Autonomous underwater vehicles

Also known as AUVs, Ocean gliders, Argo floats, Uncrewed submarines

Autonomous underwater vehicles are robots that travel and measure in the ocean without a pilot on board or a cable to a ship. Argo floats, ocean gliders and under-ice vehicles now collect large amounts of ocean data, but batteries, the lack of GPS underwater and, beneath ice, the lack of any surface contact still limit how far and how long they can work.

CommercialDemonstratedReviewed 21 Oct 2026
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

In plain language

Autonomous underwater vehicles (AUVs) are robots that carry out missions in the sea without a pilot on board and without a cable to a ship. Some are self-propelled vehicles, such as the Autosub Long Range vehicle nicknamed Boaty McBoatface. Others are much simpler. Argo floats drift with ocean currents, sinking and rising in cycles to measure properties of the water, and ocean gliders move forward on small wings by changing their buoyancy, which uses far less power than a propeller.

Water blocks the radio and satellite signals people use to find their position. Most underwater robots therefore estimate where they are from their own movement, and surface from time to time to get a satellite fix. Under an ice shelf they cannot surface at all, so they must find their way on their own for long periods and return to the place they entered. Battery capacity is the other main limit, which is why missions are planned around how long a vehicle can run and how much data it can collect.

Technical explanation

Most ocean robots fall into three groups. Argo floats are profiling floats that repeat a 10-day cycle, drifting at depth and then rising to the surface to send their data, until their batteries are used up. The Argo2020 design aims to contain 4,000 core floats, 1,200 deep floats and 1,000 floats that also measure biogeochemical properties (BGC-Argo). Ocean gliders are buoyancy-driven vehicles that carry sensors on long, slow dives. Rutgers-operated gliders have completed missions lasting 221 days (RU27, North Atlantic, 2009) and 330 continuous days at sea (RU29, Indian Ocean, 2016 to 2017). Self-propelled AUVs such as Autosub Long Range carry scientific instruments and can work beneath ice shelves.

Navigation is the central engineering problem. Without GPS, an AUV estimates its track by dead reckoning, integrating its speed and heading over time, so position errors grow with time unless the vehicle surfaces or receives an acoustic fix. The RU27 glider surfaced every eight hours to get a GPS fix and contact its operators. Under ice shelves there is no surface contact, so the vehicle must complete its survey and return to its entry point by its own estimate. On its first under-ice mission in 2018, Boaty McBoatface spent 51 hours under Antarctic ice and travelled 108 km, and the team had no communication with it for about 90% of its time in the water.

Scale is the strongest evidence for the field. The Argo programme says it has deployed over 15,000 floats in total, and it reached its original goal of 3,000 active floats in November 2007. Seabed mapping is the other global measure: Seabed 2030 reported in June 2025 that 27.3% of the seafloor has been mapped to modern standards. Its announcement does not explain how that percentage is calculated, and the number of Argo floats active today was not stated in the sources reviewed here.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Demonstrated Shown in a published experiment, test or shipping product.

The Argo programme says it has deployed over 15,000 floats in total and reached its original goal of 3,000 active floats in November 2007.

Sources: [1] · Global array

Rutgers glider RU27 crossed the North Atlantic in 2009 in a 221-day voyage, covering about 5,300 km as the crow flies.

Sources: [4], [5] · Distance and duration

Rutgers glider RU29 spent 330 continuous days at sea and covered 7,570 km on a leg from Perth to Colombo, Indian Ocean, between November 2016 and September 2017.

Sources: [5] · Announcement text

On its first under-ice mission in 2018, Boaty McBoatface spent 51 hours under Antarctic ice, travelled 108 km and reached 944 m depth, and the team had no communication with it for about 90% of its time in the water.

Sources: [6] · Mission details

Reported, unverified Stated by a company or team but not independently confirmed.

Each Argo float repeats a 10-day cycle until its batteries are exhausted, and the UCSD Argo page says floats spend most of their life below the surface, which may be as long as 10 years.

Sources: [2] · About Argo · medium confidence

On 21 June 2025 Seabed 2030 reported that 27.3% of the world's ocean floor has been mapped to modern standards, with more than four million square kilometres of newly mapped seafloor.

Sources: [3] · medium confidence

Proposed A design or plan that has not yet been built or tested.

The Argo2020 design aims to contain 4,000 core floats, 1,200 deep floats and 1,000 BGC-Argo floats.

Sources: [1] · Argo2020 design

The International Thwaites Glacier Collaboration planned to send Boaty McBoatface, a Hugin robot and six ocean gliders beneath and around the Thwaites ice shelf, and noted that thick sea ice can stop even an icebreaker.

Sources: [7] · Vehicles and sea ice · medium confidence

Disputed Contested by other credible sources.

The two Argo programme pages give different float lifespans: about 6.5 years for Gulf of America BGC-Argo floats on the AOML page, and as long as 10 years for floats generally on the UCSD page.

Sources: [1], [2] · medium confidence

Limitations and open problems

  • The number of Argo floats active today was not stated in the sources reviewed. The programme pages give cumulative deployments (over 15,000) and the 2007 goal of 3,000 active floats, so the current active count needs checking against the live float map.
  • Lifetimes differ between sources: the AOML page gives about 6.5 years for Gulf of America BGC-Argo floats, while the UCSD Argo page says floats may spend as long as 10 years below the surface. Lifetime should be read per float type and programme.
  • Underwater vehicles get no GPS signal and usually have little or no contact with the surface. During the 2018 under-ice mission the team had no communication with the vehicle for about 90% of its time in the water.
  • Antarctic access is limited by sea ice. The Thwaites expedition page notes that even a powerful icebreaker cannot get through thick sea ice, so the team monitors ice extent to plan access.
  • The Seabed 2030 announcement does not explain how coverage is calculated or define 'modern standards', so the 27.3% figure cannot be checked from that page alone.

Possible future uses

Speculative

Ideas, not predictions. None of these has been demonstrated.

  • Gliders stationed at the mouths of ice-shelf cavities to report changes in the warm water reaching the ice in near real time.
  • Low-cost profiling floats in coastal waters that the open-ocean Argo array does not cover.
  • Autonomous survey fleets that could speed up seabed mapping if coverage can keep pace with the Seabed 2030 target.

Timeline

  1. Nov 2007The Argo programme reaches its original goal of 3,000 active floats. Sources: [1]
  2. 2009Rutgers glider RU27 crosses the North Atlantic on a 221-day voyage, covering about 5,300 km as the crow flies. Sources: [4], [5]
  3. 30 Sept 2017Rutgers glider RU29 is recovered after 330 continuous days at sea, having covered 7,570 km on a leg from Perth to Colombo. Sources: [5]
  4. 14 Mar 2018Boaty McBoatface returns from its first under-ice mission, having spent 51 hours under Antarctic ice and travelled 108 km. Sources: [6]
  5. 4 Jan 2022The International Thwaites Glacier Collaboration announces an expedition using Boaty McBoatface, the Hugin robot Ran and six ocean gliders around the Thwaites ice shelf. Sources: [7]
  6. 21 Jun 2025Seabed 2030 reports that 27.3% of the seafloor has been mapped to modern standards, with more than four million square kilometres of newly mapped seafloor. Sources: [3]

Futures this could help bring about

AI illustration
How far away?

A complete map of the world's seabed

Scaling up · 2 of 6 steps done

Glossary

Argo float
A drifting ocean instrument that sinks and rises in cycles, measuring temperature and salinity, and sends its data by satellite.
Ocean glider
An underwater robot that changes its buoyancy to glide up and down through the water on small wings, using very little power.
Dead reckoning
Working out a position by estimating movement from speed and heading over time, without an external fix.
CTD sensor
An instrument that measures conductivity (linked to salinity), temperature and depth of seawater.

Sources

  1. other
    Argo program
    NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), 2026. Accessed 21 Oct 2026.
  2. other
    About Argo
    Argo Program (argo.ucsd.edu), 2024. Accessed 21 Oct 2026.
  3. other
    Seabed 2030 announces millions of square kilometers of new seafloor data on World Hydrography Day
    Seabed 2030 Project (Nippon Foundation-GEBCO), 21 Jun 2025. Accessed 21 Oct 2026.
  4. news
    Remotely Piloted Underwater Glider Crosses the Atlantic
    IEEE Spectrum, 26 Feb 2010. Accessed 21 Oct 2026.
  5. university press release
    Challenger Glider Sets New World Record in the Indian Ocean
    Rutgers, The State University of New Jersey, Oct 2017. Accessed 21 Oct 2026.
  6. news
    Boaty McBoatface returns from first mission under the ice
    Phys.org, 14 Mar 2018. Accessed 21 Oct 2026.
  7. other
    Mission begins in Antarctica's remote Thwaites Glacier
    International Thwaites Glacier Collaboration, 4 Jan 2022. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.

Changes on 21 Oct 2026
Published on owner instruction (content loop iteration 52)895577d
Sources and claims re-checked against originalsfbb434c
Initial profile drafted from primary sources7e66249