Research On High Resolution Imaging Algorithms Of Maneuvering Platforms For Ship Targets

The competition for marine resource has become increasingly fierce,coastal countries vigorously develop the power of maritime military forces.The rich marine resources of our country have attracted the attention of surrounding countries,resulting in a continuous escalation of maritime antagonism,and the safety risks of sea passages cannot be ignored.The use of fighters,UAV(Unmanned Aerial Vehicle),missiles and other maneuvering platforms to carry out precise strikes on enemy warships is an important military means to ensure the safety of our country’s maritime channels.The main content of the paper can be summarized as the following three aspects:1.The influence of the echo signal’s two-dimensional spectrum caused by the high speed and high maneuverability of the maneuvering platform is analyzed first.Then,the influence of complex motion of the ship on the spatial variability of the Doppler parameters is analyzed by comparing the stationary target with the ground moving target and the ship target,which lays a theoretical foundation for the high-resolution imaging of the ship target in the following chapters.2.Considering the shortcomings of the current single imaging mode of Synthetic Aperture Radar(SAR)or Inverse Synthetic Aperture Radar(ISAR),combined with the maneuverability of the platform,a coarse-to-fine ship target imaging method of maneuvering platforms is proposed.First,the maneuvering motion of the radar platform is compensated to complete the coarse focusing of the ship target.Then,the mixed visual attention mechanism is used to extract the single ship target data from the coarse focusing SAR image to perform the residual distance migration correction.Finally,the residual ratio based iterative termination condition is adopted to perform azimuth fine focusing process,completing the refined imaging of the ship target.The simulation and measured data processing results verify the performance of the proposed method.3.A GNIAA based hybrid SAR/ISAR super-resolution imaging algorithm is proposed to solve the problem of low Fourier transform resolution caused by the short apertures formed by the radar echoes damaged or missing condition.On the basis of coarse focusing and ship target detection in Chapter 3,a generalized noise local Fourier basis is constructed to reduce the influence of noise on the performance of azimuth signal spectrum estimation.Then,the periodogram method is used to complete the initialization.Finally,the weighted least squares method is used to iteratively solve the problem,and the super-resolution image of the ship target is obtained by performing GNIAA super-resolution reconstruction on the azimuth signal processed by the PGA.The effectiveness of the proposed method has been fully verified in the simulation and measured data processing results.