Forecasting of ionospheric time delays using ARMA model under Geomagnetic storm conditions

Ionospheric time delay variations are highly variable and random in the low latitude Indian region. It is a key responsible parameter for the range error in Global Positioning System (GPS) ranging signals which is proportional to the total electron content (TEC). Dual frequency GPS receiver at KL University, Vaddeswaram (16.31° N, 80.37° E), India (falls under the transition zone of the Equatorial Ionization Anomaly in low latitude) is considered in the analysis. An Auto Regressive Moving Average (ARMA) model is implemented for short term forecasting of the VTEC (Vertical TEC) values. Three Geomagnetic storms occurred in the current solar maximum period (2013-2014) are considered to test the performance of ARMA model. The forecasted VTEC values are compared with original VTEC the values and IRI models. The forecasted results indicate that ARMA model would be useful to set up an early warning system of ionospheric disturbances.