By John Oncea, Editor
Military applications of infrared technology have rapidly evolved, enhancing detection capabilities and aiding in various critical operations. You can add maintaining temperature stability and improving tracking to the list.
The military uses infrared (IR) technology in many ways, including in night-vision goggles, heat-seeking missiles, and jamming and countermeasures. With the help of IR an unmanned aircraft can detect hot spots and find and map land mines. IR also can be used on heat-seeking missiles to detect heat sources, like aircraft engines.
Less than five years ago U.S. Army researchers enhanced the military’s capabilities to detect and identify hidden targets with a specialized infrared camera that incorporates polarization sensitivity, making it easier to find targets camouflaged in natural clutter than with thermal imaging alone.
Based on the properties of thermal electromagnetic radiation emitted light, each object possesses a distinctive polarization signature depending on the object's surface properties and shape. The IR polarimetric camera, called Pyxis, is capable of distinguishing the polarization signature of human-caused objects from that of natural backgrounds.
But that was 2019 which, in the rapidly evolving world of IR, feels like an eternity. Here then are two new ways the military is using IR to maintain temperature-stable lasers and track moving targets up to 40 miles away.
The Current Situation
The military uses IR because people, vehicles, and aircraft generate and retain heat. IR light can help spot targets, intruders, and hidden bombs. It also can reduce the size, weight, and power of systems in helicopters and aircraft.
“The most familiar uses of IR by the military are airborne forward-looking infrared (FLIR) scanners, guidance heads for missiles, and night vision goggles,” writes Cool Cosmos. “By detecting warm objects in cooler surroundings, FLIR scanners not only help pilots fly in fog, they also detect sources giving off heat, like people and tanks. Night vision goggles allow soldiers to see in levels of light approaching total darkness by letting them see things around them like people, animals, or moving vehicles that are glowing in the IR.”
Military IR has become instrumental in saving lives by detecting concealed land mines. With an estimated 85 million land mines hidden across the globe, tens of thousands of people are killed or injured by land mines every year. Due to the increasing use of non-metallic landmines, finding and clearing them has become more challenging, as they cannot be detected by metal detectors. Instead, military personnel now use IR to locate and chart land mines for clearance teams.
A field containing land mines produces a recognizable pattern of identical hotspots. Using IR sensors, unmanned aircraft flying above battlefields can detect patterns of hot spots, and effectively locate and chart the land mines.
IR is also used to detect the sites of mass graves in war zones. Sensitive cameras onboard satellites can differentiate between packed soil and soil that has been recently disturbed, revealing the location of mass graves.
Engineers, Chemists, And Physicists Working Together To Advance IR Laser Tech
A team of researchers at the University of North Texas (Go Mean Green!), buoyed by a $4.4 million grant from the U.S. Department of Defense Air Force Office of Scientific Research, is investigating methods for maintaining temperature-stable lasers after long duration and high-power conditions. The results of the research will initially go toward military use, but the outcomes could influence future technology in mobile phones and cars.
The research team involves five professors – Zhang and Tae-yul ‘Theo’ Choi in mechanical engineering: Arkadii Krokhin and Jens Neu in physics and Jeff Kelber from chemistry, according to the university. “We want to ensure that a laser can move through something like a lens without burning out and without damaging the lens,” Zhang says, “So we’ll be studying that reaction and finetuning the laser source as we go.”
While some might not connect chemistry and lasers, Kelber is investigating how semiconductor films react when exposed to laser beams, possibly decomposing or melting. “I typically work on surface chemistry with issues related to microelectronics,” Kelber says. “This is like when your GPS says to make a ‘soft left.’ It’s a step in a new direction, but not too different. It’s very exciting.”
Super Hornets Can Track Moving Targets Up To 40 Miles Away
The U.S. Navy has recently equipped F/A-18 Super Hornet fighter jets with Stormbreaker, a high-tech weapon capable of tracking moving targets for distances up to 40 miles. This new generation of air-dropped bombs utilizes three different types of target guidance technologies and has been in development with the Air Force and Raytheon for many years.
“The weapon’s development began as what was called the Small Diameter Bomb II, and its signature advantage was the pioneering use of a ‘tri-mode’ seeker – a guidance, sensing, and, targeting system able to use infrared, millimeter wave, and semi-active laser technologies to track targets,” writes Warrior Maven. “Renamed Stormbreaker in more recent years, the weapon uses a two-way data link to track targets in all weather conditions over distances up to 40 miles. Although a single air-dropped bomb and not a cruise missile, it almost has a Tomahawk-like ability to loiter to a degree as it tracks changing target specifics.”
“Stormbreaker features an innovative multimode seeker that guides the weapon by using an imaging infrared camera, millimeter-wave radar, and semi-active laser in addition to, or with, GPS and inertial navigation system guidance,” a Raytheon essay explains.
An F/A-18 equipped with bomb versatility provides tactical advantages in foggy conditions where targeting is difficult. “In this case, millimeter wave or infrared targeting might prove optimal,” Warrior Maven writes. “Conversely, should a target be moving and less obstructed by adverse weather, a laser spot might be the quickest and most efficient way to attack.”
“Painting” targets with laser designations can be done either on the ground or in the air, and each method has its tactical advantages. For instance, targets with a horizontal or ground-facing volume area, such as doors and windows, are better designated from the ground, while targets that are more easily observable from an aerial or “vertical” perspective are better “lit up” from the air.