STUDIES OF THE ANGULAR-CORRELATION FUNCTION OF SCATTERING BY RANDOM ROUGH SURFACES WITH AND WITHOUT A BURIED OBJECT

The discrimination of the scattered wave from an object buried in shal low ground from that of the rough surface is a difficult task with pre sent ground penetrating radar (GPR) systems. Recently, a new approach for this classical problem has been proposed and its effectiveness has been verified. This new method is based on the angular correlation fu nction (ACF) of the scattered wave observed at two or more different i ncident and scattered angle combinations. It has been shown that the a ngular memory signatures of rough surfaces are substantially different from those of typical man-made targets and by choosing the appropriat e incident and scattered angles, the surface scattering can be minimiz ed whereas the scattering from the target is almost unchanged. In this paper, we will present detailed numerical studies of the ACF of the s cattered wave from rough surfaces with and without a buried object. To obtain the ACF, the three averaging methods: realization, frequency a nd angular averaging, are tested numerically, It is shown that a singl e random rough surface of moderate extent can exhibit memory effect by using frequency averaging. Frequency averaging with a aide bandwidth is also effective for suppressing fluctuation in ACF and is most usefu l for practical applications. Numerical simulations indicate that even when the ratio of scattered intensities with and without the buried o bject is close to unity, the corresponding ratio of ACF magnitude can be more than 10 dB. Thus, using the ACF is superior to using the radar cross section (RCS) in the detection of buried objects.