Patent ID: 7042393

Claim:
A thinned antenna array system comprising: an antenna having a plurality of core subarrays and a plurality of peripheral subarrays surrounding said core subarrays; each said subarray including N antenna elements operable to provide respective output signals in response to impingement of a radar return; all N of said antenna elements of said core subarray being active to participate in further signal processing; less than N of said antenna elements of predetermined ones of said peripheral subarrays being active to participate in further signal processing; each said subarray including a manifold for receiving and combining the antenna signals from said active antenna elements; all of said manifolds of all of said subarrays providing at least a first output signal in response to said antenna signals from said active antenna elements; only said manifolds of said core subarrays additionally providing second and third output signals in response to said antenna signals from said active antenna elements; a plurality of first, second and third digital receivers; a digital receiver control circuit for providing predetermined weighting functions to said plurality of digital receivers each said first digital receiver being connected to receive a said weighting function and said first output signal from a said manifold to provide a first digital receiver output signal; each said second digital receiver being connected to receive a said weighting function and said second output signal from a said manifold to provide a second digital receiver output signal; each said third digital receiver being connected to receive a said weighting function and a said third output signal from a said manifold to provide a third digital receiver output signal; a digital beamformer responsive to all of said output signals from said plurality of first digital receivers to generate a sum beam; said digital beamformer being responsive to all of said output signals from said plurality of first digital receivers, as well as to all of said output signals from said plurality of second digital receivers to generate an azimuth difference beam; said digital beamformer being additionally responsive to all of said output signals from said plurality of first digital receivers, as well as to all of said output signals from said plurality of third digital receivers to generate an elevation difference beam; and a radar processor for processing said sum, azimuth difference and elevation difference beams.