A note on the group delay and phase advance phenomenon associated with GPS signal propagation through the ionosphere

The propagation of a GPS signal through the ionosphere causes a group delay in the code signal and an advance of equal magnitude in the carrier signal. This paper explains this phenomenon by extending Jorgensen's derivation for ionospheric effects on a carrier signal modulated by a single-frequency sinusoidal modulation. The explanation is based on an inverse Fourier transform model of the GPS signal at the GPS receiver antenna output and the expression for the delay of a single-frequency wave in the medium. It is much easier to understand than more common explanations in the literature that involve deriving group and phase velocities in the time-space domain.