DIRECTION FINDING OF HF SIGNALS SCATTERED BY IONOSPHERIC IRREGULARITIES USING SMALL SIZE ANTENNA

Abstract

Purpose: A modification of the Doppler Interferometry Technique is suggested to enable estimating angles of arrival of comparatively broadband HF signals scattered by random irregularities of the ionospheric plasma with the use of small-size near-omnidirectional antennas. Desing/methodology/approach: The technique is based on the measurements of cross-spectra phases of the probe radiation recorded at least in three spaced points. Findings: The developed algorithm has been used to investigate the angular and time-and-frequency characteristics of HF signals propagating at frequencies above the maximum usable one for the direct radio path Moscow–Kharkiv. The received signal spectra show presence of three families of spatial components attributed, respectively, to scattering by plasma irregularities near the middle point of the radio path, ground backscatter signals and scattering of the sounding signals by the intense plasma turbulence associated with auroral activations. It has been shown that the regions responsible for the formation of the third family components are located on the equatorial slope of the maximum of the precipitating particle energy. The drift velocity and direction of the polar ionosphere plasma has been determined. Conclusions: The obtained estimates are consistent with the classical conception on the magnetospheric convection and plasma convection in the polar regions and do not contradict to the results of investigations of the auroral ionosphere dynamics using the SuperDARN network.

Keywords

• ionospheric plasma
• scattering
• direction finding
• polar ionosphere
• auroral oval
• velocity and direction of plasma drift