Method for bistatic ISAR one-dimensional range profile based on sparse decomposition

In bistatic Inverse Synthetic Aperture Radar (ISAR), resolution of one-dimensional range profile is restricted not only by transmission signal bandwidth but also by imaging bistatic angle, which result in the bistatic ISAR range profile resolution far lower than monostatic ISAR with the same transmission signal bandwidth. To resolve the range profile resolution decline problem caused by imaging bistatic angle, a method for range profile creation is presented based on the analysis of sparse characteristic of target baseband echo signal. The sparse decomposition coefficients of target baseband signal in the according redundant basis are used to create the one-dimensional range profile. If the equivalent time-delay cell used for the construction of sparse decomposition redundant basis is shorter, the range profile resolution is higher. Base on this idea, the time-delay cell proportional to half bistatic angle cosine and inverse proportional to transmission signal bandwidth is created. Then the redundant basis is constructed via this time-delay cell. And the extended generalization FOCUSS (Focal Underdetermined System Solver) algorithm is used to estimate the sparse decomposition coefficients of baseband echo signal. Finally, one-dimensional range profile immune to bistatic-angle-influnence is created by the sparse coefficients. Simulation experiment of space target with ideal scatters validates the algorithm.