• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1091-1093
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• 1999

This paper discusses the surveying of a power transmission line using Real Time Kinematic(RTK) GPS technology. The use of RTK provides users with an accurate position at the moment in time. Application result of a 765kV transmission line surveying proved to be more accurate and efficient than using a traditional EDM (Electro-magnetic distance measurement) method. More, decrease in numbers of trees cut down which is a major cause of public discontents was achieved. Improvements in doing a surveying of a power transmission line using GPS is expected in the future.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.169-171
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• 2010

The goal of this study is to evaluate the performance of different solution types(a GPS-only, a GLONASS-only, and a GNSS solution) on GNSS positioning modes which are point positioning and relative positioning(DGNSS-, Static-, and Kinematic-solutions). I started with GNSS sites of seoul metropolitan government's RTK network which providing combined GPS/GLONASS observations : Gangseo(GANS), Dobong(DBON). The positioning accuracy of different solution types on positining modes are compared. Considering the compared results of all cases, can find not only the difference of the performance between the GNSS solution and the GPS-only solution is very small, but also the GLONASS-only solution is not far from the other solution types taking into consideration that GLONASS system is not (yet) a complete system.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.12
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• pp.1036-1043
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• 2001

It is well-known that positioning accuracy can be improved by the use of carrier phase of GPS up to the centimeter level. In order to obtain good accuracy, we need to know integer ambiguity in the carrier phase accurately. In this paper, we propose a fast ambiguity determination method(FADM) which combines Kalman filtering and the search method, and show the improvement of the positioning performance by static and kinematic simulation compared with known methods such as Kalman filtering, LSAST (Least Squares Ambiguity Search Technique), ARCE(Ambiguity Resolution with Constratint Equation), LLL(Lenstra, Lenstra, and Lovasz) algorithms.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.15-23
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• 2006

On this study, realtime GPS technique and combination of GPS/GLONASS technique are used to extracting coastline. Th￡ object of coastline is Gwanganri beach located in Busan. The coastline is observed along the traces of coastline when high wave of scar by using digital map of 1:1,000 and at random time zone, coastline is surveyed along the boundary line that is contacting with sea water level. When the coastline of random time zone is converted by height of tide table, the coastline when high wave of scar and converted coastline are shown as coincident approximately.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.197-203
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• 1999

Depending on geographical features and error sources in the survey field, inaccurate data is inevitable in GPS kinematic survey for positioning with feature codes. In this study, the trimmed mean and the first order differential equation are used to develop an inaccurate positioning data detection algorithm, and a cubic spline curve and a linear polynomial are used to interpolate the inaccurate data. Based on interpolated data, a digital map for 30 km range of rural highway is produced and a corresponding GIS coverage map is obtained by analyzing and solving the problem associated with the map.

• Journal of Information Technology Services
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• v.22 no.3
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• pp.85-100
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• 2023

The development of Airside Vehicle Control System(AVCS) at Gimpo Airport aims to reduce ground safety accidents in movement area and improve airport operation efficiency and safety management service quality. The vehicle is controlled by a brake controller RTK-antenna and On-Board Diagonostics(OBD) module. Location data is transmitted to a nearby communication base station through a Wi-Fi router and the base station is connected to the AVCS by an optical cable to transmit location data from each vehicle. The vehicle position is precisely corrected to display information using the system. The system allows airport operators to view registered information on aircraft and vehicles and monitor their locations speeds and directions in real time. When a vehicle approaches a dangerous area alarm warnings and remote brake control are possible to prevent accidents caused by carelessness of the driver in advance.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.4
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• pp.393-401
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• 2003

Automatic control technologies for the marine pile driving provides accurate and rapid intruding into the planned positions of the pile with planned slope and direction, so that the construction maintenance and management are more efficient and the quality of the construction is more promising. Therefore, in this study, the application scheme of RTK GPS to the automatic control of the pile driving presented. It is expected that the presented scheme using the precise RTK GPS technique assures the efficient and economic 3D positioning accuracy for the precise marine construction management like the precise foundation of marine structures made of piles and the dredging work. It is found that the suggested scheme decrease 60% of the construction error compared with specifications reference because marine position accuracy is measured within 4cm in real time. In addition, the automatic position control system using GPS reduced the construction period and cost compared with existing methods about 30% and 35%, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.327-332
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• 2006

In airborne gravimetry, there are two data streams. One is the specific force measured by an air/sea gravimeter or accelerometers, the other is kinematic acceleration measured by DGPS. And the difference of them provides the gravity disturbance information. To satisfy the requirement of most applications, an accuracy of 1mGal $(1mCal=10^{-5}m/s^{2})$ with a spatial resolution of 1km is the aim of current airborne gravimetry. There are two different methods to derive the kinematic acceleration. The generally used method is to differentiate the position twice, and the position can be calculated by commercial DGPS software. The main defect of this method is that integer ambiguities need to be fixed to get the precise position solution, but it's not a trivial thing for long base line. And to fix integer ambiguities, the noisier iono-free measurement is used. When differentiation is applied, noise is amplified and will influence the accuracy of acceleration. The other method is to get carrier phase acceleration by differentiate the carrier phase first, and then using the acceleration of GPS satellite to derive the vehicle acceleration. The main advantages include that fixing integer ambiguities is not needed anymore, position can be relaxed to about 10 meters, and smoother acceleration can be got since iono-free measurement is not needed. In some literatures, it's considered that the dynamic performance of the second method is inferior to that of the first. Through analysis, it is found that the performance degradation in dynamic environment results from the simplification of the GPS carrier phase observable model. And an iterative algorithm is presented to compensate the model error. Using a dynamic GPS data from an aeromagnetic survey, the importance of this compensation is showed at last.

• 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 Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1032-1039
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• 2012

The present paper deals with precise relative positioning of formation satellites with long baseline in low Earth orbit making use of L1/L2 dual frequency GPS carrier phase measurements. Kinematic approach means to describe the motion of objects without taking its mass/dynamics model into consideration. The advantage of the kinematic approach is that information about dynamics of the system is not applied, which gives more flexibility and could improve the scientific interest of the observations made by the mission. The ionosphere terms, which are not canceled by double differenced measurement equation in the case of the long baseline, are explicitly estimated as unknown parameters by extended Kalman filter. The estimated float ambiguities by EKF are solved by existing efficient integer vector search strategy under integer least square condition. For the integer vector search, we employ well known MLAMBDA. Finally, The feasibility and accuracy of processing scheme are demonstrated using the GPS measurements for two satellites in low Earth orbit separated by baselines of 100 km.