Large-aperture sparse array antenna systems of moderate bandwidth for multiple emitter location

Spatial-linear-prediction-filter antenna systems of large aperture width (in wavelengths) are described for the superresolution estimation of multiple emitter locations over moderate bandwidths. To accomplish this difficult task with reasonably few degrees-of-freedom from the large aperture, the system employs interferometer/sparse array techniques in conjunction with a shaped-reference beam which may be steered to the spatial sector of interest. Computer simulations on several multiple-source examples have demonstrated that the concept is feasible, provided that true time-delay steering is employed on the shaped reference beam. The optimal estimation system configuration results when time-delay steering is also applied to the interferometer elements, because this focuses the sample covariance matrix and minimizes the degrees-of-freedom required