Netted Iridium ‘radios’ prove indispensible in battlefield test

A yearlong test in Afghanistan of about 100 Netted Iridium phones that give warfighters a push-to-talk, one-to-many capability has been so successful that plans are in place to deliver thousands more Netted Iridium radios in 2010.

The radios are providing an unprecedented level of situational awareness for disadvantaged warfighters - those without access to ground infrastructure, especially units venturing deep into isolated areas of the countryside and those who are not authorized to use a tactical satellite channel. It's a capability that military leaders say takes away some of the Taliban's advantages in the mountains of Afghanistan.

"By the time the bad guy figures it out, smoke is coming out of the hole," said Army Brig. Gen. Mark Bowman, director of architecture, operations, networks and space at the Army's Office of the Chief Information Officer. "We need to figure out how to get these [radios] faster."

The job of addressing that need falls to the Naval Surface Warfare Center's Dahlgren Division in Virginia. The unit is the research and development lab for the Marine Corps, and it is developing the technology under the Distributed Tactical Communications System (DTCS) program, which includes the Netted Iridium handsets, training and support for Marines and soldiers.

In a way, Netted Iridium is like the party line of olden days, when numerous people could listen in on a single telephone conversation. But instead of letting everyone be able to talk at the same time, Netted Iridium is a push-to-talk, one-to-many capability, meaning that pushing the talk button on the radio locks out everyone else in the net so all they can do is listen. And because transmission is via the Iridium satellite network, the connection between the talker and listeners occurs almost instantaneously.

"The battlefield is not suited to dialing 12 digits and waiting 30-45 seconds for the routing to establish a call," said Igor Marchosky, DTCS technical manager. "That's too long, and it requires both of us to maintain a link with a satellite to maintain the call. Also, a telephony-based system cannot scale because if every listening radio or telephone in the network is taking a channel, then the network has to scale by a factor of how many listeners are in the network."

"What we did is take telephony out of the equation and turn the Iridium constellation into a packet switched network in the sky," Marchosky said. "The satellites become nothing more than broadcast devices. When the talker sends traffic to the satellite, the satellite simply broadcasts that traffic back down to the network. A subscriber to the net has only to listen to the traffic, and because all listeners are passive, that means that the architecture can now scale. The setup time for a talker to get on a channel is reduced from 30 seconds to two seconds."

Urgent Operational Need

The Netted Iridium capability and DTCS are being developed at the behest of the Joint Capability Technology Demonstrations Office, which is part of the Office of the Undersecretary of Defense for Acquisition, Technology and Logistics. The technology demonstrations office is responsible for developing new operational concepts and facilitating the rapid acquisition of new technologies.

DTCS is considered an interim solution that addresses capacity limitations of older satellite systems, such as the Navy's Ultra High Frequency Follow On (UFO) satellite network, which has been in operation since the early 1990s. Those limitations will be addressed more fully by the Mobile User Objective System (MUOS) UHF satellite constellation, scheduled for launch later this year. But that doesn't mean that the DTCS program will end once MUOS becomes operational.

"We do not intend DTCS to replace MUOS or UFO but rather complement them," Marchosky said. "There will be a series of mission sets that will require MUOS or UHF (tactical satellite), but for those missions that don't require the complexities of MUOS or UFO, then maybe DTCS is a good complement. The DTCS architecture is designed for tactical responsiveness, so that if some day we were called to fulfill a higher mission we could, but we didn't necessarily set out to solve those problems."

In addition, a program such as DTCS is not likely to end any time soon because the military will continue to rely on commercial satellite networks for most of its satellite transmission needs.

"Does Netted Iridium go away once MUOS becomes operational? No," said Scott Scheimreif, Iridium's vice president of government programs. "Eighty percent of DOD satcom use comes from commercial satellite providers. Whether it remains 80/20 or moves to 70/30 or 50/50 will be seen over time."

DTCS is in Phase 1, in which satellite communications cover a 100-mile footprint at 95 percent reliability. Although the number of users on the system is theoretically unlimited, the number of possible nets on the system during Phase 1 was capped at 250, though only a couple dozen have been supported during testing so far, Scheimreif said. Phase 2 of the program is scheduled to begin in mid-2010, when Iridium will make in-orbit upgrades to the satellites and ground infrastructure to increase the footprint to 250 miles and the number of nets to as many as 2,000.

Another of the major goals of Phase Two will be to reduce the combat load on the Marine or soldier.

"Combat load is not just the weight of the actual radio -- which is 1.1 pounds -- but weight in terms of the batteries, weight in terms of the training and weight in terms of the logistics to maintain the radio," Marchosky said.

To ease the program's logistics, the radios run on rechargeable batteries instead of throwaway batteries, which cuts down on the number of batteries that must be delivered to and stored at forward operating bases.

"The lesson learned is that although we developed the radio to use disposable off-the-shelf batteries, our initial deployment was to users that came back to their FOB on a daily basis," Marchosky said. "They requested rechargeable batteries rather than disposable ones so they wouldn't have to incur a supply of batteries."

Another lesson learned during testing in Afghanistan was the need to make devices that could overpower the noisy environment of vehicles on the move. In addition, the engineers at the Naval Surface Warfare Center's Dahlgren Division are working to introduce a way to deliver information to the user about signal strength and battery life without adding a display to the ITT-manufactured radios because displays are the element most susceptible to failure.

Every Netted Iridium radio can also function as a data modem, so it can connect to a laptop PC for communications with headquarters, for example. That capability will evolve further this summer when the Navy lab introduces a prototype Netted Iridium radio called C2 - for command and control.

The C2 terminal will combine the functionality of a laptop PC and personal digital assistant with that of a radio.

"But don't think of it as an e-mail device," Marchosky said. "It is for practical data. For example, if I am in a convoy, I can use my C2 device to receive new information, send spot reports or provide medevac requests. These are things that could be done with voice, but are more effective as data."