Summary The GNSS-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) is an ionospheric monitoring software system that relies on Global Navigation Satellite System (GNSS) data from NASA's Jet Propulsion Laboratory (JPL) Global Differential GPS (GDGPS) network to detect natural hazards. GUARDIAN provides near real-time (NRT) total electron content (TEC) time series data that allows users to explore ionospheric perturbations resulting from natural and anthropogenic e...