• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.677-685
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• 2011

In order to enhance public transportation and to maintain information credibility, improvement of accuracy regarding route and positional information of public transport is very significant. There have been a variety of methods using GPS to measure accuracy of location-based services. However, the researches of evaluation regarding kinematic position of linear objects measured by vehicle/kinematic GPS are still insufficient. That's why our paper aims to suggest method of evaluation accuracy on a real-time bus route surveyed by GPS by SBM(Single Buffering Method). To make it come true, we compared the findings on the static and dynamic positioning by using PP(Point Positioning), DGPS and GPS/INS integrated systems and analyzed the accuracy and error effects among them, focusing on Anyang city. Consequently, we can find out that in case of P.P. comparing positioning accuracy between RTK DGPS and GPS/INS, both of them have survey result within a margin of error of 5m. More importantly, we can evaluate positional accuracy of each GPS system based on the work provision of a public survey such as error for P.P.(14.5m, 18.1m), DGPS(16.9m, 18.5m), and GPS/INS(18.4m, 18.5m). We are expecting that proposed method in our paper can be utilized in a wide range of categories such as feasibility testing of GPS field survey and high accuracy of positioning for Bus Information System.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.61-69
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• 2003

The study is the open area keeping a few visible satellites and the urban area covered with the high building, an electric pole were chosen for evaluation of accuracy of satellite positioning. First, suggest the validity of RTK-GPS, RTK-GPS/GLONASS and compared the accuracy with that of the classical surveying method. As a result. In urban area, in case of real time kinematic positioning when compare between the method combined by GPS/GLONASS and by GPS alone the result of GPS/GLONASS - combination more excellent. And in open ana positioning combined GPS/GLONASS was more excellent than GPS alone in both real time differential and real time kinematic. So, RTK-GPS, RTK-GPS/GLONASS contribute to the digital mapping of Basic map and the existed map necessary for the building of PBLIS to the computerization of cadastral map in the effectiveness in time and in cost and hereafter the combined GPS/TS is expected to contribute to the development of NGIS, Re-investigation of a land register, the execution drawing on site.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.183-190
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• 2002

This study is about the extraction of highway's superelevation using real time kinematic surveying among of GPS surveying methods which is economic method to construct data base in the side of highway maintain management. Using the developed vehicle, center line and shoulder of highway are measured and enough precision is obtained after analyzing the result. The result is show that 1.3 cm to 2.0 cm error in the clothed and about 0.8 cm to 1.2 cm error in the circular curve. Those errors are proved error to lane making during construction. This study is expected to become efficient method for extraction of highway alignment elements in the Mobile Mapping System.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.157-158
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• 2020

항만용 자율주행 야드트럭운행 환경은 무신호교차로 주행, 낮은 GPS정확도, 악천후상황주행, 이송 컨테이너 위치변경등과 같이 일반 도로의 센서기반의 자율주행차량 운행과 다르게 매우 복잡하다. 이를 위해서는 항만내 특성을 반영한 실시간 위치, 속도 등에 대한 정확한 인식이 중요한 요소이다. 이를 위해서 센서융합과 V2X기반의 복합적인 항만용 실시간 로컬 동적지도 (Local Dynamic Map) 생성 및 V2X기반의 협력측위를 통하여서 기존의 독립적인 자율주행차량의 위치 인식보다 더 개선된 고정밀 위치 인식 정보추출이 필요하다. 본 연구에서는 복합적인 항만용 동적지도 생성관리시스템의 설계 방안 및 협력측위 기술 적용 방안을 제시하고 이를 활용한 항만 구역내 자율주행차량 및 모든 화물 이송장비들의 실시간 위치 인식뿐만 아니라 이동체의 사전 충돌예측 및 비상정지 안전 제어 가능한 V2X 기반의 인텔리젼스 한 3차원 관제시스템 설계 방안을 제시하고자 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.220-223
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• 2004

지금까지 배송에 관한 연구는 주로 최적화된 차량의 배송 경로의 생성에 있어서 계획 생성까지의 시간의 단축이나 경로계획의 안정성의 확보에 초점을 두었다. 그러나 고객의 높은 서비스 수준을 만족시키기 위해서는 다양한 요구 사항을 충분히 반영한 동적인 운송계획의 수립과 함께 배송 단계에서 빈번히 발생하는 다양한 예외상황에 대한 적절한 대처가 필요하게 되었다. 본 연구에서는 최적화, GIS, GPS, ITS, Mobile등의 기술을 이용하여 동적으로 변화하는 실시간 환경에서 높은 서비스 수준을 제공할 수 있는 적응 운송 시스템의 모습을 제시하고자 한다.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.341-353
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• 2014

In order to deliver a centimeter-level kinematic positioning solution with GPS carrier-phase measurements, it is prerequisite to use correctly resolved integer ambiguities. Based on the mathematical modeling of GPS network with application of its geometrical constraints, this research has investigated an instantaneous ambiguity resolution procedure for the so-called 'integer constrained least-squares' technique which can be effectively implemented in real-time structure monitoring. In this process, algorithms of quality control for the float solutions and hypothesis tests using the constrained baseline for the ambiguity validation are included to enhance reliability of the solutions. The proposed procedure has been implemented by MATLAB, the language of technical computing, and processed field trial data obtained at a cable-stayed bridge to access its real-world applicability. The results are summarized in terms of ambiguity successful rates, impact of the stochastical models, and computation time to demonstrate performance of the instantaneous ambiguity resolution proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.617-624
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• 2008

In general, RTK-GPS(Real Time Kinematic GPS) based on the single reference station is able to determinate the high accurate position of rover on the spot using error correction information of transmitted carrier phase from the base station via wireless modem. However, single reference station method has some weak points to decrease positioning accuracy because it must be obtained carrier phase from the each satellite continuously, allowed to transmit without obstacle and limited to short base line distance between base and rover station. This paper aims to attempt network based GPS carrier phase differential positioning using three multi reference stations to overcome the method of single reference station and RTK network is realized by real time monitoring program with Visual C++. The optimum error correction value of three multi reference stations by RTK networking is selected automatically to correct the position of rover station. In this paper, this algorithm is applied to determine sea water level using GPS buoy, and the accuracy results of water level change were analyzed and compared with each other using single and multi reference stations.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.232-238
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• 2007

In this research, we constructed a 3D riverbed surveying system that is able to acquire the topographical information of a riverbed in real-time. The system consists of a RTK-GPS receiver and a echo sounder for collecting simultaneously the position and the water depth information of riverbed. A program for data composition and transformation was designed to generate the 3D coordinates by combining data of a GPS receiver and a echo sounder and made GIS database construction easy. We extracted TIN, digital elevation model and cross sectional maps of the riverbed by using GIS software from 3D data constructed through test surveying. It was shown that the accuracy of the result was RMS error of 0.069m when compared with the existing methods which use a total station and staffs. It is expected that the 3D riverbed surveying system wiil be able to be utilized to various surveying for water resources management in rivers, sea, dams, storing reservoirs and so forth.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.63-64
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• 2002

GPS 시스템을 사용하면 전세계에 걸쳐 언제든지 수$\pm$10m 이내의 오차범위에서 위치를 측정할 수 있다. 이보다 더 정밀한 위치가 필요할 경우에는 Differential GPS (DGPS)방식을 자주 사용한다. DGPS방식은 실시간 처리(Real time kinemetic: RTK)와 후처리(post-processing)방식으로 나눌 수 있다. 측위정도는 정적 후처리방식이 동적 후처방식이 보다 높은 것이 일반적이다. (중략)