國家級高程基準的維護有賴潮位站提供的精準、正確的潮位。台灣長期海水面觀測由於受儀器汰換更新、參考水準點遺失、地震或其他因素之影響，造成部份潮位站(Tide Gauge)的潮位零點(Tide Gauge Zero)位置變動，間接影響潮位資料的正確性。本研究使用一裝載三具大地測量等級天線之GPS浮標(GPS Buoy)，於高雄港潮位站旁進行三次各72小時連續觀測，並與潮位站觀測進行共站的比對。本研究進行港區的水面觀測與浮標姿態的計算。經過浮標與潮位資料計算後，估計高雄港潮位儀的大地起伏值為19.631 ± 2.5 mm，此結果可提供潮位站位置的變化情形，可納入未來的潮位站維護工作的一部分，以提高水面資料觀測的品質。 Accurate water level observations collected by tide gauges are essential for establishing a national vertical datum. Some of the tide gauges in Taiwan have suffered change of the tide gauge zero due to replacement of instruments, loss of tide gauge benchmark, coseismic displacement and others. As a result, the accuracy of the water level measurements from those gauges is in jeopardy. A GPS buoy with 3 geodeticgrade antennae was deployed next to the tide gauge at Port Kaohsiung for a 72-hour continuous data collection. The GPS solution was compared with tide gauge records. The geoid undulation at the tide gauge is estimated to be 19.631 � 2.5 mm with respect to the GRS80 Ellipsoid. The information can be adopted in the regular maintenance of the gauge to ensure the fidelity of its water level measurements.
