Obscuration

Smoke and other obscurants have been used in wars dating back to the ancient Greeks. On today's battlefield, smoke can counter new generations of smart weapons. Smoke is used as camouflage, as blinding smoke laid directly on enemy positions and as a decoy to confuse and mislead enemy forces. These basic smoke applications are used to increase survivability, buy maneuver time for the attacker and protect forward-assembly areas and high-priority rear areas for the defense.

Smoke particles scatter or absorb radiant energy used by troops and smart weapons for target acquisition and for weapon guidance and control. Smart weapon sensors operate in three main parts of the electromagnetic spectrum: visible, near-, mid-and far-infrared wavelengths, and millimeter wavelengths. The most effective scattering smokes are aerosols that are the same size as the operating wavelengths of the sensor to be defeated. The best smoke for the visible spectrum may be transparent in the far-infrared area. The entire chain of electro-optical, infrared and millimeter-wave devices linking a smart weapon to a target is susceptible to smoke and other obscurants. In addition to absorbing light, some smokes emit heat, which can cover or clutter the thermal images of targets.

The reflection of laser or radar beams from smoke clouds can produce false targeting information for smart weapons, which can be blinded and defeated by smoke. Battlefield obscurants allow combatants to take advantage of technology overmatch. In Operation Desert Storm, U.S. ground forces used infrared-viewer technology at night to achieve dramatic results.The Army uses several models of smoke-generation systems, including: the M56 Coyote, the M58 Wolf, the M157A2 Lynx and the M1059/ M1059A3 Lynx. In addition, the M6 countermeasure discharger provides self-screening protection to individual combat vehicles.

The M56 Coyote Smoke-Generation System (SGS) provides large-area obscuration in the visual and infrared spectra. It is a Humvee-mounted, large-area, smoke-generator system. In addition to providing enhanced spectrum coverage, the M56 system provides smoke generators with a new wheeled-vehicle platform. The system is mounted on the new expanded-capacity M1113 Humvee and provides greater payload capacity and higher mobility for supporting smoke units.

Six M56 Coyotes form a smoke platoon. They support light and airborne maneuver units by disseminating smoke on the move or from stationary positions to defeat enemy sensors and smart munitions, such as tank thermal sights, guided munitions, directed energy weapons and other systems operating in the visible through far-infrared regions of the electromagnetic spectrum. The system is modular and uses a gas turbine engine to disseminate obscurants. The visual screening module is capable of vaporizing fog oil at a rate equal to the M157 smoke generator for up to 90 minutes. The infrared screening module can disseminate particulate material to provide 30 minutes of screening. M56 program planners cite the expanding global use of infrared targeting and sighting devices for prompting development of the M56 Coyote, the Army's first large-area smoke system capable of generating visible and infrared blocking screens.

The M56 Coyote was type-classified "standard" in September 1994 and was followed by an initial production contract award for 296 systems in March 1995. First-article and production verification testing were successfully completed in September 1996. By the end of February 2000, 231 systems had been fielded to U.S. Army Training and Doctrine Command (TRADOC), U.S. Army Forces Command (FORSCOM) and U.S. Army Reserve Command (USARC). Fielding continues to FORSCOM and USARC with a follow-on six-year contract.

A materiel change program to add a millimeter-wave module began in FY 2001. This program will provide extended spectral coverage to defeat threat weapon systems operating in the millimeter regions of the electromagnetic spectrum.

The fielding of new M56 Coyotes pushed older M157 SGSs down to lower priority units. The last chemical unit with the aging M3A4 smoke-generation systems received M56 Coyotes in the first quarter of FY 2002.

The M58 Wolf Smoke-Generation System places the capabilities of the M56 on a derivative of the tracked M113 armored personnel family. In addition to its current multispectral obscurant screening capabilities, planned materiel changes will allow the addition of a millimeter-wave (MMW) obscuration module, providing the capability to counter the threat arising from the wide proliferation of advanced visual and infrared sensors and future MMW sensors.