Rotation motion estimation for high resolution ISAR and hybrid SAR/ISAR target imaging

The problem of very high resolution Inverse Synthetic Aperture Radar (ISAR) imaging of moving targets is considered. In particular, the focus of the paper is on the estimation of those parameters concerning the target rotation motion, needed to correctly focus and scale the target images. To this aim, two new estimation techniques are proposed based respectively on the Maximum Likelihood and Constrast Optimisation criteria. Both cases of constant and variable rotation rate are considered. A complete theoretical performance analysis and examples of application to very high resolution live ISAR data are provided showing the effectiveness of the proposed approach.