AIDA: A Real-Time Global Ionosphere/Plasmasphere Data Assimilation Model

The Advanced Ionospheric Data Assimilation (AIDA) is a real-time data assimilation model of global 3D ionosphere and plasmasphere electron density. Changes in the local space environment can occur on very short timescales, particularly during disturbed geomagnetic conditions. This space weather has an impact on many modern systems including Global Navigation Satellite System (GNSS) signals and High Frequency radio communications. To provide an ionospheric specification in real-time, AIDA ingests data streams from over 2000 GNSS receivers, using observations from both the Global Positioning System (GPS) and Galileo constellations, along with ionosonde-derived characteristics from the Global Ionosphere Radio Observatory (GIRO). These measurements are assimilated using a particle filter into the empirical NeQuick ionosphere model and Neustrelitz Plasmasphere Model (NPSM). The GNSS receiver Differential Code Biases (DCBs) are solved self-consistently using Rao-Blackwellized particle filtering. AIDA produces output at three latencies, the real-time Ultra Rapid product, the near-real-time Rapid product which operates at a 90-minute delay, and the Final product with a one day lag. The Ultra Rapid and Rapid products also include forecast products out to 6 hours ahead of real time.