The constrained MUSIC problem
R.D. DeGroat, Eric M. Dowling, Darel A. Linebarger · IEEE Transactions on Signal Processing · 1993
The MUSIC-based direction-of-arrival (DOA) method is generalized to include constraints involving known signal information. Projection operators are used to constrain the noise subspace to be orthogonal to a set of prespecified direction vectors. By incorporating known source directions, the estimation of unknown source directions can be significantly improved. Simulations are performed over a wide range of scenarios to demonstrate the usefulness of the approach.>