A Brighter Future for Battlefield Vision

A soldier with the 172nd Stryker Brigade Combat Team looks for insurgents during a nighttime raid in Mosul, Iraq. Operations in Iraq have impelled the U.S. Army to speed advanced sensor development and deployment to warfighters.

An Army directorate develops a wide range of new sensors to serve the warfighter.

The U.S. Army is speeding next-generation imaging systems to the field in response to experiences gleaned in Afghanistan and Iraq. Adversaries waging asymmetric warfare have impelled the Army to improve existing technologies and to seek innovative new capabilities in the field of electro-optics.

The focal point for much of this work is the Army’s Night Vision and Electronic Sensors Directorate, which is in the Army Research, Development and Engineering Command’s Communications and Electronics Research, Development and Engineering Center. The directorate’s sensor development largely concentrates on equipment designed for the dismounted fight. However, battle experiences also have influenced its vehicle-mounted programs.

The wars have shifted the directorate’s emphasis away from solely focusing on the Army’s Future Combat Systems (FCS) and toward a more balanced approach. While the directorate still works on FCS-enabling technologies for the future, it devotes an equal amount of time to supporting the warfighter now. Much of this work is for the Rapid Equipping Force Office under the Army vice chief of staff, which is tasked with moving technologies directly into theater.

Warfighters in Iraq and Afghanistan have expressed interest in a variety of new night vision systems, reports Dr. A. Fenner Milton, director of the Night Vision and Electronic Sensors Directorate in Fort Belvoir, Virginia. While countering improvised explosive devices (IEDs) is at the top of their list of concerns, these troops also are looking for sensor technology improvements and innovations to help them solve other battlefield challenges.

Accordingly, Milton reports that the most important improvement to come out of the night vision and electronic sensors directorate has been the maturation of uncooled infrared technologies. A new family of uncooled infrared imagers operating in the long-wave infrared spectrum works day and night. These imagers have been demonstrated on a wide variety of platforms, and some of them already are being deployed in limited numbers.

“They give you basically a FLIR [forward looking infrared] but at much smaller size, weight, power consumption and cost,” Milton says.

Bob Massie, associate director for war programs in Milton’s directorate, notes that the need for sensitive night vision systems is especially acute during a cloudy night on an Afghan plateau. Most image intensifiers are limited under these conditions, and an uncooled infrared system would be very handy to troops there. The same holds true for a cave operation.

One unit is known as the personal miniature thermal vision system, or PMTV. Only a few months old, it draws on technology funded by the Defense Advanced Research Projects Agency, and it is manufactured by Irvine Sensors Corporation, Costa Mesa, California. It includes a focal plane array from Raytheon Company, Waltham, Massachusetts. Milton offers that this system can be mounted all over the battlefield on ground vehicles, small unmanned aerial vehicles, unattended ground sensors and infantrymen’s helmets.

The uncooled microbolometer-based thermal imager has a multifunctional design that allows it to serve as sight for urban operations. It can be configured as a weapon sight, a pocket scope or a camera. With the push of a button, a user can shift the PMTV’s display from black-hot to white-hot. A user can select either a 20-degree field of vision or a 40-degree field, depending on mission requirements.

Just two AA batteries power the PMTV. With these batteries it weighs about two-thirds of a pound. It can run for about five hours at room temperature, although its operating range is from –40 degrees Celsius to 60 degrees Celsius.

Milton says that the device’s small size and low power consumption should revolutionize land warfare by allowing a much larger number of imagers on the battlefield. Some advanced versions have been used in Iraq and Afghanistan by special operations forces and other specialized units. According to these groups, the devices have made an enormous difference, especially in urban fights.

“It is a new world for infrared imaging,” Milton declares.

While this device heads the directorate’s sensor list, several other sensing systems are emerging from the center’s research and development. One effort aims to develop solid-state, low-light-level television. The goal is to move beyond current image tube technologies in image intensifiers. Describing it as a very serious technical challenge, Milton explains that success will depend on reaching a combination of low noise and low power with solid-state technology.

Success in this arena—which is not guaranteed—would produce low-light television imagers that would be much smaller and less expensive than existing systems. Soldiers would have less weight on their heads from helmet-mounted optical imagers. And, they would be able to perform image processing. Prototype arrays are still in early development.

Milton allows that successful development is a question of readout design. It must have a noise factor of 1 or 2 electrons to be competitive with conventional systems. Achieving this is very challenging, he adds.

Another directorate program aims to put mercury-cadmium-telluride on silicon for long-wave infrared detection with low defect density. The standard infrared detection material is placed on the alternate silicon substrate to allow bigger wafers and lower costs.

Some of this work has been funded by the Missile Defense Agency, Milton offers. Several U.S. companies, including Rockwell and Raytheon, are involved in the project along with British concerns.

The challenge has been to achieve good operability in the low wavelengths, Milton relates. Scientists are working to overcome lattice mismatches between the two different layers.

A third directorate thrust focuses on developing ground-penetrating radar for countermine applications. Most countermine ground-penetrating radar systems that exist today are plagued by a high false alarm rate. The technology under development by the directorate aims for a low false alarm rate, and Milton relates that scientists have had some success achieving much lower rates. A vehicle-mounted version currently is being developed.

While the ground-penetrating radar effort is part of an ongoing countermine program, that overall program has shifted course to help defeat IEDs. This threat is considerably different from the land mine threat in that IEDs tend to be at the side of a road in clutter, they tend to be almost always metallic and they involve humans in their fuzing process. Unable to go into detail, Milton notes that the directorate has several programs associated with finding and neutralizing IEDs.

One development area related to sensors involves eyesafe laser imaging. Milton relates that the directorate is developing laser illumination to achieve high-resolution images at long ranges. While laser imaging has been available for decades, it usually entails using shorter wavelengths that are not eyesafe. Now, the directorate is employing high quantum efficiency tubes that perform well at the 1.5-micron wavelength, which is eyesafe.

A new tube version for laser rangefinding has worked well, and Milton describes its technology as “reasonably mature.” The tube is range-gated to take care of dark current, and this has improved its efficiency.

One new system is the Helios laser warning device. This unit combines seven 70-megawatt eyesafe lasers in a Gatling gun construct, and it allows its user to put a bright light on anyone approaching. During the day, it can put a 1.5-meter spot on subjects at distances of more than 100 meters. It meets the same standards at night using one-third the energy level.

The directorate’s new personal miniature thermal vision system, or PMTV (bottom), is an uncooled thermal imager that performs all of the functions of a larger progenitor. The small device can be mounted on a host of devices, including a soldier’s helmet, and it runs for several hours on two penlight batteries.

Not only does it permit a soldier to distinguish between an attacker and a noncombatant, it will stop a person who is not aggressively charging the soldier. Milton suggests that a person who continues to drive a vehicle forcibly when illuminated with this light may be considered a threat to be defended against.

Helios is capable of being mounted on an M-16, M-2, M-4 and M-240. Weighing less than 2 pounds, the unit can run continuously for two hours. Massie relates that it has been tested on 50-caliber machine guns in Iraq, and troops have lauded its effectiveness. A total of 60 are now in Iraq.

Soldiers also may soon have night vision goggles with a wider field of vision than is currently available. For many years, goggles have been limited to a 40-degree field of view, but now the directorate has improved that range to 55 degrees. Milton credits improvements to near-infrared image tubes and low-weight optics that are similar in weight and cost to the 40-degree versions.

This wider field of view can make a significant difference in an urban fight, Massie offers. Wearers need not shake their heads to achieve good situational awareness at night.

Several systems already have been built, and they work extremely well, Milton states. The combination of an excellent tube with lightweight plastic optics has produced good results, he adds. These goggles could be useful to aviators as well as ground-based warfighters, and the aviator applications could provide a field of view as wide as 95 degrees, Massie offers.

The directorate also is working on a short wavelength infrared (SWIR) system that features a slightly longer wavelength than conventional SWIR technologies. The new technology is a low-noise passive system that can produce good imagery on a moonless night, and it can prove especially useful against concealed or camouflaged targets.

The main technological hurdle has been materials-oriented. Researchers are using a new material that is sensitive in this wavelength, and they must ensure low-noise performance. Milton relates that scientists have built cameras that have generated good imagery, and he describes the program as “coming along well.”

These seven technology thrusts compose the Holy Grail of the directorate’s work. Other related technologies focus on exploiting and expanding existing capabilities.

One vital effort aims to fuse image intensification with infrared technologies. Success in this endeavor is important to the goal of putting “infrared on the head,” Milton states. The individual soldier would have the capability of infrared detection as part of his goggle construct instead of only through an additional device.

The directorate’s first approach is optical overlay fusion—bringing the two optical trains together for a single display in the soldier’s system. This would advance to an all-digital approach in which the two video streams would be fused digitally into an optimal picture for display in the soldier’s goggles.

The biggest issue remains power consumption, Milton contends. “We can make these cameras, but they tend to use more power than the individual soldier wants.”

Among other work, the directorate is striving to develop a third-generation FLIR. The goal is to produce a high-performance infrared imaging technology that provides both long-wave and mid-wave infrared images simultaneously. FLIRs traditionally have been one or the other. Because each technology works better in different conditions, having both at hand would give the user the best of both worlds, Milton warrants. A user could view a fused image or select either of the two wavelengths.

He continues that the Army recently has conducted a lot of work examining targets and backgrounds, and it has found considerable but differing amounts of scatter in many cases. Being able to bring both wavelengths to the user through a single sensor represents a new FLIR generation.

It may take the development of new array technology that is sensitive to both wavelengths. The biggest challenge to achieving this goal is to develop the appropriate dual-band focal plane arrays, Milton adds. Cost and operability are determining factors. Success may lead to more robust imagers, smaller apertures and performance that covers a wider range of atmospheric and background conditions.

Other efforts may enhance the capabilities of third-generation infrared systems. Multispectral aided target detection and shape-based aided target detection would enhance the system’s ability to identify and track diverse targets in a variety of conditions. New automatic target recognition algorithms offer promise in this technology.

Progress in the basic components of all of these electro-optics has been spectacular, Milton offers. This has been due to good partnerships among government laboratories, industry and the Army. Many new systems will be empowered by this progress.

Above all, what the Army needs to fill its sensor requirements are affordable solutions, Milton declares. With the Army stretched thin financially, it needs to be able to provide improvements in large quantities.

The need for many of these technologies is driven by requirements to improve existing capabilities. Milton cites a requirement for affordable, lightweight laser designators because of a greater need for precision fire.

The directorate’s support to the warfighter encompasses many other efforts. Last summer, it completed a cave and urban assault advanced technology demonstration (ATD) that focused on different approaches to putting infrared on the head of the individual warfighter.

“The kind of combat that we have gotten into has encouraged us to increase our emphasis on urban warfare and sensors that are appropriate to that,” Milton declares.

While that ATD addressed the dismounted fight, other programs work on vehicle-mounted systems. Milton cites one effort, the distributed aperture sensor, which would give armored vehicles 360-degree situational awareness with closed hatches. Fixed imaging systems would ring the vehicle, and software would stitch their images together. Several operators would be able to access this imagery to drive the vehicle.

Milton adds that this is possible only if camera costs come down. It is relatively easy to do in visible light, and directorate researchers are working to fuse visible images with low-cost uncooled FLIR imagery to provide an acceptable image for day or night 360-degree viewing.

This is especially vital when potential adversaries are close and can approach the vehicle from any direction. Troops inside a Bradley Fighting Vehicle can determine where the enemy is positioned before they dismount from the vehicle, secure in the knowledge that they have full situational awareness of their immediate surroundings.

Even the directorate’s modeling and simulation division is playing a key role in supporting urban warfighters. Instead of modeling to recognize and identify combat vehicles, this division is working on identifying dismounted threats. This effort may go as far as distinguishing combatants from noncombatants. Milton allows that it entails a completely new set of tasks for predicting performance.

The simulation work aims to determine how much resolution is necessary to identify a particular object. For a person, the goal is to learn how to determine whether that individual is carrying a weapon. Moving videos can help identify patterns of motion particular to hostile acts. “The ranges are shorter, but resolution still must be very high because you are distinguishing fine points,” Milton observes.

 

Web Resources
Army Night Vision and Electronic Sensors Directorate: www.nvl.army.mil
Irvine Sensors Corporation: www.irvine-sensors.com
Raytheon Company: www.raytheon.com