Ship target ISAR imaging method based on fractional Fourier transform

The invention provides a ship target ISAR imaging method based on fractional Fourier transform. The ship target ISAR imaging method comprises the steps of: acquiring a radar echo signal of a scattering point of a ship target in each distance unit; modeling the acquired radar echo signals in the distance units into multi-component secondary frequency modulation signals through pulse compression andmotion compensation; determining estimated parameters of scattering point echo signals in the distance units according to the secondary frequency modulation signals; updating radar echo signals in the distance units by adopting the estimated parameters of the scattering point echo signals in the distance units; and acquiring an ISAR image of a ship target by utilizing the updated radar echo signals. The ship target ISAR imaging method adopts a symmetrical correlation function, fractional Fourier transform and multi-product processing for the radar echo signals in sequence, avoids the couplingof time and time delay, e