Total Electron Content (TEC) and Model Validation at an Equatorial Region

The ionosphere has practical importance in GPS applications because it influences transionospheric radio wave propagation. The parameter of ionosphere that produces most of the effects on radio signals is Total Electron Content (TEC). By modelling this TEC parameter, the evaluation of the ionospheric error and the correction of these ionospheric errors for differential GPS can be done. A new approach in the determination of the differential ionospheric error to sub- centimeter accuracy is described in this paper utilizing a developed model. An ionospheric delay model was developed to accurately determine the difference in ionospheric delay expected over a short baseline so that a more accurate differential GPS correction could be made. An ionospheric error correction model should be made applicable to any location including the equatorial region. The results showed that the developed algorithm is a function of elevation angle and TEC from the reference station path to the satellite and could give differential ionospheric delay in sub-centimetre accuracy.