Measurement of angular spread of signals in SWellEx-96 using multitaper array processing

Abstract

Detection and bearing estimation in shallow water is difficult due to multipath. As array aperture increases, angular resolution increases and observation of multipath becomes more likely. The SWellEx-96 experiment provides a publicly available dataset along with detailed environmental information. Ray simulations suggest there are multiple arrival paths at the arrays of interest. This thesis explores whether the horizontal line arrays deployed in the SWellEx-96 experiment have enough angular resolution to observe multipath in their environment. In the context of bearing estimation, the traditional, well established techniques of conventional and minimum power distortionless response (MPDR) beamforming are compared to a new multitaper beamforming framework proposed by Wage. The SWellEx-96 dataset requires the design of tapers for irregularly sampled data as the arrays are nonuniformly spaced. The multitaper array processor proves to be a useful tool, often displaying multipath arrivals more clearly than the conventional and MPDR beamformers.