臺灣衛星連續站坐標時間序列分析與平面坐標基準適用期之探討

A Study on the Coordinate Time Series Analyzing of CORS and Applications of the Horizontal Coordinate System in Taiwan

臺灣位於歐亞板塊與菲律賓海板塊交界處，為板塊運動活躍地區，由於板塊間的相對運動，使得臺灣目前使用的一九九七坐標系統2010年成果（簡稱TWD97[2010]），在精度上逐漸失去其準確性。近年來，臺灣地區逐步利用衛星觀測資料建立國家坐標系統，藉以維護其精度及延長適用期。本研究進行357個GPS衛星連續觀測站每日坐標的時間序列分析，以瞭解臺灣地區衛星連續觀測站的坐標時間序列擬合精度，成果顯示臺灣地區衛星連續觀測站在水平方向的時間序列擬合精度（95%信賴區間）為±12.0 mm，並利用坐標時間序列分析得到的GPS衛星連續觀測站速度推得臺灣地區的地表應變速率，以搭配測量作業規範檢視臺灣各地區TWD97[2010]成果的應用精度，提出各行政區適用的坐標系統建議，以提升測繪作業精度。依據本研究結果顯示，臺灣多數地區的TWD97[2010]公告成果在使用約10年之後，即無法符合高精度測量作業的需求，特別在西南部以及東部地區即有更新坐標系統之必要。

Taiwan is located at the plate boundary between the Eurasian plate and Philippine Sea plate. Due to the relative motions between the two plates, the accuracy of the current static geodetic datum, TWD97[2010] are decreasing with time. In recent years, Taiwan has gradually established the national geodetic datum using the GPS data for maintaining the internal accuracy. By means of analyzing the coordinate time series on 357 continuously operating reference stations (CORS) data in Taiwan, the results showed the accuracy average is ±12 mm (under 95% confidence interval) in the horizontal component. In addition, based on the strain rate estimation from the CORS data, this study provided the suggestions on choosing the optimum coordinate system to maintain the accuracy of the field surveying in Taiwan. As the results, it showed that the coordinate system could only be used within 10 years for the requirements of the field surveying at a high level in most area of Taiwan. Especially in the southwest and the eastern regions of Taiwan, the coordinate system should be update in time.