Forecasting ionospheric delay during quiet and disturbed days using the Holt-Winter method

The main cause of errors in the navigation of the Global Positioning System (GPS) satellite is the ionospheric delay. Therefore, ionospheric delay forecasting studies play an important role in the reduction of the positioning error. This paper focuses on forecasting of ionospheric delay using the statistical Holt-Winter method during the quiet and disturbed days in October 2011, using GPS Ionospheric Scintillation and TEC Monitor (GISTM), over the Universiti Kebangsaan Malaysia (UKM) station at geographic coordinate of 2.55 °N, 101.46 °E. The forecast was carried out on the daily, hourly variation. Based on the result, the maximum difference between the actual and forecasting delay was 0.5 m and 0.6 m during the quiet and disturbed days respectively. The Holt-Winter method has been proven to effectively forecast the ionospheric delay with an accuracy of 95 % during the quiet days and 93% during the disturbed days.