地磁暴期间北半球高纬度地区电离层变化特征及对精密定位的影响

基于加拿大地区高纬度电离层观测网的电离层闪烁观测数据，分析了2018年8月26日地磁暴事件引发的北半球高纬度地区电离层总电子含量（TEC）异常变化、TEC变化率指数（ROTI）及电离层相位闪烁的变化特征.结果表明:加拿大地区最大异常值约6 TECU，磁暴引发全球电离层TEC异常峰值高达20 TECU；加拿大地区电离层相位闪烁发生率最大增至12.6%，而磁静日期间约为1%；强电离层闪烁期间，电离层相位闪烁指数与ROTI之间具有较强的一致性.对GPS双频精密单点定位（Precise Point Positioning，PPP）结果进行分析发现:无闪烁期间定位误差随测站纬度的增高呈现出增大趋势，但均方根误差小于0.4m；闪烁发生期间各测站的定位误差均显著增大，水平和垂直方向定位误差分别增至约0.9m及1.7m. 

Impact of Geomagnetic Storms on Ionosphere Variability and Precise Point Positioning Application in High Latitudes of the Northern Hemisphere

Based on the ionospheric scintillation data of the Canadian High Arctic Ionospheric Network (CHAIN), the variation characteristics of ionospheric Total Electric Content (TEC), phase scintillation and Rate of TEC Index (ROTI) were analyzed during the 26 August 2018 geomagnetic storm period. Results show that the TEC anomalies reach 20TECU on global scale and 6TECU over Canadian regions, respectively. The occurrence of phase scintillations is about 12.6% during the selected stormy day, which is only around 1% during geomagnetic quiet period. The occurrence of ROTI exhibits high correlation with that of phase scintillations during stormy geomagnetic conditions. The impact of ionospheric scintillations on positioning performance was analyzed by means of GPS Precise Point Positioning (PPP). It is proved that the 3D positioning root mean square errors are within 0.4 m for all test stations during the quiet geomagnetic condition. When it comes to the high geomagnetic condition, the magnitude of positioning errors significantly increase, which reaches 0.9 and 1.7m in horizontal and vertical directions, respectively.