Results of the acoustic observatory array topology study

In 1997, the Naval Studies Board recommended a focus on exploitation of the intrinsic coherence of the ocean to achieve 20 dB greater detectability by sonar systems. That same year, the JASONs suggested achieving these gains by elimination of shipping discretes. The Acoustic Testbed Working Group evaluated adaptive beamforming technology used in conjunction with various passive acoustic array topologies to suppress noise from discrete shipping and achieve the desired performance gains. These studies indicate that acoustic arrays of limited spatial extent, with both horizontal and vertical aperture make the most efficient use of large numbers of phones. This is because the motion of discrete shipping in typical littoral environments limits the amount of time integration that can be applied when using large horizontal apertures.