Precise point positioning degradation in the presence of a SITEC

The ionosphere is one of the main contributors to errors in the GNSS satellite-receiver ranging. In dual frequency precise point positioning (PPP) ionospheric effect may be reduced by means of the ionospheric-free linear combination (Zumberge et al., J. Geophys. Res. 102 (B3), 1997, pp. 5005–5017). However, ionospheric irregularities (characterized by rapid total electron content (TEC) fluctuations) such as equatorial plasma bubbles, ionospheric storms or solar flares induced sudden increases in TEC (SITEC), still are a main threat on GNSS-based techniques since they may cause cycle slips which compromises ambiguities estimation and originates a position accuracy degradation.