Inertial measurement unit Unmanned and autonomous survey vessels Unmanned surface vehicles (USVs; also known as unmanned surface vessels or in some cases autonomous surface vehicles (ASVs), uncrewed surface vessels, or colloquially, drone ships) are boats or ships that operate on the surface of the water without a crew. USVs operate with various levels of autonomy, from simple remote control, to autonomous COLREGs compliant navigation. An autonomous survey vessel is an unmanned vessel fitted with survey equipment and capable of operating without human supervision while performing survey work, either uploading the data in real time, or at pre-programmed stages, or on a remote command. Autonomous underwater vehicles set up for survey work are a subclass of autonomous survey vessels that operate underwater. unmanned survey vessels are usually relatively small and therefore economical to acquire and operate, and can be sent to areas too hazardous for a larger or crewed vessel, as well as for extensive and time-consuming but routine surveys. USVs are valuable in oceanography, as they are more capable than moored or drifting weather buoys, but far cheaper than the equivalent weather ships and research vessels, and more flexible than commercial-ship contributions, and, with solar cells to power their electronics, can have months of marine persistence. Powered USVs are a powerful tool for use in hydrographic survey. Using a small USV in parallel to traditional survey vessels as a 'force-multiplier' can double survey coverage and reduce time on-site. History References See also Office of Coast Survey United States Coast and Geodetic Survey Ship types Survey ships