Radar equations in the problem of radio wave backscattering during bistatic soundings

Abstract

This paper outlines a method of obtaining the relation between the singly scattered signal and the Fourier-spectrum of medium dielectric permititvity fluctuations, with due regard for the fact that the scattering volume is determined by antenna patterns and is not small. On the basis of this equation we obtained the radar equation relating the scattered signal spectrum to the spatial spectrum of fluctuations. Also, a statistical radar equation is obtained, which relates the mean statistical power of the scattered signal to the spectral density of the dielectric permitivity fluctuations without a classical approximation of the smallness of the irregularities spatial correlation radius. The work deals with the bistatic sounding case, when the exact forward and exact backward scattering are absent, and sounding signal have sufficiently norrow spectral band for scattered volume to change slowly on ranges of Fresnel radius order. The statistical radar equations obtained differs from the classical ones in the presence the coherent structures with big correlation radii, and so the received signal spectrum can differ from intrinsic spectrum of irregularities.