Bistatic clutter measurements

Empirical data have been obtained from which estimates of the bistatic reflection coefficient have been determined. Measurements were made on two terrain types (grassy terrain and an area of tall weeds and rough ground) at low grazing bistatic angles of , and , and to azimuth angle. The terrain was illuminated at wavelengths of 3 cm and 23 cm, with horizontal polarization. Both like and orthogonal polarizations were received at each wavelength; four channels of data were recorded. The measurement technique utilized an aircraft with the 3-cm and 23-cm transmitters on board; receivers were mounted on a tower. The transmissions were pulsed, and coherent signals were recorded by utilizing a separate air-to-ground link for the receiver local oscillator signal.