• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.424-431
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• 2017

These days land vehicle navigation system is a subject of great interest. The GNSS(Global Navigation Satellite System) is the most popular technology for out door positioning. However, The GNSS is incapable of providing high accuracy and reliable positioning. For that reason, we applied Network-RTK in vehicle to improve the accuracy of GNSS performance. In this network-RTK mode, the GNSS error are significantly decreased. In this paper, we explain ntrip client program for network-RTK mode and show the result of experiments in various environments.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.09a
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• pp.152-155
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• 2010

본 연구에서는 서울특별시 네트워크 RTK 시스템의 활용 및 Virtual RINEX 실용성 검토를 위해 수행하였다. 네트워크 RTK 시스템의 활용 다양화를 위해서는 NTRIP을 통하여 타기관의 사용자 시스템으로 실시간 전송, 시설물의 변위에 대한 GNSS로 모니터링 방법, GNSS Internet Radio Client와 Radio Modem을 이용한 RTK측위를 소개하고, Virtual RINEX 실용성 검토는 VRS RTK 측위 결과와 이동국 측위 지점에 대한 Virtual RINEX 데이터의 후처리 성과를 비교하였다. 그 결과, Virtual RINEX와 GPS 관측 성과는 거의 동일하여 향후 Virtual RINEX도 후처리 데이터로 사용할 수 있는 가능성을 확인하였고, VRS RTK 측위 성과는 Virtual RINEX 후처리 성과와 수 mm 이내 차이를 보여 산출된 성과가 거의 같음을 확인할 수 있었다.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.4
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• pp.431-439
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• 2024

The International GNSS Service (IGS) provides real-time satellite orbit, clock, and bias corrections through its Real-Time Service (RTS). In addition, Galileo has offered the Galileo High Accuracy Service (HAS) since January 24, 2023, further improving positioning accuracy for GPS and Galileo satellites. HAS data are available through Galileo's E6 signal and Ntrip, enhancing positioning accuracy for GPS and Galileo satellites. This study compared Galileo HAS corrections data and IGS RTS corrections data obtained from the BKG Ntrip client (BNC) on February 1 and June 23, 2024. The orbit, clock, and bias corrections of each satellite were analyzed, revealing that HAS and IGS RTS correction values followed similar trends for most satellites. Additionally, satellite position and clock values computed from these corrections were compared with SP3 and CLK data for accuracy. To perform positioning using HAS, a Code-PPP algorithm was developed, and positioning accuracy was evaluated for GPS-only, Galileo-only, and multi-constellation modes using both GPS and Galileo. Tropospheric errors were mitigated using the Global Model of Pressure and Temperature (GPT) with the Global Mapping Function (GMF), and ionospheric corrections were applied using the Global Ionospheric Map (GIM). As a result, sub-meter level positioning accuracy was achieved. Among the correction types, IGS RTS corrections provided better accuracy for GPS-only measurements, while Galileo HAS corrections yielded superior accuracy for Galileo-only positioning.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.3
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• pp.1-13
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• 2024

This paper proposes a cost-effective system design and user-friendly approach for the key technological elements necessary to configure an autonomous mobile robot. To implement a high-precision positioning system using an autonomous mobile robot, we established a Linux-based VRS (virtual reference station)-RTK (real-time kinematic) GNSS (global navigation satellite system) system with NTRIP (Network Transport of RTCM via Internet Protocol) client functionality. Notably, we reduced the construction cost of the GNSS positioning system by performing dynamic location analysis of the established system, without utilizing an RTK replay system. Dynamic location analysis involves sampling each point during the trajectory following of the autonomous mobile robot and comparing the location precision with ground-truth points. The proposed system ensures high positioning performance with fast sampling times and suggests a GPS waypoint system for user convenience. The centimeter-level precision GNSS information is provided at a 30Hz sampling rate, and the dead reckoning function ensures valid information even when passing through tall buildings and dense forests. The horizontal position error measured through the proposed system is 6.7cm, demonstrating a highly precise dynamic location measurement error within 10cm. The VRS network-RTK Linux system, which provides precise dynamic location information at a high sampling rate, supports a GPS waypoint planner function for user convenience, enabling easy destination setting based on GPS information.