Maximum Eigenvalue (Vector) Beamforming with an Adaptive Antenna Array
N.L. Owsley · The Journal of the Acoustical Society of America · 1971
An adaptive array beamforming technique based on an eigenvector interpretation of the conventional (i.e., time delay and sum) single-frequency array directional response pattern is presented. In particular, the directional response pattern of a K-element antenna array can be expressed in terms of the spectral density matrix of the spatially received data. This directional response pattern can, in turn, be expressed as a sum of K terms, each involving a single eigenvector of the spatial spectral density matrix where each term in the sum is weighted by the corresponding eigenvalue. The array beamforming technique presented exploits the fact that positional information regarding the spatially coherent, source-like components of the array's environment concentrates in the larger spatial eigenvalues and related eigenvectors. This “clustering” effect allows the conventional directional response pattern to be approximated by a truncation of the eigenvalue-weighted sum. A single-term approximation to the conventional bearing response pattern is the subject of this paper. An adaptive array processing technique is proposed which recursively obtains the single-term truncation approximation to the bearing response pattern. The potential of this array processing technique for automatic multiple source location and tracking is examined.