無差分GPS精密單點定位技術(PPP)之動態定位精度：以輔助航空攝影測量空中三角測量為例

The Kinematic Positioning Accuracy of Using GPS Precise Point Positioning (PPP) Technique: a case study in supported Aerial Triangulation

陳國華(Kwo-Hwa Chen) ； 劉新達(Hsin-Ta Liu) ； 黃金土(Jin-Tu Huang)

《航測及遙測學刊》 14卷1期 (2009/03) Pp. 65-81

https://doi.org/10.6574/JPRS.2009.14(1).6

摘要

在GPS動態定位中，由於每個移動位置的觀測量較少，為了提昇其定位精度並消除大部分定位誤差的影響，傳統上，常採取差分定位(Differential GPS, DGPS)方式進行動態位置之解算。然而，DGPS易受限於基線長度之影響使得其動態定位隨著基線之增長而亦趨困難。近年來，精密單點定位(Precise Point Positioning, PPP)技術已廣泛應用於GPS動態定位之中，本文嘗試藉由比較傳統網形差分動態定位與PPP動態定位成果之差異，分析PPP動態定位可達之精度。本文選擇2007年台北市南區5個航空攝影測量空中三角測量作業天之航機GPS蒐集資料以及地面5個取樣間隔為1 sec的GPS基準站觀測資料，分別以DGPS網形差分與PPP方式進行解算，除了比較兩者像片投影中心定位成果的坐標差異外，亦與傳統航空攝影測量空中三角測量平差結果進行比較。由分析之結果可以得知，在使用43個地面控制點以及基線長度不大於50 km的情況下，PPP與DGPS動態定位成果的坐標差異量，N、E、H方向標準偏差(Standard Deviation, SD)的平均值分別為 ± 0.012 m、± 0.018m以及 ± 0.045 m，顯示兩者成果趨於一致。並將PPP解算的像片投影中心視為附加觀測量套合至航空攝影測量空中三角測量平差計算之中，得知97%觀測量的後驗精度在N、E、H方向分別為 ± 0.068 m、± 0.064 m 以及± 0.059 m。

關鍵字

精密單點定位 ； 全球定位系統 ； 空中三角測量

並列摘要

Traditionally, because the lack of observations of each surveyed position in GPS kinematic positioning assignments, the differential GPS (DGPS) technique has been frequently used to reduce the most of the GPS positioning errors and then to improve that of accuracy of the kinematic positioning results. However, in the DGPS strategy, the longer the observed-baselines were measured, the more difficult the observations were resolved. Recently, Precise Point Positioning (PPP) has been applied in the various estimations of GPS kinematic positioning. In this paper, the kinematic positioning accuracy of PPP was analyzed by comparing with those of the estimated results from DGPS and PPP, respectively. The airborne GPS observations from 5-day aerial triangulation in the south area of Taipei and the 5 GPS permanent-site observations with 1 second sample rate were estimated by DGPS and PPP in this paper, respectively. This paper not only showed that comparisons of kinematic positioning results from both of DGPS and PPP but also compared the estimations of principle point position by GPS and traditional aerial triangulation methods. From the analyzed results, under the state of using 43 ground- control-points and all of the baseline lengths were not more than 50 km, the average standard deviations of difference of the kinematic positioning position from PPP and DGPS were ± 0.012 m in N direction, ± 0.018 m in E direction, and ± 0.045 m in H direction, respectively, showing that the PPP results were consonant with that of DGPS. Furthermore, the posterior accuracy were reached to ± 0.068 m, ± 0.064 m, and ± 0.059 m in N, E, and H direction in 97 % adjusted observations, respectively.

並列關鍵字

Precise Point Positioning ； Global Positioning System ； Aerial Triangulation