Three-Dimensional Interferometric ISAR Sensors Imaging for the Ship Target with Two-Dimensional Sparsity

There are great challenges for traditional three-dimensional (3-D) interferometric inverse synthetic aperture radar (InISAR) imaging algorithms of ship targets with 2-D sparsity in actual radar imaging system. To deal with this problem, a novel 3-D InISAR imaging method is proposed in this paper. First, the high-precision gradient adaptive algorithm was adopted to reconstruct the echoes in range dimension. Then the method of minimizing the entropy of the average range profile was applied to estimate the parameters which are used to compensate translation components of the received echoes. Besides, the phase adjustment and image coregistration of the sparse echoes were achieved at the same time through the approach of the joint phase autofocus. Finally, the 3-D geometry coordinates of the ship target with 2-D sparsity were reconstructed by combining the range measurement and interferometric processing of the ISAR images. Simulation experiments were carried out to verify the practicability and effectiveness of the algorithm in the case that the received echoes are in 2-D sparsity.