Ionospheric Response to the Total Solar Eclipse of August 21, 2017, and Its Impact on GNSS Positioning

Abstract

The solar eclipse on August 21, 2017, passed through North America and considerably affected the electron density in the ionosphere. By taking advantage of a global navigation satellite system (GNSS) for monitoring the ionosphere, the ionospheric response to the eclipse and its impact on GNSS positioning were investigated using data from the Oregon Real-Time GNSS Network (ORGN). From the dual-frequency GNSS observation, total electron content (TEC) was extracted along the signal ray path between a satellite and a station for observing the abnormality of the ionosphere. From the TEC observations during three sequential days—the day before, the day of, and the day after the eclipse—the rate of change of TEC (ROT) was derived to analyze the impact of solar eclipse on the ionospheric response. A distinctive reduction of the ROT was found on the day of eclipse. Moreover, the impact of the eclipse on GNSS positioning was examined by conducting an experiment of the baseline processing. Because of the unusual dynamics of the ionosphere during the eclipse, the GNSS positioning error during the event was notably increased. This experiment shows that the eclipse increased the ionospheric gradient between a station in the path and a station outside of the path of totality that significantly degraded the positioning performance.