Preliminary Analysis of Satellite Navigation Effects of the Strong Solar Flares during Solar Cycle 24

Abstract

Solar flares can affect Earth’s navigation system through disrupting GPS accuracy. It may be associated with coronal mass ejection or it can have other effects like geomagnetic storms which may occur several days after the flare event. This study examined the satellite navigation effects of the four strongest solar flares during solar cycle 24 over a GNSS station located at Taguig City, Philippines (station ID: PTAG). Particularly the primary effects such as GPS positioning error or any secondary impact like geomagnetic storms. The researchers obtained RINEX observation and navigation files for PTAG station from IGS Data Center, and calculated positioning error over this location through gLAB. Sun’s x-ray radiation and radio emissions (at 610, 1415 and 2695 MHz) were analyzed together with the positioning error to identify any direct effect of solar flares. While Dst and Kp indices were plotted in order to recognize geomagnetic activity post-flare event. Results indicated that not all solar flares will trigger geomagnetic storms. It is also worth mentioning that there are considerations when investigating solar flare consequences such as the observer’s location relative to the flare event and coronal mass ejection associated with it. A solar x-ray flux with lower intensity may still induce degradation in GPS positioning accuracy. Hence, it is important to track and catalog solar activity so that we will be prepared for any of its adverse effects.