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BATTLEFIELD GEAR
October 2007
Researchers Push for Advances in Night Vision Technology
By Stew Magnuson
 The U.S. military no longer “owns the night.” Rather, it “shares the night.”
Night vision technology once gave the nation’s armed forces an edge on the battlefield, but the devices have proliferated around the world.
In response, government and industry researchers are pushing to improve the technology in several areas. They hope that advances can help ground troops, pilots and special operators to regain the night — or at least see better than adversaries who can now buy first generation night vision scopes, goggles or binoculars on the Internet.
And there is plenty of room for improvement, suggested Joseph Estrera, chief technology officer at Northrop Grumman’s electro-optical systems division.
They “should be as light as a pair of glasses,” Estrera said of night vision goggles at an Institute for Defense and Government Advancement conference. But they’re not.
The technology gives users a limited field of view. It’s better than not seeing at all, but the effect is like putting a soda straw in front of the face when adversaries are shooting at you, he added.
Weight, size and power, the three bugaboos for almost all the equipment mounted on a modern day Marine or soldier, remain critical issues.
Helmet mounted systems are bulky, heavy and cause neck strain. Increasingly sophisticated systems may require more power. Smoke and sand, for example, degrade performance.
Depth of field is another concern for soldiers, said J. Chris James, chief engineer of the improved night vision demonstrator program at the Georgia Tech Research Institute. Depth of field measures the distance between objects from closest to farthest that are in focus.
To take in more light, night vision devices must have a wide aperture — about a 1.2 f-stop on a common camera. But as professional photographers know, the wider the aperture, the less the depth of field. Soldiers using the technology must adjust their goggles by hand, which is not what they want to be doing in the middle of a pitched battle.
“Nobody is going to throw away their night vision goggles because of the poor depth of field, but the full promise of night vision isn’t realized until this problem is overcome,” James said.
The Marine Corps asked Georgia Tech researchers to work on this problem, and a hands-free prototype will be delivered in late September, James said.
The hands-free digital technology demonstrator marries two solutions to the depth of field problem, he said. One involves wavefront coding, a technology now commonly found on portable phone cameras that allows users to take pictures without focusing. Wavefront coding takes an image produced by a digital sensor, processes it digitally to produce an image with increased depth of field. This improves the depth, but it doesn’t provide the infinite focus the Corps asked for, so an autofocus feature with an eye tracker has been added.
The demonstrator will only show that the concept works, James said. Creating soldier-ready devices will require further investments in the size, weight and power departments.
Along with more depth, there are two ongoing programs to increase the horizontal and vertical fields of view.
The average human has a horizontal field of view of about 160 to 170 degrees. Current night vision devices whittle that down to 40 degrees, which creates the so-called “soda straw effect.”
Northrop Grumman is in the final stages of an upgrade that will give soldiers about 70-degree horizontal and 55-degree vertical view, Estrera said. Better vertical vision is becoming more important as soldiers operate in urban battlefields. They need to see what is happening above them as they walk down streets surrounded by high buildings.
The increase in the field of view is a result of adjustments to the lenses, which are now angled slightly more apart, Estrera said. The new model, PVS-25, is entering low-rate production, but he would still like to get the weight down further.
For pilots, the Air Force has produced a panoramic night vision goggle, which will use four lenses to expand the field of view, said Jim Barnaba, chief engineer for the 641st Aeronautical Systems Squadron at Wright-Patterson Air Force Base in Ohio.
The system uses four optical tubes instead of the two found on the standard AN/AVS-9 goggles currently in use. The four tubes merge to give pilots a 95-degree horizontal and 38-degree vertical view. Another result is a higher resolution in the central viewing area. The wider field of view lessens the need to constantly move the neck back and forth, thus reducing strain on the muscles, he said.
“There’s an improved situational awareness just due to the nature of being a wide field of view,” Barnaba said.
The system also reduces the halo effect, which crops up when bright lights overwhelm the image. It can be taken off in less than two seconds in case the pilot has to eject from the aircraft. The panoramic goggles can be mounted on a standard HGU-55 flight helmet.
The system would not be feasible without reducing the weight of the 16-mm optical tubes. They weigh about half of the AN/AVS-9’s two 18-mm tubes.
“We can go to four tubes instead of the traditional two and have only a slight increase in weight.” They are about 25 percent heavier than the AN/AVS-9, he said.
The program, 10 years in the making, has had some technical snafus, but A-10 Thunderbolt pilots are now using them in combat. Feedback from aviators has been mixed with one-third loving them, one-third indifferent and one third preferring the AN/AVS-9s, Barnaba said.
The Army and U.S. Special Operations Command has expressed interest in the program for their pilots and ground forces, he said. The Navy and Marine Corps are also looking at the program for their pilots. Getting more customers on board could drive the cost of production down. Price is another problem as the system is in low-rate production.
“Is this enough of a situational awareness enhancer? Is this enough of a safety [enhancer] that I want to pay the additional price? We may never get into a high rate production situation that’s going to help us with this,” Barnaba noted.
Wider field of view, hands free focusing and better depth of field are important incremental improvements to current night vision technologies, Estrera said.
“We have to push the technology base for night vision both on the complex side and the very simple,” he added.
While these small improvements promise to advance the technology, on the “complex side,” fusion concepts may radically change how soldiers fight in the darkness.
Fusion involves overlaying other sensing technologies onto the “image enhancement” optics, which gives night vision its characteristic green glow.
Infrared, for example, does not rely on ambient light, but picks up heat signatures. Infrared goggles and weapon scopes are now separate devices, but fusing the two together will allow operators to see camouflaged targets and offer better contrast, experts said.
ITT Industries is producing an optically fused enhanced night vision goggle (ENVG) for PEO-soldier. The company so far only has delivered a small number of goggles for testing. ITT, however, lost the competition to develop the next generation, digitally fused ENVG. BAE Systems received a contract to deliver five digital ENVG systems by the summer of 2008, said Jay Herther, director of the MicroIR commercial products division.
The digital enhanced night vision goggle fuses a low light level thermal imaging system to the image-enhancing optics and is intended for day and night use. Daytime applications should allow soldiers to see through obscurants such as fog, smoke and dust.
The digital system will allow users to send their images over the military network.
“Once you go digital, there’s a lot you can do with the data,” he said.
BAE Systems will incorporate the same uncooled sensor technology in the enhanced goggle that is also used in the thermal weapon sights the company supplies to the Army, said a BAE news release.
It is unclear whether the Army intends to mass produce the optically fused ITT goggle or wait for the digital system to mature. Among the technical challenges expected in the digital goggle are image resolution — difficult to achieve on tiny displays — and power consumption.
PEO-soldier is requiring that the prototypes be lightweight, use about 2 watts of power and be low cost, Herther added.
Another fusion program may radically increase the resolution of night vision devices. A Defense Advanced Research Projects Agency program, the multispectral, adaptive, networked, tactical imaging system (MANTIS) has the potential to be a “quantum jump in technology,” said the program’s manager, Jeffrey Paul.
DARPA is working with PEO-soldier and the Army’s night vision and electronic sensors directorate in Fort Belvoir, Va., to fuse three optical sensors — the visible range, long-wave infrared and short-wave infrared (SWIR).
The addition of SWIR to the mix is what promises to radically alter how clearly goggles will be able aid vision at night, he said. It may one day completely replace image enhancement technology, he asserted.
One of the pioneers in the short-wave sensor field, Sensors Unlimited of Princeton, N.J., serves as one of the MANTIS contractors. The technology is used in a variety of commercial and industrial uses, and as demonstrated by Paul at the conference, provides a sharp, black and white image without the halo effects that plague image enhancement. And unlike infrared, which cannot function through glass, SWIR clearly shows who or what is inside a vehicle or visible through windowpanes.
The program is entering its fourth year of development and has proven the ability to fuse the sensors together in the laboratory. However, the system must be reduced down to goggle size. Key to accomplishing that will be the microprocessor chip currently under development, Paul said. The chip will digitally fuse the three optical ranges together. That will take about another year of development, he predicted.
“The challenge is of course size, weight and power. We’re not there yet,” he said.
Like BAE’s fusion system, MANTIS should also allow soldiers to transmit what they are seeing onto the network or to other members of their squad, he said. An Air MANTIS program for pilots is also under consideration, he added.
“It’s the first time we’ve seen [progress] as dramatic as this in a long time,” said Paul, who has worked in the field for several decades.
Please email your comments to SMagnuson@ndia.org
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