• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.4
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• pp.389-398
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• 2002

As the necessity of land information has increased according to development of computer and Information-communication, people have been interested in the satellite measurement system that can update Cadastral and Geographical information rapidly and exactly. Most Cadastral base points which had limitation of measurement technology in the 1910s were less accurate and were destroyed through the Korean War. They also many problems in the process of reinstallation. So, they require the quick and correct method of measurement in re-equipment of a base point and a parcel based survey and so on. This study intends to present the GPS survey direction by understanding and analysing all sorts of problems rising in case of applying the GPS to cadastral area in order to increase the efficiency of the GPS measurement, and also develop the GPS kinematic survey program to apply to the efficiency of a kinematic survey. As a result of research, I could confirm the accuracy of Cadastral base points in Kwangju area by using Korea GPS array and a base point, and could get the result similar to existent cadastral survey result with the coordinate conversion program of Cadastral technology research institute. We however have to pay our attention to the transformation of the plane coordinates because the difference between tens of cm and the existing result can outbreak according to the Gauss conformal double projection method. And, I could figure out the practicality of the developed GPS kinematic survey program, compared with common use program. I expect that it can be applied to the digital cadastral survey and the cadastral map renewal as well.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.105-110
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• 2006

우리나라에 GPS 위성측량이 도입되기 시작한 것은 최근에 이루어 졌으며 많은 발전을 해오고 있지만 해결해야 할 많은 문제점을 가지고 있다. 현재 우리나라의 GPS 위성측량의 사용에 있어서 여러 가지 문제점 중 현재 지구 주위를 운항하고 있는 24개의 GPS 위성으로 지상 어느 곳에서나 24시간 동안 위성신호를 수신할 수 있게 되었지만 고층 빌딩과 같은 도심 계곡, 복잡한 한국지형, 산악지역 등에서의 위성 장애물에 의한 신호의 차단으로 한계가 발생하고 있다. NAVSYNC의 CW25 GPS 수신기는 -156dBm이하의 신호강도에서도 확실한 위치 fix가 가능하고, 이러한 능력은 도심지나, 울창한 숲과 심지어는 건물 안과 같이 신호가 미약한 지역에서도 사용될 수 있다. 이에 본 연구에서는 Indoor GPS 수신기를 이용하여 측지분야에서 검증된 GPS측량방법을 통해 수신데이터를 비교 분석하고 수신기의 정밀도 향상에 관한 연구를 하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4595-4600
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• 2014

A geoid has great meaning as a vertical reference plane, and at this point when GPS measurement is vitalized, it is an important factor that makes level measurements with GPS possible. This study carried out GPS and leveling of newly created complex control points targeting Daejeon. The geoid for the precise area was built by calculating the plane location, elevation and the geoid of each reference point using GPS/Leveling. In addition, this study evaluated the potential of GPS leveling throughout the site calibration. The geoid for the precise area intervals of approximately 1.5km throughout the study was determined. The results highlight the possibility of leveling by estimating direct leveling performance and mean altitude deviation by less than 2cm. Based on the results, if a geoid model for the precise and wide area can be developed throughout ongoing research, survey tasks that require elevation can be streamlined and the efficiency maximized.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.2
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• pp.155-161
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• 2001

When determining a three dimensional position for engineering purposes, we can use the GPS survey to find position. According to the enhancement of precision for domestic Geoid model, the positional accuracy of GPS about precise method of vertical position has been also increased. But by considering Geoid undulation, it is difficult to measure GPS-derived elevations. Because Geoid undulation has changed little in local sites, GPS-derived elevations are similar to orthometric height. By ignoring Geoid undulation, it is possible to measure GLT-derived elevations at the local. small construction sites. GLT(GPS Leveling Technique) provides a method for computing orthometric heights. GLT processes the data more rapidly than conventional measurement devices. We only considered the weight factors affecting accuracy between the points. That is, the GPS procedures to produce satisfactory elevation accuracy depends on the method of observations, receivers and conditions of the local environment. A comparison was performed between the GPS survey using Geoid model and GLT at a part within Pusan National University and construction model sites in South Korea. And the writers proved the GPS surveying is efficient in positioning accuracy, time, and cost on a construction sites.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.1
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• pp.53-62
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• 2004

This paper deals with a new approach to acquire the exterior orientation parameters based on GPS(Global Positioning System) in combination with IMU(Inertial Measuring Unit), which enables us to achieve the same accuracy with minimal ground control points comparing to the conventional photogrammetric method. To prove the possibility of practical use of GPS/INS photogrammetry, a survey flight was conducted loading with all necessary photographing systems. The observed data set by GPS/IMU were analyzed and verified :he accuracy performance of kinematic GPS, and also compared to those of conventional photogrammetry in various points of view.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.71-78
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• 2009

In general, it is necessary to establish the dedicated GPS base station at the central point of the survey area in GPS/INS aerotriangulation. Although this base station is needed to achieve the required survey accuracy, there are some difficulties in practical operation. To tackle these difficulties and to achieve the effective GPS/INS aerotriangulation, the GPS data of CORS was interpolated and used in stead of those of the usual ground base station. Through this study, it was found that the interpolated CORS data was accurate enough to substitute dedicated GPS base station in GPS/INS aerotriangulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.561-567
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• 2008

In this study, shoreline change was analyzed by RTK-GPS and advanced airborne LiDAR survey. For extraction of coastline, first of all, tide correction was conducted at all RTK-GPS points through the comparing with the corresponding tidal height, and cross section providing coastline was produced using Autocad Civil3D program. Comparing with two results of RTK-GPS (first, 29 Aug 2007; second, 6 Oct 2007) surveys, coastline of the first result had been decreased about 21m compare with that of the second. And it was also demonstrated that the length of coastline by the first RTK-GPS was 15m shorter than that by the airborne LiDAR survey (Dec. 2006). In addition, we recoquized that the erosion appeared in the top right-hand (dock area); the sediment in the bottom left-hand (Chosun beach area) of the Haeundae beach. As a result, therefore, it was learned that artificial sand filling for beach open and natural effects such as a typhoon, current drift, wind direction gave cause for area changes and coastline.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.167-172
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• 2002

본 연구는 GPS를 이용하여 위성 영상의 입체 해석으로 산출된 SPOT영상의 기준점 및 수치 표고 모형의 평가에 목적이 있다. 이를 위해 삼각점 및 상시관측소를 고정으로 한 GPS 해석을 수행하였으며 정지측량과 이동측량의 정확도를 비교함으로써 위성 영상의 기준점과 수치 표고 모형의 평가를 위한 측량 방법을 분석하였다. 연구 결과, SPOT영상의 해상력을 고려할 때, 이동 GPS측량기법으로도 수치 표고 모형의 정확도 평가가 가능하였으며, 기준점 좌표 산출에 있어서 고정점에 삼각점 대신 상시관측점들을 사용함으로써 경제적인 GPS 측량을 꾀할 수 있었다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.125-128
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• 2009

The accuracy of GPS surveying is affected by orbit ephemeris, atmospheric and ionospheric effects and also various analysis conditions. In this study, we intended to analyses the difference of the GPS data which are processed by another user under same or other conditions as like GPS data processing software and orbit ephemeris and career of user.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.257-258
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• 2010

Recently data, which are obtained by the airborne laser scanner system have been utilized to rapidly obtain three-dimensional location coordinates for a large area. According to operation regulation, the distance between a GPS base station and a aircraft GPS is fixed within a radius of 30km. In this paper, we compare data obtained by GPS observation station operated in National Geographic Information Institute with those obtained by GPS base station for making a airborne laser survey.