Bistatic Clutter Suppression in Low-frequency SAR

Abstract:
This paper discusses the possibilities of suppressing clutter returns in low-frequency (VHF-band) SAR using bistatic radar geometries. It is noted that strong clutter returns in many low-frequency SAR scenes are caused by a dihedral-like scattering mechanism. For example, this is often the case in forest-covered terrain or urban scenes. The bistatic scattering lobes of such clutter returns are, however, rather narrow and the clutter may therefore be reduced by a sufficiently large separation in angle of the transmitter and receiver using a bistatic configuration. Target scattering, on the other hand, is less sensitive to bistatic angular separation. In the paper, we show results from electromagnetic simulations in the frequency band 20-90 MHz, which illustrate the principle and indicate a significant improvement of the target-to-clutter ratio.