Real-Time Mapping of VTEC and Slab Thickness in Cooperation of IGS’ GNSS and GIRO Sensor Networks

This work presents early results from a near-real-time ionosphere mapping system combining ionospheric data from two separate sensor networks: IGS permanent GNSS receivers providing VTEC measurements and GIRO high-frequency ionosonde sounders providing data for 3D mapping of the bottomside ionospheric plasma density. Near-real-time mapping systems can be considered as a step towards real-time systems, at the moment an extremely important and difficult to solve problem, not only considering mapping process itself, but also data gathering from all over the world, data delivery to the computational center, quality control, validation, mapping and releasing of final product in possibly unnoticeable amount of time. VTEC values gathered from IGS GNSS receivers and peak density of F2 layer NmF2 from GIRO ionosondes allows computation of an equivalent slab thickness, a derived descriptor of the near-Earth plasma layer up to the GNSS spacecraft altitudes that characterizes the skewness of its shape. The combination of IGS and GIRO real-time capabilities brings an intriguing possibility of evaluating dynamics of the topside ionosphere and plasmasphere, even though crudely, using only ground-based resources whose realtime performance can be engineered to accomplish below one minute latency of nowcast.