Multiorder Phase Error Compensation for High-Resolution MIMO Radar Imaging System

Abstract

High-resolution multiple input multiple output (MIMO) radar imaging systems utilize virtual aperture synthesis via multichannel configurations to achieve rapid electronic scanning and high frame rate monitoring. However, such architectures are highly susceptible to channel inconsistencies including gain phase mismatches and transmit–receive coupling which manifest as amplitude drifts and phase distortions. These impairments degrade virtual aperture equivalence, leading to severe image defocusing and artifacts. To mitigate these degradations, this article proposes a multiorder phase error compensation (MOPEC) method. The core of MOPEC lies in a hierarchical framework that deconstructs residual phase errors into low-order components (primarily inducing azimuth defocusing) and high-order components (impairing range focus). Specifically, a parameter-based estimation strategy is developed to rectify low-order errors, while a tailored autofocus-based correction scheme is integrated to adaptively compensate for high-order distortions. By decoupling and addressing these multiorder errors sequentially, the proposed method ensures robust image reconstruction even in the presence of strong channel coupling. Experimental results using real-world measurement data demonstrate that the MOPEC method substantially improves focusing accuracy and suppresses image artifacts, outperforming conventional calibration techniques in both precision and reliability.