Research On Imaging Algorithms Of Ship Targets In Large Squint Mode And Atrocious Sea Condition

In the anti-ship missile,missile-borne SAR works in large squint mode.Ship target is different from ground targets,it will be under the influence of waves on the sea.The motion of swinging ship targets under different sea condition is also different,the higher the sea condition,the more serious the swing.These lead to a lot of technical problems for SAR imaging.In order to get high quality image,this paper mainly research on SAR imaging algorithm at two bad conduct of large squint and high sea condition.This has important implications for subsequent research.First,this thesis researches on the Range-Doppler(RD)algorithm in side-looking and small squint mode.For the problem of large squint imaging,such as range cell migration(RCM),second range compression(SRC)and azimuth focusing,this article obtained the SRC imaging algorithm,which is suitable for large squint mode.In the actual situation,SAR imaging use two-dimensional plane for actual three-dimensional space,which will produce space geometry deformation problem.In this paper,a mathematical correction formula is derived.Then in three-dimensional imaging scenarios,the impact of balanced straight line motion for SAR imaging is studied,and the function of Doppler parameters is obtained through theoretical analysis.Finally the paper analyses the impact of the motion of swinging ship targets for imaging,and obtains motion compensation algorithm based on Fractional Fourier Transform.The effectiveness of the proposed method is verified by simulation.