TILT MODULATION OF HIGH-RESOLUTION RADAR BACKSCATTER CROSS-SECTIONS - UNIFIED FULL-WAVE APPROACH

The unified full wave approach is used to determine the tilt modulation of the like and cross polarized (high resolution) radar backscatter cross sections for the rough sea surface. Thus, real or synthetic aperture radars (SAR) with small effective footprints (resolution cells) are considered here. Since the unified full wave approach accounts for Bragg scattering as well as specular point scattering in a self-consistent manner, it is not necessary to adopt a two-scale model for the rough sea surface. The sea surface slope probability density functions is assumed to be Gaussian in this work. The backscattering cross sections are evaluated for all angles of incidence (normal to grazing). For tilts in the plane of incidence, the modulation of all the cross sections is largest at angles of incidence THETA0' = 10-degrees. The cross-section modulation due to tilts perpendicular to the plane of incidence critically depends upon the incident and scattered polarizations. The effective filtering of the large scale spectral components of the rough sea surface by the high resolution radar is accounted for and the dependence of the cross section tilt modulation upon the size of the effective footprint is determined.