WITH A MULTITUDE OF WARFIGHTERS in what seems to be a never-ending array of locations, making sure they stay in contact has become more difficult than ever. Often, this situation is further challenged by rough terrain, which blocks line-of-sight (LOS) tactical radios. As a solution to this problem, Iridium Communications, Inc.'s Distributed Tactical Communications System (DTCS) leverages a global network architecture without requiring any deployed infrastructure. In fact, the US Naval Surface Warfare Center Dahlgren just awarded a follow-on task order to implement Phase 3 of the DTCS program.

Also called "Netted Iridium," DTCS handheld push-to-talk (PTT) radios use the Iridium satellite network to provide over-the-horizon, beyond-LOS tactical networks for warfighters on the move (see photo). There are currently 5600 active Netted Iridium radios. With the task-order investment, valued at $13.4 million, Iridium will make further enhancements to the overall DTCS infrastructure. It plans to implement "theater-wide" or Global Reach nets, allowing greater efficiency, higher capacity, and improved quality of service.

The DoD has already deployed DTCS radios to support operations in Afghanistan and Iraq. In addition to PTT voice calls, the devices can transmit real-time position location information, providing a common tactical and operational picture for all network users. According to Iridium, its goal is to provide beyond-LOS, two-way command and control. It also seeks to provide improved situational awareness down to the handheld device.

The Phase 3 implementation will support a high volume of reporting devices on a realtime basis. With such enhancements, DTCS could eventually satisfy requirements for realtime data distribution across multiple platforms including sensors, vehicles, operational centers, and dismounted personnel.