A resolution measure for the MUSIC algorithm and its application to plane wave arrivals contaminated by coherent interference

The authors present a deterministic approach to the resolution analysis of the MUSIC algorithm for resolving plane waved contaminated by coherent interference when ensemble average covariance matrices are used. A resolution measure to describe the resolution potential of MUSIC in resolving two plane waves in noise is introduced. A closed-form solution for the resolution measure is given, and the result is compared to the resolution threshold derived by M. Kaveh and A. J. Barabell (1986) when the covariance matrices are estimated from a finite number of snapshots. An approximate expression for the threshold signal-to-interference ratio (SIR) is derived for the cases when SIRs are large and the coherent interference and direct arrivals are well separated in spatial frequency. Illustrations are given, using an 11-element uniform array, for the cases of plane wave reflection from an infinite plane and scattering from an infinite conducting circular cylinder