Interferometric ISAR Imaging of Maneuvering Targets with Arbitrary Three-Antenna Configuration

In order to compensate for the shortcomings of inverse synthetic aperture radar (ISAR) imaging in target recognition, a three-dimensional (3-D) interferometric ISAR (InISAR) imaging technique is developed. The traditional InISAR imaging with three antennas usually assumes that the baselines are orthogonal to each other and the target moves steadily. However, in practical applications, due to the existence of system error and the unknown moving condition of the noncooperative targets, the baselines used for interference are difficult to be absolutely orthogonal and the movement of the target also tends to be complicated. In this article, a practical maneuvering target 3-D imaging algorithm based on the InISAR of an arbitrary three-antenna configuration is investigated. The main contributions of this article are as follows: 1) abstracted from an actual application scenario, a three-antenna InISAR system model with the baselines being nonorthogonal is established; 2) a joint translational motion compensation strategy, involving a joint accumulated cross correlation method for the envelope alignment and a joint Doppler centroid-tracking approach for the phase correction, is devised for the image coregistration in the range dimension; 3) a complicated movement model of the maneuvering target is described, and a fast high-resolution ISAR imaging algorithm maximum likelihood (ML)-fractional Fourier transform (FRFT), which incorporates the ML with the FRFT, is proposed; and 4) a coordinate correction technique is developed to eliminate the distortion of the 3-D image caused by the nonorthogonality of baselines. The effectiveness and performance of the proposed algorithm are evaluated by several simulations at the last of the article.