The Influence of Geomagnetic Storm of 7‐8 September 2017 on the Swarm Precise Orbit Determination

Abstract

AbstractWe analyze a recent geomagnetic storm event on 7‐8 September 2017 to investigate the impact of geomagnetic storm on the precise orbit determination (POD) of Swarm constellation. The storm time performance of POD is analyzed. The quality of Swarm orbits are severely degraded during the storm main phase on 8 September and the maximum precision degradation reached over 10 cm. The enhanced thermospheric mass density at Swarm altitude during the storm enlarges the atmosphere drag for low Earth orbit satellites, which makes main contributions to the storm time degradation of Swarm orbit. This negative effect of enhanced atmosphere drag on the orbit estimation is mostly suppressed by estimating a more frequent atmosphere drag parameter. The higher‐order ionospheric effects on the POD of Swarm are also analyzed. The vertical total electron content derived from the Swarm onboard Global Positioning System receiver presents a larger enhancement on the dayside at low latitude and midlatitude during the storm main phase. This leads to an increase in the high‐order ionospheric effects, especially in the second‐order terms. No evident precision improvement is observed after correcting the high‐order ionospheric effects. The results demonstrate that during this geomagnetic storm, the enhanced thermospheric neutral density serves as a stronger error source than the enhanced ionospheric plasma density for the low Earth orbit satellite orbit determination processing.