傳統單一參考站的即時動態定位(Real Time Kinematic, RTK)受電離層、對流層等系統誤差影響，使得移動站只能在參考站大約10公里範圍內才有可能達到公分級的定位精度；雖然中距離(< 50公里)即時動態定位演算技術已經證明可以達到公分級的定位精度，但隨著基線距離的增長所需的整數週波未定值求解收斂時間也就越久，主要原因是二次差無法有效地消除觀測量中的系統誤差影響量；因此若能利用區域內多個GPS固定站的資料即時地對區域性的系統誤差模式化，從而得到區域內觀測數據的系統誤差影響量，這樣可大大增加RTK之可用範圍，同時提昇系統的效率及可靠度。
　
　　本文設計出一種演算法，利用卡曼濾波解算出參考站網的週波未定值，從而建立區域內即時性的系統誤差模式，利用此系統誤差模式以內插的方式根據移動站的概略坐標產生虛擬參考站(Virtual Reference Station, VRS)，最後此虛擬參考站與移動站進行標準的短基線RTK定位得到移動站之點位坐標。文中以兩組實驗資料(參考站間距為65~80公里)驗証演算法的可行性，及分析其定位精度及效率；成果顯示，本文所提出之多參考站即時動態定位演算法之平面定位精度在5公分以內，高程定位精度在15公分以內，而即時動態定位過程均能在數筆(1~4筆)資料內完成搜尋整數週波未定值並解算出移動站坐標。

　　Conventional single-reference station Real-Time Kinematic (RTK) positioning is affected by systematic errors such as ionospheric and tropospheric errors, so that rover must be located within about 10 Km of the reference station in order to acquire centimeter-level accuracy. Medium-range (<50 Km) RTK have been proven feasible and can be used for high-precision applications; however, the time for resolving integer ambiguity becomes longer as baseline length increases. This is due to the fact that systematic errors cannot be eliminated effectively by double-differencing. Recently, network approaches have been proposed to overcome the limitation of single-reference RTK. With the use of reference station network, real-time systematic error modeling can be achieved and systematic biases within the network are derived from the model. In this way, the effective coverage area of RTK is increased; efficiency and reliability of the RTK system are also improved.

　　This study proposes a network-based RTK algorithm in which Kalman filter is implemented for resolving ambiguities within the network. Then real-time systematic error model is built using information from the network, and location-dependent systematic biases are obtained via interpolation. These interpolated biases are sequently used in the generation of observations of a Virtual Reference Station(VRS) which simulates a local reference station near the rover. At last standard short-baseline RTK is performed between the VRS and the rover. Two groups of test data (reference stations about 65~80 Km apart) are used to examine the feasibility of the algorithm, positioning accuracy and efficiency are also analyzed. Test results show that the horizontal positioning accuracy of the proposed network-based RTK algorithm is within 5 cm, and within 15 cm for the height component. For the efficiency of the RTK positioning process, all ambiguities are revolved within 4 epochs.

摘要-----------------------------------------------I
ABSTRACT------------------------------------------II
誌謝---------------------------------------------III
目錄----------------------------------------------IV
表目錄--------------------------------------------VI
圖目錄-------------------------------------------VII

第一章 緒論----------------------------------------1
　　§ 1-1 前言-------------------------------------1
　　§ 1-2 文獻回顧---------------------------------2
　　§ 1-3 研究方法---------------------------------4

第二章 全球定位系統即時動態定位--------------------5
　　§ 2-1 GPS定位原理------------------------------5
　　§ 2-2 GPS觀測量--------------------------------5
　　　　§ 2-2-1 虛擬距離觀測量---------------------6
　　　　§ 2-2-2 載波相位觀測量---------------------7
　　§ 2-3 觀測量誤差來源---------------------------8
　　§ 2-4 相對定位--------------------------------12
　　　　§ 2-4-1 一次差分--------------------------13
　　　　§ 2-4-2 二次差分--------------------------14
　　§ 2-5 雙頻載波相位觀測量之線性組合------------15
　　§ 2-6 單一參考站即時動態定位------------------17
　　§ 2-7 多參考站即時動態定位--------------------18

第三章 多參考站即時動態定位演算法設計-------------21
　　§ 3-1 多參考站即時週波未定值解算--------------22
　　　　§ 3-1-1 電離層與對流層之影響--------------23
　　　　§ 3-1-2 卡曼濾波估計----------------------26
　　　　§ 3-1-3 LAMBDA 低相關化搜尋固定解---------30
　　§ 3-2 產生虛擬參考站的觀測量------------------38
　　　　§ 3-2-1 系統誤差改正量內插----------------38
　　　　§ 3-2-2 組成虛擬參考站觀測量--------------40
　　§ 3-3 虛擬參考站與移動站短基線RTK定位---------42

第四章 實驗與成果分析-----------------------------45
　　§ 4-1 實驗資料--------------------------------45
　　§ 4-2 系統誤差內插成果分析--------------------48
　　§ 4-3 零基線定位成果精度分析------------------56
　　§ 4-4 虛擬參考站與移動站定位成果精度分析------60

第五章 結論與建議---------------------------------65

參考文獻------------------------------------------67

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