High Resolution DOA Estimation of Coherent Distributed Millimeter-Wave Radar

Achieving high angular resolution estimation is essential for enhancing environmental perception and accurately detecting extended targets. However, implementing a large aperture radar system as a single sensor faces significant technical and economic challenges. Radar networks, comprising multiple individual radar sensors, offer a promising solution to these obstacles. In this article, we propose a method for high resolution direction-of-arrival (DOA) estimation tailored for coherent distributed millimeter-wave radar systems. Our approach leverages multiple-input multiple-output technology and distributed arrays to construct a virtual sparse array capable of synthesizing a full uniform array covariance matrix through specific correlation transformation. Furthermore, we introduce a joint optimization method for directly angle finding that efficiently addresses large-scale optimization problems by exploiting both sparsity and low-rank properties, thereby circumventing the traditional sequential steps of matrix reconstruction and DOA estimation. We employ the alternating direction method of multipliers to ensure reliable convergence. Our proposed model and method have been extensively validated through comprehensive simulations, highlighting their advantages within the realm of distributed radar systems.