Unmanned surface vehicles (USVs), also known as autonomous surface vehicles (ASVs), are water-borne vessels that are capable of operating on the surface of the water without any onboard human operators. Originally created by retrofitting previously manned craft with radio controls, a wide variety of purpose-built unmanned surface vehicles are now available. USVs are more versatile than buoys but less costly than full manned craft, making them popular for a range of marine applications.
Propulsion methods include petrol engines, electric outboard motors and waterjets. Some USVs may be partly or fully powered by solar, wave or wind energy or by a combination of these. Such vessels are often capable of missions lasting several months without needing to return to base.
Unmanned surface vehicles can be deployed from shore or from the deck of a larger ship. Some are remotely controlled by a human operator, while others are fully autonomous, programmed either to move along a linear path or to travel via a set of GPS waypoints. The vessel may also be programmed to remain in a particular area as a station-keeping platform, with allowable drift parameters set by GPS. Data gathered may be relayed back to shore via a satellite uplink, or over shorter distances via wireless broadband.
USVs can be linked together as part of a swarm with individual craft acting as a node in a communications or sensor network,, allowing them to be used as a force multiplier either for defense applications such as minesweeping or patrolling, or completing scientific surveying or sampling missions more rapidly.
Due to the lack of crew, an unmanned or autonomous surface vehicle can be outfitted with more sensors and equipment than an equivalently-sized manned craft. Such equipment may include sonar, imaging systems, radar, ISR systems, environmental sensors and dataloggers, weapons payloads, or a small unmanned underwater vehicle (UUV). Equipment may also be towed behind the USV.
Military applications for USVs include border and littoral zone patrol, minesweeping, submarine hunting, ISR, seaborne targets and offensive capabilities. USVs are also used in commercial sectors such as oceanography and environmental sciences, exploration and the oil and gas industry.