Page 75 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

incremental goals, waypoints in mobility situations, on a continuous basis, from off the vehicle and via a tethered or radio/acoustic/optic/other linked control device. In this mode, the UMS may take limited initiative in reaching the assigned incremental goals.
• RC: A mode of operation of a UMS wherein the human operator, without benefit of video or other sensory feedback, directly controls the actuators of the UMS on a continuous basis, from off the vehicle and via a tethered or radio-linked control device using visual line-of-sight cues. In this mode, the UMS takes no initiative and relies on continuous or nearly continuous input from the user.
3.2.3 Communications linkage to the vehicle
The linkage to the vehicle can come in several forms or methods depending upon the distance and
medium through which the communication must take place. Such linkages include:
• Hard-wire communication (either electrical or fiber optic)
• Acoustic communication (via underwater analog or digital modem)
• Optical communication (while on the surface)
• Radio frequency (RF) communication (while on or near the surface)
What is communicated between the vehicle and the operator can be any of the following:
• Telemetry: The measurement and transmission of data or video through the vehicle via tether, RF, optical, acoustic, or other means.
• Tele-presence: The capability of a UMS to provide the human operator with some amount of sensory feedback similar to that which the operator would receive if inside the vehicle.
• Control: The upload/download of operational instructions (for autonomous operations) or full teleoperation.
• Records: The upload/download of mission records and files.
ROVs receive their power, their data transmission, or their control (or all three) directly from the surface through direct hard-wire communication (i.e., the tether). In short, the difference between an ROV and an AUV is the tether (although some would argue that the divide is not that simple).
3.2.4 Special-use ROVs
Some of the special-use ROVs come in even more discriminating packages:
• Rail cameras: Work on the drilling string of oil and gas platforms/drilling rigs (a pan and tilt camera moving up and down a leg of the platform to observe operations at the drill head with or without intervention tooling).
• Bottom crawlers: Lay pipe as well as communications cables and such while heavily weighted in the water column and being either towed or on tracks for locomotion
• Towed cameras: Can have movable fins that allow “sailing” up or down (or side to side) in the water column behind the towing vehicle.
3.2 Underwater vehicles to ROVs 63