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Black Laser Learning® is your source for information on autonomous underwater vehicles. These underwater robots are fast becoming the work horses of the underwater survey world.
Introduction to AUVs
The autonomous underwater vehicle, better known by its acronym AUV, is a self-propelled, self-controlled unmanned submersible, which can perform a wide variety of tasks from surveying pipelines to finding mines. These submerged vehicles can carry sensors which range from acoustic mapping tools to sophisticated chemical and biological samplers. If you’re working with the military, you will also hear these vehicles referred to as unmanned underwater vehicles or the acronym UUV.
The AUV or UUV is really a system of systems, each one providing the vehicle with a specific function all enclosed in an unmanned submersible. Some vehicles have flooded or wet compartments while others are completely dry. Other vehicles are modular, with several plug and play sections that can be added or removed as the mission requires.
The most common system among all types of vehicles is propulsion, whether you’re using an electric motor or buoyancy to drive the vehicle through the water, every vehicle has the ability to autonomously move through oceans under its own power. Not all vehicles fly – some even crawl across the sea floor.
To propel these robots each and every vehicle also has an energy source. The electricity powers the sensors and computers as well as the motors or other means of propulsion. Power sources are commonly some type of battery assembly however some AUVs operate fuels cells. Semi-submersible AUVs can take advantage of a snorkel using air breathing diesel power.
On the surface, a vehicle can incorporate information from global positioning satellites also known as GPS. Once submerged the vehicle must rely on other sensors. Vehicle heading can be determined by a flux gate compass or a more sophisticated gyrocompass. Underwater doppler velocity logs, also know by the acronym DVL, measure the vehicle’s progress through the water, which can be combined with acoustic positioning from ultra short or long baseline navigation systems. More sophisticated vehicles will include inertial navigation systems, also know by the acronym INS. The robot’s submerged position can be determined by one or a combination of positional inputs, all of which are processed through the onboard computer.
These self-propelled, self-navigating systems carry a wide variety of sensors from side scan sonar to chlorophyll monitoring sensors. Systems now can even carry their own mass spectrometers for measuring minute chemical properties.
AUVs are commonly used to map the sea floor, survey pipelines, find mines, survey oils rigs, assist with harbor security, salvage operations, archaeology, and a host of other tasks. Vehicle operations are gradually becoming more autonomous, with less human input as artificial intelligence becomes more advanced. An AUV can now decide how best to follow a pipeline without a pre-programmed route, and can automatically adjust its position for optimal data collection.
Some AUV autonomous behaviors include structure inspection, obstacle avoidance, homing and docking, mission abort and in-mission tracking as well as sophisticated launch and recovery interfaces. AUVs can operate to depths of 6000 meters, with mission duration lasting from a few hours up to over nine months at sea.