The Use of GPS for Monitoring of the Ionospheric Disturbances

Abstract

Since January 1995 GPS observations performed by Polish IGS network stations have been used for monitoring the ionosphere. During January-May 1995 we revealed a number of violations of the ionospheric structure from regularity. The disturbances resulted from magnetic storms with sudden onsets. The storms caused an increase of ionospheric delay by a factor of 1.5–3.0. During disturbances gradients and TID’s effects are also increased. We found that such severe ionospheric conditions have an effect on the determination of GPS equipment biases. The biases determined from code data for disturbed days are different from those for quiet days. The differences can reach up to 0.3–0.5 m in differential delay. It can be expected that the effects will be even more appreciable during the next solar maximum.