Expanding the functionality of night vision devices based on unified modules.

Expanding the functionality of night vision devices based on unified modules..

Expanding the functionality of night vision devices based on unified modules.

GOEV Alexander Ivanovich,
candidate of technical sciences

EXPANSION OF FUNCTIONAL CAPABILITIES OF NIGHT VISION DEVICES BASED ON UNIFIED MODULES  

At present, night vision devices (NVD) are actively used in special and anti-terrorist operations, to protect facilities, to ensure the work of border and customs services, and law enforcement agencies. In this regard, the problem of NVD modernization will always be relevant.

The work [1] examines the main principles of NVD modernization and shows a method for its quantitative assessment.

Let us now consider the main directions of NVG modernization based on the use of unified modules. The creation of such modules is very convenient from a production point of view, and their use will allow for a comparatively simple modernization of NVG practically without serious structural reworking.

Significant progress in this direction was achieved by the Litton company (USA) [2]. It developed a number of standardized modules of lenses, eyepieces, adapters and various devices that make it relatively easy to adapt the NVG to new application functions. The M944 night monocular, based on the third-generation image intensifier tube [3], was used as the basic module.

Figure 1 shows a diagram of the NVG modernization based on 4 standardized modules, made by the Litton company [2], where:

1 – lens with focal length f = 27 mm, relative aperture O = 1:1.2;
2 – lens with f = 75 mm, O = 1:1.3;
3– standard lenses for television (TV) cameras with f = 25 mm, O = 1:1.4; f = 75 mm, O = 1:1.3, ZOOM lens with variable focal length f = 7.5 – 75 mm, O = 1:1.8;
4 – standard photo lenses;
5 – adapter for mounting lenses for TV cameras;
6 – adapter for mounting photo lenses 4;
7 – body of the M944 monocular, containing an image intensifier (IIC), its power supply system and controls; the mounting surfaces of the body 7 are mated with the modules of the lenses 1– 4, eyepieces 8 and relay lenses 9, 10;
8 – eyepiece with 10X magnification;
9 – relay lens transmitting an image in 1:1 scale from the image intensifier tube screen to a video camera (or TV camera) 10 of 1 or 2/3 inch format using an adapter 11 or to a photo camera 12 using an adapter 13;
14 – relay lens transmitting an image in 1:0.67 scale to a video camera (or TV camera) 15 of 2/3 or 1/2 inch format;
16 – protective shield;
17 – eyepiece with protected output;
18 – handle for holding the NVG in your hand;
19 – tripod;
20 – belt for attaching the NVG to a vehicle;
21 – hard case for storing the entire NVG kit together with spare parts;
22 – bag for carrying the NVG itself;
23 – light filter to ensure daytime operation in order to check the operability of the NVG;
24 – protective glass to protect the input optical surface of the NVG lens from mechanical damage;
25 – power supply unit;
26 – drying cartridge.

Fig. 1. Scheme of NVG modernization based on 4 unified modules, made by Litton.

There are three classes of NVG modernization schemes based on unified modules.

Fig. 2 shows a diagram of a multifunctional NVD based on a single housing, in which interchangeable image intensifier tubes of generations II+, II++, III, IV [3,4} can be installed, and with which interchangeable modules of lenses, eyepieces, relay lenses for coupling the NVD with TV cameras and photo cameras, various accessories for ensuring versatile use of the NVD can be coupled. Such a unified NVD allows direct observation and aiming, photo and video shooting, installation on any carrier.

Fig. 3 shows a diagram of a class of passive-active NVDs operating in the traditional (0.4–0.9 μm) and also in the promising near IR spectral region (1–1.8 μm). In this case, NVDs should operate mainly in the passive mode (without illumination), but at sharply reduced illumination levels and in complete darkness – in the active mode (with illumination). This mode is implemented by using standardized illuminators based on IR semiconductor laser emitters and IR LEDs operating in continuous mode. For NVD operation at increased ranges with small illumination angles (about 1? or less), laser emitters are used, in other cases – LED emitters. If the task is not only to see in the dark, but also to work in low-transparency conditions (haze, fog, rain, snowfall, etc.), when exposed to light interference in combination with the need to accurately measure the distance to the object of observation, then the active-pulse mode of operation is used [7].

Its implementation requires the use of unified illuminators based on IR-pulse laser semiconductor emitters or pulse IR-LEDs, and in the NVD itself it is necessary to introduce a strobing unit [7] that controls the synchronous operation of the illuminator and the NVD. The operating principle of the NVD in active-pulse mode is described in detail in [7].

Fig. 4 shows a diagram of a class of multichannel integrated unified devices operating in the visible, near IR, thermal (3–5 or 8–14 µm) and radio frequency (millimeter) spectral regions. Such a diagram allows for the implementation of a round-the-clock and all-weather operating mode, since the shortcomings of some channels are compensated by the capabilities of others [7], precise measurement of the distance to the object of observation, its coordinates and temperature.

In particular, the combination of a night vision device with a daytime sight allows for round-the-clock surveillance, with a thermal imaging device – additional all-weather operation, remote measurement of temperature and its distribution over the surface of the object of surveillance, with a radar station – detection of the object of surveillance in difficult visibility conditions, measurement of its coordinates and distance to it, a laser rangefinder – round-the-clock surveillance and precise measurement of distance, a pyrometer – remote measurement of temperature (in combination with round-the-clock surveillance, if the pyrometer includes a daytime sight).

When implementing these schemes, the cost of their main unified modules should be taken into account. According to data from the Internet as of April 2002, the cost of the most important modules is:

• fixed focal length lens objectives – $50–300;
• variable focal length objectives – $200–3000;
• generation II+ image intensifier tubes – $400–600, generation III – $1500–1800, generation IV – up to $10000;
• eyepieces – 10–30;
• LED emitters – $1–5;
• semiconductor laser emitters – $100–400;
• beam shaping objectives – $5–10;
• pumping units – $20–30;
• strobe units – $150 – 300;
• pyrometers – $200 – 400;
• portable laser rangefinders – $500-1000;
• thermal imaging devices – $5000 – 30000;
• portable radar stations $3000 – 5000;
• daytime sights – $100 – 300.

Based on such prices, in each specific case it is possible to compose from standardized modules such a night vision device that has the maximum cost/effectiveness ratio.

For a multifunctional first-class NVD according to the diagram (Fig. 1) we have:

1 – NVD housing containing interchangeable modules of the II+, III, IV generations of the image intensifier tube with a built-in high-voltage power supply (VPS);
2 – interchangeable lens objectives with a constant focal length of f = 20, 25, 50, 80, 100, 150, 200 mm and a relative aperture of 1:1.2 – 1:1.4 or interchangeable ZOOM lens objectives with a focal length of 15 – 150 mm, 20 – 300 mm and a relative aperture of 1:1.4;
3– interchangeable mirror-lens lenses with focal lengths of 100, 150, 200, 250 and 300 mm and an effective relative aperture of 1:1.2;
4 – standard photographic lenses with constant or variable focal length [5], mated to body 1 using adapter 5;
6 – standard lenses [6] with constant and variable focal length for TV cameras, mated to body 1 using adapter 7,
8 – filter KS-17, KS-19 (to increase image contrast), CdTe:Zn filter [7] and silicon filter [7] for operation with illumination by IR lasers and LEDs; the filters are connected to body 1 and lenses 2–6 using adapter 9;
10 – rubber covers with small-diameter holes (for lens lenses – one hole in the center of the cover, for mirror-lens lenses – three holes along the periphery at equal angular distances from each other) for adjustment work during the daytime;
11 – a plug that closes the input part of housing 1 in the absence of a lens;
12 – a primary power source (batteries for 3, 6, 9 or 12 V DC), through a corresponding voltage converter 13 connected to the image intensifier in housing 1;
14 – a plug that closes the input part of housing 1 in the absence of an eyepiece or relay lens;
15 – a biocular magnifier with 5X magnification and an eyecup 16– to convert a night vision device into a night binocular;
17 – a pseudo-binocular with 10X magnification and two eyecups 18 for the right and left eyes, respectively – to convert a night vision device into night vision goggles or into a night observation device with an increased range;
19 – a sight eyepiece with 10X magnification, with an eyecup 20, containing a sighting mark with a device for its illumination, a mechanism for its adjustment in two coordinates and having a significant exit pupil distance (about 50 mm);
21 – an eyepiece with a magnification of 10X or 12X with an eyecup 22 for conventional night vision monocular observation;
23 – a relay lens with an image scale of 1:0.5 for coupling the image intensifier tube in housing 1 via an adapter 24 with a TV camera 25 of 1/3 or 1/2 inch format;
26 – a relay lens with an image scale of 1:1 for coupling the image intensifier tube in housing 1 via an adapter 27 with a TV camera 28 2/3 or 1 inch format;
29– a photo camera, connected to the image intensifier in housing 1 via adapter 30 and relay lens 26;
31 – a face mask, attached to the headband 32 for installing the NVG on the operator’s head;
33 – a belt for hanging the NVG on the belt and for mounting it inside the vehicle;
34 – a handle for holding the NVG in the hand;
35 – a threaded hook for attaching the NVG to a tree;
36 – a bracket for attaching the NVG to a wall or inside a vehicle;
37– adapter for installing the NVG as a sight on a weapon;
38 – standard photographic tripod;
39 – limb for providing rotation of the NVG in azimuth and target elevation angle when mounting the NVG on a tripod 38 or tripod 40;
41 – lever for rotating the NVG in azimuth and target elevation angle when mounting the NVG on a tripod 38 or tripod 40;
42 – case for the NVG;
43 – soft stowage bag for carrying the NVG from place to place;
44 – a hard case for placing a night vision device with replaceable modules and spare parts 45;
46 – a drying cartridge.

Fig. 2.

For the class of passive-active multifunctional night vision devices according to the diagram (Fig. 3) we have:

1– NVG housing; for simplicity, this diagram omits the modules in Fig. 2, which the NVG may be equipped with;
2 – LED illuminator operating in continuous mode;
3 – radiation shaping lens [7] for narrowing the angular divergence of the LED radiation (it may not be there, since there are LEDs with a built-in lens providing divergence angles of 5?, 10?, 15? [8]);
4 – IR LED (LEDs operating in the visible spectrum can also be used, for example, green for the NVG to function underwater) [8];
5 – primary power source (batteries);
6 – voltage converter-stabilizer;
7 – laser illuminator operating in continuous mode [9];
8 – radiation shaping lens;
9 – laser semiconductor emitter operating in continuous mode [9];
10 – primary power source;
11 – pumping unit;
12 – bracket for mounting illuminators 2 and 7to the body 1 of the NVD;
13– control panel (if necessary) for switching on the illuminators and adjusting their luminous intensity;
14– LED illuminator operating in pulse mode;
15– radiation-forming lens [7] (it may or may not be there);
16– IR LED;
17– primary power source;
18– voltage converter-stabilizer;
20– radiation-forming lens;
21– pulsed laser semiconductor emitter [9];
22 – primary power source;
23 – pumping unit;
24 – bracket for mounting illuminators 14, 19 to the body 1 of the NVD;
25 – strobing unit to ensure synchronous pulsed operation of the NVD and illuminators 14, 19;
26– a control panel containing toggle switches and mode indicators (passive, active-continuous, active-pulse), a range indicator, and various controls. 

Fig. 3.

For the third class of multifunctional integrated devices according to the diagram (Fig. 4), we have:

1 – NVG housing (Fig. 2, 3);
2 – pyrometer, for example, “Termotest 3P” [10] with adapter 3for mounting to the body of 1 NVG;
4 – portable laser rangefinder, for example, DL-10 [11], with adapter 5 for mounting to the body of 1 NVG;
6 – portable radar station, for example, “Speedgun” [12] with adapter 7 for mounting it to the body of 1 NVG;
8 – compact thermal imager, for example, TN-4604MP [13] with adapter 9 for mounting to the body of 1 NVG;
10 – daytime sight, for example, PO 4×34 [14] with adapter 11for fastening to the body of 1 NVG;
12 – control panel (if necessary) for controlling the integrated device.

Fig. 4.

This approach to the construction of devices, as follows from the diagrams in Fig. 2, 3, 4, is sufficiently flexible, provides the ability to adapt the NVD to a wide range of applications, as well as to round-the-clock and all-weather operation in combination with multifunctionality.

Literature

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2. Litton M944 Gen 3 Modular Night Vision System. Brochure of Litton Electron Devices, USA, 1990.
3. Salikov V.L. Night vision devices: history of generations. Special equipment, 2000, No. 2, pp. 40 – 48.
4. Volkov V.G. Night vision devices of new generations. Special equipment, 2001, No. 5, p. 2 8.
5. Photographic optics. Prospectus of JSC KMZ, RF, Krasnogorsk, Moscow region, 2001.
6. Lenses for television cameras. Catalogue of Computar, Japan, 2002.
7. Geykhman I.L., Volkov V.G. Fundamentals of improving visibility in difficult conditions. Moscow, Nedra-Business Center, 1999.
8. Semiconductor emitting diodes Prospectus of NPC OEP “OPTEL”. Moscow, 2002.
9. Laser semiconductor emitters. Catalogue of Research Institute “Volga”, Russian Federation, Saratov, 1992.
10. Family of infrared pyrometers. Prospectus of MNPO “Spectrum”, Russian Federation, M., 2002.
11. Optical devices and instruments. Catalogue of Belomo. Belarus, Minsk, 2002.
12. Uncooled thermal imagers “TN-4604MP” and TN-4604MB”. Prospectus of Research Institute MNPO “Spectrum”, Russian Federation, M., 2002.
13. Multifunctional radar “Speedgun”. Prospectus of St. Petersburg Scientific and Production Enterprise “Sintez”. Russian Federation, St. Petersburg, 2001.
14. Optical sights PO 4×34, PO 3-9×39, PO 4.5-13×56. Prospectus of PO ZOMZ, RF, Sergiev Posad, 2001.