Multi-platform distributed ISAR for surveillance and recognition

In this paper we exploit the data acquired by multiple radar systems carried by multiple air platforms to increase the cross-range resolution of ISAR images. The distributed ISAR technique is devised for two different cases: (i) multistatic with a single platform carrying an active radar and the remaining platforms equipped with receiving only devices, (ii) MIMO with each platform carrying an active radar. The processing chain needed by the distributed ISAR is shown with the results obtained against simulated ISAR data for both multistatic and MIMO cases; the performance analysis shows that the proposed technique is able to provide an increase of the cross-range resolution up to the number of radar systems in the multistatic case or even higher in the MIMO case, if the platforms are properly located. The performance degradation arising from errors in the knowledge of both the target rotation motion and the acquisition geometry is also analyzed. Results obtained by processing the experimental data collected by a ground based radar operating together with a rotating platform are shown to validate the proposed approach.