Klobuchar Model and Global Ionosphere Maps Performances in Brazil

Abstract

Among the methods for mitigating the first-order effects of the ionosphere, the Klobuchar model and final Global Ionosphere Maps (GIM) produced by the International GNSS Service (IGS) are widely used. Previous studies have looked at their effectiveness in discrete periods and locations of Brazil, but this may have led to incomplete conclusions. Aiming to contribute to this discussion, this paper presents a more comprehensive evaluation of the Klobuchar model and IGS GIM performances in single-point positioning using data from the whole year of the solar cycle 24 peak from six stations of Brazilian Network for Continuous Monitoring of the GNSS Systems (RBMC). When compared to the solution without using correction for the ionosphere, improvements of approximately 39% and 52% were obtained with the Klobuchar model and the GIM, respectively. The results suggest that the lower intensity of solar cycle 24, the location of the GNSS station relative to the geomagnetic equator, and the occurrence of post-sunset ionospheric irregularities contribute to the worse performance of the assessed models when compared to research done with GNSS data from solar cycle 23.