Doppler Radar Return from Two-Dimensional Random Rough Surfaces

Doppler return from the general case of a two-dimensional random rough surface is investigated. This is an extension of work recently reported for a special case of rough surface. Helmholtz integral approach is used, employing Kirchhoff´s approximations in order to evaluate the integral for the plane-wave case. Two-dimensional transmitter/receiver gain function and reflection coefficients are used. The shape of the Doppler spectrum is at variance with those offered by the usual theories in that it is not centered at the mean Doppler frequency. Furthermore, a study of the spectrum shape shows a significant surface modulation effect, antenna gaim functions, and surface reflectivity parameters, in view of the fact that a designer needs to consider these effects. A Univac 1108 computer was used for numerical calculation, and the resulting data are plotted.