Translational Motion Compensation Techniques in ISAR Imaging for Target with Micro-Motion Parts

In inverse synthetic aperture radar (ISAR) imaging, micro-motion structures on the target will induce additional time-varying frequency modulations to the radar echoes. Due to the disturbance of these mechanical vibration or rotation parts, it will be difficult to obtain a well-focused ISAR image of the target using conventional translational motion compensation methods. To solve this problem, two improved translational motion compensation techniques have been proposed in this paper. Firstly, the power transform is used in the range bin alignment processing to depress the disturbance of the micromotion parts. Then, an improved autofocusing methods based on range bins selection is presented, which only uses the range bins of the radar returns from the main body scatterers for the phase adjustment. The imaging results from the measured data are given to verify the validity of the improved translational motion compensation techniques proposed in this paper.