The Research Of ISAR Imaging

The comprehensive aperture radar is mainly studied in this paper imaging, and the foundation of the turntable imaging is ISAR imaging. Motion compensation is a key step in ISAR imaging, which usually includes range alignment and phase correction, while range alignment is the basis of phase correction. Some method commonly used in the range alignment is introduced, such as scattering point of the basic law, the frequency domain method, the airspace method, the whole related law and so on. Some method commonly used in the range alignment is introduced, such as scattering point standards law and doppler center tracking method and so on.The correlation is the most widely used in range alignment. In the traditional correlation method the range shift obtained is not precise. The range shift obtained is an integer. But the actual range shift may not be an integer. Delay in time domain is represented as a linear additional changing phase with frequency, namely a fixed group delay, so delay compensation can be realized by phase compensation in frequency domain. With correlation and group delay compensation, based on an arbitrary group delay a new algorithm ISAR range alignment is proposed in the paper. In this paper, the proposed algorithm is based on the traditional correlation method, then in frequency domain range shift can be further compensated based on the compensation factor, finally the aligned two-dimensional data can be got after IFFT. The proposed algorithm is tested by results of ISAR.