[论文解读] Resolution-Aliasing Trade-off in Near-Field Localisation

Baptiste Sambon, Gilles Monnoyer+2 more|arXiv (Cornell University)|Feb 2, 2026

Electromagnetic Compatibility and Measurements被引用 0

一句话总结

这篇论文提出一个统一的基于啁啾的框架，以联合表征 XL-MIMO 的近场定位中的分辨率与混叠，提出几何工具来分析权衡并指导 NF 阵列设计。

ABSTRACT

Extremely Large-scale MIMO (XL-MIMO) systems operating in Near-Field (NF) introduce new degrees of freedom for accurate source localisation, but make dense arrays impractical. Sparse or distributed arrays can reduce hardware complexity while maintaining high resolution, yet sub-Nyquist spatial sampling introduces aliasing artefacts in the localisation ambiguity function. This paper presents a unified framework to jointly characterise resolution and aliasing in NF localisation and study the trade-off between the two. Leveraging the concept of local chirp spatial frequency, we derive analytical expressions linking array geometry and sampling density to the spatial bandwidth of the received field. We introduce two geometric tools--Critical Antenna Elements (CAEs) and the Non-Contributive Zone (NCZ)--to intuitively identify how individual antennas contribute to resolution and/or aliasing. Our analysis reveals that resolution and aliasing are not always strictly coupled, e.g., increasing the array aperture can improve resolution without necessarily aggravating aliasing. These results provide practical guidelines for designing NF arrays that optimally balance resolution and aliasing, supporting efficient XL-MIMO deployment.

研究动机与目标

• Motivate near-field localisation with XL-MIMO and the need to balance resolution with aliasing under sparse or distributed arrays.
• Develop a unified framework to jointly characterize localisation resolution and aliasing in near-field scenarios.
• Introduce geometric tools (Critical Antenna Elements and Non-Contributive Zone) to interpret how array geometry affects resolution and aliasing.
• Provide design guidelines for NF arrays that optimize the resolution-aliasing trade-off.
• Extend understanding beyond one-dimensional analyses to multidimensional array configurations.

提出的方法

• Extend the chirp-based framework to multidimensional arrays to relate array geometry and sampling density to the spatial bandwidth of the received field.
• Define local spatial frequency as the gradient of the phase of the received field to capture the near-field chirp behaviour.
• Derive closed-form expressions for maximum and minimum spatial frequencies to determine the spatial bandwidth along each axis.
• Define the Aliasing-Free Region as the intersection of directional AFRs and show how it maps to aliasing conditions.
• Introduce Non-Contributive Zone and Critical Antenna Elements to connect array geometry with resolution and aliasing.
• Analyse resolution via the relation delta xi = 2pi / Bi and link Bi to the H spectrum of the received field.

实验结果

研究问题

• RQ1 How do array geometry and sub-Nyquist spatial sampling affect resolution and aliasing in near-field localisation?
• RQ2 Can a unified chirp-based framework jointly characterize resolution and aliasing for multidimensional NF arrays?
• RQ3 What array-design insights (e.g., CAEs and NCZ) help balance resolution and aliasing in NF localisation?
• RQ4 How can we extend Aliasing-Free Region concepts to rectangular and circular array geometries?

主要发现

• Increasing aperture can improve resolution without necessarily increasing aliasing.
• Aliasing-free conditions can be defined beyond Nyquist and depend on the maximum local spatial frequency across the array.
• Two geometric tools, CAEs and NCZ, offer intuitive identification of antennas contributing to resolution and/or aliasing.
• The framework extends to multidimensional arrays and provides design guidelines for NF antenna configurations.
• Rectangular and circular array analyses illustrate how geometry affects the resolution-aliasing trade-off.