Hardware and Algorithmic Features of Radiation, Reception and Processing of Signals Using Incoherent Scatter Technique

The paper considers the variants of improving the operation modes of high-power ground-based means of near-Earth space remote sensing, i.e., radars that employ the method of incoherent scattering (IS) of radiowaves in ionospheric plasma. Examples of experimental results of obtaining values of the electron concentration in ionosphere using the measurement of height power distribution of IS signal and its processing are presented. The functional block-diagrams of IS radar for different operation modes, in particular using the orthogonal excitation antenna dipoles and ring bridge, were also presented. Peculiarities of radiation and reception of radiowaves with both linear and circular polarization are considered. In the first case, the effect of Faraday rotation of radiowave polarization plane is used that causes typical IS signal fading when this signal is received by the linearly polarized antenna and consequently fluctuations in the height power profile of IS signal and also in the function obtained by processing the orthogonal components of signal that is used for the calculation of electron concentration. In the second case, the values of electron concentration are obtained by using the profile of IS signal power, in which the impact of the Faraday effect is eliminated. The results of conducted experiments simultaneously for the upper and lower ionosphere are presented including the calculation of concentration of ionospheric plasma electrons with sufficient height resolution dependent on the duration of elements of composed probing signal. The radiation mode of two-element radio-pulse with the direction change of polarized wave rotation has been proposed for simultaneous measuring of ionosphere parameters in a wide range of heights.