• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.157-165
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• 2000

When the GPS system was come to the operation, the U.S Coast Guard initiated development of differential GPS system based on a marine radiobeacon. It has rapidly been spread out to many countries. DGPS equals to P(Y) code in a positioning accuracy. USA has recently determined to expand the coverage of DGPS to inland in order to install a nationwide DGPS chain. Korea is under processing for improving the DGPS as a nationwide positioning system. Before expanding the service area inside Korea, we need to verify the relation between the field strength and DGPS accuracy for the service area. The Japanese DGPS data is received in the southern Part of the Korean peninsula. The Korean DGPS was not a complete system, so we selected the Japanese DGPS data as a model for the study. This paper investigate accuracy and reliability characteristics of RBN/DGPS over the effective service area. Through the experimental and simulation study, we obtained the reliable and stable positioning accuracy in the southern part of the Korean peninsula. In addition, the characteristics of RBN/DGPS were examined in the land over the effective coverage from Japan. The results would be a basic reference to research the RBN/NDGPS in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1350-1357
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• 2012

Korean NDGPS, which consists of the ocean-based reference station of 11 site and the land-based reference station of 6 sites, are operating. The land-based reference stations provide the output power of 500W, the service shadow regions are occurred due to mountains and nation topography. In this paper, the service coverages of land-based reference stations are analyzed in the viewpoint of output power enhancements of land-based reference stations within 1KW. Also, we suggest virtual land DGPS reference stations 2 sites to resolve the service shadow regions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.521-523
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• 2010

Reseatch and Analysis on the DGPS radiobeacon propagation measurement of Domestic ferry lines Starting with maritime DGPS Base stations of Palmido, Ochongdo which have been operated since 1999, truly our nation has become the most powerful country possessed with total of 17 DGNSS base stations in the field of DGNSS operation infrastructure. This paper intents to consider the development direction of the country's DGNSS services as identifying the services range of the maritime DGPS base stations in the south coast domestic ferry lines which sections are Busan$\rightarrow$Jeju, Jeju$\rightarrow$Nokdong.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.491-499
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• 2011

Starting with maritime DGPS base stations of Palmido, Ochongdo which have been operated since 1999, truly our nation has become the most powerful country possessed with total of 17 DGNSS base stations in the field of DGNSS operation infrastructure. This paper examines into the country's DGNSS services as measuring the service range of the maritime DGPS base stations in the domestic ferry lines which sections are from Jeju to Incheon, from Busan to Jeju, from Jeju to Nokdong, the propagation characteristics of the radio waves of 300 kHz bands on sea and land path. As a result of identifying the service range of the DGPS in the sea routes of the southern sea and the western sea, the measured results of the DGPS signals are confirmed more than 100 NM(recommended service range). It can be possible to practical use the position information, which is safe navigation and various marine traffic management systems. It will be useful an expansion of maritime DGPS reference station in the near future.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.279-286
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• 2017

The international maritime organization(IMO) has defined performance requirements for future maritime navigation through IMO resolution A.915(22) in 2001. Many DGPS systems currently providing DGPS services do not meet the performance requirements specified in IMO resolution A.915(22). The use of SBAS is considered as one of the DGPS replacement and supplementary system for coping with the increase in demand performance and providing safe positioning service. In particular, since a large amount of budget is required to rearrange the existing DGPS reference stations, a method which transmits differential corrections generated by using SBAS message has been proposed. In this paper, we compare and analyze the performance of NDGPS which is operated by the National Maritime PNT Office of the ministry of oceans and fisheries(MOF) in Korea and MSAS in Japan. Also, we verify that SBAS, as alternative and complementary system, meets the performance requirement specified in IMO resolution A.915(22).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.277-283
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• 2013

GPS RTK surveying has an issue that the positioning error increases as the base line distance between the reference station and rover station increases. However, nowadays, an accuracy assessment that can handle such issue is surely required because of the modernization of GLONASS, Galileo project, and other improvements of satellite receiving conditions. Therefore, in this research, we compared and analyzed data sets collected with the CORS network, placed at NGII and NDGPS, using Internet RTK surveying in different satellite receiving conditions. As a result, there was a negative effect on the positioning accuracy as the base line distance increases. Furthermore, we could collect quantitative data of the accuracy of RTK surveying. When national-wide GNSS system is fully established, this result will contribute the growth of various GNSS industries including survey industries and land survey industries.