The azimuth time-varying Doppler frequency

caused by the complex movement of maneuvering target

deteriorates the azimuth focusing quality.Conventional Range-Doppler (RD) imaging algorithm

Wigner-Ville distribution (WVD) imaging algorithm and Radon-Wigner imaging algorithm

due to Poor image quality and inefficient operation and so on

are unfit for ISAR imaging of the complex motion target.To solve these problems

a novel ISAR imaging method based on coherent integration cubic phase function (CPF) for maneuvering target is proposed in the letter.First

the echo data in a range bin after translational compensation are transformed into the time-chirp rate plane via CPF.Then

the auto-terms energy can be coherently integrated in the time-chirp rate distribution plane and can effectively suppress the troublesome cross-term interference and spurious peaks

and then obtain the distribution of the scatter energy in frequency-chirp rate plane.Finally

the azimuth ISAR image can be obtained via a simple maximization projection from the two-dimensional accumulated plot to the azimuth dimension

and the non-uniform fast Fourier transform (NUFFT) is also adopted to reduce the computing complexity.Computer simulation results verify the effectiveness of the proposed method.