Novel ISAR Imaging Algorithm for Maneuvering Targets Based on a Modified Keystone Transform

A novel inverse synthetic aperture radar imaging algorithm is proposed for application when the maneuverability of an uncooperative target is not too severe, and the Doppler variation of the subechoes from the scatterers can be considered a first-order polynomial. Based on a modified keystone transform, the proposed algorithm can simultaneously transform all multicomponent linear frequency modulation subechoes into multicomponent single-frequency signals. Hence, the fast Fourier transform can be used for cross-range imaging. Simulation results also proved that the proposed algorithm is much more effective and computationally efficient than the previously reported range-instantaneous Doppler algorithms such as the Radon-Wigner transform algorithm.