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Night Vision Equipment: The Illuminating Work of NRC Aerospace

Flying at night has always been challenging for pilots because of reduced visual information compared to what they see during daytime VFR flights. Military, police, search-and-rescue, and other types of rotary-wing operations sometimes occur over areas where there is little, if any, ambient light. Recognizing these challenges and developing night vision systems for pilots has been part of the work of the National Research Council of Canada Institute for Aerospace Research for more than a decade.


March 31, 2008
By Blair Watson

Topics

Flying at night has always been challenging for pilots because of
reduced visual information compared to what they see during daytime VFR
flights. Military, police, search-and-rescue, and other types of
rotary-wing operations sometimes occur over areas where there is
little, if any, ambient light. Recognizing these challenges and
developing night vision systems for pilots has been part of the work of
the National Research Council of Canada Institute for Aerospace
Research for more than a decade.
 
NRC Aerospace, as it is known, is Canada’s national aerospace research
organization. It is funded by taxpayers’ dollars through the Ministry
of Industry. NRC Aerospace, which has a research institute in Ottawa
and a technology centre in Montreal, employs more than 300
professional, technical and support staff in five laboratories.

A team of engineers, neuroscientists, psychologists and test pilots has
worked with night vision technology (NVT) since the mid-1990s. The
research team has completed more than 500 hours of flight testing
involving night vision goggles (NVGs) and other vision-enhancing
systems for pilots. The systems allow objects illuminated by a
relatively faint light source to be seen by the user. Because NVT
alters the way pilots see, perceive and process information, developing
NVGs has involved specialized research and testing, aircraft and helmet
modifications, pilot training, and more.

nightvision1
All Canadian helicopter
operators using NVGs must provide specialized training for pilots,
which NRC Aerospace has helped to develop. There are two National
Research Council test pilots and two Transport Canada NVG certification
pilots. Pictured here is NRC test pilot Rob Erdos.

NRC Aerospace employs experts in ergonomics, the field that studies
human interaction with machines. Ergonomics play a key role in
aviation, affecting cockpit design, instrument configuration and how
information is relayed to pilots. Part of the development work done by
NRC Aerospace personnel relates to “augmented reality displays,”
information in the form of alphanumerics and other symbols that
communicate to a pilot wearing NVGs aircraft data such as airspeed,
altitude, heading, etc.

NRC Aerospace has two helicopters used for flight testing, a Bell 205
and 412, which have been modified to fly-by-wire for the purpose of
adjusting their handling characteristics. For example, in the early
stages of testing a particular NVT it is important that the helicopter
be easier to fly because the pilot needs to focus on adjusting to the
new night vision equipment. As the pilot becomes more proficient with
it, the fly-by-wire helicopter can be adjusted accordingly.

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The history of night vision systems dates back to the Second World War.
During the Vietnam conflict, the U.S. military introduced night vision
devices (NVDs), which had an image intensifier that amplified ambient
light about 1,000 times. Used in army helicopters and other
applications, NVDs of 40 years ago were bulky and required moonlight to
function properly.

Today, night vision equipment requires comparatively little light;
illumination from a dim star is adequate. The light amplification of
third-generation NVGs is approximately 30,000 to 50,000 times. NVGs
operate in the near-infrared wavelength band of about one micrometre.
By comparison, the diameter of the average human hair is 50
micrometres. Our eyes require a light wavelength of 0.4 to 0.7
micrometres to see. Unlike passive infrared systems, which detect heat
radiation and can operate in complete darkness, NVGs require some
ambient light.

Intensifier tubes in NVGs—which look like binoculars—operate on the
photoelectric effect. As photons from an object illuminated by
starlight, for example, collide with a detector plate inside each tube,
the chemical coating on the plate emits electrons, which are then
amplified by an electrical charge into a cascade of electrons that
light up a phosphor screen. The colour of what the user sees is
monochromatic neon green.

nightvision2
Unlike passive infrared
systems, which detect heat radiation and can operate in complete
darkness, NVGs require some ambient light.


NVGs are attached to the front of a pilot’s helmet and positioned about
one centimetre in front of their eyes. To see the helicopter’s
instruments and switches, the pilot tips his head back and looks below
the goggles. A battery pack on the back of the helmet provides power to
the NVGs and acts as a counterbalance to reduce neck strain. In terms
of the pilot’s field of vision, one NRC Aerospace test pilot described
the experience of using NVGs as looking through two soup cans with the
ends removed.

The latest generation of NVT is Omnibus-VII. Unlike third-generation
night vision equipment, OMNI-VII devices have an automatic gated power
supply that regulates the photocathode voltage, allowing the device to
instantaneously adapt to changing light conditions.

Because OMNI-VII NVGs have a thinned or removed ion barrier in each
tube compared to previous generations of NVT, about 40 per cent less
light is required. Also, there is less image ‘noise’. The disadvantage
of OMNI-VII technology, however, is a decrease in tube life of about 25
per cent compared to third-generation equipment. 

Canadian Forces is the country’s largest user of NVT. A Sept. 15, 2005
press release said: “The air force currently uses night vision
technology in the CH-146 Griffon and CH-149 Cormorant fleets; however,
the new night vision goggles [OMNI-VI technology] and the associated
aircraft equipment will enhance operational performance.” The release
adds: “The CH-124 Sea King will also gain night vision goggle
capability allowing the maritime helicopter community to obtain
training that will be directly transferable to the new CH-148 Cyclone
helicopter fleet.

nightvision3
NRC Aerospace has two
helicopters used for flight testing, a Bell 205 and a 412 (pictured
here), which have been modified to fly-by-wire for the purpose of
adjusting their handling characteristics.


“Night vision equipment will enable downed aircrew to move to a
rendezvous point at night with the ability to carefully observe their
surroundings. This capability will be achieved through the use of a
compact lightweight monocular [a one-tube unit] carried in the aircrew
survival vest.

“Search-and-rescue missions frequently occur at night in mountainous
terrain and over water and in most cases timing is critical. The new
night vision capability will greatly increase safety and capability
when undertaking these challenging missions.”

The Forces’ Omnibus Night Vision Capability Project will provide
“helmet-mounted night vision goggles and night vision aids to all
tactical and search-and-rescue fleets. This project will ensure
commonality of night vision equipment, reduce life cycle cost, simplify
training and reduce procurement time.”

NRC Aerospace has done NVG work not only for Canadian Forces, but also
non-military helicopter operators such as the Ministry of Natural
Resources (MNR) in Ontario. NVGs have applications for the ministry’s
Aviation and Forest Fire Management Program (AFFMP) such as detection
of forest fires, extractions of firefighters in emergency situations,
mapping of active fires, and enforcement patrols.

In conjunction with NRC Aerospace, MNR-AFFMP has been evaluating NVT
since 2005. In June 2007, MNR received Transport Canada approval and
operations specification to allow the integration and use of the
technology in the ministry’s aircraft. The NVGs used are military grade
and made by US-based ITT Industries, one of the world’s largest
manufacturers of night vision equipment. Cockpit and external lighting
modifications were required involving two MNR helicopters, an AS350 and
EC130.

nightvision4
Because night vision
technology (NVT) alters the way pilots see, perceive and process
information, developing NVGs has involved specialized research and
testing, aircraft and helmet modifications, pilot training, and more.
(Photo courtesy of Steven Jaquiery)


All Canadian helicopter operators using NVGs must provide specialized
training for pilots, which NRC Aerospace has helped to develop. There
are two National Research Council test pilots and two Transport Canada
NVG certification pilots. Training consists of ground school and flight
training; instructor pilots have extensive military or police NVG
experience. 

The effectiveness of NVGs was proven last summer when an AFFMP aircrew
detected, from a distance of 14 kilometres, a small (0.1-hectare) fire
started by lightning. Enhanced nighttime fire detection should result
in fewer hectares of burned forests.

NRC Aerospace continues to develop and test systems utilizing the
latest NVT. For example, a head-tracking system has been designed
consisting of a low-power laser mounted on the aft cockpit and diodes
on the back of the pilot’s helmet. Like a laser scanner in a grocery
store, the laser ‘scans’ the helmet. When the test pilot turns his
head, the movement is ‘captured’ and can be duplicated in a motorized
mount containing a camera or sensor.

Future ‘illuminating’ work of NRC Aerospace will involve panoramic
night vision goggles, digital night vision systems, and equipment that
combines image intensification with thermal imaging. NRC Aerospace
professionals will continue to develop systems that enhance the ability
of helicopter pilots to fly at night.


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