NUFFT-based parameter estimation algorithm for ISAR imaging of targets with complex motion

For inverse synthetic aperture radar (ISAR) imaging of targets with complex motions, the received signals have to be modeled as multi-component cubic phase signals (CPSs) after motion compensation. The innovation of this paper includes the introduction of the nonuniform fast Fourier transform (NUFFT) algorithm to obtain high-quality ISAR images rapidly. Because of the application of the NUFFT and the SCFT via chirp-z transform (CZT) with respect to the lag-time axis and time axis, respectively, the proposed algorithm can achieve a compromise between performance and low computational complexity in estimating the parameters. Both the theoretical analysis and the simulation examples demonstrate the effectiveness of the proposed algorithm.