Low Complexity Compensation for Range-Angle Migration in High-Resolution MIMO Radar Systems

Abstract

High angular resolution is essential for fine images in modern radar applications, which typically requires a large virtual antenna array. However, such large arrays give rise to near-field effects, necessitating wavefront-curvature compensation and consequently increasing computational complexity. In this paper, we propose a low-complexity two-stage sensing method that accounts for wavefront curvature in multiple-input multiple-output (MIMO) radar systems. In the first stage, the range response and coarse angle spectrum are generated using a subset of antenna elements under the far-field approximation, enabling wavefront-curvature estimation. In the second stage, the estimated wavefront curvature is used for range migration compensation by shifting the range response and for angle migration compensation by multiplying by the complex conjugate of the second- and higher-order phase terms induced by the wavefront curvature. Subsequently, a range-angle response is generated using Dirichlet-kernel interpolation and the chirp Z-transform. Experimental results demonstrate that the proposed method improves the range and angle resolutions by 60% and 42%, respectively, resulting in a 5.77 dB processing gain in the range-angle response. Furthermore, the proposed method reduces the computation time by a factor of 1.94 compared with the zero-padded FFT for range-angle response generation. These results confirm that the proposed method provides high sensing performance with reduced processing time in MIMO radar system