Military

Editor’s Note: Reinventing JTRS

By Charlotte Adams | August 1, 2006

This month's issue updates readers on the U.S. military's vast Joint Tactical Radio System (JTRS) program, which is developing a family of interoperable software defined radios that will, it is hoped, eventually connect aircraft at the tactical edge of the battlefield to each other, ground forces and the rest of the Global Information Grid (GIG). Other segments of the program focus on radios for ground vehicles and dismounted troops.

Four years into the effort there have been numerous well-publicized problems caused by a decentralized management structure, an unstable requirements base and immature technologies. As frequently happens in ambitious programs, the goals turned out to be more difficult than expected. But that doesn't mean they are out of reach.

The Joint Program Executive Office (JPEO), created in February 2005 to reassess the program, has centralized management and adopted an incremental approach. The technical challenges remain, but the workload has decreased and high-level oversight has increased, so that problems receive more attention and progress is monitored more closely. The reconstructed program is still new--first discussed with reporters in May 2006--and needs to be given a chance.

JTRS is an important program and should continue, says Phil Finnegan, a program watcher and director of corporate analysis for the Teal Group, an aerospace research firm in Fairfax, Va. Progress has been slower than expected, and the units will cost more than expected, but with breakthrough technology that's not a surprise, he says.

The wideband networking waveform (WNW), for example, has had a difficult gestation. JPEO has reduced its deliverables in the first phase of the program from four signals to two. But this Internet-compatible networking waveform is considered crucial, as it would enable backbone communications for a broad set of users, with ground-to-ground, air-to-ground and some air-to-air applications. Using the Internet protocol (IP), WNW also would link tactical forces to ground networks.

Progress has been made. In field testing at Ft. Huachuca, Ariz., WNW developer, Boeing, demonstrated the ability to form a link at about 14 miles line of sight. The primary WNW signal, known as orthogonal frequency division multiplexing, is being tested in Boeing's Anaheim, Calif., system integration lab. It currently supports a data rate of 1 Mbit/s in the point-to-point mode, according to the company. Expansion to 2 Mbits/s is planned by summer 2008.

Boeing cites other milestones in a separate JTRS competition with Lockheed Martin to develop software radios for small form factor airborne applications, among other tasks. This Airborne, Maritime and Fixed site (AMF) program now includes rotary-wing, as well as fixed-wing platforms, a JPEO decision based on helicopters' stringent weight and power constraints. The Boeing AMF team has demonstrated hardware running WNW simultaneously with a JTRS version of a legacy signal, which proves the feasibility of key JTRS concepts, waveform portability and simultaneous waveform operation.

Rockwell Collins also has generated excitement with the Tactical Targeting Networking Technology (TTNT) link, which will be transitioned into JTRS through the Multifunctional Information Distribution System (MIDS) segment of the Airborne and Maritime domain. Another IP-capable waveform, TTNT can link tactical users back to command centers.

Challenges remain. The requirement to support ad hoc, networked operations, the use of software as well as hardware encryption technologies and the need to function at multiple security levels make information assurance a more difficult problem than with conventional radios. Waveforms are still in development, and weight, power, size and integration issues remain hurdles for airborne platforms. Still, JTRS has become a new program in many ways. Because of its importance to future network centric operations, the effort needs to be given time to succeed.

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