Low sidelobe robust imaging in random frequency-hopping wideband radar based on compressed sensing

LIU Zhen(刘振), WEI Xi-zhang(魏玺章), LI Xiang(黎湘)

(School of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China)

Abstract:High resolution range imaging with correlation processing suffers from high sidelobe pedestal in random frequency-hopping wideband radar. After the factors which affect the sidelobe pedestal being analyzed, a compressed sensing based algorithm for high resolution range imaging and a new minimized l₁-norm criterion for motion compensation are proposed. The random hopping of the transmitted carrier frequency is converted to restricted isometry property of the observing matrix. Then practical problems of imaging model solution and signal parameter design are resolved. Due to the particularity of the proposed algorithm, two new indicators of range profile, i.e., average signal to sidelobe ratio and local similarity, are defined. The chamber measured data are adopted to testify the validity of the proposed algorithm, and simulations are performed to analyze the precision of velocity measurement as well as the performance of motion compensation. The simulation results show that the proposed algorithm has such advantages as high precision velocity measurement, low sidelobe and short period imaging, which ensure robust imaging for moving targets when signal-to-noise ratio is above 10 dB.

Key words:random frequency-hopping radar; high resolution range profile; sidelobe suppression; motion compensation; compressed sensing