將國際坐標框架套合於台灣GPS連續站觀測網之最適方法探討

Strategy for building a coordinate reference frame suitable for Taiwan

本研究考慮台灣及其離島地區在板塊及地理上之特殊性，提出一套適合於台灣之區域坐標框架策略，並利用國內26個GPS連續站，與鄰近國際IGS站聯算求得套合於國際坐標參考框架下之國內連續站坐標，進而求解全台367個連續站在2009年12月至2010年1月之坐標。經由不同策略之比較與分析，發現利用區域網（14個IGS站加上26個國內核心站）求得之參考站坐標與加入世界網合併之坐標比較後，發現具有公分級之系統平移量，而內部網型之差異較小。2010年前後所解算之坐標成果與ITRF2005官方公佈之坐標已有公分級之差距，其原因在於2006年提出之ITRF2005官方坐標無法反應之後因不同因素所產生之偏移或非線性行為。最後，解算全台灣367個連續站之成果，其坐標三方向之加權均方根（wrms）分別為0.7 mm，0.8 mm和2.7 mm，其成果具高度重複性。 We provide a novel strategy to build a coordinate reference frame in Taiwan using observationsfrom continuous GPS stations. Twenty six CGPS core stations in Taiwan and fourteen IGS sites werecalculated together and their coordinates were derived in different definition of reference frames.Furthermore, 367 CGPS sites coordinates were estimated in the ITRF2005 frame. The results showthat the coordinate differences between regional and international networks have systematic offsetsand the coordinates have high consistencies after removing the systematic offsets between these twonetworks. The weighted root mean square (WRMS) of GPS coordinate time series from 367 CGPSsites in Taiwan are 0.7 mm, 0.8 mm, and 2.7 mm in NS, EW, and vertical components, respectively.

We provide a novel strategy to build a coordinate reference frame in Taiwan using observationsfrom continuous GPS stations. Twenty six CGPS core stations in Taiwan and fourteen IGS sites werecalculated together and their coordinates were derived in different definition of reference frames.Furthermore, 367 CGPS sites coordinates were estimated in the ITRF2005 frame. The results showthat the coordinate differences between regional and international networks have systematic offsetsand the coordinates have high consistencies after removing the systematic offsets between these twonetworks. The weighted root mean square (WRMS) of GPS coordinate time series from 367 CGPSsites in Taiwan are 0.7 mm, 0.8 mm, and 2.7 mm in NS, EW, and vertical components, respectively.