Enhancing The Accuracy of GPS Point Positioning by Modeling the Ionospheric Propagation Delay

The ionospheric propagation delay is one of the major error sources in GPS positioning. This effect is as a result of the fact that the GPS signals are affected by the ionized layer of the ionosphere. Subsequently, the signal reception time will be delayed, which causes an increase in the measured pseudo-ranges and phase measurements of GPS observables.In this paper the linear combination observables technique was used to estimate the ionospheric propagation delay effect on the measured pseudo-ranges and GPS point positioning. The use of the free linear combination technique was found to reduce the ionospheric propagation effects significantly.