太空時代，衛星於民生用途的通訊以及定位導航，已經深深影響人類生活。全球導航衛星系統(Global Navigation Satellite System， GNSS)為覆蓋全球的空間定位衛星系統，其於台灣方面目前至少有160餘個GNSS觀測站。此外，赤道電漿泡(Equatorial Plasma Bubble， EPB)為低緯度電離層盛行的電漿不規則結構，主要發生於日落後，其電漿密度的分布不均勻，會導致電波訊號行經時產生偏折，造成訊號品質劣化與不穩定，導致GNSS衛星載波相位閃爍、訊號振幅衰減，進而降低GNSS精密單點定位(Precise Point Positioning， PPP)之精度與穩定性。利用PPP-AR技術，研究赤道電漿泡事件對GNSS定位的影響，並進一步探討可能的修正與改善策略。分析台灣地區GNSS測站觀測資料，結合精密衛星軌道與鐘差產品，進行PPP-AR定位解算。比較EPB發生與否，東西、南北、上下(ENU)方向上的定位誤差。利用計算之電離層閃爍指數(S_4 index)，對GNSS測站觀測資料進行篩選，提升有無EPB〖 S〗_4 對PPP-AR解算之影響。比對篩選前後的定位資料顯示，篩選後的資料可大幅減少EPB的影響進而降低PPP-AR定位誤差，並提升其定位穩定性。整體研究成果可大幅提升低緯度地區GNSS定位精準度。;In the space age， satellites have become indispensable for modern society， particularly in telecommunications and positioning and navigation applications. The global navigation satellite system (GNSS) is a worldwide satellite-based positioning system， and currently more than 160 GNSS reference stations are operated across Taiwan. Equatorial plasma bubbles (EPBs) are plasma irregularities that commonly occur in the low-latitude ionosphere after sunset. The non-uniform plasma density associated with EPBs causes radio wave refraction and signal degradation， resulting in carrier phase scintillation and signal amplitude fading of GNSS signals. Consequently， the accuracy and stability of precise point positioning (PPP) are significantly degraded. This study investigates the impact of EPB events on GNSS positioning performance using precise point positioning with ambiguity resolution (PPP-AR) and further explores possible mitigation strategies. GNSS observation data collected from reference stations in Taiwan， together with precise satellite orbit and clock products， were processed using the PPP-AR technique. Positioning errors in the east， north， and up (ENU) directions were compared under EPB and non-EPB conditions. Furthermore， the ionospheric scintillation index (S4 index) was calculated and used to screen GNSS observation data in order to evaluate the influence of EPB-related scintillation on PPP-AR solutions. The positioning results before and after the screening process demonstrate that the proposed method effectively mitigates the impact of EPBs， significantly reduces PPP-AR positioning errors， and improves positioning stability. The overall results indicate that the proposed approach can substantially enhance GNSS positioning accuracy in low-latitude regions.
