Study On Algorithm And Simulation Of Microwave Imaging

ISAR imaging of space moving object is always the focused point to be studied. Since any kind of moving object can be summed up as the rotating object after motion compensation, therefore, the rotating object imaging becomes the basis of ISAR imaging as well as the study emphasis of the paper.First of all, the paper introduces the basic theory about ISAR imaging. Based on the rotating object, the foundational theory concerning the rotating object imaging is presented, in which the scattering point model of ideal object and the mathematical model of the rotating object imaging are included. Since the radar commonly work with LFM (linear frequency modulated) signal, in the present paper, the LFM system is introduced, which includes two methods of pulse compression as well as the weighting process after pulse compression. Moreover, for two-dimensional imaging, range resolution and cross-range resolution are also mentioned in the paper.Secondly, the paper introduces two foundational algorithms for ISAR imaging. One is the Range-Doppler(R-D) imaging algorithm, the other is the polar reformatting imaging algorithm. Detailed introduction and discussion are given to the R-D imaging algorithm in the paper. Especially, in the R-D imaging procedure, in order to restrain the side lobe and improve the imaging quality, five common window functions are introduced and discussed in the present work, which makes the basis for the later imaging simulation.At last, with the help of MATLAB, the present work adopts R-D imaging algorithm to simulate different kind of objects. The detailed simulation work is divided into three steps: a) Understanding that different window functions have different restraining capacity to the side lobe and different effect to the imaging results, five common window functions are applied to cylinder object and cross shaped object respectively, b) Discuss the influence brought by the sampling interval to the imaging quality and efficiency, c) In order to test the MATLAB imaging program, a group of data of the official reflected radar signal of Mig-25 fighter is introduced and applied.