An Algorithm for ISAR Ship Imaging Based on S-Distribution

Under the sea wave, ship target experiences three-dimensional rotations and its echo Doppler frequency changes complexly. In order to improve the quality of ship image, a new algorithm based on S-distribution is proposed. The instantaneous ISAR image can be obtained by calculating the S-distribution of each range bin. In comparison with the classical time frequency distribution, S-distribution produces high concentration at the instantaneous frequency for arbitrary signals, its cross-term interference can be easily removed by recursive method, and its calculation is effective. The simulation results demonstrate the effectiveness of this imaging method.