Dynamic ISAR Imaging of Maneuvering Targets Based on Sequential SL0

For maneuvering targets, the time-varying Doppler shifts will produce blurred inverse synthetic aperture radar (ISAR) images for a long coherent processing interval (CPI). By exploiting sparsity of the target scene, sparse recovery (SR) algorithms have been applied to achieve high cross-range resolution within a short CPI, during which the Doppler shifts nearly remain constant. For practical applications, however, the required pulse number for attaining an acceptable image is difficult to designate in various scenarios, and the common recovery procedure suffers from low efficiency because of having to solve a new SR problem from scratch when the new echo pulses are sequentially available. In this letter, we present a dynamic ISAR imaging algorithm based on sequential smoothed L0, which is proposed as an efficient recursive implementation of the SR approach. Furthermore, by defining the proper stopping rules, we can seek the optimal pulse number required in each CPI. Simulation results show that the proposed dynamic algorithm is more suitable for ISAR imaging of uncooperative targets.