Multiuser navigation and telemetry performance issues in shallow water environments

Achieving robust and reliable acoustic position fixing and telemetry performance in shallow water is complicated by the highly dispersive nature of the medium. This dispersion manifests as both time and frequency spread by virtue of the acoustic multipath phenomenon, which presents at a macroscopic (geometry influenced) and microscopic (forward scattering) scale. Platform dynamics in conjunction with the intrinsic variability of ocean propagation and forward scatter mechanisms lead to variations in both the macroscopic and microscopic behaviour of multipath. It is both the extent and the variability of shallow water multipath which makes reliable acoustic measurement and telemetry so challenging in these environments.