Influence of the geomagnetic activity on the GPS signal

The Global Positioning System has been largely used to indicate the position of a receiver. The stability of this system depends on the medium propagation characteristics. In the present work we study the influence of 2 geomagnetic storms on the variations of the amplitude (scintillation) of the GPS signal in different periods of the year. This scintillation in the GPS signal is due to the presence of ionospheric irregularities. We verified that on the April 2000 storm, that occurred in a period of low incidence of ionospheric irregularities, the geomagnetic storms led to large scintillations of the GPS signal, while during November 2003 when the scintillations are usually high, the geomagnetic storms lead them to fall down. The storm main phase time of occurrence, that was different for each analysed storm, is proposed to be the cause of this different response of the ionospheric irregularities to the magnetic storms.