New applications, markets sought for underwater communication system.

• Author: Magnuson, Stew

* A new technology designed to communicate with submarines as they travel stealthily at great depths and speeds is now being looked at as a means to send messages to special operations divers and commands to unmanned underwater vehicles.

The Deep Siren tactical paging system, produced by Raytheon, seeks to answer a need that the Navy has had for years: how to link to its submarines as they travel underwater without exposing their positions to potential enemies.

Company representatives said Deep Siren is at an advanced technology readiness level--seven in a one-through-nine ranking, which means it has been successfully tested in operational environments. But the Navy has not made any decisions on whether to add the system to its submarine fleet. The Navy awarded Raytheon a $5.2 million contract in 2007 to develop the technology and run a series of tests.

Since then, the United Kingdom's Royal Navy has also tried out the underwater communication system.

"We know the product works. It's now a matter of demonstrating it to customers," said Trevor Barron, Deep Siren system engineer. "We continue to evolve the product's capabilities with our internal funding."

Submarine commanders can be ordered to run silent and deep for months without any way to send or receive messages. Communicating with a command center often means rising close to the surface where a periscope with an antenna can be raised above water. That makes the ship vulnerable and can expose its presence to the enemy.

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The Space and Naval Warfare Systems Center ran the first tests on Deep Siren, which allows a submarine to "send a page" to surface ships or command and control centers or vice versa without having to surface or stop its engines.

It was developed as part of the Navy's communications at speed and depth program. The 2008 trials used a buoy ejected from the submarine's trash chute to establish a link to the outside world. It enabled a submarine to be connected to the network while actively participating in military operations.

After the buoy is ejected from the trash chute, it hovers at a predetermined depth as the submarine continues its journey, explained Barry Murphy, director of undersea networked communications at Raytheon.

When the submarine is far enough away, the buoy ascends to the surface, deploys floatation devices and sends a message to a command and control center through an Iridium satellite. Once a link between the...