LAUSR

Intense L-band solar radio bursts (SRBs) can affect acquisition and tracking of signals from the Global Navigation Satellite Systems (GNSS) by receivers located in the sunlit hemisphere of the earth and have been regarded as a potential threat to GNSS stability and performance. To obtain the occurrence characteristics and evaluate the probability of GNSS L-band SRB events, we take a survey using the latest 20-year event set (1997–2016). The bursts data were archived and provided by the Space Weather Prediction Center (SWPC) of National Oceanic and Atmospheric Administration (NOAA). The results indicate that, during this period, a total of 2384 L-band radio bursts were observed, including 1384 minor events, 859 moderate events, 120 strong events, 17 severe events, and 4 extreme events. As expected, these bursts are generally closely related to solar activity and solar cycle. But, for the severe and extreme events, bursts occurrence is sporadic and random, which not only occurs at solar maximum but also at other intervals. Compared to X-ray solar flares, the L-band SRB events do not occur frequently, and the ratio of annual SRB events with peak flux exceeding 100 SFU to X-ray flares is approximately 0.12. Statistically, the occurrence frequency of strong, severe and extreme SRB events is conservatively about 6.00, 0.85, and 0.20 bursts per year, respectively. The data fitting shows that L-band SRB events yield a power law distribution with an exponent of about – 1.791.