A method for extracting micro-motion feature of target with rotating parts based on Bi-ISAR system

If the target or any structure on the target undergoes micro-motion dynamics, such as mechanical vibrations or rotations, it will induce Doppler frequency modulation on the returned signal that generates sidebands about the target´s Doppler frequency, which is referred to as the micro-Doppler effect. The micro-Doppler signatures enable certain properties of the target to be determined that may be used for target recognition. In this paper, taking the Micro-Doppler effect caused by the rotation of target in Bi-static inverse synthetic aperture radar (Bi-ISAR) system as example, a novel extraction method of the micro-motion feature is presented. With the proposed method, the micro-motion parameters of the target can be detected rapidly from the spectrogram and the computational efficiency can be enhanced compared with that of the modified extended Hough transform. A computer simulation is given to illustrate the effectiveness of the proposed method.