A method for assessing the state the snow-ice cover is proposed, based on the identification layers snow-ice cover by the dielectric permittivity obtained indirectly as a result inclined sensing the underlying surface by an electromagnetic wave with vertical polarization. Determination Fresnel reflection coefficients depending on the angle incidence at the interface layers the controlled area, followed by calculation Brewster angles based on the minimum reflection coefficients from the interface layers, which are the initial data for calculating the permittivity each subsequent underlying layer snow-ice cover.

Under normal sensing the underlying surface, in the form snow-ice cover, by radio waves with vertical and horizontal polarization, the obtained values the reflection coefficient from the interface layers the received signals are identical. Oblique sensing by a vertically polarized wave in the range from 40 to 90 degrees leads to a sharp dip in the values the reflection coefficient from the interface layers at certain angles, so for dry snow – 47...55°, dry firn – 55 ... 58° and dry ice – 58...61°. These angles characterize the dielectric properties the layers (permittivity), which are explained by the complete polarization the reflected wave in a plane perpendicular to the plane incidence, since at this moment the vibrations the layer's electrons along the direction their movement do not lead to the emission electromagnetic waves in the direction the reflected wave (absent).

The given estimated values the complex relative permittivity snow-ice cover as two component media air and ice at a temperature from minus one to minus forty degrees, or three component media air, ice and water at zero temperature are a sample for establishing the identity the characteristic properties layers.

The purpose this article is to develop a method for assessing the state the snow-ice cover based on the identification, obtained characteristics layers snow-ice cover based on the results radar sensing with calculated data, used in determining the possibility performing a safe landing of a helicopter – type aircraft on an unprepared site with snow-ice cover.