Steering invariant robust sidelobe cancellation implementation for large arrays

Adaptive beamforming (ABF) using a conventional beamformer (CBF) output interference estimator-subtractor (ES) is known as sidelobe cancellation (SC). SC forms a very low dimensional data vector, called the auxiliary vector, as an input to the adaptive ES function. After a treatment of robust and steering invariant SC background, the frequency dependent auxiliary vector formation from geometrically thinned, sparse array apertures is considered. The corresponding auxiliary aperture spans the full array aperture and consequently does not sacrifice the potential for mainlobe interference rejection while still maintaining essentially optimum SC. Robust steering invariant (SI) SC is compared to a full element space ABF.