Remote-controlled underwater vehicles equipped with advanced sensors
could help Navy submarines explore waterways that would be too shallow
for most boats to operate in, officials said.
Two-thirds of the Yellow Sea in Southeast Asia and three-fourths
of the Persian Gulf are shallower than 180 feet. To operate in these
waters, the Navy needs small surveillance platforms, such as unmanned
underwater vehicles (UUVs), that could perform clandestine mine
reconnaissance and collect tactical intelligence, noted Scott Farnsworth,
the Navy’s deputy program manager for UUVs.
Among the top priorities is to develop a “mission-reconfigurable”
vehicle that has a common frame but can be equipped with different
sensor payloads, he said. Funding for this program will be available
One application of UUVs has been the semi-autonomous hydrographic
reconnaissance vehicle (SAHRV), said Navy Lt. Cmdr. Doug Horner.
The four-year $25 million program is funded by the U.S. Special
Operations Command and is designed for the special naval warfare
units, called Navy SEALS.
The SAHRV is launched from a special operations craft, or it could
be launched from a submarine. It is used by SEALS to scan sections
of the ocean from the 21-foot to the 10-foot mark, said Horner.
It used side-scan sonar to identify obstacles. “The idea is
to provide post-operation information in the form of hydrographic
charts,” he said. The data would be sent to the commander
of the amphibious force deployed in the area.
The SAHRV navigates via transponders that are installed 60-100
nautical miles from the shore. “The key is placing the transponders
accurately,” said Horner. SEALS in the craft can monitor the
operation in real time and can reprogram the vehicle. The SAHRV
can search a 800 by 1,000-yard area in about 3.5 hours. The batteries
last 60 days.
In addition to the side-scan sonars, the vehicle has conductivity
sensors to measures water salinity, temperature, depth and an optical
backscatter to gauge the clarity of the water.
The data is converted to graphics-friendly reports and charts,
but a human operator has to review the side-scan records manually
and flag potential hazardous objects in the water.
Recent tests with four vehicles off the coast of San Diego were
successful, said Horner. He expects that 14 vehicles will be operational
by February 2003.
The Special Operations Command plans to fund future upgrades to
the SAHRV in 2003-2006. These include:
For underwater mine detection, meanwhile, the Navy’s largest
development is the so-called remote mine-hunting system (RMS). Some
of the technology in SAHRV “can be leveraged with RMS,”
said Capt. Terry Briggs, the RMS program manager.
RMS is one among seven systems that make up the Navy’s organic
mine-countermeasure concept. Five are airborne, RMS and the so-called
long-term mine reconnaissance system (LMRS) are UUVs.
The vehicle is launched from the decks of host surface ships, specifically
Aegis destroyers. “It allows the host ship to remain off shore,
safer from coastal fires,” said Briggs.
Built by the Lockheed Martin Naval Electronics division, the RMS
weighs 14,000 pounds, measures 4 feet in diameter and is 23 feet
long. It’s powered by a 370-horsepower diesel engine and carries
240 gallons of fuel. Its search speed is 8-12 knots, and it can
operate for up to 24 hours. On-board sensors include forward-looking
sonar for obstacle avoidance. A masthead camera allows the operator
on the ship to take control manually. There is a mission recorder
on board for post-mission analysis.
The towed sensor package weighs 1,000 pounds. It carries a forward-looking
sonar, a volume-search radar to classify mine-like objects, a side-look
sonar and a gap-filler sonar.
The other mine-hunting submersible, the LMRS, “expands the
reach of the submarine sensors,” said Capt. John Lambert.
Two UUVs will be deployed from the new Virginia-class attack submarines.
They will be carried in the torpedo room. With an endurance of 12-15
hours, the LMRS will have a forward and a side sonar. The 21-inch
vehicle (the size of a torpedo tube) weighs 2,800 pounds and moves
at a speed of 8 knots. The Boeing Co. received a development contract
in November 1999 for 12 units.
In a separate program, the Navy plans to deploy a new UUV for explosive
ordnance detection by 2006, which would replace human divers and
dolphins, said Capt. Rick Kiser. The vehicle would be equipped with
low-light cameras and would cost $150,000, not including sensors,
The goal is to develop a small UUV to cover 10-by-10-nautical mile
areas at depths of 10 to 300 feet. This technology, said Kiser,
could be used to locate aircraft crash sites.