Bistatic ISAR Imaging for Maneuvering Target With Complex Motion Based on Phase Retrieval-Assisted ICBA

Compared with monostatic inverse synthetic aperture radar (ISAR), bistatic ISAR (Bi-ISAR) avoids the problem of a limited version for geometric imaging and can obtain more target motion information. However, the complex motion of maneuvering target makes the imaging projection plane (IPP) change continuously, causing 2-D spatial-variant phase errors. To tackle this issue, we propose a bistatic ISAR imaging algorithm based on phase retrieval-assisted image contrast-based focusing algorithm (ICBA). First, this article establishes the signal model of the bistatic 3-D non-uniformly rotating target and analyzes each phase error term. Then, the ICBA algorithm performs phase coarse compensation by estimating velocity and acceleration. Finally, without parameter estimation and signal modeling, the phase retrieval (PR) algorithm can achieve the compensation of 2-D spatial-variant phase errors. The aperture function is utilized to sample the spectrum traversal, recording the low-resolution intensity information in the spatial domain. Alternating iterations with the mapping relation in the frequency domain are used to perform the spectrum reconstruction. Simulation results are conducted with scattering point data and electromagnetic data, and the superiority and robustness of the algorithm are presented in the experimental results.