INITIALIZATION-FREE IMPLICIT-FOCUSING (IF2) FOR WIDEBAND DIRECTION-OF-ARRIVAL ESTIMATION

This paper proposes a novel method to focus or align array manifolds at different frequencies to a single reference frequency in wideband Direction of Arrival (DOA) estimation.Unlike existing methods, our focusing can be performed without explicitly constructing focusing matrices, or requiring any pre-liminary DOA estimates. Instead the focusing is done implicitly by obtaining focused measurements as the solution to a rank minimization procedure. This paper also provides theoretical guarantees for exact focusing via rank minimization. We call this procedure Initialization-Free Implicit-Focusing (IF2). Numerical simulations are provided to demonstrate the resilience of IF2 in various SNR regimes compared to past and recent wideband DOA recovery methods, and its lack of error saturation in highSNR regimes.