• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.6 no.2
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• pp.19-27
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• 1988

In determining the horizontal positions, economic, speedy, and accurate analytical adjustment methods have studied and developed for a long time. From now on, the adjustment methods using both angles and distances are expected because the development of more precise instruments, E.D.M, and electronic total station provide us with more advantages than the conventional measurement system. The objective of this paper is to study the characteristics of triangulation, trilateration, and combination method due to change of the weight factor of angles, distances, azimuthes, and control point coordinates of combined geodetic network. The results of this study show that combined method is more accurate and effective than other methods in case of combined geodetic network as the other simple networks.

• Spatial Information Research
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• v.12 no.4 s.31
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• pp.371-382
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• 2004

Continuously Operating Reference Stations (CORS) provides GPS measurements to support high accuracy CPS positioning. The CORS improves GPS positioning productivity by eliminating the requirement for GPS users to operate two receivers. Previously, this is achieved by providing data from CORS to users in post-mission mode. However, the efficiency of the CORS will be maximized by upgrading it in real-time operation using RTK-GPS surveying because users can obtain centimeter-level accuracy in real-time without operating their own reference stations. In this research, authors extracted the arbitrary point's coordinate which is using GPS CORS data, now served in RINEX FORMAT via Internet, with observation network of the existing triangulation and GPS CORS data. And then, RTK GPS was performed with this arbitrary point as reference station.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4228-4233
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• 2010

This study analyzed the positional accuracy of cadastral control points where central datum points and eastern datum points meet in the area of standard datum of geographic coordinate, in order to suggest the possibility of converting cadastral coordinates into global coordinates in the future in areas between cadastral datum. 12 GPS observation data points were extracted from the station of triangulation in the experimental area, and the accuracy of coordinate conversions in the area where central and eastern datum points meet was analyzed. The results show that the x-coordinate RMSE was ${\pm}0.0014m$ and the y-coordinate RMSE was ${\pm}0.0011m$. Such excellent results indicated that it is possible to convert to the global coordinate system. Thus, in converting to the global coordinate system, it appears possible to convert even borderline datum point areas if points with stable outcomes are selected by inspecting various triangulation markers, then used to carry out the conversion.

• Spatial Information Research
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• v.18 no.5
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• pp.37-45
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• 2010

AT(Aerial Triangulation) is the essential procedure for creating orthophoto and transforming coordinates on the photographs into the real world coordinates utilizing GCPs (Ground Control Point) which is obtained by field survey and the external orientation factors from GPS/INS as a reference coordinates. In this procedure, all of the GCPs can be collected from field survey using GPS and Total Station, or obtained from digital maps. Collecting GCPs by field survey is accurate than GCPs from digital maps; however, lots of manpower should be put into the collecting procedure, and time and cost as well. On the other hand, in the case of obtaining GCPs from digital maps, it is very difficult to secure the required accuracy because almost things at each stage in the collecting procedure should rely on the subjective judgement of the performer. In this study, the results from three methods have been compared for the accuracy assessment in order to know if the results of each case is within the allowance error: for the perceivable objects such as road boarder, speed bumps, constructions etc., 1) GCPs selection utilizing the unique LiDAR intensity value reflected from such objects, 2) using LiDAR DSM and 3) GCPs from field survey. And also, AT and error analysis have been carried out w ith GCPs obtained by each case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.21-28
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• 2011

The femtocell is a miniaturized Base Station (BS) with low-cost and low-power using general broadband access network as backhaul. It is expected not only to improve indoor coverage but also to reduce a service charge. However, in IEEE 802,16e femtocells, when the Mobile Station (MS) scans neighbor BSs for handover, it takes a long time due to too many number of femto BSs. Also the size of the neighbor advertisement message that will be periodically sent by a serving BS is increased as the number of target femto BSs for scanning increases. In this paper, we proposed an efficient femtocell scanning scheme, using a triangulation mechanism and a femto BS monitoring scheme to reduce the number of scanning operations and the size of the neighbor advertisement messages. The proposed scheme can avoid wasting air resources and reduce scanning overheads by minimal scanning operation. The simulation results showed that the proposed scheme could improve scanning performance and avoid wasting air resources, compared with the conventional scheme of the IEEE 802.16e system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.1
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• pp.61-66
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• 1993

Position fixing is determined by triangulation, traverse surveying and astronomy surveying, However, when the station like a car move, it is impossible to determine the location of car. Satellite position fixing system can be used anywhere on earth arranged in 20, 000 km high with 24 satellites. The theoretical method of the fixing composition is possible to use satellite position fixing system. This paper is the part of the experiment which is dose for the development of the system used in Car-position fixing system. Also, this study is the comparison of one point positioning system and relative positioning system.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.2 s.29
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• pp.29-35
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• 2004

The plenty of availability and high precision of GPS CORS is the reason why it become important more and more in the fields of surveying widely. In this study, I extracted the arbitrary point's coordinate which is using GPS CORS data, now served in RINEX FORMAT via Inter-Net, with observation network of the existing triangulation and GPS CORS data. Then, with this arbitrary point as reference station RTK GPS was performed. And I will study VRS-GPS concept which reduces the time and cost in the fields of surveying.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.279-286
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• 2018

In the civil works, the measurement of earth-volume is one of the important elements in the estimation of the reasonable construction cost. Related studies mainly used GPS (Global Positioning System) or total station to obtain information on civil work areas. However, these methods are difficult to implement in inaccessible areas. Therefore, the aim of this paper is to use the UAV (Unmanned Aerial Vehicle) to measure the earth-volume. The study area is located in a reservoir construction site in Sangju-si, Gyeongsangbuk-do, Republic of Korea. We compared the earth-volume amounts acquired by UAV-based surveying to ones acquired by total station-based and GPS-based surveying, respectively. In the site, the amount of earth-volume acquired by GPS was $147,286.79m^3$. The amount of earth-volume acquired by total station was $147,286.79m^3$, which is the 96.13% accuracy compared to the GPS-based surveying. The earth-volume obtained by UAV was $143,997.05m^3$ when measured without GCPs (Ground Control Points), $147,251.71m^3$ with 4 GCPs measurement, and $146,963.81m^3$ with 7 GCPs measurement. Compared to the GPS-based surveying, 97.77%, 99.98%, and 99.78% accuracies were obtained from the UAV-based surveying without GCP, 4 GCPs, and 7 GCPs, respectively. Therefore, it can be confirmed that the UAV-based surveying can be used for the earth-volume measurement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.95-103
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• 1984

This paper is a study on improving the accuracy of control points by suggesting angular requirements which make geometric conditions to be optimum. For this purpose, a equation, by which the accuracy of control point coordinates measured in an arbitrary station can be estimated, is derived. This equation is integrated and average standard error of the coordinates is computed, so that the optimum location of observatory station is determined. In the case of triangulation, a regular triangle has been generally considered as the best geometric condition, but because the precision of each side is different, the $52.77^{\circ}$ isosceles triangle is founded to be the best one. Also in trigonometric leveling, the geometric condition is founded to be optimum when the base angle of a isosceles triangle is $45^{\circ}$. In control surveying for close-range photogrammetry the optimum relation between base length($B_0$) and object distance($D_0$) can be founded to be as follow; $D_0=0.357587-0.357967B_0+0.308555B_0{^2}$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.53-59
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• 1994

The purpose of this paper is to use geo-spatial information system for effective operation and management of the underground facilities. The subject area is selected and collected all of the drawing in order to get the coordinate points(tic), which become the standard of the subject area and that can be gotten by way of practising control surveying from a existing triangulation station spatial information and attribute information are classificated from obtained data. Also, after giving the code in the attribute information to make it data-based, connecting spatial information with the attribute information to overlap layer each other, and compared the positional accuracy of the data. From the results of this study, conclusions are acquired as follows; 1) To construct the Database of the spatial and attribute data, which contain all kinds of drawings in underground structures, the reservation of registers and the details of changes and so on, results in easily referencing, compiling and analyzing the reserved data in system as their own purposes. 2) It is expected that we can effectively operate and manage the situation among the underground facilities so accurately that we may obviate the safety accidents or the damages of life and property.