Source Localization for Constant Modulus Signals Using a Structured Matrix Recovery Technique (SMART)

We study the source localization problem for constant modulus (CM) signal using a uniform linear array. Existing results on parameter identifiability show that the maximum number of CM signal sources that can be uniquely localized can exceed the number of sensors, but a practical algorithm is still lacking so far. In this paper, we propose a structured matrix recovery technique (SMART) for CM signal source localization. In particular, the source localization problem is cast as a rank-constrained Hankel-Toeplitz matrix-based feasibility problem, in which signal structures are fully exploited. The alternating direction method of multipliers (ADMM) algorithm is applied to solve the resulting rank-constrained problem and the sources are uniquely retrieved from the numerical solution. Numerical results demonstrate that the proposed SMART can localize more sources than sensors.