Subscribe to Feed      Register
Christopher Larsen

Know your gear…

Night Vision & Observation Devices

by Christopher E. Larsen

1 August 2011

horizontal line


For the record, Night Observation Device (NOD) is the more encompassing term, as compared to Night Vision Goggles (NVG) and Night Vision Devices (NVD), which generically refer to both passive and active light amplifying equipment. This distinction may seemed nuanced, but when we think in terms of NOD we must avoid thinking of only NVG.

As we’ll discuss, NVG represent some of the most significant advances in NOD and therefore in night fighting. Regrettably then the tendency for many tactical units is to lean on the crutch of NVG technology rather than employing NVG as a means to enhance already sound night fighting Tactics, Techniques and Procedures (TTP).

This article will not address night fighting TTP, per se. They are ably covered elsewhere. However, we will look at the larger spectrum of NOD and define how each system helps us conduct the business of warfighting in periods of darkness.

First and foremost we must define the function of all NOD under the umbrella of three applications – visibility, detection and targeting.

Visibility has the broadest function and includes everything from driving and piloting vehicles, to navigating terrain on foot, to reading maps or text documents, to medical care. Visibility is the catch-all application for tasks that are not enemy-oriented, yet still must be achieved in periods of darkness.

Detection is the function of discovery. In this application NOD not only help us find the enemy, they may also help us determine friend from foe.

Targeting is a slightly different function from detection then in that targeting means we need to make ready a specific weapon system to engage an enemy or suspected enemy. Of course, we don’t actually engage the target until we determine whether it is friend or foe. Typically detection comes first, then targeting. But this is not always the case.

Forward Looking Infra-Red


Forward Looking Infra-Red (FLIR) is used primarily for detection and targeting. FLIR devices represent the most advanced break through in NOD. These devices include the older tripod-mounted AN/TAS-6 NODLR, as large as a microwave oven and whirring noisily, to the newer AN/PVS-22 and T-14 that are small and light enough to fit comfortably onto an M4 carbine and still offer the same picture clarity as the older models.

FLIR turns night into day, and sees even through vegetation and smoke during daylight operation. When looking for a sniper team in late spring, a search team walked more than a kilometer of dense tree line visibly looking at the ground for the hidden team in broad daylight. Back at the sniper team’s target, the same search team then turned on their T-14 FLIR and could instantly, clearly detect and target the two-man sniper team in spite of their being hidden with ghillie suits under heavy vegetation more than 300 meters away. The sniper team might as well have had a neon sign lit overhead. Through FLIR they were hopelessly exposed to counter fire.

FLIR may be used for navigation but only on expensive, extremely specialized vehicle platforms. Those rare instances aside, FLIR in its current form is not useful for map reading, walking over the mountain while avoiding cliff drop-offs, or administering aid to casualties during hours of limited visibility – yet.

For the time being, FLIR is most advantageous when used for targeting and detection. We’ll continue to see advances in this very promising NOD technology.

Passive Light Devices


Passive light devices amplify ambient light in an optical tube so that an image is created for the viewer during conditions of darkness. Because no form of light is projected, other forces using similar passive light systems cannot detect the use of a passive light optic.

There have been a series of developments and advances in passive light devices since the late 1960s beginning with the first generation AN/PVS-2 rifle scope. Second generation AN/PVS-4 scope and AN/PVS-5 night vision goggles were considerable steps forward in clarity of the tubes and image. And third generation AN/PVS-7 goggle and the versatile AN/PVS-14 monocular goggle/scope permit light gain even when used in conjunction with other intense light sources. This allows the user see into dark shadows and corners with other light sources present.

Passive light devices are used for the widest range of function including the full spectrum of visibility, detection and targeting. Some devices are, however, dedicated to a specific function. Scopes for example are often used exclusively for targeting, while the more common goggles are used to scan the battlespace to navigate as well as detect and target the enemy.

Active Light Devices


A precursor to the passive light system, active light collecting tubes gain projected infra-red (IR) light – invisible to the human eye. Used for detecting and targeting purposes, an enemy force without similar technology would be completely unaware that they were being illuminated at night. However, forces with other active or passive light systems would see another active light system clearly due to the projected IR light.

Active light systems still exist today, though active light systems are less commonly used for detection these days due to the fairly common access to commercial active and passive light NOD. Currently, active light systems are often dedicated to targeting, such as the IR laser pointer in the AN/PEQ series targeting devices.

Additionally there are specific active light systems for medical support and combat service support functions.

White Lens Weapon Light


One of the most recent additions to NOD is actually one of the oldest. The flashlight. However weapon lights offer significantly more power, putting out 65, 120 and even 220 lumens compared to the old camp flashlights dim 5 to 10 lumens. It puts a spotlight in the hands of each warrior!

The blinding power of the popular SureFire and Blackhawk Gladius series lights can temporarily disorient a foe without inflicting any harm. This gives the weapon light a definite advantage in targeting, and also for the confirmation of targets prior to engaging with deadly force. This makes the weapon light ideal for nighttime raids and ambushes.

Regrettably, many warriors carry the weapon light on their weapon, switch ready, while patrolling. This is a recipe for disaster as the warriors carrying their weapon light in such a manner tend to experience an alarming number of negligent discharges of brilliant white light, visible to even the naked eye. This makes the entire patrol vulnerable to enemy detection.

Weapons lights are not suitable for detection, as a general rule of thumb. The white lens may give the user a feeling of confidence due to the spotlight effect, but it also makes the user an easy target for enemy gunners! Scanning the battlespace for enemy can only be achieved safely in very specific instances. When used in this mode, weapon lights are commonly coupled with an IR lens covers so that the weapon light becomes a powerful part of an active light system.

Color Lens Flashlight


Flashlights have been around for quite some time now. Of course white light renders the flashlight a tactical liability in the battlespace. However with red, blue, green or diffused lens covers such flashlights become viable NOD for use in visibility applications.

Patrols can signal each other, vehicle drivers can guide on different colored lens, leaders can read maps, medics can tend wounds, radio operators can read documents and vehicle crews can pull maintenance all with colored lens flashlights.

And since colored lens put out considerably lower levels of visible light, they are more difficult to detect with the human eye than white light. Indeed, recent advances in light division technology has seen several new lens introduced that are surprisingly difficult to detect even with passive and active light systems.

Pyrotechnic Flare


For centuries field artillery has employed the pyrotechnic flare. This NOD is used primarily for detection, though with a few techniques riflemen and artillery gunners can employ their weapons for targeting purposes.

Most effective for detection are aerial parachute flares which when fired in sequence can provide sustained light for extended periods of time. Of course, the problem is that regardless of the type of flare, such pyrotechnics work both ways. Flares allow the enemy to see just as well, and are a clear indicator to the enemy that they have come upon an enemy force.

But when used cleverly, pyrotechnic flares illuminate the enemy as they’re moving through open terrain for friendly forces that are already in camouflaged, defendable fighting positions.

Strobe & Chemical Cyalume Light


Various colored chemlights (Cyalume) and strobe lights, including those with IR coverings are NOD used for a variety of visibility applications. In addition to the nearly identical applications of colored lens flashlights, strobe and chemlights are commonly used to guide patrols plus airborne and land-borne vehicles by marking targets, paths, boundary limits, and even landing zones.

In rare instances chemlights and strobes have been used for targeting and detection. Employed as field expedient backlighting, particularly in urban operations, these relatively low-light NOD can create enough light to detect and even target enemy movement.

Guy Lines


Didn’t see that one coming, did you? Yes, almost as old as fire is the use of twine or gut as a guide for warriors moving at night – making guy lines one of the oldest NOD in our inventory. Of course more recently it has been communication field phone wire, a dying relic on the battlefield.

Nonetheless, guy lines are still a valid form of NOD used for visibility applications to mark paths, boundaries, assault positions, and targets. Guy lines are employed almost exclusively for navigation, yet when used in conjunction with chemlights can become quite a sophisticated system for moving troops at night. Guy lines do require plenty of advanced planning and placement during daylight scouting missions.

Of course, the guy line works both ways if found by the enemy. But again, depending on the level of sophistication even this fact might work in our favor.

The important take-away from this article is that NVG such as the superbly efficient PVS-7 becomes all the more effective when used in tandem with other forms of NOD and their unique capabilities. Furthermore, when used with existing TTP for the various other forms of NOD, we have backup systems upon backup systems. And that makes us better night fighters.

horizontal line

[Christopher Larsen is the author of The Small Unit Tactics SMARTbook (The Lightning Press 2008) and a founding member of One Shepherd's Technical Institute of Leadership.]




Leave a Comment:
Comments
On 8/1/2011 10:49:00 PM,
Aswayze said:
Don't forget Cat Eyes. While seemingly minor, they can be the difference between a patrol doing the mission they started off to do and a patrol conducting search and rescue operations.

On 8/1/2011 10:57:00 PM,
Christopher said:
Good point, Allan. I overlooked illumination tape (aka "cat eyes") that is commonly worn on the back of head gear so that patrols keep visual contact with the troop in front of them. UV lights are now used to illuminate the tape - and the human eye cannot detect UV light. Fascinating stuff. And decades old technology. - Christopher




Light Infantry Tactics