Multi-sensor rotation motion estimation for distributed ISAR target imaging

The use of multiple radar systems, carried by a set of air platforms flying in formation, has been demonstrated to be able to provide ISAR images of rotating surface targets with increased cross-range resolution, up to the number of considered platforms or even higher. The achievement of the desired cross-range resolution improvement from distributed ISAR data requires the knowledge of the target motion characteristics in order to correctly focus the multi-sensor ISAR image. To accomplish this task a new estimation technique, based on the maximum likelihood criterion, of the target rotation motion from the distributed ISAR data is here proposed. A complete simulated performance analysis is provided showing the improvement arising with respect to conventional (single sensor) techniques. Moreover examples of application to live ISAR data are provided showing the effectiveness of the proposed approach.