Electronic Design

Technology At War

Advanced electronics mean troops are better protected, better informed, and more lethal.

Unmanned aircraft dominate the skies above the theater. A swarm of unmanned ground vehicles with sensors that can see, hear, and maybe even smell prowls the forests and fields of our enemies. High above the theater, peering down from space, are spacecraft that are being refueled in orbit. Their onboard electronics and software are being upgraded and replaced as easily as sliding a PCMCIA card in and out of a laptop."

That's the battlefield of the future, according to Gary Graham, deputy director of the Tactical Technology Office (TTO) of the U.S. Defense Advanced Research Projects Agency (DARPA). He delivered these remarks on behalf of TTO director Arthur Morrish at last year's DARPATech symposium in Anaheim, Calif.

His remarks weren't just the stuff of sci-fi speculation, though. Many of these developments are only five to 10 years away. In fact, some have places right now amidst the battlegrounds of Iraq and Afghanistan.

"A helicopter glides over the battlefield and drops a box of missiles," Graham continued, describing a likely scenario. "This box is identical to a bunch of missile boxes already in place on the battlefield, many sitting in the rear compartments of Humvees, except the former missiles aren't attended by human operators and already know where they are. Each has a GPS and a comm link. They sit, poised, waiting for command signals.

"A corporal out in the field sees the enemy coming over the hill. 'I need fire support now!' he radios. Missiles in the dropped box already know where friendly and foe forces are, and the first wave of them is launched. The slower missiles come first, loitering over the battlefield and providing a post watch. Next, faster precision missiles are launched and detonate on their targets. One of the missiles loitering overhead surveys the scene, detects a surviving moving target, and dives down to finish the job. The battle is over."

Such combat techniques would be impossible without anticipated advances in microsystem device technologies like microelectromechanical systems (MEMS), nanoelectronics, and electro-optics. Improved semiconductor and composite materials are vital, too. These developments will eventually lead to spectacular autonomous and interactive military systems that can sense, reason, communicate, and actuate.

"We'll interact with these systems in ways that will make The Matrix Reloaded look like an old episode of Lost in Space," said Zachary Lemnios, director of DARPA's Microsystems Technology Office (MTO). The MTO is busy developing new classes of semiconductor materials and devices to extend the military's dominance of the electromagnetic spectrum through radar, electronic warfare, and communication systems.

Specifically, the office has come up with antimonide-based compound semiconductors with narrow bandgaps whose carrier mobilities are over 10 times greater than silicon and can operate at less than 1 V. Wideband semiconductors under development include gallium nitride and silicon nitride to form the sensors and actuators of radar and communication systems.

The military's wide-ranging expectations for technology advances involve every aspect of military life: arms, armaments, armor, communications, intelligence and counterintelligence, helicopters, manned and unmanned aircraft, warships, submarines, and robotics. Also, the military expects to use commercial off-the-shelf (COTS) hardware and software in these technologies while meeting stringent reliability requirements—and that's a tall order.

DARPA's Advanced Technology Office (ATO) is investigating new materials that will enable small- and medium-caliber lightweight projectiles to be fired at very high rates without the need for internal moving parts. Its Mach 5/50 program is looking into producing medium-caliber projectiles (50-mm or larger bore) that will have a minimum velocity of 1600 m/s (approximately Mach 5), firing at 600 rounds per minute or more.

The TTO envisions a hands-free weapon that can be extremely useful in urban warfare, where rifles and pistols tend to be of little use. Such a weapon would consist of electronically fired caseless ammunition that's fired from the forearm. It could also double as a chemical and biological hazard detector that dispenses neutralizing agents.

SCALING DOWN DEVICES IS KEY
The scaling down of ICs with higher densities will continue not only in the electronic domain, but also in the photonic, mechanical, chemical, and even biological areas. This scaling down is needed for building 3D microsystems to overcome the limitations posed by wiring delays, heat removal, packaging constraints, clock synchronization, and interconnect capacitance.

The military must integrate multiple sensors into space-, weight-, and power-constrained systems. It also needs to build circuits that can quickly extract information from increasing amounts of data becoming available. DARPA's vertically integrated sensor arrays (VISA) program is intent on making this happen (Fig. 1).

Also, improved sensor-to-shooter cycle times—the time required to make a firing decision about a potential target—demand a new model for target acquisition and determination (Fig. 2). The aim is to produce microsystems that will integrate sensing, processing, actuation, and power-management functions. These devices will feature multispectral functionality and adaptability in response to a changing environment while performing real-time data analysis.

For example, DARPA's adaptive focal-plane array consists of dense structures of addressable and programmable pixels, resulting in a hyperspectral imager on one chip. MEMS devices are used for frequency domain filtering, and electronics perform the high-speed control. Photonics elements form the principle transducer, which consists of mercury-cadmium-telluride (MCT) photodetectors.

Sensing technology offers multifunctionality. For example, it can detect chemical signals to identify explosives as well as identify individuals or groups of people on a battlefield. DARPA's ATO has a program to determine and identify unique chemical signatures (e.g., explosives) that emanate from specific high-level-of-interest individuals within groups of enemy troops or combatants. The basis for this approach is the major histocompatibility complex (MHC) phenomena, which has been successfully observed in mice.

Most recently, researchers at Israel's Technion Institute of Technology devised a means of identifying previously undetectable explosives, such as those worn by suicide bombers. The institute's peroxide explosive tester (PET) can detect triacetone triperoxide (TATP), a chemical commonly used in suicide bombs.

BETTER BODY ARMOR
Soldiers wear helmets, bulletproof vests, and shoulder armor to help them survive the rigors of combat, but their arms and legs remain exposed. These extremities can receive serious and crippling, if not lethal, injuries. Statistics show that 75% to 80% of killed soldiers die from getting hit by shrapnel and ensuing excessive bleeding.

To ameliorate this situation, nanotechnology is coming to the rescue. Under a partnership with Armor Holdings Inc., researchers at the Advanced Center for Composite Technologies at Florida State University are developing and testing first-of-its-kind body armor for soldiers' arms and legs. They're experimenting with carbon nanotubes that improve the strength of fabrics used to make bulletproof armor.

Ballistics tests show that bound multiple layers of fabrics and plastics are better at stopping bullets than conventional bulletproof vests. At the same time, they provide the necessary aesthetic and mechanical properties that make the armor comfortable to wear. The researchers already devised lightweight custom leg supports for U.S. Navy Seabees with severe leg wounds, as well as for athletes.

Some scientists are convinced it will take more than technology to produce better armor materials. For instance, a better understanding of nature's animal structures can go a long way toward this goal. Case in point: By studying mollusk shells, bird bills, deer antlers, and animal tendons, researchers at the University of California at San Diego are attempting to develop biology-inspired, or what they call biomemtic, structures for a new generation of armor materials.

Future soldier uniforms will feature more than high strength properties, though. They'll also contain sensors that constantly monitor a soldier's health, as well as rapidly identify a wide variety of external chemical and biological weapons.

One of the more ambitious DARPA ATO efforts, the self-healing minefield program, doesn't rely on anti-personnel landmines for dismounted breach protection. The self-healing mine system is an intelligent entity that responds to an enemy's attempt at breaching by physically reorganizing itself. To build such a system, DARPA is investigating individual impulse-based mine mobility concepts, low-power mine-to-mine communication methods for determining mine location, robust healing algorithms, and compact yet effective warheads.

MORE MUSCLE
Through funds from the U.S. Army, the Massachusetts Institute of Technology (MIT) is working with other industrial partners to develop nanomaterials that can act like exterior support muscles. While this may be several years away, many researchers say the technology could one day find its way into DARPA's "exoskeleton" project, which would help soldiers run faster, jump higher, and lift more weight.

Other research efforts are looking at human-enhancement technologies that range from genetic engineering to molecular robotics. Many researchers agree that it's theoretically possible to place molecular-sized "bots" in the bloodstream and then send them to a person's brain extremities. Soldiers could use the "bots" to combat biological warfare by accelerating the actions of the human immune system. The "bots" also could be programmed to move to the front part of the brain, where they would dispense certain chemicals and speed up the individual's anticipation and response time.

DARPA has already awarded a $750,000 20-month grant to the NanoTech Institute of the University of Texas at Dallas to create chemically powered artificial muscles for military applications. Electrically powered artificial muscles, based on conducting polymers and carbon nanotubes, can exceed the performance of natural muscles by generating 100 times their force and elongate twice as fast. But they also provide less contraction, have shorter lifecycles, and lower energy conversion efficiencies. The move to chemical power is expected to solve these problems.

A ROBOTIZED MILITARY THEATER
The military is aggressively looking at all kinds of unmanned military craft for ground, air, and sea combat, and it sees robotics as an essential ingredient of the mechanized army of the future. The Pentagon has responded by using over 100 tractorized unmanned ground vehicles (UGVs) to perform a variety of tasks, such as surveillance, landmine detection and neutralization, and bomb disposal.

Essentially remote-controlled robots, UGVs are seeing action in Iraq searching for and dismantling bombs and mines. These lightweight robots, weighing between 50 and 150 lb, use a robotic arm and vision systems (standard, infrared, and night vision) to perform their jobs. They also use water cannons to blow apart the triggers of explosive charges. Military planners envision more expanded use for these vehicles, such as guarding base perimeters and conducting reconnaissance and scouting missions behind enemy lines.

Despite the obvious advantages of robotic vehicles in combat, the present generation of machines suffers from short communication ranges, a lack of a standardized sensor interface, and a low level of video latency. Obviously, more sophisticated and more robotic-compatible sensors are needed. But for now, these continually improving robots are performing useful battlefield functions.

For example, a few dozen Talon robots made by Foster-Miller are now busy disabling bombs and roadside mines in Iraq. Soldiers control the robots via a suitcase-sized box located within the robot's range. Pushed by demands from the Pentagon, Foster-Miller is creating software for the Talon to comply with the military's Joint Architecture for Unmanned Systems (JAUS) protocol, enabling the robots to communicate with overhead unmanned aerial vehicles.

Foster-Miller also is working with the Army's Picatinny Arsenal in New Jersey to develop the SWORDS (Special Weapons Observation, Reconnaissance Detection Systems) robot (Fig. 3). This powerful robot, an armed version of the Talon, can carry different-caliber weapons. It can fire (via a soldier's remote control) 5.56-mm rounds at the rate of 750 per minute, or 7.62-mm rounds from 700 to 1000 per minute.

Another robot making news in Iraq is the 39-lb (basic frame) PackBot from iRobot. This device can be augmented with cameras, batteries, or a robotic arm, depending on the mission (Fig. 4). It has searched tunnels under Baghdad Airport, looked for Iraqi soldiers hiding in an agricultural building, and examined a booby-trapped airfield.

Robots are also taking to the air and the seas with new unmanned aerial vehicles (UAVs) and unmanned underwater vehicles (UUVs). UAVs include the Global Hawk, the Desert Hawk, and the Predator. These aircraft already are patrolling the skies over Iraq and Afghanistan at high altitudes for strategic applications and at low altitudes for tactical uses.

Look for unmanned blimps like the high-altitude airship (HAA) to emerge. The solar-powered $40 million HAA is under development by the U.S. Missile Defense Agency. This unmanned platform contains a wide range of infrared and electro-optical sensors for communications, weather/environmental monitoring, short- and long-range missile warning, surveillance, and target acquisition. Flight tests are expected by the summer of 2006.

Lithium-ion (Li-ion) batteries will power the HAA at night. The batteries are recharged by a 90-ft by roughly 50-ft amorphous-silicon solar panel bonded to the airship's frame. One HAA prototype is 500 ft long and 150 ft in diameter. It will have speeds of 70 to 75 knots at altitudes of 60,000 to 75,000 ft.

Altogether, the Pentagon earmarked $1.3 billion for UAV spending alone in fiscal year 2004. Larger budgets are being called for in the future. That said, funding for manned aircraft is much higher—nearly $6 billion is slated for three future manned fighter programs alone.

One of DARPA's more ambitious endeavors comes from its Defense Sciences Office (DSO). This group is investigating wing morphing, which enables aircraft to serve multiple missions (Fig. 5). At low speeds, the aircraft could have a high-aspect-ratio configuration for reconnaissance missions. Morphing the wings to perform at high speeds converts the aircraft into a low-aspect-ratio configuration for conducting strike missions. Technical challenges with morphing structures include the development of materials that can change form while retaining adequate stiffness for flight.

MORE ADVANCED HELICOPTERS
The DARPA ATO's Helicopter Quieting Program is investigating the design of quieter helicopter rotor blades by significantly improving their acoustics. The program involves the Georgia Institute of Technology, Rockwell Scientific Corp., and the University of Maryland. DARPA's efforts to enhance helicopter performance involves the use of new architectures, materials, and algorithms.

Most recently, the Georgia Institute of Technology successfully flight-tested the GT Max, the first rotary-wing UAV that thinks for itself on the fly. This aircraft maneuvers aggressively. Also, it automatically plans a route through obstacles thanks to its Open Control Platform system, which gives the UAV the ability to reconfigure its software systems autonomously in flight. It relies on is onboard cameras instead of traditional navigation systems.

The test flight represents the completion of a DARPA/Air Force project to develop an innovative new software-enabled control system with applications for UAVs. In the GT Max's final test at Fort Benning, Ga., the aircraft used eight different low-level flight-control systems and three guidance systems in a single flight. These were all used for adapting to primary flight-control system hardware failures, environmental factors, and changes in aircraft configuration.

One concept under development, the A-160 Hummingbird, is designed to achieve higher efficiency, longer endurance, and quieter operation via variable-speed rotors. The Hummingbird's optimum-speed rotor varies its speed as a function of the helicopter's gross weight and speed to maintain overall efficiency. It's designed to support a wide range of sensors, including radar, infrared, and optical sensors.

NEED MORE INFORMATION?
Armor Holdings Inc.
www.armorholdings.com

DARPA
www.darpa.mil

Florida State University
www.eng.fsu.edu

Foster-Miller Inc.
www.foster-miller.com

Georgia Institute of Technology
www.gatech.edu

iRobot Inc.
www.irobot.com

Massachusetts Institute of Technology
www.mit.edu

Rockwell Scientific Corp.
www.rockwell.com

Technion Institute.
www.ats.org

University of California, San Diego
www.ucsd.edu

University of Maryland
www.umd.edu

University of Texas, Dallas
www.utdallas.edu

U.S. Army Picatinny Arsenal
www.pica.army.mil

U.S. Missile Defense Agency
www.acq.osd.mil/mda

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