基于联合稀疏恢复的可编程超表面离网格DOA估计方法

      Off-Grid DOA estimation method based on joint sparse recovery using programmable metasurface

      • 摘要: 波达方向(direction of arrival, DOA)估计是阵列信号处理的关键技术。基于可编程超表面的DOA估计方法能够在单通道接收架构下有效降低系统硬件成本与实现复杂度,但现有方法通常依赖空间角度离散化建模,其性能易受网格失配问题的制约。针对上述问题,本文提出了基于联合稀疏恢复的可编程超表面离网格DOA估计方法。首先,基于一阶泰勒展开构建同时包含网格项与导数项的联合过完备字典,建立联合DOA估计模型,从而实现对离网格误差的显式建模与校正。进一步地,为降低联合模型在二维场景下的计算与存储开销,提出了基于Kronecker分解的模型简化方法,将高维运算转化为低维矩阵运算。在此基础上,分别设计了联合正交匹配追踪(joint orthogonal matching pursuit, JOMP)算法及其基于Kronecker分解的高效实现算法(KJOMP)用于模型求解。仿真与实测结果表明,在单目标与多目标、不同超表面规模、编码次数及信噪比条件下,所提JOMP算法在一维和二维DOA估计精度方面均表现出优于传统网格化方法的估计性能;KJOMP算法在保持与JOMP算法估计精度基本一致的同时,运行时间和空间复杂度大幅下降。本文方法在雷达、物联网、6G通信、定位导航及无人机等应用场景中具有良好的应用潜力。

         

        Abstract: Direction-of-arrival (DOA) estimation is a fundamental technique in array signal processing. DOA estimation methods based on programmable metasurfaces enable single-channel reception architectures, significantly reducing system cost and hardware complexity. However, most existing approaches rely on spatial discretization, and their performance is severely degraded by grid mismatch errors. To address this issue, this paper proposes an off-grid DOA estimation method for programmable metasurfaces based on joint sparse recovery. By employing a first-order Taylor expansion, a joint overcomplete dictionary incorporating both grid terms and derivative terms is constructed, enabling explicit modeling and correction of off-grid errors. Furthermore, to reduce the computational and storage complexity of the joint model in two-dimensional scenarios, a Kronecker-decomposition-based model simplification strategy is introduced, transforming high-dimensional operations into low-dimensional matrix computations. Based on the formulated models, a joint orthogonal matching pursuit (JOMP) algorithm and its Kronecker-based efficient implementation (KJOMP) are developed. Simulation and experimental results demonstrate that the proposed JOMP algorithm achieves significantly improved DOA estimation accuracy in both one-dimensional and two-dimensional scenarios under various metasurface sizes and signal-to-noise ratios. While maintaining estimation accuracy comparable to that of the JOMP algorithm, the KJOMP algorithm achieves significant reductions in both computational time and spatial complexity. The proposed method is well suited for applications in radar, Internet of Things (IoT), sixth-generation (6G) communications, positioning, navigation, and unmanned aerial vehicles.

         

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