The Easytrak Nexus has been successfully deployed on various subsea tracking surveys across the globe since its introduction in 2009 and is currently being used nearer to home during the geophysical survey of sections of North Sea, close to shore.
The Geosurvey Department of EMU Ltd, a marine development, research and planning company based in Southampton, UK, is using the Applied Acoustics' system on several high resolution Windfarm Engineering and UXO (Unexploded ordnance) surveys off the East coast. It is currently on the 12m vessel EMU Surveyor, being used to track towed sensors in less than 5m of water. Two further Nexus systems are on hire for similar jobs, one on the 24m Survey vessel RV Discovery and one on a charted vessel Nabcat II.
EMU has found the Nexus system particularly reliable and accurate in shallow water environments compared to other USBL systems they have used, and have been impressed with the consistency of results.
"We undertake a wide range of geophysical and hydrographic surveys for a variety of customers including scour monitoring, pipeline surveys and ports and harbour surveys in addition to the Coastal Windfarm Engineering and UXO survey we are currently engaged in," said Richard Hamilton, Marine Geophysicist with EMU, "and of course in each case we always employ the latest technology from our survey vessels to provide cost effective world class results. The selection of the Easytrak Nexus system for positioning and tracking towed sensors is yet another example of us sourcing the best kit available."
Easytrak Nexus is a rack-mounted USBL positioning system incorporating Digital Spread Spectrum Technology in its design. This reduces the transmitted acoustic signals' susceptibility to interference enabling the calculation of accurate positioning information. The technology also rejects unwanted reflected signals that have made operating in challenging locations such as ports and harbours difficult in the past.
The North Sea survey work currently being undertaken by EMU represents the early stages of significant windfarm expansion plans formulated by the UK Government that is committed to raising the proportion of energy derived from renewable sources from 2.4% to 15% by 2020.