Improvement of Continuous Wave Radar Measurements in a Partially Controlled Environment

A continuous wave (CW) radar system within a partially controlled environment measures scale model aircraft for mono-static and fully polarimetric radar imaging. Due to a pseudo-far-field setup, wavefront curvature manifests primarily as geometric distortion. Recently proposed phase error models show induced geometric distortion to be independent of aperture size which are verified via measurement for Sensors and Signals Exploitation Laboratory (SSEL) collections. The partially controlled nature of the SSEL introduces stray infrastructural reflections into the measured data. Three methods to reduce stray signals are explored namely: true background subtraction (TBS), running average (RA), and spatial filtering (SF). Of the three methods, SF provides 15 dB improvement in dynamic range revealing underlying SSEL structure. Defocus due to quadratic phase error (QPE) is considered, but shown to be negligible for typical aperture sizes of 20 degrees