지적측량에 효율적 적용을 위한 Network-RTK 측량의 정확도 분석 연구

Network-RTK를 지적측량에 적용할 때의 측량 정확도를 분석했다.

In this study, for the efficient application to the cadastral surveying, a survey was conducted for the cadastral control points and parcel boundary points using Network-RTK method; the measured data were analyzed for the accuracy with those measured by existing TS(Total Station). Based on the analysis results, a way to utilize Network-RTK surveying in cadastral surveying efficiently in the future was presented.

The process of study is as follows: The scope of the study was separated by temporal, spatial, and content range; the research method were theoretical study of the cadastral surveying, literature review for precedent studies by existing Network-RTK, and data analysis through experimental measurement of the study area. The study area was selected from a confirmed cadastral surveying area located in Songsan-Li, Jeungpyeong-Eup, Jeungpyeong-Gun, Chungcheongbuk-Do.

The experimental observations were by Network-RTK method for the 19 cadastral control points and 187 parcel boundary points, after the network configuration that includes the study area using VRS Service provided by the National Geographic Information Institute, and the coordinate transformation through localization, and the communication with the controller by internet connection with mobile AP functions using a 3G smartphone for a seamless connection with the server.

The observation was performed during April 22-30, 2012, and the measured data were analyzed for the accuracy with those measured by existing TS to propose an effective way of cadastral surveying using Network-RTK survey in the future.

Results through the analysis of the data: In this study, in order to analyze the accuracy of Network-RTK for efficient application for cadastral surveying, the analysis was performed based on the triangulability and decision acceptable accuracy specified in Surveying & Hydrographic Survey and cadastral act and the special act on cadastral resurvey project; errors connecting each station were calculated with computed vertical and horizontal line error; RMSE was calculated and analyzed for the vertical and horizontal line error and connection error; and the variation for the error of each station was presented in a graph.

The RMSE of vertical and horizontal line error calculated for 19 cadastral control points showed X = 0.016m, Y = 0.016m, proving good performance; and RMSE of connection error calculated using vertical and horizontal line error was analyzed to be 0.023.

In addition, in the analysis for the performance determination range of the cadastral control point required by law, the Surveying & Hydrographic Survey and cadastral act was met for boundary coordinates register enforcement area 0.15m, and other areas of 0.25m, but the special act on cadastral resurvey project was not met in some stations for the criteria of ± 0.03m for cadastral control point The RMSE of vertical and horizontal line errors computed for the 187 boundary corner points were X = 0.052m, Y = 0.043m, which means a good performance; the RMSE of connection errors calculated using the vertical and horizontal line errors was 0.068m.

The RMSE of vertical and horizontal line errors calculated for 185 points after removing gross errors was calculated to be X = 0.038m, Y = 0.035m; the RMSE of connection errors calculated using the vertical and horizontal line errors was analyzed to be 0.052m. According to these analyses, total number of stations exceeding 0.1m regulated by the Surveying & Hydrographic Survey and cadastral act was a total of six, accounting for 3% of the total; their error amount was analyzed to be 1cm-4cm out of 0.10m, showing local applicability limited to area without a problem of the satellite reception for the cadastral survey for the positioning of the current parcel boundary.

However, according to the analysis based on the criterion of the special act on cadastral resurvey project 0.07m, which is more precise than the Surveying & Hydrographic Survey and cadastral act, a total 33 stations exceeded the standard of 0.07m, accounting for 18%. The amount of error was 2-7cm, showing a large difference than the analysis result by the Surveying & Hydrographic Survey and cadastral act. It is considered that this will influence greatly when calculating area according to the positioning of the parcel boundary in a cadastral resurvey project.

Therefore, according to the analysis results, it would be impossible to apply Network-RTK directly in cadastral resurvey, and be most effective to conduct a survey using TS first, and then apply Network-RTK for the purpose of performance test.