Horizontal GPS positioning accuracy during the 1999 solar eclipse

Although GPS positioning errors are now well described, there are still som e uncertainties regarding the impact of some rare space weather phenomena o n GPS positioning accuracy. Solar eclipses have been considered as one sour ce of such rare events, so the 1999 solar eclipse gave the opportunity to c ollect horizontal GPS positioning data for further analysis. The results of statistical analysis show no deterioration of horizontal GPS positioning a ccuracy. Space weather, ionospheric and geomagnetic conditions were also ca refully analysed and showed no significant activity. In conclusion, the exp eriment confirmed negligible impact of the 1999 solar eclipse on horizontal GPS positioning accuracy, and opens discussion concerning application of s atellite positioning systems in space and ionospheric weather monitoring.