Low-Angle Radar Land Clutter

2.5 SUMMARY

The data available from the Phase Zero program comprise calibrated clutter files covering all of the clutter within the field-of-view from 106 different sites. Extensive analyses of these data lead to an understanding of a basic unifying mechanism underlying what appears at first consideration to be extreme variability and little predictability in low-angle clutter spatial amplitude distributions. This understanding is based on the fact that, at the very low angles of illumination of surface radar, ground clutter largely consists of backscatter from a sea of discrete clutter sources. That is, a wave is skimming over the landscape at grazing incidence, and backscatter is being measured from all the vertical sources that rise up from ...