Deviation Frequency in the Carrier Phase Scintillation Spectrum of Transionospheric Signals

We propose a methodological model for the carrier phase of navigation satellite signals to evaluate the border between weak ionospheric events and non-informative noise in the phase variation and scintillation spectrum. The carrier phase model suggests that an increase in the scale and intensity of the scattering irregularities leads to an increase in the deviation frequency, but the studied parameter almost does not change for low intensities of about 1%. The deviation frequency values obtained in the carrier phase modeling were confirmed by the experimental estimates obtained in the carrier phase measurements of GPS signals in weakly disturbed geomagnetic conditions. On the whole, variation ranges of experimental estimates and theoretical results do not contradict each other.