Several natural phenomena on Earth and in space, such as tsunamis, volcanic eruptions, earthquakes, and geomagnetic and solar storms leave a readily detectable signature in Earth's ionosphere. Monitoring the ionosphere in real-time can greatly enhance our early warning systems for these events. Traditionally, the ionospheric response to these sources has been studied several days to weeks after an event occurs. For the ionosphere to be used as a medium for hazard warning, it must be monitored in near real-time (NRT) with analyses provided in a timelier fashion.

The GNSS-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) is a state-of-the-art NRT monitor designed to provide estimates of the ionospheric line of sight total electron content (TEC) from L-band radio-frequency signals transmitted by the Global Navigation Satellite System (GNSS) constellation of satellites. The GUARDIAN team combines, cleans, and filters phase data to generate TEC time-series for multiple constellations from nearly 90 stations around the Pacific Ring of Fire with an approximate latency of 3 minutes. GUARDIAN builds on NASA's Jet Propulsion Laboratory (JPL) Global Differential GPS (GDGPS) capability and the International GNSS Service (IGS) network, which aggregates GNSS phase data from a network of real-time worldwide stations.

In this presentation, we will discuss the architecture of the GUARDIAN system, highlight several examples and use cases, and share future plans for its development, with the hopes of enhancing existing hazard warning frameworks to safeguard communities around the world.

To learn more about space geodesy datasets, services, and tools visit NASA's Crustal Dynamics Data Information System (CDDIS).