GPS/BDS雙星單頻精密單點定位之多時刻演算法

Abstract

隨著物聯網（Internet of Things, IoT）的快速佈局與蓬勃發展，未來IoT的各式應用中，將對衛星定位產生更高的依賴度，因此僅使用單系統並無法提供更佳的導航服務，本研究整合全球定位系統(Global Positioning System, GPS)與北斗衛星導航系統(Beidou Satellite Navigation System, BDS)進行單頻精密單點定位，並希望達到即時定位之目的。 為了完善地整合GPS與BDS，本研究使用Helmert方差分量估計調整兩系統的系統權重以求達到最佳估測。觀測量誤差部分，使用IGS提供的Ultra-Rapid精密星曆修正GPS的衛星軌道誤差與衛星鐘差，使用IGS提供的廣播星曆修正BDS的衛星軌道誤差與衛星鐘差，使用IGS提供的全球電離層地圖修正電離層延遲誤差，對流層延遲誤差則是使用UNB3m模型進行修正。 定位演算法部分，本研究提出適應性多時刻演算法的概念，並進行了定位精度提升效率與程式計算時間的分析，其實驗結果與單時刻演算法進行比較後發現，在合理的時間成本增加下，適應性多時刻演算法確實能夠大幅地提升靜態單點定位精度。

With the rapid and vigorous development of Internet of Things (IoT), many kinds of IoT applications will more highly depend on satellite positioning system in the future. Merely single system cannot provide better navigation service, so we integrate Global Positioning System (GPS) with Beidou Satellite Navigation System (BDS) for single frequency precise point positioning, and hope to achieve the purpose of real-time positioning. To integrate GPS with BDS well, we use Helmert variance component estimation to adjust the weighting of GPS and BDS. About the elimination of measurement errors, we use the Ultra-Rapid ephemeris provided by International GNSS Service (IGS) for correcting satellite orbit errors and satellite clock errors of GPS. IGS also provide broadcast ephemeris for BDS and was used here for correcting satellite orbit errors and satellite clock errors. The Global Ionospheric Map provided by IGS was adopted for correcting ionospheric delay errors. Moreover, UNB3m model was chosen for correcting tropospheric delay errors. On the positioning algorithm, the concept of adaptive multi-epoch algorithm was proposed. The positioning accuracy and the operation time were investigated. Comparing with the single-epoch algorithm, the experimental results show that adaptive multi-epoch algorithm can substantially enhance the precision of static positioning with reasonable cost of the operation time.