mmMirror: Device Free mmWave Indoor NLoS Localization Using Van-Atta-Array IRS

2025-05-16

AI Summary

To address collision risks in Industry 4.0 human–machine collaboration scenarios—particularly under non-line-of-sight (NLoS) conditions (e.g., corner occlusions) where vision, LiDAR, or conventional RF localization fails—this work proposes a Van Atta-based, reconfigurable intelligent reflecting surface (IRS) operating at millimeter-wave frequencies, compatible with FMCW radar. The method integrates RF image reflection principles, dynamic multi-target beamforming, and time-slot-adaptive scanning to achieve passive, high-precision NLoS localization. Experimental validation using a commercial 24 GHz FMCW radar and a PCB-based IRS prototype demonstrates centimeter-level accuracy within a 3-meter range, supporting multi-radar coordination and real-time multi-target tracking. Key contributions are: (1) the first Van Atta-type IRS architecture designed specifically for FMCW radar; (2) an NLoS sensing paradigm that requires no active terminals and operates without direct-path signals; and (3) a lightweight, accurate, robust, and practically deployable solution.

Technology Category

• Intelligent Robots: Localization, Mapping, and Navigation
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Hardware-aware ML

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Search and Retrieval-Augmented AI: Vertical and domain-specific search

Abstract

Industry 4.0 is transforming manufacturing and logistics by integrating robots into shared human environments, such as factories, warehouses, and healthcare facilities. However, the risk of human-robot collisions, especially in Non-Line-of-Sight (NLoS) scenarios like around corners, remains a critical challenge. Existing solutions, such as vision-based and LiDAR systems, often fail under occlusion, lighting constraints, or privacy concerns, while RF-based systems are limited by range and accuracy. To address these limitations, we propose mmMirror, a novel system leveraging a Van Atta Array-based millimeter-wave (mmWave) reconfigurable intelligent reflecting surface (IRS) for precise, device-free NLoS localization. mmMirror integrates seamlessly with existing frequency-modulated continuous-wave (FMCW) radars and offers: (i) robust NLoS localization with centimeter-level accuracy at ranges up to 3 m, (ii) seamless uplink and downlink communication between radar and IRS, (iii) support for multi-radar and multi-target scenarios via dynamic beam steering, and (iv) reduced scanning latency through adaptive time slot allocation. Implemented using commodity 24 GHz radars and a PCB-based IRS prototype, mmMirror demonstrates its potential in enabling safe human-robot interactions in dynamic and complex environments.

Problem

• Enables precise device-free NLoS localization for human-robot safety
• Overcomes occlusion and privacy limitations of vision/LiDAR systems
• Uses mmWave IRS for cm-level accuracy in dynamic environments

Innovation

• Van Atta Array mmWave IRS for NLoS localization
• FMCW radar integration with centimeter accuracy
• Dynamic beam steering for multi-target scenarios