The application of the ionosphere free combination for GNSS dual frequency data allows mathematically the elimination of the first order ionosphere effects. However, the higher order ionosphere effects are not eliminated and are generally neglected in GNSS data processing. In this paper, there will be discussions and analysis related to the higher order ionospheric effects computation which involves calculating TEC from different combinations, the geomagnetic reference system IGRF-11, the ionosphere free linear combination for three GPS frequencies L1, L2 and L5 and other. The triple frequency combination allows eliminating the second order effect, however the propagated precision of the combination is worse than the value of the effect itself. It was accomplished data processing in the static and kinematic PPP aiming to evaluate the influence of the higher order effects in the solar cycle 24.The GPS data were corrected from higher order effects by using the "RINEX_HO" software available in the NGS-NOAA-TOOLBOX. The results showed that neglecting the higher order effects in the PPP can produce variations of the order of millimeters to centimeters considering periods with low and high ionosphere activity, respectively.
Higher Order Ionosphere Effects; Triple Frequency Combination; PPP; Solar Cycle
