Slow-Time SAR Signal Processing for UWB OFDM Radar System

Orthogonal frequency division multiplexing (OFDM) signals, commonly used for a variety of purposes in modern communication systems, are considered from the radar perspective. An experimental system configured as ultra-wideband (UWB) software-defined radar (SDR) has been assembled and tested in the synthetic aperture radar (SAR) mode at Miami University. Phase history - necessary for slow-time processing of SAR signals - was previously extracted from a single sub-carrier of OFDM pulses; in this paper we examine a more robust solution of phase history estimation using all sub-carriers. The results of the estimation are compared with the ideal single-frequency phase history reconstruction. Simulation examples of cross-range recoveries in noise using both methods are provided and discussed. It is shown that the proposed novel method of slow-time OFDM SAR signal processing is, indeed, a promising technique for multicarrier UWB systems.