Bistatic 3D interferometric ISAR phase unwrapping

Interferometric ISAR is a promising technique which uses phase difference between ISAR images generated by multiple sensors to obtain the height information and the effective rotational motion of the target with respect to radar. However, the phase of the interferogram must be unwrapped to remove the modulo-ambiguity before estimating the height and rotation of the target. In the conventional phase unwrapping operation, it is assumed that the true (unwrapped) phase difference between adjacent pixels is beyond the range [-π,π]. In the ISAR applications, the rapid changes in the true intrinsic phase will violate this assumption. Inconsistencies can lead to phase unwrapping errors. In this paper, a phase unwrapping method is developed to solve this problem. Simulations have been carried out to verify the effectiveness of our method.