Bistatic Doppler Spectra of the Signal Reflected by Rough Water Surface Measured by Modified Monostatic Radar

This paper presents the results of experimental measurements of the Doppler spectra in bistatic scheme of observation. The measurements were carried out on one of the bridges over the Oka River in Nizhny Novgorod in the spring and autumn of 2019. The experiments were organized to verify the original approach proposed in previous works for calculating the Doppler spectrum of radiation reflected by the water surface in the quasi-specular directions. In the framework of this approach, the sea surface is described by 6 second-order statistical moments and the received radiation can be found in the Kirchhoff approximation taking into account the radiation patterns of the emitting and receiving antennas. An important feature of the approach is the explicit dependence of the characteristics of the Doppler spectrum on the parameters of the sea surface. The paper presents bistatic measurements of the Doppler spectrum of a signal reflected by a water surface performed under various conditions of wave formation, as well as at different angles of incident and received radiation. A comparison of field measurements with theoretical estimates is carried out, which confirms the operability of the proposed approach for describing the Doppler spectrum of reflected radiation in a bistatic formulation of the problem.