In collaboration with Geoscience Australia we have utilised a Simrad EM3002 (D) 300 kHz multibeam sonar system for the mapping of discrete locations within Tasmanian waters.
Motion referencing and navigation data is collected using an Applanix Position and Orientation System, coupled witha C-Nav GPS. EM3002 data were acquired using Kongsberg's Seabed Information System (SIS) software. This software provides a high level of real-time information on the helmsman display and supports Applanix true heave logging used in post-processing of multibeam data to reduce heave artefacts so that the quality of bathymetric data is optimal.
During the surveys, vessel speeds can vary up to between 5 and 10 knots, with slower speeds for inshore and shallow water areas. Initial processing of the multibeam data to account for tides and vessel motion (pitch, roll and heave) was completed during the survey using Caris Hips and Sips v6.1 software. Final processing to remove more complex artefacts, such as elevation errors caused by dynamic draft of the vessel, is completed after the surveys by Geoscience Australia.
Multibeam sonar bathymetric map of south eastern Tasmania based on a 2 m grid (inset, location map of the Tasmanian study sites)
(Nichol, S. L., Anderson, T.J., McArthur, M., Barrett, N., Heap, A., Siwabessey, J.P.W. and Brooke, B.P. (2009) Southeast Tasmania Temperate Reef Survey: Post Survey Report. Geoscience Australia Record 2009/43. Canberra: Geoscience Australia, 73 pp. Available online: http://www.ga.gov.au/resources/publications/marine-publications.jsp).