Real time ISAR imaging algorithm of maneuvering targets based on the fractional fourier transform

Real time ISAR imaging of maneuvering targets is studied, when the target´s maneuverability is not too serious and the Doppler variation of scatterer sub-echoes can be approximated as a first order polynomial. A FRFT (fractional Fourier transform) based ISAR range-instantaneous Doppler (RID) imaging algorithm of maneuvering targets is presented. In this algorithm, the FRFT, instead of FFT, is employed to accomplish the cross-range resolution. The prior information of target motion is utilized to reduce its searching range and thus its computational complexity. Experiments on real data show its validity and efficiency. High quality ISAR images of maneuvering targets can be obtained with much less computations using this algorithm than other existing ones. It´s suitable for real time ISAR imaging of maneuvering targets.