• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.412-417
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• 2022

In this paper, multi-GNSS network RTK MAC correction generation software developed based on MATLAB GUI is introduced. The software was developed as a post-processing software based on simulation data to evaluate the feasibility of an algorithm for generating correction for multi-GNSS including GPS, GLONASS, and Galileo. As a result of software operation, network RTK correction for each system of multi-GNSS is output in MATLAB file format. In this paper, to evaluate the performance of the developed software, the residual error was analyzed after applying the correction generated through the software to the user. As a result of the analysis, it was confirmed that effective network RTK correction could be generated by confirming that the residual errors of users were maintained at 10 cm or less.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.418-426
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• 2022

Unlike OSR(observation space representation), the SSR(state space representation) augmentation system is suitable for a one-way broadcasting service because it provides the same corrections to all users in the service area. Due to this advantage, several GNSS(global navigation system) systems such as Galileo, BDS(beidou navigation satellite system), QZSS(quasi zenith satellite system) are establishing PPP (precise point positioning)/PPP-RTK precision positioning services based on SSR messages. Therefore, in this paper, we try to understand the trends of satellite-based PPP/PPP-RTK correction services by analyzing the system configurations, characteristics, and precise positioning performance of satellite-based SSR correction broadcasting services.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.139-144
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• 2004

This study aims to analyze the accuracy of rover speed change in route surveying using RTK-GPS. Route surveying methods using GPS contain Static, DGPS, and RTK-GPS. Much research of navigation system, positioning of vehicles by DGPS, and accuracy analysis by GPS surveying have already been done. From this study, it is firstly found that DGPS is suitable for car navigation and sea navigation with an error of meter scale but not good for detailed construction, designing maps and updating GIS databases. Secondly, RTK-GPS can be used for managing gas pipes, water supply and drain pipes and fiber-optic cable that are needed to be controlled in a real time basis. Thirdly, since the accuracies of route surveying by RTK-GPS and DGPS are not correctly matched with the change of rover speed, the choice of route surveying method from those two should follow the need of accuracy fidelity Further study should focus on Cycle Slip problem and coordinate change problem in tunnel and mountainous areas.

• 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.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2009.04a
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• pp.293-294
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• 2009

정밀한 관측을 요하는 측량장비의 기능을 보정하거나 검증하는 것은 측량시 매우 중요한 일이다. ISO17123-8 규격은 GNSS RTK 정확도를 결정 할 때 사용되는 야외실험 절차와 규정을 명시하고 있으며 정확도 평가방법으로는 약식시험절차와 엄밀시험절차를 제시하고 있다. 본 연구에서는 GNSS RTK 정확도 평가방법 중 엄밀시험절차에 대해 시험할 목적으로 GNSS RTK 규격에 따라 Test-bed를 구축하였고 성능실험을 실시 위하여 GNSS RTK 규격에 제시된 정확도 평가방법을 적용하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.411-415
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• 2006

In recent years there has been considerable interest in the network GPS RTK surveying. Single RTK has some limit in long distance and it has an accuracy problem depend on the baseline length. The significant improvement of GPS network technology, RTCM V3.0 correction format and telecommunication technology can eliminate the weakness of single GPS RTK. This paper is the practical field result of GPS network RTK.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.291-291
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• 2002

DGPS(Differential Global Positioning System) and RTK(RealTime Kinematic) is in one of today's most widely used surveying techniques. But It's use is restricted by the distance between reference station and rover station and it is difficult to process data in realtime by it's own orgnizational limitation in precise measurement of positioning. To meet these new demands, In This paper, new DGPS and RTK correction data services through Internet and PSTN(Public Switched Telephony Network) have been proposed. For this purpose, we implemented performance a DGPS and RTK error correction data transmission system for long-distance using the internet and PSTN network which allows a mobile user to increase the distance at which the rover receiver is located from the reference in realtime. and we analyzed and compared DGPS and RTK performance by experiments through the Internet and PSTN network with the distance and the time.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.67-73
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• 2021

The need for precise location data is growing across numerous markets, and so is the number of affordable high-precision GPS receivers. In this paper, we validated the performance of RTAP2U, a low-cost high-precision RTK receiver that was recently released. Two positioning modes were tested: static and driving. The static test conducted Zero-Baseline Single-RTK and Network-RTK survey for 57 hours and 51 hours, respectively. For the driving test, Network-RTK survey was conducted using VRS services provided by NGII based on Trimble PIVOT and Geo++ GNSMART. The static test showed about 1 cm horizontal and vertical accuracies, which is very stable considering the test duration longer than 50 hours. The integer ambiguity FIX rate marked a solid 100%. The driving test result also reached a 100% FIX rate. Horizontal and vertical accuracies were better than 2 cm and 3 cm, respectively. Researchers can refer to this paper when considering affordable high-precision GPS receivers as an option.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.619-626
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• 2012

One-way Network-RTK(Real Time Kinematics) is considered as a method which can satisfy moving vehicle's recently-required high accuracy and mobility. When we use one-way Network RTK for vehicle navigation, multiple cells-based system is required to provide the service continuously in wide area. The rover which moves through various cells inevitably experiences a correction discontinuity, which is not eliminated by the DD(Double Difference) method and to cause 13cm(horizontal) and 48cm(vertical) position error. We suggest three solutions to reduce this discontinuity, which are identification of master RS with neighbor networks, duplication of communication module to receive corrections from other cells, and ambiguity adjustment between neighbor cells. All of our suggestions reduce the error to 1/4 wavelength in measurement and 3cm in position-domain, and we suggest the ambiguity adjustment is the best when we consider the extendibility of service area and the cost of rover device.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.375-383
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• 2018

In order to apply the Network RTK (real time kinematics) technology, which has been used for positioning of stationary points, to the navigation of vehicles, its infrastructure should provide correction data with a quality indicator that can show the expected accuracy in real time. In this paper, we analyzed various indicator generation algorithms such as I95 (ionospheric index 95) / G95 (geodetic index 95), SBI (semivariance based index) and RIU (residual interpolation uncertainty). We also applied them to the raw observables from the reference stations of National Geographic Information Institute and VRS (virtual reference station) users, and then examined its feasibility to be used as a real-time performance index of the Network RTK rover. 24 hour data analysis shows that the RIU index, which can represent the non-linearty of the correction, has the strongest correlation with the Network RTK rover accuracy. Therefore, RIU index is expected to be used as a real-time performance index of the Network RTK rover.