Statistical Study of Loss of GPS Signals Caused by Severe and Great Geomagnetic Storms

Abstract

AbstractLoss of satellite signals is the most significant disruption to global navigation satellite system (GNSS), such as global positioning system (GPS), associated with a geomagnetic storm. To characterize the lost GPS signals during severe and great geomagnetic storms, we define two indices, that is, the number of lost GPS signals at a single site (SLGS) and the global average rate of lost GPS signals (GLGS). We analyze the response of SLGS and GLGS to 14 intense geomagnetic storms with a minimum disturbance storm time (Dst) index less than −200 nT occurred since 2000. The results calculated from global GPS observation data showed that both the SLGS and GLGS responded well to the change of Dst index for all the studied storms, the loss of satellite signals mainly occurred during the main phase and the early recovery phase of geomagnetic storms. We found that the peak value of GLGS and the standard deviation of SLGS are exponentially correlated with the magnitude of Dst. We further compare the global distribution of SLGS with the relative differential total electron content (RTEC) and the rate of total electron content index (ROTI). The comparison results indicated that the new indices would be useful to evaluate the worst impact on GNSS performance during intense geomagnetic storms, and it is also a complementarity to the existing ionospheric indices.