Characterization of Indian ionospheric TEC behavior using PDFs and GPS satellite data

Ionosphere plays a prominent role in satellite communications. The spatiotemporal variations of the ionosphere are identified by its Total Electronic Content (TEC) that can be estimated by using dual frequency GPS receiver´s observations. To investigate the variability of ionospheric TEC, four slots of data each with two hours duration are considered. Four prominent Probability Density Functions (PDF) namely Raleigh voltage, exponential, lognormal and Weibull are used to characterize the ionospheric TEC. The parameters of the PDFs are estimated using Maximum Likelihood Estimation (MLE) technique. The best fitting probability distribution of the TEC data is obtained using Chi-square goodness of fit. It is observed that over low latitude regions (like India) ionospheric TEC variations follow either lognormal or Weibull distribution for most of the times.