Modelling of GPS signal scintillations with polynomial coefficients over the Indian region

Performance of Global Positioning System (GPS) and other satellite based navigation systems can be degraded by the ionospheric scintillations of the signal. As the ionospheric scintillations behaviour varies with geographical location (latitude, longitude) and time, modelling is required for estimating and forecasting the scintillation. In this paper, amplitude and phase scintillations (S sub(4) and [sigma] sub([phi])) of the GPS signal are modelled with the polynomial coefficients developed using the least square solution (LSS) with merit function. For the coefficients development, GPS satellites data from 17 stations of the GPS Aided Geo Augmented Navigation (GAGAN) system network in the Indian region is considered. It is found that estimated/predicted scintillations due to the developed coefficients are very close to the experimental (observed) data of Hyderabad receiver station (17.44[degrees]N, 78.47[degrees]E). The maximum deviation in predicted S sub(4) and [sigma] sub([phi]) is 0.03 and 0.3 rad, respectively. With the developed coefficients temporal, latitude and longitudinal variations of S sub(4) and [sigma] sub([phi]) are analysed for Hyderabad station (17.44[degrees]N, 78.47[degrees]E).