Divers may make spot mudline measurements where reference points such as pilings can provide xy-positioning to be paired with depth measurements.
vehicle (ROV) as a survey platform. An ROV, with its power distribution and data transmission capabilities, could be deployed with a sonar profiler in order to collect bottom elevation information throughout the survey footprints in the restricted-access portion of the berths. SeaVision reached out to ROV services provider SeaView Systems, Inc. (SeaView). It was determined that a SeaEye Falcon DR afforded an ideal survey platform that could give us the flexibility to gain access anywhere within the survey footprint under each aircraft carrier. Two parts of the equation, access and vertical measurement, could be addressed with the ROV. The challenge remained to accurately position the ROV so that we had a bathymetric model of the floor of each berth that resembled a traditional hydrographic survey. Acoustic positioning methods such as ultra-short baseline (USBL) and long-baseline (LBL) were discounted out of concern that the minimal clearance between the carrier hulls and the bottom would create multi-path issues that might adversely affect the horizontal and vertical positioning solution. It was determined that an aided inertial navigation system (INS) could provide us with real-time, accurate horizontal and vertical positioning in order to properly track the ROV through the surveys and provide an attitude and heading reference for the profiler mounted on the ROV. SeaVision and SeaView reached out to CD Limited (CDL), a developer of subsea positioning and sensing equipment, to supply an aided inertial navigation system that could be mounted to the SeaEye Falcon ROV.
26 MTR
January 2008
You don't have Macromedia Flash Player installed.
This content requires the Macromedia Flash Player.
Get Flash
www.digitalwavepublishing.com
www.MarineLink.com
www.vovcha.com