Mitigation of Ionospheric Propagation Errors with GPS

As radio waves propagate through the ionosphere and troposphere, the value of the index of refraction changes. This results in apparent range error, refraction, and, at times, amplitude and phase scintillation. These ionospheric errors can become quite significant, even in the mid-latitudes during large geomagnetic storms. This paper will describe ionospheric effects in general and the major space weather events that exacerbate the ionospheric issues. This paper will also describe different schemes to mitigate the ionospheric errors, using ionospheric models, measurements, or some combination of both.