TEC Cullen & Frey graph as a criterion for classification of ionospheric events causing GNSS PNT degradation

Global Navigation Satellite System (GNSS) ionospheric correction models optimised for real space weather, geomagnetic, and ionospheric conditions provides resilience against adversarial effects on the GNSS positioning performance. Here the Total Electron Content (TEC) Cullen & Frey graph analysis is proposed and demonstrated for advanced classification of ionospheric events, as an essential step in the process of GNSS ionospheric correction model development for targeted scenarios of GNSS ionospheric disturbances.