Power Allocation for Aerial RIS-assisted Jamming Nodes in Distributed MIMO Radar Networks

In the current rapid development of sensing systems, ensuring system security has become increasingly important. Reconfigurable Intelligent Surface (RIS) has shown potential in jamming radar localization due to their adaptive capability in reconfiguring wireless environments. In this paper, a novel jamming strategy is considered for the distributed MIMO radar system, in which the contribution of the RIS is to change the signal propagation environment to degrade radar localization performance. Firstly, we derive the Cramér-Rao lower bound (CRLB) as the performance metric. Subsequently, a joint optimization problem of RIS phase design and jamming power allocation is formulated with the aim of maximizing the minimum CRLB for locating UAV targets. On this basis, we propose a two-step-based approach to solve this non-convex problem of joint optimization. In the first step, the RIS phase design problem is addressed with semi-definite programming (SDP) and Gaussian randomization techniques. In the second step, an analytical solution for power optimization is obtained by employing the Lagrange multiplier method. Simulation results show the superior performance of the proposed strategy and verify the theoretical findings.