Impacto de tempestade geomagnética na ionosfera e no posicionamento com GNSS: estudo de caso para 20 de novembro de 2003 na regi？o brasileira

the goal of this paper is to analyze the influence of the intense geomagnetic storms in the ionosphere and gnss (gps) positioning. it was analyzed the effects of intense geomagnetic storm of november 20th 2003 using gps data from rbmc (brazilian network for continuous monitoring) located in different sites in the brazilian region and ionosphere global maps. while analyzing the results, it can be observed an increase in the electron density of the ionosphere in the regions near to the geomagnetic equator in the afternoon on the day of the storm. in the period after the sunset of the storm day, there is an increase in the density of free electrons and ionospheric irregularities in regions furthest from the geomagnetic equator, when compared to geomagnetically quiet days. when the positioning point is analyzed, it is observed high discrepancies values in planimetry and altimetry at the same position for periods of changes that occurred in the ionosphere, especially for the gps stations located furthest from the geomagnetic equator in the period after the sunset sun.