Measurements of bistatic clutter cross section

The work reported utilized the air-ground bistatic instrumentation developed previously under contract F30602-76-C-0037. Empirical data have been obtained from which estimates of the bistatic reflection coefficient have been determined. Measurements were made over snow covered terrain and over an orchard with snow cover. The snow covered terrain area was the same area of tall weeds and rough ground utilized during the 1976 measurements. Data were obtained at incident and reflective angles of 80, 70 and 60 deg (low grazing angles) and 0-180 deg azimuth angle. Measurements were made at 3 cm and 23 cm wavelengths with horizontal polarization. Both like and orthogonal polarizations were received at each wavelength; four channels of data were recorded. The measurements technique utilized an aircraft with 3 cm and 23 cm pulsed transmitters and four channel receivers on a ground based tower. Coherent signals were recorded by utilizing a separate air ground link for the receiver local oscillator signal. Approximately 146 data curves are given.