虛擬參考站技術於GPS定位上之應用研究

GPS Positioning by Virtual Reference Stations Method

崔國強(Gwo-Chyang Tsuei) ； 湯俊發(Chun-Fa Tang)

《宜蘭技術學報》 9期工學專輯 (2002/12) Pp. 275-282

https://doi.org/10.6179/nit.bce.2002.09.33

摘要

GPS高精度即時動態定位（Real Time Kinematic, RTK）可謂現行最普遍使用之衛星測量技術，但因受限於電離層與對流層效應在原始觀測量上所產生之系統誤差影響。使得實用上移動站與參考站間之距離不遠（小於10公里）時，方可有效定位。雖然可經由建立高密度參考站網以提供全面性之RTK服務，但極不符合經濟效益，較可行之方案為採用虛擬參考站技術，使參考站之系統誤差得到較好的模組，以降低或消除該系統誤差之影響，進而可增加移動站與參考站間之有效施測範圍，且減少OTF解算之啟動時間與增加系統之可靠度。本文以虛擬參考站技術，分析探討其於定位上之各種效益與成果比較。運用RTK及VRS技術在短基線網中，其定位結果頗為一致且採用不同星曆其結果亦相差甚微，緯度之最大差值為0.00022秒（約為0.66公分），經度之最大差值為0.00017 秒（約為0.51公分）。可知GPS在短距離RTK定位上已經相當精確。在中、長距離基線網中，以超快速星曆靜態解與由VRS所解算之結果相比較，當VRS產生在移動站處時，其經度差值為0.00097秒（約為2.91公分），緯度差值為0.00017 秒（約為0.51公分）。若將VRS產生在移動站5公里處與VRS產生在移動站處之計算結果相較，其經度差值為0.00006秒（約為0.18公分），緯度差值為0.00002 秒（約為0.06公分）。可知即便將VRS點延伸至距移動站5公里處以解算移動站之坐標時，其結果仍然相當精確。可知以VRS技術應用在中、長距離時，亦能即時的精確定位。

關鍵字

即時動態定位 ； 虛擬參考站

並列摘要

High accuracy real-time kinematic positioning with GPS is today's most widely used surveying techniques. But, its use is restricted by the effects of the ionosphere and troposphere which create systematic errors in the raw data. In practice, these mean that the distance between a rover receiver and its reference station has to be quite short ( ＜ 10 Km) in order to work efficiently. Although of sufficient density for reference stations networks to provide complete coverage for RTK, but that doesn't has cost-benefit, the systematic errors in the reference station data are either reduced, or eliminated. it also increases the reliability of the system and reduces the OTF initialization time.This paper use Virtual Reference Stations Method, to analyze the results and performance for GPS positioning. And made comparisons between results. Using RTK and VRS Method to short baseline. The positioning accuracies are almost the same. And using different ephemeris data into the project, the results are also nearly. Latitude difference value is 0.00022” (about 0.66 cm): Longitude difference value is 0.00017” (about 0.51 cm) .For long baseline, use IGS Ultra-Rapid Products ephemeris into VRS to analyze and compare. When VRS generate near by the rover, Latitude difference value is 0.00017” (about 0.51 cm): Longitude difference value is 0.00097” (about 2.91 cm). Even if VRS generation extend to 5 Km from rover, Latitude difference value is 0.00002” (about 0.06 cm); Longitude difference value is 0.00006” (about 0.18 cm). According to the results, we known that using VRS Method to apply into short、long baseline, also can be positioning accurately on real-time.

並列關鍵字

Real Time Kinematic ； Virtual Reference Stations