建置線上精密單點定位服務

Establish Online Precision Point Positioning Service

施亘昶(Hsuan-Chang Shih)；葉大綱(Ta-Kang Yeh)；鍾郁儀(Yu-I Chung)；呂建興(Jian-Sing Lyu)

全球導航衛星系統 ； 精密單點定位 ； 線上定位服務 ； Global Navigation Satellite System ； Online Positioning Service ； Precise Point Positioning

國土測繪與空間資訊

12卷2期（2024 / 07 / 01）

163 - 188

繁體中文;英文

近年來，精密單點定位（Precise Point Positioning, PPP）已廣泛運用在GNSS的靜態和動態定位，是一種利用高精度的衛星軌道和時鐘誤差產品，透過模型改正或參數估計的方法去精細考慮與衛星端、信號傳播路徑及接收儀端有關之誤差對定位的影響，以實現公分級定位精度的一種方法。PPP無需設置地面主站進行差分定位，僅利用一可接收多個導航衛星系統的接收儀，就可獲得在國際地球參考框架下的定位坐標；另外，PPP解算採用非差分觀測模型，過程中保留了接收儀時鐘誤差、對流層和電離層延遲等參數，有利於水汽反演和電離層監測、低軌衛星定軌等大氣科學與地球動力學的應用。隨著各國的導航衛星系統接近完成建置、PPP相關技術的提升，以及國家政策的發展需要，已有不少國家投入了建置線上精密單點定位服務，透過網頁方式讓使用者將衛星觀測資料上傳，系統立即以自動化方式進行解算，並以電子郵件通知使用者成果放置位置，此線上定位服務可大幅縮短使用者之操作時間。以政府的角度而言，提供線上定位服務可使衛星觀測資料的解算流程及定位成果的坐標系統等皆能符合一致性規範。本研究開發了基於Bernese和RTKLIB定位軟體的PPP自動化解算流程，並利用不同作業環境下收集的衛星觀測資料進行驗證，一般情況下可提供平面方向小於5公分和高程方向小於10公分的定位精度。目前本系統已開放對外測試，並將根據使用者的意見回饋進行修正，網址為https://ppponline.ntpu.edu.tw/。

In recent years, Precise Point Positioning (PPP) has been widely used in GNSS static and dynamic positioning. This technique utilizes high-precision satellite orbits and clock error products to achieve cm-level positioning. PPP eliminates the need for a ground control station in differential positioning and provides the ITRF-based coordinates through the use of a GNSS receiver. PPP employs a non-differential observation model, retaining parameters such as receiver clock error, tropospheric, and ionospheric delays. This facilitates its applications in atmospheric and geodynamic science, including the water vapor retrieval, ionospheric monitoring, and low-orbit satellite orbit determination. With the development of GNSS and PPP related technologies, investing in establishing online PPP services has become a future trend. The service allows users to upload satellite observation data through web pages, perform automatic calculations and notify users of the results via email. This online positioning service greatly reduces the user's operation time. From a government perspective, providing online positioning services can ensure the consistency of satellite observation calculations and positioning result coordinate systems and compliance with standardized procedures. This study developed the automated PPP solutions based on the Bernese and RTKLIB positioning software, and used satellite observation data collected in different operating environments to verify the accuracy of positioning results. In general, it can provide positioning accuracy of less than 5 cm in the plane direction and less than 10 cm in the elevation direction. This system is currently open for testing and will be modified based on user's feedback. The website is https://ppponline.ntpu.edu.tw/.