OPTIMAL SUBARRAY SIZE FOR SPATIAL SMOOTHING

We consider the popular spatial smoothing technique and show via the c ovariance matrix eigenvalue analysis that the simple suboptimal rule f or choosing of the subarray size exists in a practically important sit uation of two coherent equipower closely spaced sources. This rule has been derived by maximizing the distance between the signal subspace a nd the noise subspace eigenvalues of spatially smoothed covariance mat rix and it does not require any a priori information about the signal source parameters.