RIS-Enabled Passive Radar towards Target Localization

TL;DR

This paper explores how reconfigurable intelligent surfaces can enhance passive radar systems for target localization within integrated sensing and communication environments, addressing challenges of limited information and unknown targets.

Contribution

It introduces optimization techniques for RIS phase shifter updates and proposes joint estimation methods for target detection and localization in complex scenarios.

Findings

RIS improves target localization accuracy

Proposed methods outperform no-RIS baseline

Effective joint estimation with limited information

Abstract

In this paper, we study a communication-centric integrated sensing and communication (ISAC) approach, where an access point (AP) communicates with users, while a passive radar (PR) is present in the environment. We investigate the deployment of a reconfigurable intelligent surface (RIS) to enable the PR to localize a target. We derive an optimization problem for updating the phase shifters of the RIS per epoch. Due to the limited information at the PR, such as unknown payload information and unknown number of targets in the scene, we propose two methods capable of performing joint angle of arrival estimation and detection of the targets. We demonstrate the superior performance of the methods onto the proposed setting through numerical simulations, in comparison to a no-RIS baseline scheme.