• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.33-38
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• 2002

The object of this study is to verify the feasibility in the application of the GPS system data to the existing geodetic and cadastral survey system. WGS-84 data, which were converted into domestic geometric coordinate system, were compared with those of the existing triangular coordinate system in Gwangju area. The significant results in this study are summarized below ; GPS system is more speedy and accurate than the existing triangular coordinate system in the survey of points in triangular coordinate or on the map. And the error in the GPS system was more uniform than that of the existing triangular coordinate system. GPS system is more effective than the existing triangular coordinate system in the future geodetic and cadastral survey because GPS data can be processed by the computer. It is necessary to calculate the conversion coefficients to apply GPS data practically to the existing geodetic and cadastral survey system. It can be achieved by the individual investigation on how the existing data in the domestic coordinate system were determined.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.37-42
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• 2007

A network of MAC type was constructed in the Gyeonggi-do area to analyze the usefulness and validity of the Network RTK-GPS. Six sites were selected to conduct GPS observation for 24 hours, and by determining the ITRF of each site, coordinates were determined in connection with IGS network. Then check points which were established in Gimpo area were observed at least 7 times by Network RTK at 20 secs of retrieval intervals. The result showed high accuracy in the difference between the coordinates determined immediately by the in-field network survey and the current performance was 1-2cm. Its biggest benefit is the expanded range of survey and efficiency of practice. In summary, it is proved that a network survey has the accuracy, scalability and efficiency and it is expected that the network survey will contribute to the cadastral survey.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.1
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• pp.65-75
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• 2013

In this study, one of the main aims is to build up a technical foundation for promoting the cadastral resurvey effectively and to improve the accuracy of cadastral surveying is to make use of precise surveying techniques in allowance of position errors as reference accuracy in cadastral resurvey, which is proper to obtain the sufficient accuracy of the cadastral control points, and parcel boundary points by introducing the GNSS-based surveying techniques on cadastral survey. In detail, the existing procedures and outcomes of cadastral survey were compared and analyzed for suggesting a better survey technique than that of the other techniques in a variety of aspects of capability of cadastral survey. The new skills and supports could be upmost importance when doing cadastral survey. What's more, essentially, 'The Measurement Department' makes all the efforts to establish 'The Surveying Regulations'. This could possibly apply GNSS-based surveying technique to the cadastral resurvey for the foreseeable future and this research paper suggested that how to improve absolute accuracy of cadastral reference points by means of putting to use the appropriate models of measurement further.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.43-48
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• 2003

This study presents the detailed methods for university facilities mapping using GPS and totalstation. In the control survey by GPS network adjustment, the level of significance for the height value of fourth order triangulation stations was estimated about loom. The accuracy analysis of height determination by totalstation for the traverse points showed that the RMSE came out 9mm to the basis of direct leveling, so it indicated that trigonometric leveling by totalstation was correct comparatively. For GPS/RTK method, the result of accuracy analysis about traverse points showed that the RMSE came out 33㎜ in horizontal location to the basis of totalstation's outcome and 15㎜ in height value to the basis of direct leveling. In the construction survey, GPS/RTK surveying is quicker and more economical than totalstation surveying in the feasible areas of GPS surveying, but there were many impossible areas lot GPS/RTK surveying by the obstacles like a building.

• 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.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.2 s.10
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• pp.153-167
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• 1997

The purpose of this study is to estimate the precision of GPS survey for the long baseline measurement. For this, we performed the simultaneous GPS observations at two points in Korea and nine points in Japan, and analyzed the precision of GPS survey by using broadcast ephemeris and precise ephemeris. As the results, in using precise emepheris and broadcast emepheris for the baseline less than 100km, each precisions are less than 0.1ppm. But the precision of precise emepheris is more improved than that of broadcast ephemeirs in the case of the baseline longer than 100km. That is, in comparing the results of VLBI and GPS survey, the precision is 0.13ppm for broadcast ephelneris and 0.04ppm for precise ephemeris. We expect that in the future this study will be used as the basic data for using broadcast ephemeris and precise ephemeris in GPS survey for the long baseline mearsurment.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.1
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• pp.43-48
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• 2008

In this study, it was estimated efficiency of GPS/INS photogrammetry by comparison of accuracy and economical efficiency between conventional aerial triangulation and GPS/INS aerial triangulation at the base of large scale digital mapping using GPS/INS aerial survey. The results of aerial triangulation with GPS/INS showed that 40% of working amount was reduced in the process of ground control point survey compared to conventional aerial triangulation. In case of 1/5000 scale aerial triangulation, the results showed that 55% GCP work was reduced in 10 and 20 block size, and 60% GCP work was reduced in 30 block size, under the assumption of keeping the same accuracy.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.479-484
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• 2010

In the airborne laser survey with GPS/INS, based on kinematic, the installation and operation of GPS base stations is necessary to allow three-dimensional location coordinates to be obtained quickly and precisely. However, in many cases, GPS base stations operate under difficult conditions. In this paper, we investigate the substitutability of continuously operating reference stations (CORS) for base stations, and we examine the influence of the distance between aircraft GPS and CORS on the Z-value. The results of our study demonstrate that, if the performance of GPS base stations within regulation distance is replaced with that of CORS, sufficient accuracy is guaranteed. Moreover, the performance of CORS beyond regulation distance is fairly good.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.5 s.23
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• pp.75-80
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• 2002

Depending upon geographical features and surrounding errors in the survey field, inaccurate positioning is inevitable in a kinematic DGPs survey. Therefore, a data inaccuracy detection algorithm and an interpolation algorithm are essential to meet the requirement of a digital map. In this study, GPS characteristics are taken into account to develop the data inaccuracy detection algorithm. Then, the data interpolation algothim is obtained, based on the feature type of the survey. A digital map for 20km of a rural highway is produced by the kinematic DGPS survey and the features of interests are lines associated with the road. Since the vertical variation of GPS data is relatively higher, the trimmed mean of vertical variation is used as criteria of the inaccuracy detection. Four cases of 0.5%, 1%, 2.5% and 5% trimmings have been experimented. Criteria of four cases are 69cm, 65cm, 61cm and 42cm, respectively. For the feature of a curved line, cublic spine interpolation is used to correct the inaccurate data. When the feature is more or less a straight line, the interpolation has been done by a linear polynomial. Difference between the actual distance and the interpolated distance are few centimeters in RMS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6196-6203
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• 2013

This study examined cadastral surveying technology regulated under the "Special Law for the cadastral surveying", and analyzed the related surveying methods currently used. Based on the analysis, this study suggested the efficient application plan future cadastral surveying projects. The new technologies analyzed were GNSS, GPS RTK, Network RTK, GPS Augmentation System, and the mobile and auto sighting TS. As a result of the analysis, this study suggests that if a receiving technology is possible for the integrated receiving of GPS/GLONASS/Galileo systems, both the accuracy of location determination could be enhanced and stable data could be obtained. The Network RTK technology may solve the constraint receiving factors of satellite information in the long term if a GPS Augmentation System is used. Finally, mobile and auto sighting TS technologies can reduce the personnel factors, but can be applied after the offset problem is overcome.