pp.199-208
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• 2001

In this paper, an automatic route tracking algorithm using the position variables and the yaw angle of a ship is suggested, Since most autopilot systems paly only a role of course-keeping by integrating the gyrocompass output, they cannot cope with position errors between the desired route and real route of the ship resulted from a drifting and disturbances such as wave, wind and currents during navigation. In order for autopilot systems to track the desired route, a method which can reduce such position errors is required and some algorithms have been proposed[1,2]While such were turned out effective methods, they have a shortage that the rudder control actions for reducing the position errors are occurred very frequently. In order to improve this problem it is necessary to convert that error into the corresponding yaw angle and necessary to treat only yaw angle control problem. To do this a command generation algorithm which converts the rudder angle command reducing the current position error into they yaw angle command is suggested. To control the ship under disturbances and nonlinearities of the ship dynamics, the adaptive fuzzy controller is developed. Finally, through computer simulations for two ship models, the effectiveness of the suggested method and the possibility of the automatic route tracking are assured.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.375-378
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• 2009

대부분의 선박에서 송신하는 AIS 위치정보는 오차범위가 약 30미터인 일반적인 GPS 데이터에 의존하였다. 그러나 최근 DGPS의 보정정보를 활용하여 위치정확도를 개선할 수 있는 환경이 제공됨에 따라 고가의 DGPS 비콘리시버 없이 AIS 기반으로 DGNSS 메시지(17번)를 방송함으로써 위치정보를 보다 정밀하게 사용 할 수 있다.

• 한국CDE학회논문집
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• 제16권3호
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• pp.227-235
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• 2011

Ship handling simulator should have capabilities of calculating ship motions (heave, pitch, and roll) at given sea state and displaying the calculated motions through a real-time 3D visualization system. Motion solver of a ship handling simulator generally calculates those motions in addition to position for an own ship, a main simulation target, but provides only position information for traffic ships. Therefore, it is required to simulate real-time traffic ship and buoy motions coupled with ocean waves in a ship handling simulator for the realistic visualization. In the paper, the authors propose a simple dynamics model by which ship and buoy motions are calculated with the input data of wave height and discuss a method for the implementation of a ship and buoy motions calculation module.

• 수산해양기술연구
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• 제26권2호
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• pp.167-172
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• 1990

부산-제주간 선로상에서 정박중일 때와 항행중일 때 Loran C 위치를 관측하여 시간대별, 지역별, 침로별 위치의 정도와 편위오차를 수정하여 분석.검토한 결과는 다음과 같다. 1. 주야간별 위치의 정도는 큰 차이가 없었고, 수신점주위에 높은 산이 있을 경우 편위거리의 오차가 더욱 커졌다. 2. 정박중과 항행중에 편위거리의 평균치는 각각 0.188, 0.452마일이었고, 침로의 변화에 따른 측위오차의 변동은 거의 없었다. 3. 위치정도를 높이기 위해서는 속도보정과 측지계변환만으로도 정도가 높은 위치를 구할 수 있었다

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 추계학술대회
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• pp.261-262
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• 2012

본 연구에서는 레저선박 및 소형선박을 위한 지능형 충돌방지 시스템에 대한 언급하고 있다. 이 시스템의 기능은 선박으로부터 이동 물체까지의 거리와 속도를 추정하고 해당 물체와의 충돌을 회피하기 위한 제어신호를 발생하는 것이다. 본 논문에서는 칼만필터를 이용하여 대상물체의 위치와 속도를 추정하는 방법에 대해 소개한다. 실제 실험단계에서는 레이저센서를 이용하여 대상물체의 거리를 계측하고 계측된 신호에 필터링을 적용하여 대상물의 위치와 속도를 검출하게 된다. 제안한 기법의 유용성을 검증하기 위해 물체의 위치 및 속도추정에 대한 시뮬레이션을 수행하였다.