High-Resolution Forward-Looking MIMO-SAR Imaging using Automotive Mmwave Radar

Forward-looking multi-input multi-output synthetic aperture radar (FL-MIMO-SAR) is the state-of-the-art technique to achieve the high-resolution image of the front area. However, the performance of FL-MIMO-SAR is primary limited by left-right Doppler ambiguity resolution. To address this issue, a novel space-time cascade imaging framework is proposed. Concretely, the Doppler-division multiplexing MIMO (DDM-MIMO) scheme is adopted to achieve the waveform orthogonality and the back-projection (BP) time-domain algorithm is applied to obtain high-resolution SAR images. Furthermore, the effect of array errors is analyzed and calibrated, which is essential for subsequent Doppler ambiguity resolution using the linearly constrained minimum variance (LCMV) beamforming. Finally, experimental analysis is performed to confirm the effectiveness of the proposal.