Multipath effects cancellation in ISAR image reconstruction

When radar illuminates targets at low elevation angles, radar returns will change due to multipath interference. For inverse synthetic aperture radar (ISAR), the multipath effects introduce two artifacts in its reconstructed images, which greatly hinder radar target recognition and classification. A novel technique requiring no apriori knowledge of target motion parameters is developed in this paper for multipath effects cancellation in ISAR image reconstruction. This technique is based on a parametric estimation method using two-dimensional image entropy as its cost function and realized via simulated annealing (SA) algorithm to search the optimum parameters corresponding to the minimum image entropy. Simulation results shows encouraging qualities of ISAR images after multipath effects cancellation, which also confirms the feasibility of this technique.