TWD97【2010】近十年成果檢測與國家框架之維護

Resurveying of the TWD97[2010] at the epoch of 2019.0 and the maintenance of a national reference frame

臺灣目前使用一九九七坐標系統2010年成果（簡稱TWD97【2010】），由於位處歐亞板塊與菲律賓海板塊交界，受到板塊間相對運動的影響，使得TWD97【2010】在精度上逐漸失去準確性。內政部國土測繪中心於107年7月1日至108年9月30日期間，共檢測2,354個一、二、三等基本控制點，並蒐集107年12月1日至108年1月31日共432個國內連續站以及6個鄰近國際連續站資料，總計535個時段，共79,419條基線。首先，在最小約制金門連續站的自由網平差計算中，剔除了3,153條基線，共計選取76,266條可用的基線觀測量，其成果在N分量、E分量及高程方向之標準誤差平均值分別為±0.001公尺、±0.002公尺及±0.005公尺。接續，將選取的可用基線進行3種不同策略且約制於ITRF94框架2019.0時刻的強制套合網平差計算，分別得到（1）重新測設TWD97【2010】坐標之成果，在N分量、E分量及高程方向之標準誤差平均值分別為±0.002公尺、±0.002公尺及±0.006公尺|（2）僅約制金門、馬祖基線的更新坐標成果，其N分量、E分量及高程方向之標準誤差平均值亦分別為±0.002公尺、±0.002公尺及±0.006公尺，以及（3）僅維護部分的TWD97【2010】坐標成果，其於N分量、E分量及高程方向之標準誤差平均值分別為±0.006公尺、±0.006公尺及±0.016公尺等檢測結果，並建議宜每10年更新維護國家坐標系統，以確保精度品質。

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. From July 2018 to Sep. 2019, the GNSS observations from 2,354 control points, 432 continuously operating reference stations (CORS) and also 6 IGS stations were collected by National Land Surveying and Mapping Center (NLSC), consisting of 535 sessions and 79,419 baselines. First, by means of the minimum constrained on KMNM site network adjustment, 3,153 baselines were eliminated and 79,419 were used. The average accuracy are ±1 mm, ±2 mm and ±5 mm in the north, east and height component, respectively. Second, 3 results of full constrained network adjustment under the ITRF94 at the epoch of 2019.0 were obtained: (1) the average accuracy are ±2 mm, ±2 mm and ±6 mm in the north, east and height component, respectively, in the renewal TWD97[2010] network adjustment| (2) the average accuracy are also ±2 mm, ±2 mm and ±6 mm in the north, east and height component, respectively, in the network adjustment which was just only constrained to the KMNM-MUZM baseline| (2) the average accuracy are ±6 mm, ±6 mm and ±16 mm in the north, east and height component, respectively, in the partly renewal TWD97[2010] network adjustment. 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 Taiwan.