Imaging of Complex Targets With Rotating Parts via WSF–SRDI

ABSTRACT

Wideband inverse synthetic aperture radar (ISAR) imaging of targets with rotating components suffers from severe defocusing due to high‐order non‐ linear phase modulation and range cell migration (RCM). To address this problem, a wideband sub‐band fusion single‐range Doppler interferometry (WSF‐SRDI) framework is proposed. The wideband echo is first partitioned into multiple narrowband sub‐bands via a polyphase filter bank (PFB). A theoretical constraint relating the sub‐band number to RCM confinement is derived, ensuring that the RCM remains within a single range cell per sub‐band.

Within each sub‐band, a SRDI path‐integral model is then con‐ structed to simultaneously achieve sub‐band imaging and rotation parameter estimation, followed by a sub‐band fusion process to enhance the overall image quality. Finally, utilizing the estimated parameters, the rotating components are reconstructed and suppressed through least squares estimation, yielding a well‐focused image of the stationary main body.

Simulation results and contrast analysis demonstrate that the WSF‐ SRDI maintains robust performance under low signal‐to‐noise ratio (SNR) conditions. The proposed strategy provides an efficient solution for ISAR imaging of complex targets with multiple motion components.