• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.175-177
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• 2006

According to the recommendation of International Maritime Organization, the Ministry Of Maritime Affairs and Fisheries (MOMAF) of Korea provides the real time Differential Global Positioning System service using maritime radio beacon from 1999. Due to the benefit of DGPS service, the need of this system is increased from various user groups for acquiring the better accuracy and integrity. Therefore, MOMAF has extended their service to inland by installing the additional 6 DGPS stations. This nationwide DGPS service will be fully deployed at 2007. In addition to the extension of service area, MOMAF has a plan to upgrade their nationwide DGPS to High Accuracy Nationwide DGPS (HANDGPS). The planned HANDGPS service of Korea will be a kind of long range RTK or Wide Area RTK techniques to provide under 1m accuracy and start their service from 2009 using the various broadcasting and communication media like as radio beacon, Wibro, Digital Multimedia Broadcasting, High Speed Packet Data Access. The introduction of nationwide DGPS system of Korea and its evolution plan will be addressed in this paper. The research activities related with HANDGPS in Korea is also presented.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.437-442
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• 2012

As of 2012, for service-area-widening and commercialization of DGPS service, the Ministry of Land, Transport and Maritime Affairs has completed a DGPS service via Terrestrial Digital Multimedia Broadcasting and doing experimental broadcasting. In this study, kinematic positioning tests were conducted based on DGPS service via T-DMB using low-cost GPS equipments in a dynamic environment. Standalone GPS, single-reference NDGPS via NTRIP, and virtual-reference DGPS via T-DMB surveys were conducted at the same time. And horizontal positioning errors were computed by comparing them with the result of high-precision positioning. As a result, when the DMB transmission interval was 3 seconds, horizontal positioning errors of standalone GPS, NTRIP-DGPS, and DMB-DGPS were 2.3m, 1.0m, and 0.7m, respectively. When the interval was 1 second, horizontal positioning errors were 2.0m, 1.2m, and 0.8m, respectively. Thus horizontal positioning accuracies improved with the DMB-DGPS compared to the traditional single-reference NDGPS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.921-927
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• 2006

The current DGPS technique is many problems that is permission of radio station using RF Wireless Modem, that is influence of geographic obstacle using radio wave, that is frequency interference, that is finiteness of frequency resources. In this paper, we are solved many elements, IM(Interface Module) replaces RF Wireless Modem, we suggest transmission technique of correction message using mobile phone, we researched Interface Module development which is linkage of DGPS receiver and mobile phone. IM can transmit correction message passing RS-232 port and modem communication control. IM of base station is initialized RS-232 port and modem to move station for correction message transmission, IM waited response mode. IM of move station is initialized RS-232 port and modem, IM requests hand shaking to base station, completed connection establishment. Users are worked Differential surveying using receiving correction message between mobile phones.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.317-325
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• 2001

Although GPS has proven to be efficient in the fields of navigation and surveying, it has many problems of positioning in downtown areas. Therefore, if GPS is combined with GLONASS which is similar to GPS in its positioning and signal system, it is expected that accuracy will be improved. However, we should address certain problems that exist related to the coordinate, time, and signal system between the two. The purpose of this study is to develop a GPS/GLONASS combination program by considering the properties of GPS and GLONASS and to solve the problems related to differences in the coordinates system and signal system. It is also to present the efficiency of the program in navigation and geographic information through analyzing 3D positioning accuracy by GPS/GLONASS combination with an application experiment. As a result of this study, the accuracy of the DGPS/DGLONASS positioning program corresponded to that of commercial program, and that's accuracy was better than that of DGPS. Especially, the acquisition of navigation and geographic information was possible by DGPS/DGLONASS combination in downtown area where the continuous 3D positioning is impossible by DGPS only.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.4
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• pp.187-193
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• 2015

A maritime Differential Global Positioning System (DGPS) reference station broadcasts correction information to users having a DGPS receiver so that the navigation performance can be improved. A maritime DGPS reference station consists of a reference station (RS) that generates and broadcasts correction information, an integrity monitor (IM) that monitors the integrity of correction information, and a control station (CS) that controls them. A maritime DGPS reference station is continuously operated for 24 hours, and thus improvement in the ease of operation is a major element that can improve the performance of the system. In this study, a configuration of a maritime DGPS reference station that can improve the ease of operation and a relevant protocol were proposed, and an example of the implementation of the proposed system was presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.90-93
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• 2007

해양수산부에서 해양 DGPS기준국과 연계하여 전국망 위성항법보정시스템 (NDGPS) 구축 사업을 추진 중에 있으며, 2008년도 춘천기준국이 설치 완료되면 우리나라 전역에서 실시간 DGPS 측위 정보를 이용할 수 있게 되었다. 따라서 DGPS 이용 활성화를 위하여 무엇보다도 DGPS 측위 정확도의 신뢰성이 요구되는바, 실시간 DGPS 의 측위 정확도를 측정 ${\cdot}$ 분석하여 신뢰성을 검증하였다. 실시간 NDGPS 측위 정확도는 Static 측정에 있어 0.42m(RMS), 회전운동에 의한 Dynamic 측정시 0.48m(RMS)로 분석되었으며, RTK에 의한 비교 측정 ${\cdot}$ 분석도 병행하였다. 따라서 위성항법보정시스템 (DGPS)은 높은 정확도를 요구하는 GIS구축사업 분야에 직접적으로 이용될 수 없으나 실시간 측위 정보를 필요로 하는 GIS활용 분야에서 DGPS가 다양하게 이용될 수 있을 것이다.

• Journal of information and communication convergence engineering
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• v.10 no.2
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• pp.97-102
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• 2012

The differential global positioning system (DGPS) transmits a GPS enhancement signal using a top-loaded monopole antenna in the medium frequency range. The top-loaded antenna in the medium frequency band can attain a radiation efficiency on the order of 10%. The antenna ground plane characteristics affect the antenna radiation efficiency. To improve the radiation efficiency, it is necessary to install the antenna on a ground plane with large enough physical dimensions and good conductivity. The antenna radiation efficiency is a primary factor in determining the DGPS service area. The service area of the DGPS using a medium frequency band is dominantly affected by the antenna radiation efficiency. To determine antenna radiation efficiencies accurately, the antenna radiation efficiencies of DGPS are deduced from the propagation power in this paper. Based on the deduced antenna radiation efficiencies, the service area for the Korean nationwide-DGPS is analyzed and evaluated.

• Journal of the Korean Institute of Navigation
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• v.23 no.2
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• pp.51-60
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• 1999

The Japanese DGPS Data can be received easily in the area of the Korean peninsula and some Korean users may use these data. However, its analysis has not been actually investigated. This paper is a study on accuracy analysis of Japanese Marine Radiobeacon/ DGPS in the South Coast of Korea. The 3 Japanese DGPS stations, Wakamiya(295 kHz), Ose Saki(302 kHz) and Hamada(305 kHz), near the Korean peninsula were analyzed by several ways. It was concluded that the feasible result of the experimental study with an error range of no more 10 m in 2 DRMS.

• Journal of Biosystems Engineering
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• v.23 no.2
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• pp.179-186
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• 1998

This study was conducted to sense posture of an autonomous tractor using a DGPS, a gyro compass, and a potentiometer. Posture sensing system was constructed and its accuracy was evaluated. The accuracy of DGPS was evaluated under stationary and moving conditions, and the performance of the gyro compass and the potentiometer was investigated by measuring bearing and steering angles, respectively. Also, the effect of DGPS interference by obstacles was evaluated experimentally. The position accuracy was about 6.6cm(95%) under the stationary condition and 10 cm at sharp turning condition. Steering angle of the tractor could be related linearly to the output of the potentiometer that was installed on the rotating center of a knuckle arm. The positioning accuracy of the DGPS varied significantly according to the number of visible GPS satellites, but was good with more than 7 satellites. The DGPS gave bad solutions for sensing the posture of tractor when signals from satellites or the correction data from the base were interfered by obstacles.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.77-82
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• 2004

This study deals with the estimation of dredged soil-quantity using DGPS＆Echo-Sounder method. In measurement of topography, surveyors have been surveying the depth with rod and sounding lead. This method, however, is not effective because of long time and a lot of human power, in addition it is incorrect. This paper has studied on the solution of those problems using DGPS＆Echo-sounder data to calculate the dredged soil-quantity. This paper says the effective and economical methods using DGPS＆Echo-Sounder data there.