30 January 2015

Night Vision Devices

By Arun Sahgal

Indian Army’s night blindness is legendary, while successive chiefs of army staffs highlighting the absence of adequate night vision devices (NVDs) in large numbers. But situation has only changed a little.

Night vision devices occupy an important space in providing all weather, day and night fighting capabilities. Night vision devices work on two different principles of thermal imaging and image enhancement. Thermal imaging functions in the upper region of the infra red spectrum, it captures the emissions by the target in this region; whereas image enhancement works by accumulating and amplifying miniscule amounts of light including the lower end of the infra red spectrum so that it is possible to view the target. Normally it is the image enhancement products, which are commonly called Night Vision Devices or NVDs.

At the core of a NVD is an image intensifier tube, which collects and amplifies the visible and infrared light. A photo cathode converts the photons received by the image intensifier tube in to electrons; these are in turn multiplied manifold by use of a microchannel plate leading to cascaded secondary emission process. The electrons thereafter hit a phosphors screen and provide a clear image; this is possible as electrons remain in the same alignment in which the original photons were received. The image obtained is green in color and is viewed through an ocular lens or connected to an electronic display.

The World War II NVDs utilized an IR illuminator, which reflected the IR beam off the targets, that is to say they used an active infrared device. The devices used by Germans were manufactured by AEG. The Germans used Solution A – Sperber FG 1250 with Panther tanks and the Vampir man portable system for the soldiers. The Americans used M1 and M3 infrared night sighting devices. However, the generation 1 NVDs started using passive IR with light enhancement from ambient light. These devices were at a disadvantage on moonless and cloudy nights. Examples of these devices are the PNV-57E Tanker goggles and the AN/PVS-2 Starlight scope.

The next generation devices had considerable improvements in the image intensifier tubes (II Tubes) with the addition of the microchannel plate and thus were able to display images in extreme low light conditions. The images were brighter and the distortion was much less in these devices. An example is the AN/PVS-4 made by Optic electronic corporation of Dallas. It utilized a screw type 25 mm variable-gain Image Intensifier tube. These devices are still in use with batteries upgraded from a single 2.7 V mercury battery to AA batteries. AN/PVS-5 and SUPERGEN are other examples.

In generation 3 devices, currently in use by the US Army, the photo cathode has been manufactured with gallium arsenide and the MCP has been coated with an ion barrier for increasing the life of the image intensifier tube. Otherwise, there is not much change from the NVDs of 2nd generation. The AN/PVS-7 night vision goggle is a single tube device with third generation image intensifiers. The PVS-7 is protected from damage to the image intensifier by exposure to sudden intense light through auto gating. Thousands of these devices are in service and are manufactured by companies like Northrop Grumman, ITT Industries, L3 Communications, and Litton Industries. These have been extensively used in Gulf war II, Operation Enduring Freedom and Operation Iraqi Freedom. They are being replaced with AN/PVS-14 Monocular Night Vision Device (MNVD) it is being manufactured by ITT Exelis and L-3 Warrior Systems. These can also be used in hands free mode by using a head harness or by attaching it to combat helmets.

In the 4th generation, the ion barrier has been removed and an automated gated power supply has been added which enables the NVD to respond to rapidly changing light conditions. The NVD systems can move from low light to high light and vice versa environments without difficulty. AN/PVS-22 Universal Night Sight can be added to any weapon system that has a Picatinny rail and has a scope. It is mounted in front of the scope to enable night vision capability. It is being manufactured by FLIR Systems.

Other Developments

In a slight variation, the U.S. Naval Special Warfare Development Group was equipped with panoramic night vision goggles (PNVGs) in Operation Neptune Spear (of Osama Bin Laden fame). PNVGs used four 16mm image intensifiers instead of two 18 mm ones. This doubled the user’s field of view. They are in service with the US Air force. Northrop Grumman Fused Multispectral Weapon Sight and ITT’s AN/PSQ-20, the Enhanced Night Vision Goggle, ENVG have combined image intensification with thermal imaging. Night vision contact lenses developed by University of Michigan, contains a strip of Graphene between glass layers. NV by Armasight for general consumers, utilises Ceramic Optical Ruggedized Engine, which provides much better performance than generation 1 tubes.

Five important performance parameters in respect of Image Intensification Tubes (II Tubes) are defined. They are, radiant sensitivity, luminous sensitivity, luminance gain, resolution, and signal to noise ratio (SNR). The typical and best values of resolution and SNR available are 50-57 lp/mm & 81lp/mm and 18-22 & 30 respectively. The US Government applies Figure of Merit (FOM) as a method for specifying II Tubes. FOM is calculated on line pair per mm X signal to noise. It may be noted that FOM >1250 is not allowed for export (exception being Pakistan, since it is fighting Taliban). It also implies that third generation Image Intensifiers with FOM ~1700 is not available to other countries.

NVDs come in three major categories namely; Goggles: with binocular vision; Scopes: handheld, monocular and weapon mountable; and Cameras: capable of sending image to monitor/recorder. Apart from the military uses, NVDs are used by law enforcement agencies, wild life observers, hunters, navigators, security, and surveillance personal etc.

The manufacture of NVDs is a complex process involving over 400 different steps just for making the image intensifier tubes. Thus, manufacturers in different areas of the plant carry out several steps simultaneously. One of the most essential parts of the process is stringent quality control at each step of the process, this ensures correct functioning of the II Tubes. The quality control is so exercised that one cannot move to the next step if the previous step has not been quality cleared. The parameters of input materials as well as in process products are thoroughly tested.

Leading manufacturers in the world include:

ITT Night Vision-, which is the largest NVD suppliers to the US Armed forces.

FLIR Systems -which is the world’s largest commercial company specializing in the design and production of thermal imaging cameras, components and imaging sensors.

Northrop Grumman, Armasight, and L3 Warrior Systems are some of the others.

CONTROP Precision Technologies of Israel, specialises in production of thermal imagers, Image intensifiers, panoramic scanning devices gyro stabilized EO/IR payloads etc.

The Russian and Chinese companies listed below manufacture only 1st gen or 2nd gen NVDs.

Leningradskoye Optiko Mechanichesckoye Obyedinenie (Lenigrad Optical & Mechanical Enterprise, LOMO) – designs and manufactures optical devices for various applications. LOMO works not only for Russian military and space programs but also for science and industry and for the consumer products market.

Lytcarino Optical Glass Factory – is acknowledged as a leader in optical material manufacture for different regions of science and technology of the Russian Federation.

Belorussian optical-mechanical Enterprice (BELOMO) – is a major opto-mechanical assembly plant of Belarus. It is a designer and manufacturer of lasers, optoelectronics, and opto-mechanical instruments.

Kunming Kelongda Optical Instrument Co. Ltd. Biji Town, Xishan District, Kunming, Yunnan, China

Shenzhen Siyuan Digital Technology Co., Ltd. Hi-tech Park Nanshan, Shenzhen, Guangdong, China

It is a fact that in the 21st century military operations, battlefield transparency under all types of conditions would hold the key to success of an operation. The NVDs have proved to be force multipliers during the Iraq and Afghanistan operations. NVDs greatly aid the infantry in carrying out tasks such as identification friend and foe, target acquisition and target neutralization by accurate fire. One important fact that was highlighted during a seminar by Centre for Land Warfare Studies on Night Vision, on 21st and 22 Jan 2014, was that the conventional and sub-conventional operations require operations by agile, responsive, and networked infantry units in small teams that are night enabled. The device needs to be seamlessly integrated with the weapon and provide increased accuracy, lethality and standoff capability of weapon delivery system. Night devices for Surveillance and target acquisition should match the effective ranges of the weapons. Further Night vision devices are vital for operations against terrorists and insurgents who tend to move and operate by night and constantly resort to using the terrain for camouflage and concealment.

Indian Armed forces are in fact ill equipped as far as night vision devices are concerned. The NVDs held by them are lagging behind in technology and are too few in number. The Indian Army does not have third generation NVDs in sufficient quantities for equipping its soldiers, their rifles, armoured or mechanized formations. China and Pakistan both have the numbers and technological advantage in this field. It is understood that China has upgraded its entire mechanized and tank fleet to night fighting capability. Theoretically, each soldier should be equipped with a NVD however even if fifty percent of them are provided NVDs it would be a substantial enhancement of capability.

In India, two major collaborations worth mentioning are that of BEL with Photonis of France and that of Tata Power SED with Harder digital Gmbh of Germany. Photonis Night Vision is a world leader in design and manufacture of image intensifiers. It has provided Supergen (FOM 1250+) technology to BEL a couple of years back. Tata Power SED’s partner, Harder Digital Gmbh had acquired Serbian image intensifier manufacturing company Ei Sova and is now known as Harder digital Sova This company manufactures the complete range of image intensifier tubes from gen 1 to gen 3 and exports to 30 countries worldwide. The German government is said to have given clearance to Tata Power SED to import Gen 3 technology in to India as long as Indian Army does not pass it to others.

BEL has been given an order by Indian Army to supply 30,634 NVDs in March 2013. However, it is understood that the requirement of Indian Army itself is in thousands of NVDs, leaving aside other paramilitary and Police forces. BEL claims that it can easily supply second Gen and Supergen devices and is in process of upgrading to superior image intensifiers. BEL claims that it can supply 3rd Gen, II Tubes, this however is doubtful as BEL does not have any tie up with a manufacturer or a developer who can supply 3rd Gen II Tubes with FOM in the region of >1700 which permits soldiers to see in pitch dark conditions. BEL’s expertise can at best produce FOM 1400 devices, which implies that soldiers can see clearly under dusk and dawn conditions but not in starlight or pitch dark nights. BEL has supplied over 30,000 NVDs to Army and others and is capable of producing up to 4000 NVDs per month. It is also understood that BEL is likely to supply 5000 night vision sights, 1780 of the thermal imaging systems would be for BMP-1 infantry fighting fleet, 1200 for T-90 Main Battle Tanks and 2000 for T-72 Main battle tanks.

As far as border surveillance is concerned, the Government has already approved installation of night vision surveillance along the international border. The devices include thermal sensors, night vision devices, and night binoculars apart from BFSRs and other types of sensors.

Some of the BEL India

Night Vision Devices are:

Image Intensifier Tube Based Systems

Night Vision Monocular (BENM 0508) is a lightweight, water-proof, and compact Hand Held viewing system for observation and surveillance during night. Has Automatic Brightness Control (ABC).

Advanced Night vision Binocular BENG 0804 is a lightweight, durable, water-proof, and compact Night Vision Device. It has bright light cut off circuit.

Thermal Imager Based Systems

Thermal Imager (BETI 0109)- Hand Held Thermal Imager is a lightweight, battery powered cooled Thermal Imaging Camera. An ideal solution for surveillance during harsh battlefield conditions like smoke, fog, rain, dust etc.

Integrated Observation Equipment (IOE), is a Thermal Image Based System for observation and fire monitoring by Artillery. IOE comprises of, Thermal Imager (TI) provides observation capability Goniometer to get target coordinates, Laser Range Finder (LRF) to get the range, Global Positioning System (GPS) for obtaining self location, Astronomical North Finding Module (ANFM) to find North through celestial objects.

Un-cooled TI based on 388×284 Vox Micro bolometer, has Dual FOV Optics with motorized Focus, and is Designed as Front and Rear Modules. Front Module is mounted on the barrel for achieving parallelism between mechanical and Optical axes. Rear Module is mounted near stock close to the eye of the operator and thus obviating the need for design of long eye relief optics.

Advanced Un-cooled Thermal Imager BEAUTI 0910A is state of the art hand held and lightweight IR camera. It has Special Algorithms for Non-Uniformity Correction (NUC),Bad Pixel Replacement (BPR), and Histogram etc. Contains OLED Display.

Advanced Night Weapon Sight (BEANS-0804) is a high performance, waterproof and compact night vision system designed for small arms like INSAS Rifle, AK-47, Sniper Rifle etc.

Passive Night Sight BEPNS-0808 is a high performance and compact night vision system designed for CQB Carbine. It can be mounted on picatinny rail of CQB Carbine. It is provided with invisible laser designator for easy engagement / designation of targets in standalone mode.

Apart from BEL the Ordnance Factory board also produces a large number of night vision devices using the 2nd generation / Supergen Image Intensifier Tubes, some of them are:-

Passive Night Vision Goggles (PNVG) 102A with second gen/Super gen Image intensifier tube, it can be mounted on a facemask. It can detect and recognize at ranges of 275 m & 200 m respectively.

Bino Night vision Passive Cased provides high-resolution image intensified night vision and can recognize personnel at 300 m.

Passive Night Vision Binocular (Light Weight) used for commando operations is available with second gen/Supergen Image intensifiers. It can recognize personnel

at 350 m.

Passive night sight for Rifle/LMG is a lightweight passive system, which can be fitted by use of special mounting bracket.

Passive Night Sight for 84 mm Carl Gustaf Gun is meant for anti tank gun.

Drivers Passive Night Periscope for use with T-55 Tank.

Passive Night Sight for AK-47 & Passive Night Vision Monocular devices.

The NVD technology is rapidly moving from the military to the commercial space in that many of the high-end cameras have extreme low light capability. The applicability of NVDs for general public use, say in cars, spectacles, visors etc is but a matter of time. Unfortunately, for India, the indigenous development of this technology has lagged far behind and therefore, the manufacturing capability for such devices is not indigenous. This deficiency has led to inability to build upon on transfer of technology of second Generation II Tubes and develop the 3rd/4th generation variants in house. A conservative estimate places the market for such products at $ 1bn in the next 5 years, this is not surprising taking in to account the large requirements of the Indian armed forces, the paramilitary forces, the central and state police, and other security forces.

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