Micro-doppler feature extraction for wideband imaging radar based on complex image orthogonal matching pursuit decomposition

The micro-Doppler (m-D) features induced by targets with micro-motions provide important information for automatic radar target recognition. In this study, the m-D effect induced by rotational micro-motion in wideband radar is analysed, and an algorithm for the extraction of these m-D features is proposed. By making use of the amplitude and phase information of `range-slow-time image´, a dictionary with m-D signal atoms is constructed in the complex image space. The orthogonal matching pursuit algorithm in vector space is then extended to the complex image space to decompose the range-slow-time image and to extract the m-D features of the target. The proposed algorithm can extract the m-D features in the presence of migration through range cells of micro-motional scatterers, and can also work well when the sampling rate in slow-time domain is lower than the Nyquist sampling rate. Simulations are given to validate the effectiveness and robustness of the proposed method.