Reducing micro-Doppler effect in compressed sensing ISAR imaging for aircraft using limited pulses

In compressed sensing (CS)-based inverse synthetic aperture radar (ISAR) imaging for aircraft, the image of the target can be reconstructed using fewer pulses with random pulse repetition intervals than with the conventional range-Doppler (RD) method. However, the micro-Doppler (mD) effect induced by the non-stationary parts of aircraft still causes defocusing as in RD imaging. A method is proposed to reduce the mD effect in CS ISAR imaging. The CS-based short-time Fourier transform is deployed to reconstruct the time-frequency (TF) spectrogram of echoes. An L-statistics-based algorithm is applied to separate the non-stationary scatterers from a rigid main body in the TF domain. Furthermore, the CS algorithm is used to reconstruct the cross-range image of the main body after mD separation. Compared with direct CS imaging without mD removal, a better image can be obtained. The results of both simulated and real data processing demonstrate the validity of the proposed method.