Land Forces Extend Combat Range With 'Netted' Radios.

Sophisticated new vehicles and weapons aside, the success of land forces in future wars will be linked inextricably to the strength of their communications networks.

That is the emerging doctrine that will be part of the Army's so-called "transformation" process. Under this doctrine, there are no heavy tanks and much less armor. To overcome the vulnerability associated with lighter vehicles, the Army believes that soldiers will rely on advanced tactical communications systems to figure out foe and friendly positions, and thus stay out of the reach of enemy fire.

"The goal is for the leader to make intellectual contact with the enemy before the soldiers make actual contact," said Brig. Gen. Paul D. Eaton, deputy commander for transformation at the Army's Training and Doctrine Command.

But tactical communications technologies today fall short of what the Army needs to make this transformation come to fruition, said Maj. Gen. Steven W. Boutelle, the Army's program executive officer for command, control and communications. "Terrestrial-based communications will not get us where we need to go," Boutelle said during a recent Army conference in Fort Lauderdale, Fla.

Boutelle's statement points to the core of the Army's problem: ground-based tactical communications systems are not robust enough to overcome the need for line of sight. One solution, said Boutelle, is the use of tactical satellite systems or unmanned aircraft, which can relay ground messages from point to point. "We need to extend the network to the three-dimensional world, or we will have significant problems," he asserted.

Part of the Army's massive investment in its transformation includes an increase of $1.2 billion during the next five years for [C.sup.4]ISR, a catch-all phrase that refers to technologies used for command, control, communications, intelligence, surveillance and reconnaissance functions.

A large portion of that money will be spent on "advanced technology demonstrations" to bring about more robust [C.sub.4]ISR systems, explained Maj. Gen. Robert L. Nabors, chief the Army's Communications and Electronics Command.

These projects will emphasize secure, on-the-move battlefield communications technologies that will give soldiers access to useful tactical information, Nabors told National Defense during an interview in Fort Lauderdale, where he was attending an Army symposium.

Among the top priorities is a program called "Mosaic," or multifunction on-the move secure, interactive, adaptive communications. The idea is to rely on "dynamic bandwidth management on the battlefield," so that information stays in the network and ensures that it is delivered to its destination, even if two or more radios become disconnected, he explained. Such a self-healing network automatically reroutes the information, so the message gets through.

Another program called "agile commander" is designed to reduce the size of current tactical operations centers--where the commanders manage the battle-by packing information into smaller packages, said Nabors.

In the future, he added, the Army also will need "smart agents" or pieces of software that will manage and interpret the flow of information to the commander. Smart agents are programmed based on what the commander thinks is important, Nabors said. "They help commanders synthesize information."

The Army has a tough problem when it comes to tactical communications, because the terrain inevitably gets in the way of the radio waves. For the most part, radio waves cannot penetrate mountains or buildings. The laws of physics say they need line of sight.

Even HF (high frequency) radios, whose signals can reach hundreds of miles, are ineffective for going around mountains.

Satellite-based systems are not encumbered by terrain, but the Army cannot just rely on sat-com (Pentagon lingo for satellite communications), because there is limited satellite capacity, and during a large conflict such as Desert Storm, channels become oversubscribed. It was during that conflict that HF radios regained popularity

In the absence of transponder satellites or unmanned drones as a communications relay platform, the Army's next best thing is a ground-based network of radios that can route messages around obstacles, such as mountains.

During the Army's division-level exercise at the National Training Center in April, the mechanized 4th Infantry Division's Abrams tanks were equipped with onboard computers linked to the Army's Battle Command System, a digital collection of command-and-control systems that work together to provide a common tactical picture for the commander. The exercise, among other things, was designed to test the performance of netted radios and computers.

"Our radios on vehicles don't go over mountains," said Maj. Gen. B.B. Bell, the director of the exercise. With "netted" radios, "you can see tanks even behind mountains," he told reporters during a recent briefing.

The radio network that the Army is deploying on tanks and trucks is called EPLRS (enhanced position location reporting system), an ultra-high-frequency data radio that essentially functions like a radio-frequency modem. It pushes data around the battlefield.

Networked radios such as EPLRS make it possible for a commander to disperse vehicles in different directions, beyond the line of sight, without losing communications links. EPLRS "finds things to connect with," explained Bell. The signals can thus go around a mountain through any number of relays. The 4th Infantry Division has 1,500 EPLRS radios.

"Every radio can connect to up to 30 radios," said Robert D. Scherer manager of customer requirements at the Raytheon Systems Co., in Fullerton, Calif. The network self-heals if a circuit becomes disabled.

EPLRS, built by Raytheon, is one of several radio waveforms that make up the "tactical Internet." The combat net radio is the single-channel ground and airborne radio system (SINCGARS). At the tactical operations center, commanders use the mobile subscriber equipment's tactical pack et network and the near-term data radio.

A brigade has more than 400 EPLRS radios and at least 1,400 SINCGARS radios.

In the tactical Internet, those radio systems are connected via Internet routers that use the IP, or Internet protocol, the standard used by the commercial Internet and corporate intranets for transporting data packets. The Army is testing the use of IP-compatible HF radio to extend the range of local network users of SINCGARS or EPLRS, by hundreds of miles. The Harris Corp., in Rochester, N.Y., has been working with the Army to demonstrate that Internet-based technology can work over HF radios.

For the tactical Internet, the Army is developing graphics-heavy software called the Force XXI battle command brigade and-below (FBCB2), which displays on a laptop computer monitor a common picture of the battlefield.

FBCB2 is still in development and not ready for use in actual combat, said Bell. But he expects the technology to mature over time.

FBCB2 nodes--individual vehicles--can connect over EPLRS, for example, explained Richard E. Hitt Jr., director of business development for [C.sup.4]ISR tactical systems at Raytheon Systems Co. The company is a subcontractor to TRW Inc. for FBCB2.

The Army, like most other buyers of tactical radios, wants radio users to be able to communicate by voice over IP networks. IP networks are very efficient for data transmissions and, if they can successfully transmit voice, can help consolidate more than one function in a single radio.

"Voice-over-IP is happening everywhere," said Hitt. "The IP protocol is very capable to support voice communications.... Voice is just another data packet." If the sound is not clear, that does not mean that the IP protocol is incompatible with voice, but it has to do with how the network is designed, he explained. When voice is digitized, it is compressed into data packets. "Every compression algorithm drops a few bits," said Hitt. "If you drop too many, people start sounding like Donald Duck."

When data and voice travel on the same network, "voice has to tread over data," said Kevin Kane, director of business development at Harris Corp. RF Communications Division. "A mid-air collision can create errors," he said. Voice-over-IP will work, "but there will be things that will have to be sorted out."

Protecting IP networks from hackers is no more difficult than with any other digital protocol that the Army uses, such as asynchronous transfer mode, said Hitt. "The IP protocol is inherently secure. It is the operating systems and how the gate ways are put together that determine how secure the system is."

EPLRS will be upgraded to an IP-based architecture, so the radios can interface with computers, said Scherer. It will be a software-only upgrade.

Raytheon also is trying to pique the Army's interest in a five-pound version of the vehicle-mounted EPLRS, called "EPLRS Lite."

The market for this radio would be the light infantry units and paratroopers, said Scherer. "When soldiers dismount, they need a device to connect back to the vehicle or to the members of the platoon or company," he said. Unlike EPLRS, current squad radios have short ranges and don't connect into the tactical Internet that uses FBCB2.

Raytheon has built 10 EPLRS Lite prototypes, which are being tested by the Army. Last November, the company delivered the 4,000th EPLRS vehicle radio. The Army's plan was to buy 8,157, but the number was increased to 12,693, as a result of the new brigade combat teams that are being fielded. Those units each will have 700 radios.

Scherer would not speculate on the cost of the hand-held EPLRS. The vehicle-mounted EPLRS cost $50,000 to $60,000 each, when Raytheon was building 50 to 80 a month. Now, under a new multi-year buy for batches of 1,100 to 1,700 radios, the price is expected to go down to less than $20,000.

An industry source who asked to not be quoted by name said that the $20,000 price tag, given the small production runs, is "about the average price nowadays." Nevertheless, he added, "that's an awful lot of money, compared to what commercial radios cost."

Army Radio Adapted For Aircraft Applications

Several hundred Air Force warplanes are being equipped with a variant of an Army radio system that gives air crews access to the same tactical picture that the commanders see on the ground.

The Army radio is the EPLRS (enhanced position location reporting system). Ground vehicles equipped with EPLRS form a network that distributes data around the battlefield, such as the locations of friendly and enemy forces.

Air Force F-16 and A-10 fighter aircraft are using the EPLRS situational awareness data link (SADL) to connect into the Army's tactical Internet, said Maj. Gen. Steven W. Boutelle, program executive officer for command, control and communications. "It works," he told a conference of the Association of the U.S. Army in Fort Lauderdale, Fla. The idea is for both serv ices to have a "common operating picture" and to not have to rely exclusively on voice communications.

With SADL, the aircraft "nets up with the ground community" for close air support missions, so they can look on the ground for friendly forces, explained John Martin, an engineer with Raytheon Systems Co.

"It enhances the capability of the air guys to go play with the ground guys," Martin said. It also could help prevent fratricide. The SADL radio is integrated with air craft avionics over the 1553 multiplex data bus.

The F-16s and A-10s that are receiving the SADL system primarily are from guard and reserve units. "The pilots can see where the target is," Martin said. SADL gives them a ground picture and allows them to monitor the immediate air picture.

The SADL is much like the ground EPLRS, with slightly different firmware in the radio. With the turn of a switch, the radio can convert from SADL to EPLRS. More than 700 have been built for F-16s and A-lOs.

The airborne version of EPLRS initially had not been planned for the Air Force, but for Army avia tion, "even though we had a lot of problems breaking into the Army aviation world," said Martin.

Air Force warplanes typically rely on the Link 16 tac tical data network. But many guard and reserve platforms are not going to get Link 16 terminals because they are expensive, said Martin.

A SADL terminal is in the $30,000 to $50,000 price range. A Link 16 terminal runs about $200,000.

SADL provides a "gateway" to Link 16 networks, said Richard E. Hitt Jr., director of business development at Raytheon. SADL runs in a different portion of the fre quency spectrum than Link 16. "If you have a Link 16 radio next to a SADL radio, the gateway software can communicate with both radios and move data back and forth between the two networks," he explained. A SADL radio can distribute the data that it pulls from the Link 16 network to other SADL radios, Hitt said. "Those users who can only afford SADL can take advantage of the fact that there is Link 16 in the area.

"We just need one SADL radio in the tactical area, connected to one Link 16 radio in the network and, bingo, we have two networks connected."

Sandra I. Erwin