Research On ISAR Imaging Methods Of Maneuvering Targets

This paper focuses on the inverse synthetic aperture radar(ISAR)imaging methods of maneuvering targets.Based on the analysis of signal model and key problems,we propose an imaging method based on matching Fourier transform(MFT)and this method can get the well-focused images.Meanwhile,the problems in translational motion compensation of maneuvering targets have been discussed.And a new phase compensation method based on iterative autofocus of maneuvering targets is proposed.The research results have practical significance for improving the image quality.At first,it briefly describes the background and significance of this research,and introduces the development of ISAR imaging system.In addition,the development status of the ISAR imaging methods of the maneuvering targets is introduced,and the main imaging methods of maneuvering targets,the advantages and disadvantages of each method are compared by simulation.Secondly,we define the variable relative chirp rate to describe the maneuvering of the target.With the help of the relative chirp rate,an adaptive ISAR imaging method based on the matching Fourier transform is proposed.This method unifies the imaging problem of smooth targets and maneuvering targets into the same imaging model,and the imaging of the target is converted into a parameter optimization problem.The imaging results have been inproved compared with the RID algorithms and the parameter estimation methods.It can also get the images of different maneuvering targets by efficient initialization and gradient descent method optimization.The whole imaging does not need manual intervention and has strong engineering application.Finally,the phase compensation methods of maneuvering targets are discussed.We difine the variable Doppler focus shift to describe the possible linear translational motion compensation error,and the error is compensated by the method based on a two-dimensional gradient descent optimization.In addition,for the non-linear error ranslational motion compensation error,we propose an iteration autofocus method,which can effectively and robustly complete the phase compensation of maneuvering targets.