Matrix beamforming preprocessor for beamspace Root-MUSIC

The author considers the problem of interpolating a synthetic or virtual linear equispaced (LES) array from a real irregular array to effect some algebraic direction-finding technique such as Root-MUSIC. The interpolation of a virtual LES array can be accomplished through the use of a matrix beamforming preprocessor connected to the output of the real array. The author has considered how to place the `sensor´ of the virtual LES array and the design of the matrix beamforming preprocessor, i.e. the interpolation matrix. In terms of error of the interpolation, the loss of signal-to-noise ratio (SNR), and SNR resolution threshold, the construction of the virtual LES array is investigated. It is shown that the virtual LES array should have the same main-lobe beam pattern as the real array over an interpolation sector. Numerical results are presented to illustrate virtual LES array interpolation