1. A processor implemented method comprising: estimating a first subspace based on measured data for a brain; calculating a second subspace, wherein the second subspace is orthogonal to the first subspace; identifying a set of vectors of the second subspace, the vectors related to an array manifold associated with a selected region of the brain; applying a projection onto the set of vectors; and determining, using one or more processors, a location for each of at least one source based on a cost function of the projection for the selected region, and wherein the set of vectors have minimum principal angles to the array manifold.