Abstract:
At present, satellite surveying technology plays an important role in cadastral survey.In order to meet the requirement in the usage of positioning, especially for cadastral, Thailand is establishing a national positioning infrastructure to provide the RTK GNSS Network service with cm-level accuracy throughout the whole country. This research aims to conduct a study for evaluating efficiency of positioning outcome from conducting GNSS surveying techniques using 2 study areas, the first area is within the campus of Chulalongkorn University while the second area is in Lat Lum Kaeo District, Pathum Thani Province. Static, RTK and Virtual References System (VRS) survey techniques were used in the experiment. The first study area comprised of 3 cases studies i.e. (a) open area (b) area with moderate coverage and (c) area with dense coverage. A total of 30 points were selected for each case study. The second area conducted survey directly at survey mark of each land parcel with the amount of 34 points, Static and VRS techniques were used in this study area. Static technique was used as reference value for both study areas. It was found in the first area, if the ambiguity-fixed solutions were obtained, the RTK and VRS techniques produced the same level of horizontal accuracy at 4 centimeters. Both techniques were well performed in an open area and moderate coverage area. For the second area, the using of VRS technique would be received the horizontal accuracy at 3 centimeters.