建立GPS衛星測量接收儀檢校制度及設置檢校場

Abstract

GPS天線相位中心偏移量及相位中心變化量是影響GPS量測精度的關鍵因素，尤其當GPS觀測混合著不同型式的天線及接收儀進行時，相位中心偏移量與變化量在GPS資料處理時，是一定要加以考慮修正的，因為其造成測站間相對高程偏差可達10cm；即使在使用相同型式天線仍會有0.015ppm之尺度誤差。 在水平位置精度方面，雖較高程精度為高，但為求GPS量測所得基線長可以獲得更高之精度及可靠度，相關之檢定則採用工業技術研究院量測技術發展中心精度量衡國家標準實驗室驗證Mekometer ME5000精密測距儀量測基線網中之短距離基線。ME5000測距系統能達到準確度技術規範0.2mm+0.2ppm之水準。 本計畫則分別建立相位中心率定場及短距離基線場，進行GPS接收儀測量成果之檢定，以提昇GPS定位之精度。

The GPS antenna phase center offset and variation are the key factor that influence the positioning of the GPS surveying. When the GPS surveying is executed using different factory trademarks or different types of antenna, the offsets and the variations may have 10cm difference in height. Even for using the same type antennas, the offset and the variation still have 0.015ppm in scale error. Therefore, to determine the GPS antenna phase center offset and variation are necessary. Besides, for promoting the precision of the horizontal position, to calibrate the length of a baseline using ME5000 is useful. Because the precision of the ME5000 can reach 0.2mm+0.2ppm, using ME5000 to calibrate the length of a baseline is suitable. In this project, a net for calibrate the GPS antenna phase center offset and variation and a baseline field for calibrate the length of a baseline measuring using GPS surveying with ME5000 are set up. Consequently, a higher GPS positioning precision can be obtained.