Direct detection polarimetric radiometer (DDPR)

Abstract

Polarimetric signatures of terrain features and man-made objects have been measured using unique Direct Detection Polarimetric Radiometers (DDPR). The DDPRs are lightweight inexpensive systems operating at 35 and 94 GHz. Each system consists of a single antenna, amplifier, and a truncated cylindrical waveguide that directly measures Q, U, and V. The highly portable DDPRs are ideal for obtaining the Stokes vectors needed to study the physical characteristics of natural and man-made features. Field evaluations using the DDPR systems include measurements from an airborne platform over different terrain features and water, and ground based measurements of the polarimetric signature of grass, asphalt, buildings, and concealed munitions. The DDPR can function as a bistatic system by using an active source of polarization. Using this configuration and a soil chamber, we have investigated the effect of soil type and soil moisture on linear and circular polarization. This report will describe the DDPR and present the analysis of the airborne and ground based measurements, including the effects of soil type and soil moisture on sources of linear and circular polarization.