On superresolution effects in maximum likelihood adaptive antenna arrays

The superresolution performance of maximum likelihood (Frost) adaptive antennas is analyzed. Assunming that the adaptive weights have had enough time to converge to the optimal (Wiener) solution, the beampattern and spatial resolution of the array are computed. Simple expressions are derived which allow close-approximation computations of converged adaptive beampatterns using only scalar operations. The analysis applies to narrow-band line-array adaptive beamformers. Computer simulations are presented to verify the excellent match between theoretical and measured beampatterns for small angle deviations from the look direction.