MILNET Brief
  Unmanned Underwater Vehicles - UUVs - 1/26/2005
"Throughout history we have seen that the technology that has given us the best return often was looked at skeptically" at the beginning"

- Rear Adm. Paul F. Sullivan, Director -Submarine Warfare Division
A hard covered hardcopy of this briefing is available for purchase online, click here.
U.S. UUV Directory  ||  Unmanned Systems

The U.S. Navy has been embarked for some time in designing and implementing tethered, remote controlled, and autonomous underwater vehicles that could both reduce risks to their mother ships, as well as perform missions their smaller size and more covert capabilities could accomplish where no other craft could accomplish.

Imagine a remote operator aboard the U.S.S. Hawaii, a Virginia class nuclear attack sub.  The operator has been tasked by the Undersea Warfare Officer to "put a tail on bogie 3".  The bogie is an Iranian guided missile submarine which could, at any time, surface and attack shipping in the Persian Gulf.  The sub, a Russian hand-me-down, is quiet and stealthy to an incredible degree, and a product of Soviet under water stealth technology, built a long time before Glasnost.  The chances of Iran having built this on their own are nil.  However, and regardless of the anger it might raise in a few cold war soldiers, the Iranians picked this beauty up for a song and now they patrol the Gulf with jealous zeal.

The operator obeys the order and the VLS launch crew, at his behest, moves a Mark II Track and Trail UUV into the receiving tray and then the tray moves the giant 10 ton device into the opening of number four VLS tube. Once sealed inside, water is pumped in, while a steam bubble is set up. At the operator's press of the launch button, the device is jetted out into the sea with hardly a burp, indistinguishable from a groan and whistle from a whale.

The whale sound aside, there is little anyone can use to distinguish that the Hawaii has put a miracle of science into the water. The UUV now streams away from the Hawaii on a course that should intercept the track of  bogie 1.  Shortly the UUV goes into autonomous mode, the distance and speed differential increasing as the Hawaii turns away from its target, and heads back to its normal patrol route.

Meanwhile the UUV on auto, picks up the telltale signature of the Iranian sub and begins to track.  At certain points in its effort, a small buoy is released and once the signaling device nears the surface, a satellite message is squirted up to a COMs satellite watching the region. The message is relayed to the VLF array along the Pacific Coast  of the USA or perhaps to similar site on some Pacific Island.  The message gets back to the Hawaii within a few minutes, informing the operator that his "toy", designated tracker 1, is on the trail of the Iranian boat.  Info includes speed, heading, and perhaps the last three changes in each.  And of course GPS coordinates of the last buoy set free.  The buoy, by the way, actually never reaches the surface, perhaps only an antenna hitting the surface for the few seconds of data burst, and then the buoy floods and heads to the bottom of the sea. 

This is a critical mission for the toy.  It helps the sub monitor a contact, without compromising the patrol mission of the sub, and with little risk of detection or confrontation with the eager to kill Iranian boat.  Meanwhile, Hawaii might catch a whiff of another submarine lurking along the busy oil tanker routes in and out of the gulf.

Our scenario is fiction now, but in short order could become reality.  It is just one of the missions under concept development by the Navy

A 1997 Master Plan revised and released to the public in 2000 outlined ambitious Navy plans, however, the entire cost structure seemed risky at that time.  Today, in light of expenditures being executed elsewhere and because of the War on Terrorism, it appears the Navy is being asked by Congress to restructure and restart several key programs as well pull back their reach for their aggressive program.  However, many  in the Navy (and Congress as well) look at the UUV program as a long term must, believing that like the UAV air vehicle equivalent, the program has a  huge potential for saving lives and reducing risks to more expensive manned vehicles as well as dramatically improving the capabilities of the undersea force.
"Autonomy - The abilty to operate independently for extended periods -- extends sub or surface vessel's reach and their focus on more complex tasks better suited to human interaction - UUV is a smaller and less expensive platform to accomplish the task

Risk Reduction - eliminates risk to personnel and heavily capitalized equipment.

Low observability - UUVs by their much smaller size and materials used will be far more stealthy and undetectable, and less entanglement being independent.  Also, near surface operation allows antenna extension and less opportunity to be detected on surface.

Deployability - organic to the battle group, adaptable for launch from ships subs, aircraft, and shore facilities.  Recovery can be delayed and be from any one of the facilities including shore if the mission.

Environmental Adaptability - UUVs can operate from deep to very shallow water, in foul weather and seas, under tropical or arctic conditions, and around the clock." 1
Moreover, good UUV implementations could easily turn the tide in close littoral area incursions, preventing disaster as the fleet moves into denied areas near their opponents shoreline.

Thus this briefing, while noting the Congressional appropriators stern directives to the Department of the Navy, assumes that the master plan, with adjustments in timetable, will eventually accomplish much of which that original vision encompassed.  In that respect, we will then address the different types of UUV programs, list some of the baby steps taken, and then look to the future.

Note also that little information is known about other nation's UUV programs.  Once again U.S. open policy not being matched by many others.  We will endeavor to look at U.K and Canadian programs however, and provide updates to this document as information becomes available.  This document will not, however, be a "johnny-on-the-spot" updated document that will be current within anything other than a quarterly assessment and that timeframe is certainly not guaranteed either.

We should also note that the Naval Research Advisory Committee brainstormed on the subject and created the interesting tasking to "Review and assess potential concepts of operations (CONOPs) and employment (COE) of all Naval missions with respect to unmanned vehicles."  5  Their noodling came up with:

   "Examine the following:
 It is in this light that we believe the Navy's master plan hopes to fulfill the Navy's needs for UUVs.



Basics of the UUV

The modern UUV will scale from initial designs that fit the standard (and quite limiting according to inside sources) 21 inch submarine torpedo tube. Why this limitation?  The 21 inch tube is also found in deck launchers on frigates, destroyers, and cruisers, as well of course on submarines.  The Seawolf class offered a large tube, perhaps with larger UUVs in mind, and of course all future sub designs feature a plethora of vertical launch systems (VLS) that can launch a tomahawk missile.  Experiments have been performed using the VLS tubes, and this is also a promising launch scenario for subs so equipped.  In theory, an array of VLS tubes (VLA) could be used to launch a dozen or so UUVs simultaneously or in salvo fashion, enabling a swarm of UUVs both inert recon units and not so inert attack units. This fits well into pacifying a littoral region next to en enemy's shore as the fleet moves in to support land operations.  If you don't recognize it, this is the current Navy Jointness style operation envisioned for the future.

The 21 inch limitation is significant.  The tube size means the package remains around a 2 ton vehicle (average size of a Mk48 torpedo turns out to be about that weight).  However, early designs require lots of power and that means lots of batteries and the massive structure required turns out to be 10 tons or so.  Thus the Navy weapons brain trust at the Navy Future Studies Group is pulling out their hair trying to figure out how to get more power.  Rechargeable lithium batteries scare the hell out of most engineers and progress is slow. The problem with rechargeable lithium batteries is explosive sudden discharge.  Explosive as in "Bang" and things have wholes in them.  Submariners don't like holes in things anymore than surface weenies. Nuclear power cells are not politically feasible, so another source of power is craved.  That is technology barrier number one.

So what is it that goes into a UUV that requires so much power and thus so much weight and size for batteries?  Smarts, that's what.  The Navy, rightly so, is not enamored with tethered designs and everyone associated with underwater operations knows that radio waves don't travel well underwater.  At least not at the frequencies used to remotely control the airborne equivalent -- UAVs. 

Underwater communications are at very low frequencies and thus data transmission is VERY slow.  And while encryption doesn't add much data payload increase, it does require more computing horsepower to decrypt on the UUV.  More computing power means more overall power and more battery.  More size and mass, oh hell, how are we going to fit that all in a 21 inch tube that is also constrained in length too?

The more troubling aspect of "smarts", however, is autonomy.  Artificial Intelligence is still an infant science.  As NASA's scientists have found out, autonomy in unmanned vehicles is a scary thing.  Witness how certain Mars rovers sat and stewed on their own before finally deciding to reboot and reload.  Had that not occurred, millions of dollars in investment and years of work would have been for nothing.  In a combat situation, or even a resupply mission, that kind of robotic nonsense could spell real disaster and loss of thousands of lives.

And good autonomy means redundancy and redundancy requires more space. Not that AI computation comes in small packages, at least not in the scale the Navy needs.  Therefore, the Navy thinkers are facing some real challenges in both increasing the reliability and intelligence of their AIs, as well as trying to fit everything into smaller packages.  At speeds and performances levels that would make Intel wince, the Navy computing gurus are not quite close enough to sound the victory call, and some say they have a long way to go.

In any case, perusing the master plan made this clear -- the thinkers knew the technology risks, and rather than poo-poo them, had long ago decided to face them head-on and overcome them.  As any good weapons program does and has done for a century if not more.  No military system is perfect, and the Navy has clearly looked at incremental progress as the watchword.

From the master plan, comes a significant chart showing where the Navy feels technology advances are crucial.




Click to see larger, more readable image

The section most littered with yellow and red cautions and warnings for risk are in the bottom row, autonomy.

Indeed, it is pretty clear that the entire UUV program has significant risks as one looks to increasingly more capability.  So what are these capabilities?



Capabilities Desired in UUVs

The Navy's Master plan says:

1.  Deploy or Retrieve Devices, Anyplace, Anytime
2.  Gather, Transmit or Act on All Types of Information, From Anywhere to Anyone
3.  Engage Any Target:  Bottom, Volume, Air or Space

All without risk or burden to U.S. forces...low cost and self sustaining.

Broad Area denial is a real threat given technology trends (GSP, Missiles, Satellites, etc) - Both for advanced and not so advanced threats.

Undersea systems (manned and unmanned) may be the only (undenied) force (early).

The concept is logical.  Undersea forces are still some of the most stealthy and survivable, and UUVs will only serve to enhance that well known, and already well funded capability. 

The plans priorities are currently undergoing changes, however at the time of the master plan, they were:
It's not clear how the Navy will respond, or has already decided to proceed with UUV programs given the direction of Congress, however, it is clear that the priorities are not out of line.  For instance, the Near Term Mine Reconnaissance System (NRMS) is already cited as being ready for contingency operations.  The problem appears to be in the long range  LRMS system which has met with some crucial delays and one would assume resultant cost overruns. 

But what about futures.  Congressional opponents to more Navy spending focus on the difficulties in a semi-autonomous mine detection system.  Never mind that the lives saved by the system when the bugs are ironed out will be critical to our success at warfare.  Perhaps that is the problem, the UUV program is all about underwater warfare.  Most opponents don't understand how discoveries and advances will apply elsewhere just as many other military programs.

In any case, the proponents of the UUV programs can be found staring at the ceiling imagining the not too distant future when a UUV can do things a submarine simply can't and won't do because of the risks -- both to the ship and crew, but also due to politics.

Here is a list of such concepts which the Navy believes will make the UUV program so useful and indeed mandatory for the protection of sub crews and to ensure the projection of power matches our need to operate in the littoral zones:



The missions breakdown into simple scenarios which have incredible utility:

Mission
 Description
Maritime Reconnaissance
 The UUV is sent out to collect intelligence in a particular undersea or surface area, using passive or even perhaps an occasional active underwater detection sensor sweep.  Once a target is found and identified, is is designated for further surveillance by the UUV's aerial brother.  The coordinates, range, speed, and direction are relayed to a UAV launcher, and the UAV takes to the air.  The UAV sends back telemetry that might also include a visual picture of the target, and operators aboard the sub now can verify identification of the target as a hostile  A Missile is loaded into a VLS tube, and it is sent to destroy the target.  All from a safe distance, anywhere, anytime.
Undersea Search and Survey
 If no targets are immediately discernible in a possibly denied area, the UUV is sent in to map the undersea terrain, also looking for undersea detection devices, surveying features with GPS accuracy so that launch points for submarines supporting land forces can take good and mapped positions prior to launch time.  This may include a patrol to ensure no intruders enter the area while the sub moves into the ideal position.  Or during combat rescue scenarios, the UUV could be used to find downed flyers on the surface or a ship or sub which for some reason has gone silent.
Comm/Nav Aids
 Using lower cost leave and forget UUVs, the Navy envisions the ability to augment GPS systems or undersea communications by literally littering a littoral zone with these high capability UUVs.  They help in relaying signals between combat active UUVs and their mother ships, or help surface vessels assume safe positions in the combat zone -- areas that have been swept clean of sensors and ready for high connectivity communications between the Fleet's combatants.
Sub Track and Trail
 Using passive and perhaps active sensors, as well as highly autonomous AI, these UUVs can "fly out" and detect undersea or surface contacts, and then once designated, can assume tracking duties, staying with the contact as long as their fuel or battery power will allow.  Different scenarios include clandestine updates via surface buoy or using the undersea Comms network setup by other UUVs.

But there are more. For instance:
As Otto Kreisher 2 writes in an article for the Navy's Sea Power magazine:

"The submarines of 2020 also will be needed for forward engagement, the suppression of enemy coastal defenses, theater nuclear deterrence, the development of situational awareness, interdiction, covert neutralization of mines, theater missile defense, and arctic operations."

Thus the missions for the UUVs will need to aid in all of these tasks.



Multi-use Platforms

One of the problems with the UUV program is the cost of a single unit. Therefore, the Navy planners early on decided they must look at ways to reduce costs.  Taking a page from NASA's book again, they decided that a multi-use platform might be the answer.

The idea is simple in concept and both expensive and time consuming in design.  It involves designing a standard for a common "donkey" device that can take on different modules to carry out its missions.  Like a donkey, you can strap on the saddlebags and supplies you need for a particular adventure. In the case of the UUV, you might envision the passive and active sensor suites for the Sub Track mission or replace those with the relay, GPS gear, and perhaps increased power capability for longer loitering required in the Navaid mission.

Of course, all of this increases the overall cost of development, yet at the same time is supposed to drop the overall deployment costs.  And storage on the sub as well.  It is far most space effective if you store say a couple of dozen donkeys and a good mix of mission modules than to have to guess as to how many specific purpose UUVs you must store. 



Roadmap

The original plan called for a staggered means to get to those future capabilities, perhaps realizing that well laid plans need to have alternatives and flexibility.  Thus the Navy master plan cites a series of milestones that could be followed to get the UUV program into that realm of high utility envisioned. 


Click to see a larger and more readable image

The chart above tells a compelling and logical story for the UUV program.  The MILNET Analysis of the roadmap follows:

Planned Vehicles on the Books

The Navy has several UUVs already under development or in the early planning stages.  They are:

Device
 Description
 Status
SWARM
 Shallow Water Autonomous Reconnaissance Module -
Intended to proceed ahead of Fleet underwater and surface vessels in fairly (capital ship perspective) areas such as the littorals near an opponents shore.  An excellent example is the Persian Gulf and the Straits of Hormuz where the water is on the average (70% of) under 30 fathoms.  The SWARM vehicles go in to do recon, identify threats and allow other UUVs (UCUVs) to then go in and eliminate those threats all without risking the manned vessels.

Requires improvements in a number of areas before a viable protototype can be built:  Synthetic Apeture Sonar, energy storage (better batteries), demonstration of the Nav/COMs concept for UUVs, understanding autonomous group behaviors.

Typical parameters for this device are initially thought to be:
  • Weight: 500 pounds
  • Diameter: 12 inches
  • Length: 125 inches
  • Search Speed: 8 knots
  • ID Speed: 4 knots
  • Search Swatch Width: 405 yards
  • Search resolution" 1/2 x 1/2 inch
  • Range 70 miles
  • Operating altitude 20 feet
  • Production Cost: $100k (1000 unit build), $50k (>> 1000)

Assumes production of the 1998 Advanced Sensors 6.2 sensor in sufficient quanity and quality to outfit the prototype units and follow on production.

It is thought the SWARM is to be built on a common modular UUV frame, and the sensor suites can be swapped out to produce a mine sweeper/destruction module, or a combo module that allows the SWARM to dispense neutralization devices so as to not sacrifice the unit itself. 

While the COM/NAV UUV is postualted it is not absolutely necessary, however, not having the COM/NAV UUV in the mix will require the SWARM to increase dramatically in size since each will have to have the necessary independent COM/NAV capabilities on board.

Deployment from aircraft is evisioned (B-52, B-2, F-18) or via the LCAC autonomous carrier (similar to a sea version of a cluster bomb).
 Feasbaibilty (paper) study





The following tables list some of the world's UUVs:

UPDATE:

12/24/2007:  The U.S. Navy has deployed the first destroyer to be fitted with the Remote Mining System (RMS) UUV.  The U.S.S. Bainbridge DDG-96 is operating in the Mediterranean Sea, and the RMS complements the full system of anti-air capabilities with a new set of capabilities for  operation in the so called littoral areas.  The Navy has deployed the RMS on AEGIS destroyers as an interim move while the Littoral Combat Ship (LCS) continues in development.  The RMS ias an autonomous unmanned underwater vehicle that carries forward looking sonar and a system using a video camera to detect and avoid collisions with obstacles in the water. According to Military.com, "the craft can be programmed to perform autonomously or can be controlled via data link, even when beyond the horizon from the mothership, which recovers the RMS after the "mission." The RMS can detect and map the location of mines, but neither it nor the destroyer can sweep or destroy the mines."  7


See the MILNET AUV Briefing, September 17, 2006 for an update on the AUV world which feeds much of the UUV technology arena.



Conclusion

While Congress and the realistic facts surrounding available funding for future programs tend to point to a lessening in an aggressive UUV program, MILNET's analysis points to a decade not too distant in our future where the 2000 Master Plan for UUV development will only be a small sample of the kinds of capabilities actually in operation and contributing to the Navy's goals.  Thus the document remains seminal and predictive.


Sources:
  1. The Navy Unmanned Undersea Vehicle (UUV) Master Plan, (PDF 4.2MB), Department of the Navy, April 2000.(MILNET Mirror)
  2. Navy Studies Group Plots Bold Course For Future Submarines,  Otto Kreisher, Copley News Service, Navy League's Sea Power Magazine, undated.
  3. UUVs Will Foster Fundamental Change in Naval Warfare, James H. Patton, Jr., Navy League's Sea Power Magazine, July 2003.
  4. Navy Adjusts Course for Underwater Robots, Sandra I. Erwin, National Defense Magazine, May 2004
  5. Terms of Reference - Role(s) of Unmanned Vehicles, Naval Research Advisory Committee, undated
  6. GV.12.01 Mission-Reconfigurable Unmanned Undersea Vehicle, DoD Defense Technology Area Plan, U.S. DoD, 1997 (MILNET Mirror)
  7. Mine Countermeasures: Progress and Set Backs, Norman Poimer, Military.com, 12/24/2007
  8. Unmanned Vehicles for U.S. Naval Forces, CRS, FAS, 10/25/2006 (MILNET Mirror)


© Copyright 2005, Michael G. Crawford