A fast range alignment algorithm for ISAR imaging

The envelope correlation algorithm and the minimum entropy algorithm are widely used in range alignment of inverse synthetic aperture radar (ISAR) imaging. However, these types of algorithms have heavy computation burden mainly caused by the searching operation. Aiming at reducing the burden, a fast range alignment algorithm is presented in this paper. Firstly the mean location of each range profile is calculated. Then we fit the trajectory of them with linear regression model. Based on the straight line trajectory of range shift, range alignment can be accomplished. The proposed algorithm avoids the searching operation which is usually used in traditional algorithms. The computational complexity analysis shows that the computation burden of the novel algorithm is proportional to the data volume. Finally, the comparison between the proposed algorithm and the envelope correlation algorithm with real data demonstrates the validity and efficiency of the fast algorithm.