Maintaining High RTK Availability and Accuracy Throughout the Maximum of Solar Cycle 25

During the upcoming maximum in the 25th Solar Cycle, two phenomena are most likely to degrade RTK performance under different circumstances. The first one is ionospheric scintillation in the hours after sunset around the equator during season and during magnetic storms in the polar regions. The second one is mostly mid-latitude medium-scale traveling ionospheric disturbances (MSTIDs) during daytime in winter and during nighttime in summer due to amongst other atmospheric gravity waves and Perkins instability. New single-receiver indicators for fast detection of these phenomena are demonstrated: the scintillation index (SI) and the overall model test of the ionosphere gradient model. Their performance is shown for actual data examples. We show that by adapting the stochastic model used for ionosphere delay estimation, RTK performance under scintillation can improve from 55% RTK with P95 = 25 cm to 90% with P95 = 7–9 cm, with room for further improvement. RTK performance improvement during MSTIDs is still topic of further research.