A nested wideband adaptive array using multirate filter banks

In this paper, we derived a generalised subband based scaled aperture (SSA) beamformer, exemplarily for the generalised sidelobe canceller (GSC). This structure is useful for broadband beamforming where near-constant spatial resolution over a wide range of frequencies is desired. The generalised SSA beamformer decomposes broadband signal into subbands, which are grouped into octave intervals. By drawing inputs from sensors with a wider aperture for lower octave bands, an octave-invariant resolution is achieved. We demonstrate that the SSA operates well across octave boundaries and additionally can benefit from an increase performance and reduced complexity when compared to similar subband and fullband domain beamforming structures.