• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.513-519
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• 2006

South Korea is currently promoting cadastral computerization to modernize the field. Problems of cadastral mismatches are mostly resolved through cadastral mismatch organization projects. Three-dimensional cadastral drafting Is also on its way to wide adoption. In order to safeguard the property ownership rights of people and deliver accurate cadastral information quickly by constructing a three-dimensional cadastral information system, this study intends to provide solutions to survey real-time kinematic GPS (RTK-GPS) in mobile environments and to produce three-dimensional cadastral maps real-time using digital plane tables.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1209-1220
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• 2020

In the case of forest areas, the installation of ground control points (GCPs) and the selection of terrain features, which are one of the unmanned aerial photogrammetry work process, are limited compared to urban areas, and safety problems arise due to non-visible flight due to high forest. To compensate for this problem, the drone equipped with a real time kinematic (RTK) sensor that corrects the position of the drone in real time, and a 3D flight method that fly based on terrain information are being developed. This study suggests to present a method for investigating damage using drones in forest areas. Position accuracy evaluation was performed for three methods: 1) drone mapping through GCP measurement (normal mapping), 2) drone mapping based on topographic data (3D flight mapping), 3) drone mapping using RTK drone (RTK mapping), and all showed an accuracy within 2 cm in the horizontal and within 13 cm in the vertical position. After evaluating the position accuracy, the volume of the landslide area was calculated and the volume values were compared, and all showed similar values. Through this study, the possibility of utilizing 3D flight mapping and RTK mapping in forest areas was confirmed. In the future, it is expected that more effective damage investigations can be conducted if the three methods are appropriately used according to the conditions of area of the disaster.

• Journal of KIISE
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• v.43 no.12
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• pp.1315-1324
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• 2016

Recently, the increasing interest in drones has resulted in development of new related technologies. Attention has been focused toward research on swarm flight which controls drones simultaneously without collision. Thus, complicated missions can be completed rapidly through collaboration between drones. Due to low position accuracy, GPS is not appropriate for the outdoor mission involving accurate flight. In addition, the inaccurate position estimation of GPS gives rise to the serious problem of collision, since many drones are controlled in a narrow space. In this study, we increased the accuracy of position estimation through various sensors with Real-Time Kinematic-GPS (RTK-GPS). The mode switching algorithm was proposed to minimize the problem of sensor error. In addition, we introduced the outdoor swarm flight system based on the proposed position estimation.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.11-19
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• 2023

Drones, which were early operated by remote control, have evolved to enable autonomous flight by combining various sensors and software tools. In particular, autonomous flight of drones was possible since the application of GNSS-RTK (global navigation satellite system with real-time kinematic positioning), a precision satellite navigation technology. For instance, unmanned drone delivery based on GNSS-RTK data was demonstrated for pizza delivery in Korea for the first time in 2021. However, the vulnerabilities of GNSS-RTK should be overcome for delivery drones to be commercialized. In particular, jamming in the navigation system and low positioning accuracy in urban areas should be addressed. Solving these two problems can lead to stable flight, takeoff, and landing of drones in urban areas, and the corresponding solutions are expected to establish a hybrid positioning technology. We discuss current trends in hybrid positioning technology that can either replace or complement GNSS-RTK for stable drone autonomous flight.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.19-29
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• 2005

In this study, Real Time Kinematic GPS(RTK GPS) was conducted twice at the same site in two different seasons, respectively to check the possibility of it as the mapping tool, and how the factor affecting the accuracy of it. As a result, most parts of a small garden except f3r the worst environments surrounded with lots of tree canopy and several buildings were mapped using RTK GPS even in spring, full of a green foliage and winter as well. However, the mapping accuracy and the availability of RTK GPS were not so high. The study showed that it is recommended in RTK GPS mapping to utilize Total Station, etc. in the worst urban environments unable to track the satellite signals with ease.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.791-794
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• 2003

자동화 컨테이너터미널은 ATC(Automated Transfer Crane)와 AGV(Automated Guided Vehicle)와 같은 자동화 운송 장비를 사용하는 컨테이너터미널이다. 이러한 자동화 컨테이너터미널의 핵심은 생산성을 향상시키기 위한 효율적인 장비 운영이 결정적인 역할을 한다. 본 논문에서는 AGV의 이동 위치 결정을 위한 RTK-GPS(Real Time Kinematic-Global Positioning System) 위치 정보 전송 및 운용 방법에 대해서 연구하였다. 이를 위해서 기존의 무선모뎀을 이용한 RTK-GPS 전송 방법을 무선 LAN(Local Area Network) 환경에서 RTK-GPS 위치 정보 전송 방법에 대해서 제안하고, AGV 이동 위치 결정 및 계산을 실험하였다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.352-353
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• 2008

국제표준화기구(ISO)에서는 장비에 대한 표준화작업을 ISO/TC172에서 관리하고 있으며 산하의 전문위원회인 SC6에 속해있는 ISO17123 $1{\sim}8$은 주로 측량장비의 정밀도를 참조할 때 인용되는 표준으로 그중에서 ISO17123-8: GNSS field measurement systems in real-time kinematic(RTK)은 GNSS의 RTK 정확도평가방법으로서 약식시험절차와 엄밀시험절차를 규정하고 있다. 본 연구에서는 ISO17123-8의 규격을 분석하고 이 규격에 따라 GPS RTK Test-bed를 시험구축하고 정확도 평가방법에 따라 관측값 Testing하는데 목적이 있다.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.31-39
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• 2015

This paper presents the static and kinematic positioning accuracy by the real-time GPS positioning modes of the low-cost GPS receivers using NTRIP-based augmentation service. For this, acquires both the raw measurements data of the field tests by LEA 6T GPS module of u-blox AG, and correction communication via NTRIP caster with RTKLIB as an open source program for GNSS solution. With computing the positions of the check points and road tracks by six kinds of GPS positioning modes which are Single, SBAS, DGPS, PPP, RTK, and TCP/IP_RTK, compared these results to the reference position of the check points. The position error average and rmse of the static test by GPS L1 RTK surveying showed $N=0.002m{\pm}0.001m$, $E=0.004m{\pm}0.001m$ in horizontal plane, and $h=-0.116m{\pm}0.003m$ in vertical, these results are very closed to the coordinates with the geodetic receiver. Especially, in case of the kinematic test with obstacles located on both sides of road, the computed track with ambiguity fixing showed very similar trajectory considerably from VRS network RTK mode. And also, evaluate and verify the performance of the TCP/IP_RTK mode developed based on TCP/IP protocol.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.333-342
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• 2022

This paper has theoretically and practically reviewed the ISO (International Standard Organization) 17123-8 standard not only to raise the appropriateness for introducing performance criteria of GNSS (Global Navigation Satellite Systems) surveying equipment based on RTK (Real-Time Kinematic) accuracy but also to derive its proper test procedure by introducing the international standard. Field experiments have been performed to appreciate the GNSS-RTK accuracy of five selected receivers via the full testing procedure of the ISO standard, which statistically compares the so-called experimental standard deviations with themselves and with the reference accuracy. A series of statistical tests have revealed that the RTK accuracy of the same class receivers is not identical, whereas that of the different classes can be equivalent. Such a result evidences the urgency of adopting an RTK accuracy-based specification of the GNSS equipment to the performance standard, currently referenced to the static observation technique only. It is believed that this transition helps the maximization of a new generation of cost-effective receivers to legal surveying applications. Finally, this study proposes the ISO full test, comparing an experimental standard deviation with its referenced value, for a potential field verification procedure of the new performance standard.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.174-182
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• 2014

To monitor the wind-induced responses of buildings, conventional real-time kinematic (RTK) methods based on two global positioning system (GPS) receivers (e.g., a reference and a rover) are widely applied. However, these methods can encounter problems such as difficulty in securing and maintaining a space for a reference station. With the recently developed virtual reference station (VRS)-RTK approach, the position of a structure can be measured using only a rover receiver. In this study, to evaluate the applicability of VRS-RTK methods in monitoring the lateral structural responses of frame structures, we performed free vibration tests on a one-story frame model (the first natural frequency of 1 Hz) and a three-story frame model (the first natural frequency of 0.85 Hz). To assess the reliability of the displacement and acceleration responses measured by the GPS, we performed a concurrent measurement using laser displacement sensors and an accelerometer. The accelerometer results were consistent with the GPS measurements in terms of the time history and frequency content. Furthermore, to derive an appropriate sampling rate for the continuous monitoring of buildings, the errors in the displacement responses were evaluated at different GPS sampling rates (5, 10, 20 Hz). The results indicate that as the sampling rate increased, the errors in the displacement responses decreased. In addition, in the three-story model, all modal components (first, second, and third modes) could be recorded at a sampling rate of 20 Hz.