Autofocusing of SAR images using STFRFT-based preprocessing

Prominent point processing (PPP) is a very popular synthetic aperture radar (SAR) autofocus algorithm, which can estimate errors caused by any type of unknown motion or other error source and has high accuracy under the assumption that a prominent point scatterer is available within an imaged scene. Proposed is an advanced PPP algorithm with a preprocessing technique based on the short-time fractional Fourier transform (STFRFT) to relax the limitation on the scene content. The performance of the proposed autofocus algorithm is validated using real radar data.