三維即時坐標轉換輔助VBS-RTK定位技術獲得法定坐標系統測量成果之研究

A Study on VBS-RTK Determining Legal Coordinatesby 3D Real-time Coordinate Transformation

虛擬基準站即時動態定位技術（VirtualBaseStation-RealTimeKinematic,VBS-RTK）可於短時間內獲得高精度定位成果，但其坐標非法定坐標系統。內政部國土測繪中心e-GNSS即時動態定位系統（簡稱e-GNSS系統）採用VBS-RTK定位技術，提供使用者即時且高精度之定位服務，測量成果坐標系統為e-GNSS系統2013年坐標（簡稱e-GNSS[2013]）。本研究利用e-GNSS系統與RTCM3.1資料傳輸技術，建立三維即時坐標轉換輔助VBS-RTK定位技術獲得法定坐標系統測量成果之最佳轉換模型，解決VBS-RTK測量成果與法定坐標系統不同之情況，讓使用者在測量時可即時獲得法定坐標系統成果，轉換成果平面精度優於5公分，高程精度優於10公分，符合一般工程測量、中、小比例尺製圖及管測測量等工作精度需求，可節省測量工作成本與時間。為研究最佳建置模型與內插計算方法，本研究分別以諧和面法（HarmonicSurface）、克利金法（Kriging）及距離反比權重法（Inversedistanceweighted）等3種方法組成殘差網格修正模型，並以雙線性法（bi-linear）、雙二次曲線法（bi-quadratic）及雙雲形曲線法（bi-spline）等3種內插計算方法對模型精度進行驗證，驗證結果克利金法建置之殘差網格修正模型精度最佳，雙線性法內插計算成果優於雙二次曲線法與雙雲形曲線法。 VBS-RTK is an efficient technique to determine high precision coordinates within a short period of time, but the coordinates are not based on legal coordinate systems. The e-GNSS real-time kinematic positioning system of the National Land Surveying and Mapping Center was based on VBS-RTK technique to provide high precision positioning service, the coordinate system named e-GNSS[2013]. In this study, e-GNSS real-time kinematic positioning system and RTCM3.1 data transfer technique is used to solve problems about that VBS-RTK could not determine the legal coordinates immediately by establishing a 3D real-time coordinate transformation model, the transformed accuracy was better than 5 cm for horizontal coordinates, and better than 10 cm for ellipsoid and orthometric height individually. The majority of surveying assignments can enjoy the benefit and convenience of this service. This study chose Harmonic surface, Kriging and Inverse distance weighted gridding algorithm to establish transformation models, and bi-linear, bi-quadratic and bi-spline interpolation algorithm to analyze external accuracy of transformation results are used to find out which gridding and interpolation algorithm is the best for establishing transformation model. The results of this study showed that the best gridding algorithm was Kriging, the best interpolation algorithm was bi-linear.

VBS-RTK is an efficient technique to determine high precision coordinates within a short period of time, but the coordinates are not based on legal coordinate systems. The e-GNSS real-time kinematic positioning system of the National Land Surveying and Mapping Center was based on VBS-RTK technique to provide high precision positioning service, the coordinate system named e-GNSS[2013]. In this study, e-GNSS real-time kinematic positioning system and RTCM3.1 data transfer technique is used to solve problems about that VBS-RTK could not determine the legal coordinates immediately by establishing a 3D real-time coordinate transformation model, the transformed accuracy was better than 5 cm for horizontal coordinates, and better than 10 cm for ellipsoid and orthometric height individually. The majority of surveying assignments can enjoy the benefit and convenience of this service. This study chose Harmonic surface, Kriging and Inverse distance weighted gridding algorithm to establish transformation models, and bi-linear, bi-quadratic and bi-spline interpolation algorithm to analyze external accuracy of transformation results are used to find out which gridding and interpolation algorithm is the best for establishing transformation model. The results of this study showed that the best gridding algorithm was Kriging, the best interpolation algorithm was bi-linear.