The small-scale electron density irregularities in the ionosphere have a significant impact on the interruptions of Global Navigation Satellite System (GNSS) navigation and the accuracy of GNSS positioning techniques. The sporadic ionospheric E (Es) layer significantly contributes to the transient interruptions of signals (loss of lock) for GNSS tracking loops. These effects on the GNSS radio occultation (RO) signals can be used to derive the global location and intensity of Es layers as a complement to ground-based observations. Here we conduct statistical analyses of the intensity of Es layers, based on the scintillation index S4max from the FORMOSAT-3/COSMIC during the period 2006–2014. In comparison with simultaneous observations from an ionosonde network of five low-to-middle latitude ionosondes, the S4max indices from COSMIC, especially the small values, are linearly related to the critical frequency of Es layers (f_oEs). An accumulated period of less than 1 h is required to derive the short-term variations in real-time ionospheric Es layers. A total of 30.22%, 69.57% and 98.13% coincident hourly f_oEs values have a relative difference less than 10%, 30% and 100%. Overall, the GNSS RO measurements have the potential to provide accurate hourly observations of Es layers. Observations with S4max < 0.4 (f_oEs < 3.6 MHz), accounting for 66% of COSMIC S4 measurements, have not been used fully previously, as they are not easily visible in ground-based ionosonde data.

电离层中的小规模电子密度不规则性对全球导航卫星系统（GNSS）导航的中断和GNSS定位技术的准确性有重大影响。零星的电离层E（Es）层对GNSS跟踪回路的信号瞬变中断（失锁）有很大贡献。这些对GNSS无线电掩星（RO）信号的影响可用于得出Es层的全球位置和强度，作为对地面观测的补充。在此，我们根据2006-2014年期间FORMOSAT-3 / COSMIC的闪烁指数S4max对Es层的强度进行统计分析。与从五个低至中纬度离子探空仪的离子探空仪网络进行的同时观测相比，COSMIC的S4max指数_o Es）。需要少于1小时的累积时间来得出实时电离层Es层的短期变化。每小时f _o Es值的总计30.22％，69.57％和98.13％重合，其相对差异小于10％，30％和100％。总体而言，GNSS RO测量具有提供每小时精确的Es层观测的潜力。S4max <0.4（f _o Es <3.6 MHz）的观测值占COSMIC S4测量值的66％，由于以前在地面离子电离探空仪数据中不易看到，因此以前没有得到充分利用。