By Geoff Fein
Raytheon RTN] has been awarded a $5.2 million contract to provide the Navy with a tactical paging system to improve submarine communications at speed and depth.
Dubbed Deep Siren, the system uses a number of commercial-off-the-shelf components including Iridium satellite communications, an expendable buoy, and transmit-and-receive stations to enable a submarine to receive text messages without having to surface to communications depth, Bill Matzelevich, senior manager of business development, told Defense Daily in a recent interview.
Raytheon was awarded the development contract earlier this month.
“Basically, you make an Iridium phone call to an expendable buoy that can be deployed by multiple platforms. Basically you call the buoy with a message that you’d like to send to the submarine,” he said.
The buoy converts radio frequency (RF) energy into acoustic energy that a submarine can then receive through its installed sonar suite, Matzelevich said.
“The messages are put into textual format that can be read by an operator onboard the submarine,” he said.
The technology has a range of 30 nautical miles to upward of 150 nautical miles (Defense Daily, April 11).
In April, during the annual Navy League Sea, Air and Space expo, the company said the Navy would likely buy between 50 and 75 of the buoys, along with the receiver and transmitter.
Nova Scotia, Canada-based Ultra Electronics makes the buoy and Iridium Satellite, LLC makes the satellite communications system.
Today, submarines need to plan operations around the ability to use one of their antennas that they can raise through the water to receive transmissions, Matzelevich said.
“Fundamentally the communications are driven by the submarine’s availability to be at communications depth, meaning at a depth that will allow them to put an antenna out of water,” he said.
The advantage Deep Siren provides over how the Navy currently does submarine communications is that the submarine can be operating at any speed and depth posture as long as it is with the communications path that has been established by the Deep Siren acoustic communications protocol, Matzelevich explained.
“[The submarine] can be doing anything. Someone will send [it] a message, completely unplanned and unscheduled, and [the submarine] will receive the message and be able to respond to [it],” he said.
An operator at a transmitting station types in a message that is broadcast out over the Iridium satellite constellation. A buoy, equipped with a modem, antenna, and hydrophones, receives the Iridium call and converts it to an acoustic message that is then sent out to the submarine, Matzelevich said.
The submarine will receive the acoustic signal off the hydrophone in its sonar system. That sonar system takes the acoustic wave that comes in and the hydrophone will translate that wave into an electrical signal that be received by the Deep Siren receiver and translate it into a text message, not unlike e-mail, Matzelevich said.
The buoy has a life span of three days. However, the buoy’s lifespan is dependent upon its power supply, he noted.
“It can transmit for the equivalent of about 30 minutes…continuous transmissions. So you have basically 30 minutes of operational life of the buoy, but mechanically it can be serviceable for up to three days,” Matzelevich said.
The biggest challenge, Matzelevich believes, has been packaging all the components together. “It really is an engineering effort to be able to package all of things that are needed…required…to make this happen.”
“You have to have a small antenna on the buoy, you have to have a modem inside the buoy, you have to have hydrophones…projectors inside the buoy, you have to have a power supply for the buoy,” he said. “[All of that] allows [communications at speed and depth] to happen and happen in a way that it is really usable. That was, I think, the most challenging thing. It was really the process of innovation and being able to package this in the buoy and to have the protocols established from both the transmitter and receiver in order to make the whole system work.”
The Deep Siren demonstration system is completely portable, Matzelevich said. The transmit-and- receive station can literally fit into a suitcase.
The buoys are also portable, can be handled by one person, and can be carried aboard and taken off a submarine, Matzelevich added.
The transmitting station can be carried onboard a surface ship or used at a command-and-control center, and once it is set up, personnel would be off and running, Matzelevich said.
“So it’s not a big antenna farm that needs to be erected outside some base somewhere. But you would need to ensure you have good Iridium connectivity and an Iridium modem and Iridium phone at the transmitting site. You would also have to have the software that would enable the Deep Siren system,” he added.
The technology has been tested in demonstrations in early 2006 near Hawaii and later at the Rim of the Pacific (RIMPAC) exercise in July ’06. It was then selected for Foreign Comparative Testing and it became an Advanced Concept Technology Demonstration earlier this year (Defense Daily, April 11).
The Navy will take the systems it has purchased under this month’s contract and conduct a military utility assessment in the spring, Matzelevich said. The Navy will use those evaluations to determine what the course should be for Deep Siren, he added.
The initial operational capability is scheduled to occur by FY ’09.
The United Kingdom has also expressed some interest as they have identified a requirement for tactical paging (Defense Daily, April 11).
Deep Siren is just one component of a larger Navy effort to enable communications at speed and depth, Matzelevich said. “It is a family of technologies, a family of capabilities, that could provide enhanced communications to submarines while submerged.”
“The reason why it is a family of systems,” Matzelevich said, “is that it is pretty well recognized that no one system can provide the single capability you need.”