A Fast ISAR Imaging Method for Rapidly Spinning Targets using Pseudo-Polar Coordinate in Range-Doppler Domain

Designing an efficient imaging approach is one key unsolved issue faced by inverse synthetic aperture radar (ISAR) imaging for spinning targets. In this paper, a fast ISAR imaging method based using pseudo-polar coordinate system in Range-Doppler (RD) domain is developed to solve this issue. First, a precise analytic expression is derived in RD domain utilizing the principle of stationary phase (POSP). Based on that, with a novel interpolation kernel function, the well-focused ISAR image for spinning target is sampled using a pseudo-polar grid. After that, the interpolation-free Stolt mapping algorithm is adopted to further reduce the computational complexity. Compared with the available imaging methods, the proposed method has advantages in computational cost and low signal-to-noise ratios (SNR) environment due to avoiding the multi-dimension searching operation and utilizing the two-dimensional (2-D) coherent integrated gain. Finally, the simulations are provided to verify the correctness of the proposed algorithm.