LIMITED VISIBILITY OPERATIONS
This appendix presents the means and methods by which Avenger platoons cope with limited visibility. Platoons that have trained long and hard and have mastered the tactical and technical job skills required will fight effectively even when visibility is limited. Darkness limits visibility on the battlefield, but there are also other conditions that limit visibility.
Limited visibility conditions other than darkness are less predictable and more difficult to deal with. Smoke and suppressive fire, which can severely limit local visibility, are used by all armies. Dust and smoke caused by fire and movement of troops in combat often obscure parts of the battlefield. Dust and smoke are especially critical to the effective employment of long-range direct fire weapons. Rain, falling snow, fog, and natural obscurants also limit visibility. Most current night vision devices and battlefield illumination means have limited effectiveness under these conditions.
The leader's primary task is to co ordinate and control the fire and movement of his unit so that he can mass combat power. This is a demanding task when visibility is good, and it becomes even more demanding when visibility is limited. Even in limited visibility, the unit must detect targets, distinguish between friendly and enemy units, effectively engage targets, and navigate.
Modern technology has produced devices that soldiers and leaders can use to reduce the effects of limited visibility. Several of these devices are organic to the platoon. This section describes the types and number of these devices issued to the platoon and explains how they are employed.
SURVEILLANCE, TARGET ACQUISITION,
AND NIGHT OBSERVATION EQUIPMENT
Advanced surveillance, target acquisition, and night observation (STANO) equipment is either active or passive. Active STANO equipment projects some form of energy. This energy, likely radio frequency or infrared, can be detected by the enemy. Passive STANO equipment either detects existing energy emissions or uses available light as a detection means. Use of passive equipment is usually not detectable by the enemy. Active STANO equipment is generally limited to infrared illumination devices. Objects illuminated by these active devices are viewed using passive STANO equipment. There are two categories of passive STANO equipment: image-intensification devices and thermal-imagery devices.
Image-intensification devices, or starlight scopes, do not project detectable energy. They amplify the existing or ambient light at night and project an image on a viewing scope. Ambient light may be moonlight, starlight, or the glow from cities and towns. Light from flares, searchlights, and laser illumination improves the viewing capability but should not be viewed directly with these devices. Image-intensification devices are adversely affected by fog, smoke, heavy rain, and falling snow. Image-intensification devices and binoculars aid where darkness is the only limiting factor.
Thermal-imagery devices penetrate fog, smoke, camouflage, darkness, rain, falling snow, light vegetation, or a combination of these factors. The principle of this type of device is that all objects radiate energy in the form of heat. This radiated energy travels outward. Because of differences in the amount of heat being radiated, the viewer detects the shape and position of the object being viewed. Thermal-imagery devices can be used in daylight or darkness.
STANO devices greatly improve a unit's ability to carry out its mission under all conditions of visibility. Image-intensification and thermal-imagery devices aid in detecting enemy active STANO devices, such as infrared equipment.
The platoon may be issued the following STANO equipment: binoculars and AN/PVS-7 night vision goggles.
The platoon headquarters is issued two sets of 7X50-mm binoculars. Each squad is also issued a pair of 7X50-mm binoculars. They are used to acquire long-range targets. At night, binoculars can be used to extend the range of the naked eye by taking advantage of existing light. Binoculars are limited by smoke, dust, heavy rain, falling snow, or fog.
AN/PVS-7 Night Vision Goggles
The AN/PVS-7 night vision goggles (NVG) area lightweight, battery-powered (3 VDC) device. It is a passive or active night vision device with a 40-degree field of view. The NVG are worn on the head. The battery life is 20 to 75 hours depending on the type of battery used. The NVG weigh 1.5 pounds and have a range of 9.8 inches to infinity in the passive mode. The AN/PVS-7 helps the Avenger commander control the movement of the vehicle as it travels at night on roads or cross-country. The NVG have a built-in active infrared light source which can be used to provide added illumination for close-up viewing within 3 meters. In the active mode, the night vision goggles can be used to read maps, overlays, or orders. When the active mode is used, the infrared source must be shielded from enemy detection. Inside a building or vehicle, or under a poncho, there is no direct line of sight from the infrared light source to the enemy. The NVG can be used for vehicle maintenance during darkness and can be worn by a ground guide to direct the Avenger. See the Night Vision Goggles illustration.
GLOBAL POSITIONING SYSTEM
The precision lightweight GPS receiver (PLGR) provides highly accurate, continuous, all weather 3-dimensional (3-D) information on position, velocity, and time. It greatly enhances the commander's ability to deploy and fight his FUs based on the ever-changing battlefield.
The NAVSTAR GPS is a space-based navigation and timing system, referred to as AN/PSN-11. It is less than 9.5 inches long, 4.1 inches wide, and 2.6 inches deep. Its weight of 2.75 pounds with batteries makes the set easy to carry or install in any system. The AN/PSN-11 displays alphanumeric data on a 4-line by 16-character screen; the data is displayed in several formats which depend on the type of data and operation being performed. See the Precision Lightweight GPS Receiver illustration. For more in formation pertaining to AN/PSN-11, see TM 9-1425-433-10.
Artificial battlefield lighting is an easy way to penetrate darkness. Effective battlefield lighting must illuminate or silhouette the enemy without illuminating friendly forces. There is always a chance that artificial lighting may have an adverse effect on friendly troops. The characteristics of available artificial illumination systems, and how they are influenced by darkness, weather, and terrain, are addressed in this section.
Artificial light is not necessarily visible light. There are two types of artificial light: invisible and visible.
Invisible light is most often light emitted by an infrared source. It is impossible to see with the unaided eye. It offers greater security than visible light because a night observation device is needed to detect it. But, it is easily detected by active and passive devices.
Visible light is light from flares and searchlights. It requires no special equipment other than the light source itself. It is the simplest type of illumination. Visible light sources are used frequently to continue operations into the night. The disadvantage of using visible light is that it compromises friendly positions and activities.
The platoon uses the following sources of artificial visible light: trip flares, indirect fire illumination, and tank searchlights.
Trip flares are mainly defensive and are excellent EW devices. They can be set to ignite by rigging them with either a trip wire or a trigger release. Their size and limited burning time make them unsuitable for continuous illumination.
Indirect Fire Illumination
Indirect fire illumination from artillery and mortar fire is the most commonly used form of battlefield illumination. Wind direction must be considered when requesting illumination of this type. Drifting flares may illuminate friendly units. Strong winds may move the burning flare off target. The illumination will not affect the use of the night sight, but if it comes into the night sight's field of view, it will appear as a streak on the screen.
Illumination from artillery or mortar flares is dimmed by fog, dust, smoke, and falling snow. Under these conditions of limited visibility, low-illumination rounds may be used as a navigation aid.
Searchlights are on many types of tanks and in target acquisition batteries of corps artillery. Tank searchlights furnish two types of illumination: white light and infrared light. Depending on the terrain, enemy situation, and cloud cover, searchlights may provide direct illumination or reflected illumination off low clouds. They can mark targets, objectives, or boundaries. They can also be used to increase deception by illuminating an area or point outside the intended area of action. The system employing the searchlight is easily detected and extremely vulnerable. It should be used when no other system is available.
Leaders must be ready to use various techniques to control units during limited visibility. These include measures to identify friendly forces, to control movement and fire, and to navigate.
During movement, visual contact can be maintained by reducing the intervals between dismounted soldiers or vehicles. Night vision devices allow units to retain dispersion while maintaining visual contact. When vehicles are moving in any area that has friendly dismounted personnel, such as an assembly area or urban terrain, dismounted guides must be used. Leaders should move forward where they can control the direction and speed of movement.
Besides the night sight and other night observation devices, there are several techniques and aids that can be used to control the fires of the Avenger squad. One example would be when in a stationary position, range cards should be used. Range cards help orient weapons on likely targets and reference points. The platoon should use wire in the defense to establish more reliable and secure communications between the squads, OPs, and section headquarters. Tracers also can be used to denote targets and to direct fire on targets. Pyrotechnic signals, such as hand-fired flares, are other methods that can be used to call for the lifting and shifting of fire.
The GPS should be the primary navigational system for the Avenger squad, when available. It provides day and night all weather highly accurate position, velocity, and time, however to aid the navigation process. Whenever possible, guides should be used while moving over unfamiliar terrain. Compasses, visible landmarks, and night vision devices can be used as navigational aids. Artillery spotting rounds may help determine location and direction.
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