S. V. Katin - Dr.Sc. (Eng.), Professor, Deputy Director of Institute, FSUE FRPC - Measuring System Research Institute n.a. Yu.Ye. Sedakov - (Nizhny Novgorod). E-mail: niiis@niiis.nnov.ru V. A. Kozlov - Dr.Sc. (Eng.), Professor, Head of Department, FSUE FRPC - Measuring System Research Institute n.a. Yu.Ye. Sedakov - (Nizhny Novgorod). E-mail: vKozlov@niiis.nnov.ru A. L. Kunilov - Leading Research Engineer, FSUE FRPC - Measuring System Research Institute n.a. Yu.Ye. Sedakov - (Nizhny Novgorod) M. M. Ivoylova - Post-graduate Student, Research Engineer, FSUE FRPC - Measuring System Research Institute n.a. Yu.Ye. Sedakov - (Nizhny Novgorod)

In the design of perspective ground and space-based radars which use UWB-noise signals an important task is to determine possible changes in their temporal and spectral forms, as well as the change in polarization of radiated by a radar linearly polarized wave when sounding signals passing through Earth\'s ionosphere because the account of these factors will make it possible to provide optimal conditions for the reflected signal reception. During propagation in the Earth\'s ionosphere any UWB-signals interact with the ionized layers of the ionosphere, resulting in distortion connected with the phase velocity dispersion, absorption and scattering. The effects of absorption and scattering can be neglected with the given UWBN-signals parameters f 0 = 1 GHz, ΔF N = 600 MHz. When carrying out researches the ionosphere model has been used when it reached the electron concentration maximum level in the ionosphere at middle latitudes (the worst case conditions) which is observed in March in the afternoon, at 60° north latitude and 150° east longitude, at the average value of Wolf number which is equal to 150 (relative number of sunspots). While conducting modeling the research subjects were temporal and spectral forms of UWBN-signals at altitudes of 100 km, 200 km, 300 km, 600 km and 1000 km under normal propagation θ = 0. According to the results of modeling the polarization plane rotation of the linearly polarized wave at the lower limit of the UWBN-signals spectrum does not exceed 45°. In the article the dispersion distortions features of the UWBN-signals temporary form have been investigated and there is shown the absence of the energy spectrum form distortions of these signals. The functional scheme of UWB-noise radar with signal processing of the cross-correlation method (CC) and the double spectral analysis method (DSA) and the structural schemes of their models have been reviewed. Radar UWBN-signals reception issues at different altitudes have ben investigated by the modeling methods. It has been shown that in the radar with signal processing CC method a cross-correlation function peak expands and shifts to the increasing delay. In the radar with signal processing DSA method the output signal spectrum expands and its maximum shifts to the increasing frequency. The results make it possible to make corrections to the measured values of the distance from the radar to the reflecting surface.

 

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