The phase characteristics of radio waves during oblique propagation in a weakly anisotropic parabolic ionospheric layer are considered in the short-wave radio range. The case of polarization degeneracy of waves is analyzed. The correction to the wave eikonal due to the smallness of the anisotropy is calculated by the perturbation method. The two-valuedness of the solutions corresponds to two normal waves. The figures show the form of these solutions under different conditions of layer probing.
Reconstructions of high- and midlatitude ionosphere applying low- and high-orbiting radio tomography (LORT and HORT) mrthods in different regions are analyzed. LORT reconstructions reflecting local (tens of kms) ionospheric features with various shapes, orientations, and localizations and large-scale (hundreds of kms) formations with regular and irregular structure are presented. HORT demonstrates morphological variety of plasma irregularities spanning hundreds to thousands km. Examples of multi- extrema structures, ionization spots (blobs, patches), variations in locations and depths of ionization troughs, quasi-wave perturbations, high-gradient ionization “walls” are presented. Ionospheric effects of precipitations are discussed. Qualitative comparison between RT reconstructions and DMSP particle flux data is conducted.
The statistical properties of the phase (eikonal) of normal waves reflected from the regularly inhomogeneous magnetoactive ionospheric plasma containing random inhomogeneities of electron density are considered. The trajectories of the rays propagated at the pole (the Earth’s vertical magnetic field) are numerically obtained. The dispersions of the fluctuations and spatial coefficients of autocorrelation of the phase are found and analyzed for each of the normal waves at different angles of entry of the ray into the ionosphere.
The statistical properties of the group path and the group delay time of an extraordinary wave with oblique reflection from a non-uniform magnetoactive ionosphere containing random electron density inhomogeneities are considered. The trajectories of rays propagating at the magnetic equator are obtained numerically. The height dependences of the angles between the direction of the ray and the wave normal are constructed. The spatial autocorrelation coefficients of the group path at the exit from the layer are found at different angles of the ray entrance into the ionosphere.
The statistical properties of the eikonal (phase path) of an extraordinary wave reflected from the plane layered magnetoactive ionospheric plasma containing random inhomogeneities of the electron density are considered. The ray trajectories are determined numerically for propagation at the magnetic equator. The spatial coefficients of the autocorrelation of the eikonal at various angles of the ray entrance into the ionosphere are found.
In the present paper we study GNSS - reflectometry methods for estimation of sea level variations using a single GNSSreceiver, which are based on the multipath propagation effects caused by the reflection of navigational signals from the sea surface. Such multipath propagation results in the appearance of the interference pattern in the Signal-to-Noise Ratio (SNR) of GNSS signals at small satellite elevation angles, which parameters are determined by the wavelength of the navigational signal and height of the antenna phase center above the reflecting sea surface. In current work we used GPS and GLONASS signals and measurements at two working frequencies of both systems to study sea level variations which almost doubles the amount of observations compared to GPS-only tide gauge. For UNAVCO sc02 station and collocated Friday Harbor NOAA tide gauge we show good agreement between GNSS-reflectometry and traditional mareograph sea level data.
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