High-resolution forward-looking MIMO-SAR imaging approach for automotive mmwave radar

Leveraging the widespread applications of Synthetic Aperture Radar (SAR) imaging technology and Multiple Input Multiple Output (MIMO) arrays in millimeter wave radar, it is now possible to obtain high-resolution forward-looking (FL) images. Forward-Looking Multiple-Input Multiple-Output Synthetic Aperture Radar (FL-MIMO-SAR) represents the state-of-the-art technology for achieving high-resolution imaging of the area in front of a vehicle. This advanced imaging capability is crucial for numerous applications, including autonomous driving, advanced driver assistance systems (ADAS), as well as surveillance and reconnaissance. However, traditional forward-looking synthetic aperture radar is characterized by a left-right ambiguity problem, while MIMO array real aperture imaging struggles with low resolution in side-view regions. To address these challenges, this paper proposes a joint imaging method for FL-MIMOSAR. This method utilizes MIMO arrays to resolve the left-right ambiguity problem, achieving high-resolution imaging in the forward-looking region. In the squint region, higher resolution can be obtained by synthetic aperture processing because the length of the synthetic aperture is usually larger than the actual aperture. Furthermore, this paper thoroughly analyzes the amplitude and phase errors of MIMO arrays and their impact on imaging, proposing an effective calibration method to address these issues. Finally, the effectiveness of the proposed algorithm is validated through experiments with real measurement data.