Rapid advancement of antenna technology catalyses the popularization of extremely large-scale multiple-input multiple-output (XL-MIMO) antenna arrays, which pose unique challenges for localization with the inescapable near-field effect. In this paper, we propose an efficient near-field localization algorithm by leveraging a sectored uniform circular array (sUCA). In particular, we first customize a backprojection algorithm in the polar coordinate for sUCA-enabled near-field localization, which facilitates the target detection procedure. We then analyze the resolutions in both angular and distance domains via deriving the interval of zero-crossing points, and further unravel the minimum required number of antennas to eliminate grating lobes. The proposed localization method is finally implemented using fast Fourier transform (FFT) to reduce computational complexity. Simulation results verify the resolution analysis and demonstrate that the proposed method remarkably outperforms conventional localization algorithms in terms of localization accuracy. Moreover, the low-complexity FFT implementation achieves an average runtime that is hundreds of times faster when large numbers of antenna elements are employed.

翻译：天线技术的飞速发展推动了超大规模多输入多输出（XL-MIMO）天线阵列的普及，这给不可避免的近场效应下的定位带来了独特挑战。本文提出了一种利用扇形均匀圆阵（sUCA）的高效近场定位算法。具体而言，我们首先针对sUCA近场定位，定制了一种极坐标系下的反投影算法，以促进目标检测过程。随后，通过推导过零点间隔，分别分析了角度域和距离域的分辨率，并进一步揭示了消除栅瓣所需的最小天线数量。最终，采用快速傅里叶变换（FFT）实现所提出的定位方法，以降低计算复杂度。仿真结果验证了分辨率分析，并表明所提方法在定位精度上显著优于传统定位算法。此外，低复杂度的FFT实现在大规模天线单元部署下，平均运行速度提升数百倍。