Autonomous Undersea Vehicles (AUVs), also commonly referred to as Unmanned Undersea Vehicles (UUVs), have a history dating back to 1957 with the Special Purpose Underwater Research Vehicle (SPURV) developed by the University of Washington's Applied Physics Laboratory. Academia and special government programs drove the early decades of research but advancements were slow. Throughout the 1960s, 1970s, and 1980s, more explosive growth came for the Remotely Operated Undersea Vehicle (ROV) market which had two primary advantages: they were operated via a tether that provided power for the vehicle and man-in-the-loop control.

Table 1. UUV classes defined by the US Navy Master Plan

In the late 1980s and early 1990s, advancements were made under the Massachusetts Institute of Technology’s Sea Grant AUV Laboratory in the design of lower cost, autonomous vehicles that leveraged available technologies in commercial computer processing coupled with lower power ROV sensors. In 1997, Bluefin Robotics spun out of the MIT AUV Laboratory to focus on commercial development of AUVs. Several competing firms also were formed in this time-frame, giving the primary, commercially-spurred market between 15 and 20 years of experience. Several of the large US defense contractors such as Boeing, Lockheed Martin, and Northrop Grumman predated this period for AUV development, but their focus was primarily defense and the US Navy’s budgets dropped steeply in the early 2000s for AUV development. The 2000s saw slow but steady growth across the markets which included US and International Defense, Scientific, and Commercial.

Table 2. UUV Mission Areas defined by the US Navy Master Plan
Since the 2010 time-frame, the market has grown significantly as the US Navy released three large ($50M to $100M) multi-year programs for AUVs and oceanographic gliders; commercial oil and gas expanded to deeper fields off South America, Africa, and Asia; and environmental monitoring requirements grew. Further growth is anticipated in the defense markets as the US Navy shifts its focus back toward maintaining open sea lanes from supporting two decades of a land war and as international navies look to expand their maritime capabilities. Earlier this year, retired Marine Corps Gen. James Mattis, the former head of US Central Command (CENTCOM), credited a countermining exercise in 2012 in which 29 nations participated as a leading reason for Iran to back away from their threats of mining the Straits of Hormuz. On the commercial and scientific front, market growth is driven by increased utilization of ocean resources to support the world’s population growth as energy, natural resources, and food needs increase substantially. Approximately 80% of the world’s population lives in close proximity to the ocean and 90% of its global trade traverses the seas.

The growing demands are illustrated by the many new US and international AUV providers that have entered the market in addition to numerous academic institutions in the past 5 years. At the time of this article, the Autonomous Undersea Vehicles Application Center (AUVAC) catalogs 185 different AUVs from 74 different companies or institutions.

Environmental Challenges

Figure 1. Similar AUV capabilities are required for Commercial (left) and defense (right) applications.
The undersea environment is extreme and has many parallels with space exploration. It’s an expensive environment to operate in as support ship costs can be in the multiple tens or even hundreds of thousands of dollars per day. Vehicle systems must be highly reliable as maintaining them remotely can pose challenges for parts and labor and can cause mission downtime leading to extended ship expenses. Temperature extremes can range from hot, on deck pre-deployment in 120 degrees to below zero at depth or in the arctic.

Some of the environmental challenges are much more daunting than space. hours (almost 2000 miles in range) with a heavyweight class AUV. As more large AUVs enter service and become more common, these payload volumes and endurances will extend even further.

The Navy prioritized missions to be accomplished by AUVs shown in Table 2 from the Master Plan. They also mapped how these mission areas would be satisfied by vehicle class. These missions would likely be considered common for other nations developing AUVs for defense applications.

Current Developments

With the growth of the AUV market in the past several years, there has been a healthy mix of production and development efforts in both commercial and defense. One unique class of vehicle that has emerged is a hybrid AUV/ROV that combines the traditional AUV capabilities with thin fiber optic tethers that allow for real-time data transfer and manual intervention similar to ROVs (Figure 2).

In 2011, Bluefin Robotics was awarded the production contract for the Mk19 Hull UUV Localization System (HULS). This provided an AUV capability to the Navy for inspection of ship hulls for mines or contraband that removed the need to deploy dive teams to inspect ships. The coverage rates were better than what divers could do in turbid waters and the robot could ensure complete coverage of the ship hull. The tether provided real-time access to the streaming sonar imagery in the event the vehicle identified a threat so that divers could then respond. It also provided for manual control of the vehicle to allow the support diver to more thoroughly investigate a target remotely. Bluefin is currently working on adding manipulation to this platform, leveraging the tether for remote operation.

Figure 2. Hovering AUV

This concept has parallels in ground robotics where explosive ordnance teams utilize the robot for mine neutralization, thereby taking the technician out of harm’s way. This class of vehicle has commercial applications for ship hull inspection and critical harbor infrastructure. In addition, Bluefin has a significantly larger (1-ton) system in final testing for much deeper rated (4,000m) inspection and light intervention.

The small AUV market is an area of growing interest, particularly for defense and scientific applications. For defense, these vehicles can provide low-cost countermeasure capabilities for torpedo defense and mine neutralization. Additionally, the small diameters (3 to 5 inches typical) provide less drag, thereby reducing the propulsion requirements for either fast-moving, or low-speed, greater persistence applications. With lower power processing advancements, these systems will be more and more capable as the personal electronics markets advance.

Bluefin has recently completed design updates to both its man-portable and lightweight class vehicles, improving the operating depths, navigational accuracies, and payload flexibility of these systems. Both the commercial and defense markets for these classes of vehicles are growing with numerous programs being released.

The heavyweight AUV space has seen significant growth in the past several years, both in defense and commercial applications. For defense, Bluefin is completing initial development testing of Lack of line of sight to satellites makes precision navigation and high bandwidth communications to the vehicles much more difficult, if not impossible. And the pressure extremes can be formidable when operating at depth. The oceans cover 70% of the Earth’s surface with an average depth of over 12,000 feet (3,600 m). An AUV depth rating to 20,000 feet (6,000 m) allows it to operate on the majority of the ocean floor except for the trenches, which extend to the deepest place on the planet – Challenger Deep in the Mariana Trench, at nearly 36,000 feet (11,000 m). The pressure at 20,000 feet is over 9,000 pounds per square inch (psi), and nearly 16,000 psi at Challenger Deep. Considering, for scale, that the average SUV weighs 4000 lbs, this pressure is equivalent to multiple SUVs stacked on every square inch of vehicle surface at depth.

AUV Applications and Classes

Figure 3. Proteus – Large Dual Mode Undersea Vehicle
The driving applications for the vehicles vary greatly between the defense and commercial/scientific markets but the sensor needs and even vehicle systems can often be flexible enough to address both markets. By example, a Navy may require a side scan sonar, or even a synthetic aperture sonar, to survey an operational area to determine if an undersea minefield is present. A commercial survey provider for the oil and gas industry would use an equivalent survey vehicle to determine if a site were suitable for a pipeline or a laydown area for subsea processing. With the right sensors and behaviors, AUVs can address a wide range of applications from survey, to inspection, to even intervention. Figure 1 depicts typical vehicle uses for both commercial and defense needs.

In an effort to provide industry guidance and drive commonality of systems and purpose, the US Navy published a series of UUV Master Plans that focused industry on 4 vehicle classes based on size and prioritized mission areas. Table 1 provides the AUV classes from the US Navy Master Plan for typical torpedo shaped AUVs. Endurance, payload volume, and vehicle complexity/capability commonly increase with vehicle size.

Most of the world’s AUVs, whether designed for commercial purposes or defense, can be categorized into these basic vehicle classes, but typical endurances and payload sizes can vary from what was published in the UUV Master Plan. For example, the heavyweight Knifefish UUV under development by Bluefin for the Littoral Combat Ship’s Mine Warfare Mission Package has a payload of over 30 ft3. And the Naval Research Laboratory’s Reliant UUV (the precursor to Knifefish) recently completed a 109 hour mission from Boston to New York (310 miles). Straightforward concepts exist to extend this demonstrated capability to ~600 DARPA’s Distributed Agile Submarine Hunting (DASH) program with a deep rated UUV with extended persistence. Additionally, Bluefin was awarded the vehicle design effort for the Knifefish UUV which will be entering sea testing this summer. Commercially, Bluefin supported global operations from commercial survey, to the hunt for Amelia Earhart, to under-ice operations in the arctic. A recently delivered 4,500m rated commercial heavyweight AUV employs a synthetic aperture sonar with a 1000m swath. This class of AUVs will see increasing applications as more advanced energy technologies are integrated to extend their persistence further.

On the large vehicle front, Bluefin is supporting its parent company Battelle and partner, the Columbia Group, in the development of Proteus Large UUV (Figure 3). This vehicle is a dual mode vehicle that can operate with divers or fully autonomously. Bluefin provides the autonomy, navigation, mission planning and subsea pressure tolerant batteries to this vehicle which has over 300 hours of in-water testing and operation accumulated as of this printing.

This article was written by Jeff Smith, CEO, Bluefin Robotics (Quincy, MA). For more information, Click Here .