RIS-Enabled Spoofing Against Adversary Sensing: CRB-Maximizing Design and Decoying Analysis

TL;DR

This paper demonstrates how a Reconfigurable Intelligent Surface (RIS) can be designed to deceive adversary radar by creating nulls at the true target angle and decoys elsewhere, enhancing stealth capabilities.

Contribution

It introduces a compact RIS kernel model linking radar response to RIS phase, enabling analytical spoofing design and robust decoying strategies against adversary sensing.

Findings

Deep nulls achieved at true reflection AoA

Pronounced decoy peaks created for deception

Maximum-likelihood radar sensing becomes unreliable

Abstract

This paper studies the capability of a Reconfigurable Intelligent Surface (RIS), when transparently covering a User Equipment (UE), to deceive an adversary monostatic radar system. A compact RIS kernel model that explicitly links the radar's angular response to the RIS phase profile is introduced, enabling an analytical investigation of the Angle of Arrival (AoA) estimation accuracy with respect to the kernel's power. This model is also leveraged to formulate an RIS-based spoofing design with the dual objective to enforce strict nulls around the UE's true reflection AoA and maximize the channel gain towards a decoy direction. The RIS's deception capability is quantified using point-wise and angle-range robust criteria, and a configuration-independent placement score guiding decoy selection is proposed. Selected numerical results confirm deep nulls at the true reflection AoA together with a pronounced decoy peak, rendering maximum-likelihood sensing at the adversary radar unreliable.