• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.41-43
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• 2013

항로표지 시뮬레이터는 항로표지 설계, 최적 배치계획 수립을 지원하는 시스템이다. 이 시스템에서 가시화는 사용자가 항로표지의 인지, 배치 결과 예측 및 평가를 하는데 중요하다고 할 수 있다. 본 논문에서는 항로표지 시뮬레이터 가시화의 핵심 요소 및 개발 방안 도출에 초점을 두고 연구를 수행하였다. 항로표지 시뮬레이터 개발을 위한 테스트베드로 사용 중인 선박운항 시뮬레이터를 활용하여 항만, 선박, 부표 등을 배치하고 시각(Time of day), 기상상태 등을 모사하여 해상 환경을 재현 하였다. 이를 통해 항로 표지의 운동 재현, 배후광을 고려한 야간 상황 가시화, 항로표지 및 등화의 종류에 따른 가시화 등의 항로표지 시뮬레이터 기능들에 대한 개발 방안을 수립하고 계획에 반영하였다.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1615-1627
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• 2020

The purpose of this study is to compare and analyze the performance of KOMPSAT-3 Digital Surface Model (DSM) made in overseas testbed area. To that end, we collected the KOMPSAT-3 in-track stereo image taken in San Francisco, the U.S. The stereo geometry elements (B/H, converse angle, etc.) of the stereo image taken were all found to be in the stable range. By applying precise sensor modeling using Ground Control Point (GCP) and DSM automatic generation technique, DSM with 1 m resolution was produced. Reference materials for evaluation and calibration are ground points with accuracy within 0.01 m from Compass Data Inc., 1 m resolution Elevation 1-DSM produced by Airbus. The precision sensor modeling accuracy of KOMPSAT-3 was within 0.5 m (RMSE) in horizontal and vertical directions. When the difference map was written between the generated DSM and the reference DSM, the mean and standard deviation were 0.61 m and 5.25 m respectively, but in some areas, they showed a large difference of more than 100 m. These areas appeared mainly in closed areas where high-rise buildings were concentrated. If KOMPSAT-3 tri-stereo images are used and various post-processing techniques are developed, it will be possible to produce DSM with more improved quality.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.55-60
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• 2012

When operating a surveillance system in the maritime environment, its stabilization performance is degraded due to undesirable disturbance motions. For accurate target pointing of a 2-axes surveillance system on shipboard, the kinematic stabilization is first applied, which compensates a deviated motion via coordinate transformations of attitude information. Resultantly, the stabilization error is no longer reduced due to less accuracy of a MEMS sensor and kinematic constraint, leading to introduction of the image stabilization as a complementary function. And for real-time execution of the present dual stabilization scheme, a HILS (Hardware In the Loop Simulation) test bed including 6-dof motion simulator has been constructed, and through the obtained HILS data, it has been confirmed that the stabilization is successfully.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.210-212
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• 2019

위성항법시스템의 취약성에 따른 보완 시스템의 필요가 높아지면서, eLoran 시스템이 가장 현실적인 대안으로 인정받고 있다. 우리나라도 서해 일부 지역에서 eLoran 시스템의 테스트베드 구축 사업을 진행 중에 있다. 전 해양지역에 안정적인 서비스를 제공하기 위해서는 추가적인 송신국 설치가 필요하지만. 여러가지 현실적인 이유로 인해 추진되기 어렵다. 이런 문제를 해결하기 위해 기존의 NDGNSS 기준국을 활용한 측위기술이 개발되고 있다. 이미 운영 중인 NDGNSS 기준국을 활용하면 전 해상에서 탄력적 항법시스템 운용이 가능해질 수 있다. 본 논문에서는 eLoran 시스템과 NDGNSS의 기준국을 활용한 지상파 통합항법시스템의 성능을 예측할 수 있는 시뮬레이션 툴을 제작 하였다. ITU에서 배포한 송출 주파수와 거리에 따른 신호 세기, 대기잡음 등을 고려해 Cramer-Rao Lower Bound로 수신 신호의 측정 거리 오차를 계산하였다. 또한 한빛호가 항해하면서 수집한 DGPS 신호를 통해 실질적인 대기잡음을 추정하는 방법을 사용해 기존보다 정확한 SNR 계산이 가능해졌다. 해당 결과는 추후 진행될 지상파통합항법시스템 개발에 유용하게 활용될 것으로 기대된다.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.45-51
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• 2018

Autonomous ship has been sportlighted as a core technology for the maritime industry in Industry 4.0 era. Autonomous ship is expeected to improve the safety, reliability, efficiency and environment significantly. For the realization of the autonomous ship, the remote control of the ship is one of the core functionality in addition to the autonomous ship control functionality in a ship. In this paper, we address a autonomous ship control system based on remote control. This paper proposes a remote control autonomous system and standardized ship-to-shore remote control protocol with for open platform. Finally, we implemented the system and tested with a real experiments with the test ship in order to demonstrate the feasibility of the proposed remote control autonomous system.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.273-279
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• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.42-43
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• 2014

As MSI(Maritime Safety Information), navigational, meteorological warnings and forecasts, was included as one of service in the MSP(Maritime Service Portfolio), which is lists of shore based service in the e-Navigation driven by IMO for safety navigation and marine protection, and was tested in the european test bed project on e-Navigation, it's considered as one of important e-Navigation service. This paper developed a prototype of MSI service to prepare e-navigation era, which is very important in a navigation environment. Current status on MSI and NAVTEX was surveyed, and several points on limitations and improvements in the NAVTEX operations were summarized. Basic study on the MSI service prototype was developed based on S-100, which is recognized as baseline to develop CMDS(Common Maritime Data Structure) of e-Navigation.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.429-436
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• 2019

The eLoran system is considered the best alternative because the vulnerability of satellite navigation systems cannot be resolved as perfect. Thus, South Korea is in the process of establishing a testbed of the eLoran system in the West Sea. To provide resilient navigation services to all waters, additional eLoran transmitters are required. However, it is difficult to establish eLoran transmitters because of various practical reasons. Instead, the positioning with NDGNSS/AIS source can expand the coverage and its algorithm with applying continuous waves is under development. Using the already operating NDGNSS reference station and the AIS base station, it is possible to operate the navigation system with higher accuracy than before. Thus, it is crucial to predict the performance when each system is integrated. In this paper, we have developed a simulation tool that can predict the performance of terrestrial integrated navigation system using the eLoran system, maritime NDGNSS station and the AIS station. The esitmated phase error of the received signal is calculated with the Cramer-Rao Lower Bound factoring the transmission power and the atmospheric noise according to the transmission frequency distributed by the ITU. Additionally, the simulation results are more accurate by estimating the annual mean atmospheric noise of the 300 kHz signal through the DGPS signal information collected from the maritime NDGNSS station. This approach can further increase the reliability of simulation results.