e-GNSS定位作業規範適用性之探討

Research on the Applicability of Operational Specification on e-GNSS Positioning

本研究主要探討電子化全球衛星導航定位系統（e-Global Navigation Satellite System, e-GNSS）定位系統應用於加密控制及圖根測量之作業規範中的適切性。其中包括：衛星定位幾何精度因子（Position-Dilution of Precision, PDOP）值之限制、觀測時間資料筆數、重複觀測之間隔時間等規定的適用性。以e-GNSS 6小時靜態觀測之成果，透過虛擬基準站即時動態定位技術（Virtual Base Station-Real Time Kinematic, VBS-RTK）動態後處理方式，產製單星系及多星系解算坐標成果，並將觀測資料分組，據以分析評估現行作業規範中有關外業觀測作業規定之適用性。其成果顯示e-GNSS定位系統已提升為多星系統之後，由於定位系統能力增強、可視衛星數大幅提升，使得平均PDOP值由2.7降為1.5，可大幅提升其定位精度及工作效率。此外，本研究以接收時間3分鐘（180筆）觀測資料以及重複觀測之間不間隔之作業方式與現行規定接收20分鐘（1,200筆）觀測資料及重複觀測間隔1小時以上之作業方式相較，其內部精度與外部精度相當，其解算成功之成果，仍能符合使用者之精度要求。

This study mainly discusses the applicability of the e-Global Navigation Satellite System (e-GNSS) in the operational specifications of densified control and skeleton surveying. The applicability includes the value limits of the PDOP (Position Dilution of Precision), the data numbers of observations time, and the interval time between repeated observations. Based on the results of 6-hour static observation of e-GNSS, Virtual Base Station-Real Time Kinematic (VBS-RTK) dynamic post-processing method was used to produce coordinate results from single-GNSS and multi-GNSS solutions. The observations were grouped and analyzed in order to evaluate the applicability of the current operational specifications regarding the field observations. The results show that the average PDOP value reduced from 2.7 to 1.5 by upgrading the e-GNSS positioning system to a multi-satellite system, due to the enhanced positioning system capability and the significant increase in the number of visible satellites. The positioning accuracy and work efficiency have substantially improved. In addition, the results by the 3-minute period observations (180 epochs) with no interval between repeated observations were compared with the results by the current operational specification which is the 20-minute period observations (1200 epochs) with more than 1 hour repeated observation interval. The internal precisions are equivalent to the external precisions in all comparisons, and the results from the success solutions can still meet the user’s accuracy requirements.