This paper investigates the potential of near-field localization using widely-spaced multi-subarrays (WSMSs) and analyzing the corresponding angle and range Cram\'er-Rao bounds (CRBs). By employing the Riemann sum, closed-form CRB expressions are derived for the spherical wavefront-based WSMS (SW-WSMS). We find that the CRBs can be characterized by the angular span formed by the line connecting the array's two ends to the target, and the different WSMSs with same angular spans but different number of subarrays have identical normalized CRBs. We provide a theoretical proof that, in certain scenarios, the CRB of WSMSs is smaller than that of uniform arrays. We further yield the closed-form CRBs for the hybrid spherical and planar wavefront-based WSMS (HSPW-WSMS), and its components can be seen as decompositions of the parameters from the CRBs for the SW-WSMS. Simulations are conducted to validate the accuracy of the derived closed-form CRBs and provide further insights into various system characteristics. Basically, this paper underscores the high resolution of utilizing WSMS for localization, reinforces the validity of adopting the HSPW assumption, and, considering its applications in communications, indicates a promising outlook for integrated sensing and communications based on HSPW-WSMSs.

翻译：本文研究了采用宽间距多子阵（WSMS）实现近场定位的潜力，并分析了相应的角度和距离克拉美-罗界（CRB）。通过应用黎曼和，推导了基于球面波前的WSMS（SW-WSMS）的闭式CRB表达式。研究发现，CRB可由阵列两端与目标连线所构成的角跨度表征，不同子阵数量但角跨度相同的WSMS具有相同的归一化CRB。本文从理论上证明，在特定场景下WSMS的CRB小于均匀阵列的CRB。进一步给出了基于混合球面与平面波前WSMS（HSPW-WSMS）的闭式CRB，其组成部分可视为SW-WSMS对应CRB参数的分解。仿真实验验证了所推导闭式CRB的准确性，并揭示了多种系统特性。本质上，本文凸显了WSMS在定位应用中的高分辨率优势，验证了采用HSPW假设的合理性，并考虑到其在通信中的应用，为基于HSPW-WSMS的集成感知与通信系统展现了良好的应用前景。