• Spatial Information Research
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• v.15 no.2
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• pp.123-134
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• 2007

The building boundary should be registered in the cadastral map for the protection of property using the expansion of the registration items in the cadastral record and the construction of 3D-cadastral information system. In this study, the efficiency of registering the building boundary was suggested by non-target TS survey through the comparison between target TS and non-target TS survey about an accuracy and efficiency. At the result of this research, the RMSE of target TS and non-target TS survey is the X; ${\pm}0.056m$ and Y; ${\pm}0.043m$. Therefore, non-target TS survey shows the high accuracy. Also, the non-target TS survey is more efficient cost on time and personnel than target TS.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1791-1796
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• 2005

Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground between two pits named 'entrance' and 'destination', respectively. Usually a simple composition, such as 'a fiducial target at the entrance+a total station (TS)+a target on the machine', is used to confirm the planned course. However, unavoidable curved sections are present in small-sized pipe lines, which are laid after implementation of a road system, for public works such as waterworks, sewer, electrical power, and gas and communication networks. Therefore, if the planned course has a curved section, it is difficult to survey the course with the abovementioned simple composition. This difficulty could be solved by using the multiple total stations (MTS), which attaches the cross type linear LED target to oneself. The MTS are disposed to where each TS can detect the LED target at the other TS or the base point or the machine. And the accurate relative positions between each MTS and target are calculated from measured data. This research proposes the relative and absolute coordinate calculation algorithm by using three MTS to measure a curved course with 20m curvature at 30m maximum distance, and verifies the algorithm experimentally.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.91-97
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• 2014

In this research, we would try to evaluate the applicability in cadastral resurvey surveying by analysing the accuracy of building boundary surveying using the reflective sheet total station surveying. When we analyse it, we refer the reflective sheet which can supplement not only the difficulties of total station surveying and GPS surveying caused by the diversity of the building structure but also the errors of non prism total station caused by material of the object. Each reflected angles $90^{\circ}$ and $60^{\circ}$, $30^{\circ}$ of RMSE results were analyzed by RMSE between 1.2mm~2.8mm and 2.2mm~4.0mm, 2.5mm~4.4mm for each distance. The result of X RMSE was analyzed to be 0.0043m in a boundary surveying for existing building between prism surveying and reflective sheet surveying, and also Y RMSE was 0.038m. The source of error is estimated that the body of the prism can not be exactly attached to the edge of a building. Therefore, it will be very helpful to use a reflective sheet surveying with a prism in both the limit of collimation and error reductions as a building boundary measurement in cadastral resurvey surveying.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.931-936
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• 2008

Surveying by using terrestrial LiDAR(Light Detection And Ranging) is more rapid than by using total station which enables tunnel section profile surveying to be done in suitable time and minimize centerline error, occurrence of overcut and undercut. Therefore, utilization of terrestrial LiDAR has increased more and more in section profile survey and measurement field Moreover, studies of terrestrial LiDAR for accurate and efficient utilization is now ongoing vigorously. Average end area formula, which was generally used to calculate overcut and undercut, was compared with existing methods such as total station survey and photogrammetry. However, there are no criteria of spacing distance for calculating overcut and undercut through terrestrial LiDAR surveying which can acquire 3D information of whole tunnel. This research performed reverse engineering to decide optimal spacing distance when surveying tunnel section profile by comparing whole tunnel volume and tunnel volume in difference spacing distance. This result was utilized to produce CAD drawing for the test tunnel site where there is no design drawings. In addition to this, efficiency of LiDAR and accuracy of CAD drawing was compared with targetless total station surveying of tunnel section profile. Finally, error analysis of target coordinate's accuracy and incidence angle was done in order to verify the accuracy of terrestrial LiDAR technology.

• Spatial Information Research
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• v.21 no.1
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• pp.45-52
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• 2013

Recently 3D surveying is recommended to manage underground facilities systematically before refilling of site operation. As the demand of realtime localization increases, cost reduction and consistent data construction which are realizable by using one man surveying method with unmanned target, are necessary for constructing DB of all sorts of the underground facilities with more speediness and correctness. This study sets a goal to develop a new type of surveying target which allows realtime localization to be performed by one man, through making an optimum reflector(triangle, quadrangle, and semispherical shape) by using the retro-reflection principle of optical prism which is being used for surveying currently. The new surveying target makes realtime surveying possible. To check reliability of its data, the accuracy is compared with surveying coordination of total station for each type in a quantitative method. In the result, the usefulness of the reflector for Underground Facilities localization is proved. Thus the foundation for underground DB construction conducted by one man is established for acquisition of 3D location information in more efficient way through using unmanned target.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.592-597
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• 2020

Currently, river survey data is mainly performed by acquiring longitudinal and cross-sectional data of rivers using total stations or the GNSS(Global Navigation Satellite System). There is not much research that addresses the use of LiDAR(Light Detection and Ranging)systems for surveying rivers. This study evaluates the applicability of using LiDAR data for surveying rivers The Ministry of Land, Infrastructure and Transport recently launched a drone-based river fluctuation survey. Pilot survey projects were conducted in major rivers nationwide. Studies related to river surveying were performed using the ground LiDAR(Light Detection And Ranging)system.Accuracy was ensured by extracting the linearity of the object and comparing it with the total station survey performance. Data on trees and other features were extracted to generate three-dimensional geospatial information for the point-cloud data on the ground.Deviations were 0.008~0.048m. and compared with the results of surveying GNSS and the use of drone LiDAR data. Drone LiDAR provided accurate three-dimensional spatial information on the entire target area. It was able to reduce the shaded area caused by the lack of surveying results of the target area. Analyses such as those of area and slope of the target sites are possible. Uses of drones may therefore be anticipated for terrain analyses in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.553-562
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• 2017

GPS (Global Positioning System) receiver among various sensors mounted on UAV (Unmanned Aerial Vehicle) helps to perform various functions such as hovering flight and waypoint flight based on GPS signals. GPS receiver can be used in an environment where GPS signals are smoothly received. However, recently, the use of UAV has been diversifying into various fields such as facility monitoring, delivery service and leisure as UAV's application field has been expended. For this reason, GPS signals may be interrupted by UAV's flight in a shadow area where the GPS signal is limited. Multipath can also include various noises in the signal, while flying in dense areas such as high-rise buildings. In this study, we used analytical photogrammetry and auto tracking total station technique for 3D positioning of UAV. The analytical photogrammetry is based on the bundle adjustment using the collinearity equations, which is the geometric principle of the center projection. The auto tracking total station technique is based on the principle of tracking the 360 degree prism target in units of seconds or less. In both techniques, the target used for positioning the UAV is mounted on top of the UAV and there is a geometric separation in the x, y and z directions between the targets. Data were acquired at different speeds of 0.86m/s, 1.5m/s and 2.4m/s to verify the flight speed of the UAV. Accuracy was evaluated by geometric separation of the target. As a result, there was an error from 1mm to 12.9cm in the x and y directions of the UAV flight. In the z direction with relatively small movement, approximately 7cm error occurred regardless of the flight speed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.1
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• pp.35-41
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• 2020

3D laser scanners are an effective way to quickly acquire a large amount of data about an object. Recently, it is used in various fields such as surveying, displacement measurement, 3D data generation of objects, construction of indoor spatial information, and BIM(Building Information Model). In order to utilize the point cloud data acquired through the 3D laser scanner, it is necessary to make the data acquired from many stations through a matching process into one data with a unified coordinate system. However, analytical researches on the accuracy of point cloud data according to the registration method are insufficient. In this study, we tried to analyze the accuracy of registration method of point cloud data acquired through 3D laser scanner. The point cloud data of the study area was acquired by 3D laser scanner, the point cloud data was registered by the ICP(Iterative Closest Point) method and the shape registration method through the data processing, and the accuracy was analyzed by comparing with the total station survey results. As a result of the accuracy evaluation, the ICP and the shape registration method showed 0.002m~0.005m and 0.002m~0.009m difference with the total station performance, respectively, and each registration method showed a deviation of less than 0.01m. Each registration method showed less than 0.01m of variation in the experimental results, which satisfies the 1: 1,000 digital accuracy and it is suggested that the registration of point cloud data using ICP and shape matching can be utilized for constructing spatial information. In the future, matching of point cloud data by shape registration method will contribute to productivity improvement by reducing target installation in the process of building spatial information using 3D laser scanner.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.520-525
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• 2019

Mines are an important infrastructure for securing resources, but safety problems can arise in the course of operation. Recently, the mining process is very complicated due to the large scale and mechanization. Therefore, it is necessary to construct accurate geospatial information on mine for systematic and safe mine operation. The geospatial information construction using the existing total station has a disadvantage that a lot of work time is required because the target must be collimated and measured. In this study, the data of the mines were acquired with the total station and the 3D laser scanner, and the mine spatial information was constructed by using the shape based registration method. By using the static scanner data of some area applying the reference point surveying result of the total station, it was possible to construct the accurate result on the wide area acquired by the mobile scanner effectively. Also, the accuracy of the constructed geospatial information was evaluated and the deviation of mean 0.083m was shown. Point cloud products constructed through the research can contribute to the efficiency improvement of mine management by enabling quantitative analysis such as visualization of mine shape, distance, area and slope, and automation of drawing creation for cross section shape.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.79-87
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• 2016

As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.