Effect of Anisotropy of Ionospheric Inhomogeneities in the Detection of Faults in Phase GNSS Measurements

Resumo

Phase and amplitude fluctuations (scintillations) are recorded when a signal of the global navigation satellite system (GNSS) passes through the anisotropic, randomly inhomogeneous ionosphere. In this case, the Earth’s magnetic field exerts a double effect, not only on the refractive index of the ionospheric plasma but also on the shape of ionospheric inhomogeneities, which determines their “elongation” along the lines of force. This is observed in the spatiotemporal distribution of measurement faults related to the phase scintillations. It was shown earlier that the density of faults in tracking the GPS carrier phase depends on the angle between the satellite-receiver beam and magnetic field direction at the altitude of the ionosphere under disturbed conditions. In this work, these studies are also compared to measurements in calm environments and research on the aspect dependences of GPS fault densities. In addition, the performed numerical simulation of the effect of anisotropy of ionospheric inhomogeneities showed good agreement with the experimental data and made it possible to determine the factors masking the effects of anisotropy.