Comparison of 4 methods for transionospheric scintillation evaluation

A comparison is made between 4 different methods of scintillation determination (the phase screen method, the Hybrid method, geometrical optics and the Rytov method) for transionospheric paths at GNSS frequencies. Calculations are made for both phase and amplitude scintillation indices. The methods shows good agreement in the calculations of the scintillation variation with the variance of the irregularity electron density, spectral index, outer scale, path elevation and other parameters but there are some quantitative differences. The effect of varying the phase screen height, irregularity velocity and a lower cut-off frequency are also investigated.