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Joint Tactical Radio Expected To Meet Special-Warfare Needs 


by Frank Colucci 

The next-generation tactical-communications technology—the Joint Tactical Radio System—will provide conventional military units with capabilities that typically are associated with special warfare.

Currently in the early states of development, JTRS also is expected to give U.S. special operations forces improved software-defined radios, readily tailored to their mission requirements.

In their secret missions, special operations forces (SOF) rely on secure, reliable communications to interact with their own joint-service units, conventional U.S. forces and international allies.

Today, discrete radios carry voice, digital data and video at high, very high and ultra-high frequencies (HF, VHF, and UHF)—using encrypted and jam-resistant waveforms. They enable Army Rangers to talk to Air Force gunship teams and Navy SEALs to “burst” data to distant joint-service commanders, with or without satellite relays.

Special operations forces participated in setting the requirements for the development of the JTRS operational requirements document, released in 1998. SOF requirements also will be incorporated in each new “cluster” of JTRS radios.

The software-defined JTRS was designed to replace single-function legacy radios and “stovepipe” communications with multi-mode (simultaneous data, voice, and video) sets that network air, ground and maritime users. The initial versions of the new common radios are to span the entire frequency spectrum from 2 MHz to 2 GHz and effectively put several radios in a single box.

The special operations community, meanwhile, already operates software-defined radios. In recent years, the U.S. Special Operations Command (SOCOM) has purchased the AN/PSC-5 UHF/VHF Multi-Band Multi-Mission Radio (MMBMR). The manufacturer, the Raytheon Co., has delivered both man-pack and vehicular versions. It replaces several-single band radios, sending voice, data and imagery over line-of-sight or SATCOM/DAMA (Satellite/Demand Assigned Multiple Access) networks at frequencies from 30 to 512 MHz. The PSC-5 can use SINCGARS (Single Channel Ground and Airborne Radio System) and Have Quick I and II waveforms to defeat enemy jamming. An enhanced encryption key management system provides COMSEC (Communications Security) with up to 250 keys. Plug-in modules expand the capabilities of the radio as needed.

SOF units also have acquired the software-based AN/PRC-117F(C) and AN/PRC-150(C) radios from Harris RF Communications, to provide short-range and long-range capabilities. Both carry encrypted voice and data communications, and both can display and transmit precision location beamed by external GPS (Global Positioning Satellite) receivers.

SOF units use these two radio systems during reconnaissance and other operations in hostile territory to transmit information in short bursts that prevent interception and location. An automatic repeat request confirms the burst was received without errors. To ensure secure communications, both radios also incorporate U.S. Type 1 (mandated by the National Security Agency) voice and data encryption capabilities, eliminating external encryption devices.

The PRC-117F is the VHF/UHF and UHF SATCOM (30 to 512 MHz) man-pack radio currently used by Air Force tactical air controllers and others to communicate with ground and air units. Digital data-handling capacity is 64 kilobits per second, over line-of-sight channels. To maintain transmission security even under enemy jamming, the radio contains Army VHF SINCGARS and Air Force UHF Have Quick frequency-hopping waveforms in software. The radio has a built-in satellite modem with communications standards also configured by software.

The PRC-150 is an HF and low-band VHF (1.62 to 60 MHZ) radio for longer-range communications. When satellite lines of sight are unavailable, HF radios are used to bounce transmissions off the ionosphere. Unlike its special-operations HF radio predecessor, the PRC-150 provides automatic link establishment to find the best frequency based on changing ambient conditions. HF digital data transmission rates are up to 9,600 bits per second. Also unlike previous radios used by special operations forces, the PRC-150 is Type 1 encrypted for secure message traffic.

Earlier radios required hardware upgrades in order to add new features. But both the AN/PRC-117F and AN/PRC-150 can be upgraded purely through software changes. Updates in VHF SINCGARS waveforms or SATCOM protocols, for example, can be downloaded to the -117F radio through a computer interface.

Joint Tactical Radios, additionally, will provide embedded position-location reporting capabilities to enhance situational awareness. The objective sets will ultimately incorporate satellite-communication capability. And unlike today’s purpose-built radios, the JTRS will have an open architecture so it can be upgraded in the field by installing applications from a software library maintained by the JTRS joint program office.

“Think of it as a PC,” explains Army Col. Michael Cox, of the JTRS program office. “In terms of data throughputs, it will have same capabilities as legacy radios, plus ones not developed yet.” While current radios are largely proprietary packages of hardware and software, JTRS separates government-owned waveforms from modular hardware.

Radios will be delivered with waveforms and other applications installed. Hardware makers will integrate government-furnished or licensed software. Once the radios are in service, the government, the hardware manufacturer, or a third party may install new plug-and-play waveforms.

The JTRS terminals are expected to take software updates transmitted on secure networks. To comply with the requirement to have an open architecture, JTRS hardware and software will conform to a single Software Communications Architecture now under development by an industry organization called the Modular Software Radio Consortium.

JTRS is expected to result in the production of up to 260,000 radios, 100,000 of which will be in the Cluster 1 procurement. The JTRS family of radios will include different boxes clustered to fit the ground, air and maritime domains of all the services. Hardware will adhere to current commercial standards and standard interfaces will accommodate different waveforms without redesigning the waveform or the radio. Plans call for the same basic handheld ground radio for conventional Army, Navy, Marine and Air Force units and special operations forces.

There are several SOF-unique requirements. Not all handheld radios, for example, need to meet SEAL requirements to withstand submersion 600 feet below the ocean surface.

The first JTRS cluster includes ground vehicular radios for the Army and Marine Corps, radios for Army helicopters, and sets for Air Force tactical air control parties. An early operational assessment is scheduled for 2004. Cluster 2 handheld radios—designed for joint-service and SOCOM requirements—are scheduled to begin development in 2004 or 2005.

SOCOM already has launched JTRS-oriented projects, such as vehicle adapters and information networks to run commercial application software.

With common radios, a broader range of platforms will be compatible with special operations forces. With today’s dedicated radios, submarines, for example, must be specially equipped with VHF sets to communicate with Navy SEALs on specific missions.

The U.S. Navy already is investing in software-based radio technology, under the Digital Modular Radio program. Last April, the Navy Space and Naval Warfare System Command (SPAWAR) awarded a second production order of $39.6 million to General Dynamics Decision Systems, bringing the total contract value to $95.6 million.

The DMR is a software-controlled and re-configurable digital system that provides interoperability among diverse legacy radios.

The company’s wireless technology is being used under a separate contract with the JTRS Joint Program Office to validate the Software Communications Architecture (SCA).

The DMR employs commercial-standard processors and software, and will enable the Navy to train its radio operators on one platform and replace numerous, previously incompatible systems with a single system which communicates seamlessly with different armed services as well as the U. S. Coast Guard and NATO allies.

To protect data from intruders, the DMR has the Advanced INFOSEC Machine (AIM), which received Type 1 Certification from the National Security Agency. It simultaneously operates on multiple channels using different algorithms, enabling it to potentially replace many standard encryption functions with a single device.

General Dynamics is a member of the JTRS Futara Team, which is led by the Raytheon Co. The team also includes SAIC, TRW and ITT Aerospace.

The Futara team will compete for the Cluster 1 award against rival Boeing Space & Communications. Boeing’s partners are BAE Systems, Harris RF Communications and Rockwell Collins.

The JTRS program could generate up to $1 billion in sales for U.S. companies, without including foreign sales to allied nations.

One of the most technically challenging requirements in the JTRS program is the development of a new wideband waveform, which will enable thousands of users to transmit and receive heavy volumes of data, including graphics, voice and video-teleconferencing.

In 1999, Raytheon received a contract to define an architecture for the new radio. The company demonstrated VHF-FM, VHF-AM, VHF-FM public service, VHF air traffic control, Have Quick I & II, and MIL-STD SATCOM waveforms in early 2001. ITT, Rockwell Collins, and BAE demonstrated SINCGARS SIP, wideband data, HF-Automatic Link Establishment (ALE), VHF-FM, and VHF-FM waveforms. The ALE waveform was demonstrated in a Raytheon prototype radio using Rockwell-Collins software. During the architecture validation tests, JTRS prototype radios also worked with legacy ARC-164, ARC-222, VICS, VRC-100, and SINCGARS radios.

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