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  • Sensor Versus Sensor In Combat
    Posted by David A. Fulghum 4:30 PM on Jan 07, 2010

    U.S.-built sensors that detect enemy sensors searching for allied aircraft is one of several related technologies being honed for combat use in Afghanistan and Iraq. Others involve using targeting sensors to let helicopter pilots see through dust “brown outs” and finding the source of dumb small arms or unguided weapons fire.

    A strong infrared or laser surveillance device  -- operated as a radar in the terahertz frequency range -- can scan across a battlefield to create minute light reflections that can be detected by a sensitive IR receiver. These reflections contain information that can reveal and identify the passive sensor creating the reflection including night vision goggles worn by an individual or infrared sensors associated with a particular weapon.

    The concept is to find “passive receivers looking at you,” says Mark Hutchins, a program manager for CIRCM in BAE Systems survivability and protection solutions business area. “The idea is to see a glint of reflected laser light. To do so will require more energy content, but every optical system will provide a return that can be exploited.”

    While the Army is not looking for the moment at the “cat’s eye effect” of reflected IR or laser light, the Air Force and Navy are engaged in the effort with the closed-loop infrared counter measures system for the F-22 and F-35, say U.S. Army researchers.

    A laser beam can be directed into the enemy missile’s seeker head and the return glint has enough information to identify the missile type and generate the appropriate response to disable its guidance, says U.S. Army Lt. Col Ray Pickering, product manager for infrared countermeasures (IRCM). Eventually the Army will use something similar for ground to air threats.

    However, the Army has been working with the United Kingdom on a new combat technique. The British military has created helicopters simulations that would allow aircrews to fire at enemy machine gunners before the foe can correct his fire enough to hit an airborne target, Pickering says. A machine gunner has to use tracers because he can’t see his bullets. A new version of the Common Missile Warning System will be able to see the tracer rounds and warn the pilot that he is being shot at. The pilot can then conduct an evasive maneuver that has 90% effectiveness in getting the helicopter out of the kill zone before it can be hit.

    There is also is the phenomenon of technology convergence that is driving the integration of many types of sensor data. At the same time it is creating the need for advanced algorithms and massive processing power to make it all work together.

    “If you provide the pilot and co-pilot with missile, laser, small-arms and radar warning – all as separate alerts – it could be too distracting,” says Michael Maas, BAE Systems chief technical officer for electronic warfare. “Say there is a laser range finder and a radar that is associated with single weapon – a missile or an anti-aircraft gun. You want a single display that says, ‘It’s a ZSU and actively shooting at us using a laser range finder. If you have door gunners you can give them clues and they can make the decision to fire or you can provide the information to an attack helicopter.”

    Finally, in parallel to the convergence in technologies, researchers are facing a convergence in combat and non-combat threats. They believe that technologies used to detect enemy fire also can be used to lessen other dangers.

    “Threats to the platform also include flying into trees, wires, each other and the ground,” says Maas. “What you are seeing is that navigation and terrain following and EW systems are overlapping and merging. There is a fusion of sensor and processing technology that would allow us to deal with all those threats. One of the major problems that we would like to solve is brownout and it happens in the last 50-ft. and last few seconds of a flight. It doesn’t take much to get disoriented and there is a tremendous lack of depth perception.”

    The opportunity exists to use IR and MMW band transmitters to see the landscape and nearby objects through the dust, for example, as part of a single fused picture for the aircrew.

    Tags: ar99, combataviation, Iraq, Afghanistan, helicopters, sensors

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