Originally Posted by
Cazalet33
Long baseline is completely different. It involves setting out an array of seabed transponders and co-ordinating them. The ROV then self-navigates by doing what amounts to a DME/DME fix, using at least three and preferably four or five transponders. It then telemets its self computed position up the umbilical. Much more practical for deep water work like this job than USBL which will be slow and wooly. I'd be adversely surprised if these guys haven't deployed an LBL array around the locus by now.
Would the quality of the sea bed in this area (which you alluded to in an earlier post as being pretty bad) argue against the long baseline method, or do the transponders have mechanical means to mitigate issues with sea floor conditions? I'd guess that the state of the art has advanced to where you'd have kits optimized for differing conditions, and thus have some "muddy/silty" sea floor models for use in such conditions.