Effects of storm-induced equatorial plasma bubbles on GPS-based kinematic positioning at equatorial and middle latitudes during the September 7–8, 2017, geomagnetic storm

Abstract

Space weather can impact significantly on the regular equatorial plasma bubbles (EPB) occurrence. During the severe geomagnetic storm on September 7–8, 2017, penetrating electric fields associated with a long‐lasting southward IMF supported favorable conditions for EPBs development in the postsunset equatorial ionosphere. The storm‐induced EPBs formed rapidly over a broad span of longitudes in the American sector, and further plasma density depletions were streaming away from low latitudes in a northwestward, poleward direction across North America midlatitudes (up to 30°–40° magnetic latitude) toward the main ionospheric trough and auroral irregularity zone. The large-scale storm-induced EPBs and the streamed plasma depletions that persist for several hours can create a localized threat for strong plasma gradients and GPS scintillation effects. We investigated dynamics of the storm-induced irregularities of the equatorial origin and effects of these ionospheric structures on kinematic positioning by combining multi-site ionospheric observations and kinematic solutions for low-earth-orbit GPS and for 4500+\u2009 ground-based GPS stations. It was found that the dual-frequency GPS-based positioning accuracy degrades at many GPS stations located from low to middle latitudes of North America, especially within the 25°–35°N area affected by the transported storm-induced plasma depletions and associated irregularities. The estimates of 3D error for the GPS stations in the American longitude sector rose to several meters compared to the normal quiet centimeter–decimeter-level conditions. For the first time, we showed high consistency between GNSS signal phase fluctuations intensity specified by rate-of-TEC change index (ROTI) and accuracy of GPS-based precise positioning for a dense multi-site GPS network in the American sector during such an extreme EPBs development. Analysis of the kinematic and reduced-dynamic orbit solutions for Swarm satellites demonstrated that storm-induced irregularities of an equatorial origin can cause increased up to about 5 times errors in kinematic orbit for LEO satellites, even at midlatitudes.