隨著全球導航衛星系統(global navigation satellite systems, GNSS)應用層面廣泛，改善導航定位因電離層延遲所產生的誤差愈顯重要。電離層為距離地表50公里至1000公里高度含有電漿帶電粒子的近地表太空環境，其電漿密度影響電波傳遞，造成GNSS電波訊號延遲。除了電離層電漿本身，電離層的不規則電漿結構，如電漿泡因對電波訊號產生散射，進而影響接收訊號強度。電漿泡的特徵為電漿空乏區，主要於黃昏至夜間生成。對於常態的電離層延遲，一般常利用衛星雙頻觀測量的線性組合，求解出電離層電漿密度產生的延遲量。但當電漿泡事件發生時，衛星訊號通過電漿泡邊界時，因其電子密度的劇烈變化，較低頻的訊號（如GPS的L2）較易受到電漿不規則體影響，訊號強度閃爍，常發生訊號失鎖(loss of lock)或週波脫落(cycle slip)，導致無法完整連續觀測其電離層電漿泡於時空上的變化。

本研究利用GPS單頻L1差分載波相位(carrier phase)與虛擬距離(pseudorange)之組合估計電離層的延遲量，嘗試觀測電離層電漿泡結構。在求解相位之周波未定值(Ambiguity)為本研究一重要之課題，應用卡爾曼濾波器(Kalman Filter)獲得粗估之一次差分周波未定值，再透過LAMBDA(Least square AMBiguity Decorrelation Adjustment)法搜尋出最佳整數解的周波未定值，將可求出準確且連續之電離層差分延遲量。更進一步分析其在空間的梯度變化，探討電漿泡形成演化過程中在時間和空間上的影響範圍。將有助於了解於電漿泡事件中，其電離層延遲量梯度變化，對於需要基準站之差分精密定位應用造成的影響。

This thesis studies the ionosphere delay of the global positioning system (GPS) by utilizing the single difference (SD) measurements, which combines the single-frequency carrier phase and pseudorange to estimate the gradient of the ionospheric delay in between two ground-based receivers. As the methodology involves carrier phase observations, solving the phase ambiguity is important for the accuracy. The ambiguity is solved by applying Kalman filter for preliminary estimation followed by the well-known LAMBDA (Least square AMBiguity Decorrelation Adjustment) algorithm to approach the best integer solution. The developed algorithm is applied to 119 stations around Taiwan at the low latitude ionosphere where the electron density gradient due to that daytime equatorial ionization anomaly and evening plasma irregularities are actively affecting the positioning accuracy. We estimate the ionosphere gradient during a solar magnetic storm period and the plasma irregularity occurrence period in March 2015 along Taiwan to understand the impact of the ionosphere effect to the application of differential precision positioning that requires reference stations.

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