Imaging and micro-Doppler analysis of vibrating target in multi-input–multi-output synthetic aperture radar

The micro-Doppler (m-D) signature induced by the micro-motion dynamics of a component or structure on a radar target can provide additional information for classification, recognition, and identification of the object. Since the m-D signature from conventional synthetic aperture radar (SAR) is insufficient for further application, attention centred on multi-input-multi-output (MIMO) SAR. MIMO SAR employs diversity to improve SAR performance and shows great potential in applications including high-resolution wide-swath remote sensing, slow moving target detection, and three-dimensional (3D) imaging. Take vibration for research, because vibration is a basic kind of micro-motion and it occurs commonly such as vehicle engine. In this study, the vibration signal modelling is deduced and the m-D signature of vibrating target is analysed, based on short-term shift-orthogonal waveform in MIMO SAR. Simulations verify the influence of vibration parameters on imaging and time-frequency profile and show the m-D signature difference through different MIMO channels. The results demonstrate the potential of MIMO SAR for 3D micro-motion estimation.