摘要

The high range resolution profile (HRRP) can be reconstructed by combining frequency bands coherently for inverse synthetic aperture radar (ISAR) imaging of a moving target in stepped-frequency (SF) radar systems. However, the range migration and phase errors among sub-pulses in a pulse train caused by the target translational motion results in difficulty for HRRP synthesis of SF sub-pulses. In order to compensate the translational motion for SF ISAR imaging, a novel method based on adjacent pulses correlation integration and coherent processing is proposed in this study. Firstly, the radial motion parameters can be estimated by the adjacent pulses correlation integration for the range echo envelope in a pulse train. Owing to strong coherence between two adjacent pulses, the correlation integration achieves high gain of signal-to-noise ratio. It is robust to noise ensuring precise estimation of translational motion. Secondly, after compensating the phase errors, the HRRP can be reconstructed by the combination of frequency bands coherently and the inverse Fourier transform. Finally, a nice ISAR image of a moving target can be obtained by conventional range-Doppler algorithm (RDA). In the end, simulated and real data are used to demonstrate the good performance of the method proposed in this study.