Time Series Modelling of Intensity and Phase Scintillation at GPS Frequencies

A model based on phase screen diffraction theory is developed to simulate time series of scintillating trans-ionospheric radio signals. The main purpose of the synthetic scintillation time series, or SSTS, model is to test various GPS receiver systems under scintillation conditions. In order to do this, the modelled scintillation data is designed to be input into a model of a GPS receiver tracking loop. It is noted that although the main interest here is in GPS, the SSTS model may also be used at other radio frequencies and for other transmitter-receiver links (e.g. satellite based communication systems). In this paper the SSTS model is described and preliminary results are presented showing the effects of scintillation on a second order Costas loop. The Costas loop is commonly used in GPS receivers for tracking the phase of the GPS carrier.