• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.169-171
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• 2023

eLoran 신규송신국 구축 진행현황을 확인하고 eLoran 전국망 지상기반 PNT 서비스의 안정 제공을 위한 울릉도, 제주도 신규송신국 구축 가능한 해수부 부지를 사전 검토하고 부지 특성에 따른 안테나 설계 적합성 및 성능을 검토하여 적정한 안테나 배치안을 제시하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.80-81
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• 2012

Our society consist of many country's critical infrastructure such as production and distribution of electric power systems, communications technology, tele-communications, financial system, transportation systems when those systems are operated efficiently and normally. Country's critical infrastructure and its application fields of this magnitude rely on more and more P.N.T (Positioning, Navigation. Timing) systems, in which the tele-communications(Timing), financial market(Timing), logistics (Positioning, Navigation, Timing), transportation(Positioning, Navigation. Timing) is shoring. Reliability concerned about the exact position and timing of these critical national infrastructure rely on ability to provide a stable from GPS.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.2
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• pp.53-57
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• 2017

eLoran refers to a terrestrial navigation system using high-power low-frequency signals. Thus, it can be regarded as a positioning, navigation and timing (PNT) system to back up a global navigation satellite system (GNSS) or an alternative to GNSS. South Korea is vulnerable to interference such as GNSS jamming in particular. Therefore, South Korea has made an effort to develop an independent navigation system through eLoran system. More particularly, an eLoran testbed has been developed to be used in the northwest sea area and research on applicability of eLoran in South Korea has been underway. The present study analyzes expected performance of eLoran according to locations of newly built eLoran transmitting stations as part of the eLoran testbed research. The performance of eLoran is analyzed in terms of horizontal position accuracy, and horizontal dilution of precision (HDOP) information was used since it affects accuracy significantly. The target service areas of the eLoran testbed are Incheon and Pyeongtaek Ports, and the required target performance is positioning accuracy of 20 m position within 30 km coverage of the target service area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.197-199
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• 2019

4차 산업혁명 시대에서 정보는 점점 전자화되고 전자화된 정보의 중요성은 더욱 높아져 가고 있다. 해양분야에서도 이네비게이션을 통하여 전자화된 정보들을 생산하고 효율적으로 관리하기 위해 노력하고 있다. 국제항로표지협회(IALA)는 항로표지와 관련된 전자정보들의 효율적인 관리와 상호교환을 위한 국제 공통의 규격을 S-200으로 제안하고 개발 중에 있다. S-200 중 항로표지와 관련된 정보교환 표준은 S-201로 지정하여 개발 중에 있으며, 해양 PNT 정보와 관련된 전파표지는 S-240(DGNSS 기준국 정보)과 S-245, 246, 247(eLoran 관련 정보)로 지정하여 개발 중에 있다. 본 논문에서는 IALA 주도로 개발 중인 국제 해양 PNT와 관련된 전파표지의 정보교환 표준 현황에 대해 소개한다. 그리고 연구팀에서 제안한 eLoran 관련 정보교환 표준의 개발 결과와 맵 기반 S-200 테스트베드 적용 시험을 통한 검증 결과를 제시한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.97-102
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• 2019

The GNSS(Global Navigation Satellite System) provides important information such as Position and Navigation, Timing(PNT) to various weapon systems in the military. as a result, applications that employ satellite navigation systems are increasing. therefore, a number of studies have been conducted to deceive the weapon systems that employ GNSS. GNSS spoofing denotes the transmission of counterfeit GNSS-like signals with the intention to produce a false position and time within the victim receiver. In order to deceive the victim receiver, spoofing signal should be synchronized with GNSS signal in doppler frequency and code phase, etc. In this paper, Civilian GPS L1 C/A spoofing signals have been evaluated and analyzed by SDR receiver.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.251-261
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• 2022

The Centimeter Level Augmentation Service (CLAS) is the Precise Point Positioning (PPP) - Real Time Kinematic (RTK) correction service utilizing the Quasi-Zenith Satellite System (QZSS) L6 (1278.65 MHz) signal to broadcast the Global Navigation Satellite System (GNSS) error corrections. Compact State-Space Representation (CSSR) corrections for mitigating GNSS measurement error sources such as satellite orbit, clock, code and phase biases, tropospheric error, ionospheric error are estimated from the ground segment of QZSS CLAS using the code and carrier-phase measurements collected in the Japan's GNSS Earth Observation Network (GEONET). Since the CLAS service begun on November 1, 2018, users with dedicated receivers can perform cm-level precise positioning using CSSR corrections. In this paper, CLAS-based VRS-RTK performance evaluation was performed using Global Positioning System (GPS) observables collected from the refence station, TSK2, located in Japan. As a result of performing GPS-only RTK positioning using the open-source software CLASLIB and RTKLIB, it took about 15 minutes to resolve the carrier-phase ambiguities, and the RTK fix rate was only about 41%. Also, the Root Mean Squares (RMS) values of position errors (fixed only) are about 4cm horizontally and 7 cm vertically.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.808-814
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• 2021

The International Maritime Organization (IMO) explicitly stipulates the required performance of satellite based radio-navigation systems available for navigational purposes. Until 2019, the IMO had only recognized systems that could be serviced globally for satellite based radio-navigation. However, India's regional navigation satellite system has been approved recently, and other regional navigation satellite systems have also been made available for maritime navigation. Thus far, the IMO has approved the use of a total of five satellite navigation systems, such as the GPS, GLONASS, Galileo, BeiDou, and NavIC. In Korea, in addition to the four satellite based radio-navigation systems that are used excluding NavIC, Japan's regional navigation satellite system that has not yet been approved can be received. Japan has requested the IMO to recognize the QZSS as a WWRNS to formalize its use for ocean navigations. Given that the service coverage of the QZSS is not limited to Japanese territorial waters and also includes Korean waters, the suitability analysis of the QZSS for domestic navigation is important for maritime safety. This study aims to analyze the suitability of using the QZSS for domestic navigation. Accordingly, this work explores the status and plans of the QZSS as well as the performance required by the IMO for recognition as a WWRNS. The methods and environmental conditions examined in this work are described, and the analyzed results are presented in terms of positioning accuracy and availability.

• Journal of Navigation and Port Research
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• v.45 no.1
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• pp.26-32
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• 2021

In ocean field, the spread of the Fourth Industrial Revolution based on information and communication technology requires high precision and stable PNT&D (Position, Navigation, Timing and Data). As the IMO (International Maritime Organization) and IALA (The International Association of Marine Aids to Navigation and Lighthouse Authorities) are requiring backup systems due to mitigate vulnerabilities and the increase of dependency on GNSS (Global Navigation Satellite System), Korea is conducting a research & development of R-Mode. An DGPS (Differentiate Global Positioning System) reference station that uses MF, an existing maritime infrastructure, and AIS (Automatic Identification System) base stations that use 34 integrity station and VHF will be utilized in this study to avoid redundant investment. Because there are radio shadow areas that display low signal levels in the west sea, the establishment of new R-Mode reference and integrity station will be intended to resolve problems regrading the radio shadow area. Because the frequency has a characteristic in that radio wave transmits well along the ground (water surface) in low frequency band, simulation and measurement were conducted therefore this paper to propose candidate sites for R-Mode reference and integrity station resulted through p wave's propagation characteristics analysis. Using this paper, R-Mode reference and integrity station can be established at appropriate locations to resolve radio shadow areas in other regions.

• Information and Communications Magazine
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• v.32 no.10
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• pp.3-10
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• 2015

위성항법시스템은 사회 전반에서 활용되고 있는 필수 인프라로 전세계 어디서나 위치 및 시각정보를 제공한다. 하지만 위성항법시스템은 수신신호의 세기가 미약하고 항법시스템과 통신시스템이 별도로 구축되어 있어 서비스를 제공하는데 제약이 따르므로 이를 해결하기 위한 대안 체계 개발 및 기존 항법시스템의 향상 연구가 지속적으로 이루어지고 있다. 본고에서는 해외국가들의 항법시스템 개발 현황 및 특성을 분석하고, 결과를 바탕으로 한반도 환경에 적합한 한국형 지역항법시스템 구축 방향에 대하여 기술한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.94-97
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• 2019

자율운항선박, 스마트 항만 등 4차 산업혁명 기술이 해상 환경에 확산되고 있는 상황에서 해상 광역인프라인 항로표지를 정보의 디지털화, 정보교환 체계의 표준화, 정보수집의 다양화, 통합 DB 구축 및 첨단 ICT 기술을 접목하여 스마트함으로써 정보의 생산·수집·가공·공유를 위한 플랫폼 체계를 구축하여 미래 해상환경 수요에 충족하고자 한다.