• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.263-267
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• 2013

This paper describes the progress and the plan of 'Wide Area Differential GPS (WA-DGPS) Development' project supported by Korean Ministry of Oceans and Fisheries. The project develops the main algorithms of the WA-DGPS which guarantees the improved accuracy, availability, and integrity all over the Korean peninsula. After the establishment of WA-DGPS ground infrastructure system, a real-time demonstration using pseudolite installed on the ground will be conducted in the final year. Also, the development of Korean Satellite-based Augmentation System (SBAS) is expected to be started from 2014, and the algorithms and the results in the WA-DGPS project will be used in the SBAS development.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.1-9
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• 2014

Goheung aeronautical center is located in the area of Goheung of which land is reclaimed from sea and has a runway of length 700m, width 25m with test facility which has been used for flight test of UAV and small aircraft. To support the enhancement of aircraft safety, 1090ES ADS-B ground system as the ground surveillance system has been implemented. ADS-B system based on GPS and digital data link provides the function of enhancing the aircraft safety through flight information among aircrafts. This paper gives the result that the implementation of ADS-B ground system and the flight test with onboard ADS-B transmitter has been conducted.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.319-326
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• 2013

This paper describes the orbital dynamics operation results for the launch and early operations phase (LEOP) of KOMPSAT-3, which was successfully launched on May 18, 2012. At the initial phase, operational orbit determination was carried out using ground tracking data and GPS navigation solution. And, both in-plane and out-of plane maneuvers were executed in order to change the orbit from the injection orbit to the mission orbit. In addition, the accuracy of precise orbit determination was indirectly evaluated by overlapping method using GPS raw data of KOMPSAT-3 and international GNSS service data from worldwide-distributed ground stations. Currently, KOMPSAT-3 is operated in pre-defined mission orbit, and its various kinds of orbit data are generated and distributed to support the normal mission operations.

• 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 the Korean Society for Aeronautical & Space Sciences
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• v.31 no.10
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• pp.51-59
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• 2003

A method of autonomous update is presented for onboard orbit propagator. On board propagator is an alternative means that could be used for navigation purpose in case of CPS receiver's failure. Although the ground station is not a able to upload a new propagator, the onboard propagator must be maintained most up-to-date. For this, a filtering technique is proposed wherein GPS data are effectively used to continuously update the on board propagator which was uploaded previously. Even if the ground station has generated the on board propagator based on the wrong information, the onboard propagator with updating scheme can automatically correct the errors in the coefficients of residual reconstruction function. Several scenarios were used to show the validity of the scheme for updating the onboard propagator using KOMPSAT-1 orbit data.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.121-126
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• 2014

ETRI(Electronics and Telecommunication Research Institute) has joined National GNSS Research Center program of Defense Acquisition Program Administration and Agency for Defense Development in 2010. The research subject is technology for MSAR(Military Search and Rescue) system configuration. In this project, we analyses the ways in order to improve the accuracy, reliability, availability for MSAR system from M&S(Modeling and Simulation). The MSAR System M&S Software can be used for performance analysis of new elements, such as ground elements and satellite elements without any hardware development. In this paper, after introduction of the architecture design and functional scope of the simulator, the performance analysis result for MSAR M&S software is presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.95-96
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• 2018

This paper deals with the development status of eLoran system which is the best backup position, navigation, and timing (P NT) system of Global Navigation Satellite System (GNSS) and its performance result. I t especially explains the status of eLoran testbed implementation for the eLoran test service, development of eLoran transmitting system, differential Loran (dLoran) system, integrated operation and control system (IOCS), and integrated eLoran/GNSS receiver. The paper discusses about the future plan for the build up test transmitting station and backup P NT service to succeed to the trial operation of eLoran testbed system.

• Journal of Satellite, Information and Communications
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• v.2 no.1
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• pp.35-40
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• 2007

COSPAS-SARSAT is the search and rescue system for providing a distress alarm and a position identification using an international satellite and ground facilities. Aviators, mariners and land users worldwide are equipped with COSPAS-SARSAT distress beacons, which could help save their in emergency situations anywhere in the world. As the existing COSPAS-SARSAT system is generally operated by LEO(Low-altitude Earth Orbit) Satellite System, the time from the distress beacon to the rescue is more than 1 hour with average and the accuracy of the distress location is about 5 Km. Therefore, in order to overcome this problem, the development for the next generation SAR(search and rescue) system which uses the MEO(middle-altitude Earth Orbit) satellites is going on the Galileo project. EU is developing this project for the full operation capability in 2011, and this project will have SAR payloads and support to the Search and Rescue service-herein called SAR/Galileo. SAR/Galileo will have the performance of a few meter accuracy, within 10 minutes to rescue from reception of distress messages, and Return Link Service(from the SAR operator to the distress emitting beacon), thereby facilitating more efficient rescue operations and helping to reduce the rate of false alerts. As the disaster is larger every year, the ground station, MEOLUT for next generation ASR/Galileo is urgently needed for the lifesaving for the larger disaster, the research for beacon and the ground station such as MEOLUT for introducing the next generation SAR/Galileo in Korea is very timely and is important. This paper presents the procedures and the strategies for the participation, the area to develop reasonably, and the propulsion organization for developing the SAR/Galileo ground system in Korea.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1619-1625
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• 2017

Civil global navigation satellite system (GNSS) does not meet user performance requirements for specific PNT (Positioning, Navigation, and Time) applications. Therefore, various differential systems are used to augment GNSS for improving positioning accuracy and integrity. The MTSAT satellite augmentation system (MSAS) is the Japanese satellite based augmentation system. This paper is for analyzing the characteristics of Japanese MSAS in Korean peninsula. First of all, it was done for analyzing not only DGNSS navigation signal but also the navigation parameter through simulation and experimental tests. As a result of data analyses, the sufficient navigation satellites to determine 3-D position based on DGNSS are simultaneously available at MSAS monitering station and the southern region of Korean peninsula. It was verified that the carrier to noise signals are stable to maintain the reliable 3-D position and that the level of 2m (2drms) accuracy is very similar to the ordinary worldwide DGNSS as well.