RIS-Aided Cooperative ISAC Network for Imaging-Based Low-Altitude Surveillance

TL;DR

This paper introduces a RIS-aided cooperative ISAC network for low-altitude surveillance, utilizing active RIS and compressed sensing to improve imaging and detection performance at low altitudes.

Contribution

It proposes a novel RIS-assisted low-altitude imaging system with active RIS and compressed sensing, providing theoretical analysis and practical performance evaluation.

Findings

ARIS outperforms passive RIS in imaging quality

Effective target detection up to 300 meters altitude

Derived CRLB for system performance analysis

Abstract

The low-altitude economy is integral to the advancement of numerous sectors, necessitating the development of advanced low-altitude surveillance techniques. Nevertheless, conventional methods encounter limitations of high deployment costs and low signal strength. This study proposes a reconfigurable intelligent surface (RIS)-aided cooperative integrated sensing and communication (ISAC) network for low-altitude surveillance. This network employs RISs to reflect ISAC signals into low-altitude space for sensing. To enhance signal strength, we employ active RIS (ARIS) to amplify the signals. Moreover, in order to avoid error propagation and data association in traditional sensing methods, we model low-altitude surveillance as an imaging problem based on compressed sensing theory, which can be solved through the subspace pursuit algorithm. We derive the Cramer-Rao lower bound (CRLB) of the proposed RIS-aided low-altitude imaging system and analyze the impacts of various system parameters on sensing performance, providing guidance for ISAC system configuration. Numerical results show that ARIS outperforms passive RIS under identical power constraints, achieving effective imaging and target detection at altitudes up to 300 meters.