Phase Compensation and Image Autofocusing for Randomized Stepped Frequency ISAR
Randomized stepped frequency (RSF) waveforms are attractive for inverse synthetic aperture radar (ISAR) imaging due to their synthetic bandwidth system architecture and outstanding electronic counter countermeasure characteristics. However, the extra complexities of the RSF radar's frequency oscillator and the target echo model make phase compensation and image autofocusing more complicated. In this paper, we introduce a novel method for the phase compensation and image autofocusing of RSF ISAR. The new method consists of the following two stages: the first is a parametric coarse compensation for target radial motion, and the second is a non parametric fine compensation for motion residuals and radar system imperfection. Two target models, a naive target consisting of unit point scatterers and a Yak 42 target obtained from field experiments, are used for numerical analysis, which shows the effectiveness and superiority of the proposed method.
IEEE Sensors Journal