VHF airborne passive bistatic radar ground clutter investigation

Airborne passive bistatic radar is currently experiencing renewed interest for both air-to-air and air-to-ground operation. An experimental airborne passive bistatic radar demonstrator system, that uses FM broadcast transmissions as an illuminator of opportunity, has been designed and constructed and flown on airborne experiments to collect data. This paper demonstrates the application of a Doppler Beam Sharpening technique with a 3 second Coherent Processing Interval in order to obtain a range and cross-range map of the surface stationary ground clutter. The median scattering cross-section for low grazing angle stationary ground clutter is estimated from the stationary clutter map and found to vary with bistatic angle, from −45 dB in the vicinity of β = 90° to −15 dB as the bistatic angle approaches 180°.