Ionospheric range error correction models

Single frequency users of Global Navigation Satellite Systems (GNSS) need to correct link related ionospheric range errors of up to 100 m. Since this range error is proportional to the Total Electron Content (TEC) of the ionosphere, correction information can be provided by TEC maps deduced from corresponding GNSS measurements or by model values. In this paper we compare ionospheric correction models such as the Klobuchar (GPS) model, the NeQuick model, and the NTCM-GL model recently developed in DLR. It has been found that the NeQuick and NTCM-GL models show a similar performance which is by a factor of about 2 better than the performance of the Klobuchar model at the European sector. NTCM-GL needs only 12 coefficients and is fed by the solar radio flux index F10.7 to take into account the level of solar activity. Thus, the coefficients are fixed over a full solar cycle, no updating of coefficients is required. Hence, NTCM-GL may easily be used as a correction model for single frequency GNSS applications having a better performance than the Klobuchar model.