Electronic Weapons: Twilight Vision

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October 18, 2011:  After a decade of effort, the U.S. Army believes it has found the final element for the new fire control system for its AH-64 Apache helicopter gunships. Called Arrowhead, it uses the latest night vision devices (light enhancement and thermal, or heat, based) and fire control electronics to enable AH-64 crews to operate more safely, and effectively, at lower altitudes and in any weather. This is particularly critical in urban areas. As AH-64s were equipped with Arrowhead over the last two years, and sent into action, reports started coming back about one weakness; difficulty using the night sensors in low-light (pre-dawn and dusk) conditions. A solution was quickly found in a 900 gram (two pound) VNsight sensor. This small item combined night vision and visible light to present the pilots with a more accurate view of what's out there in the murk.

Work on Arrowhead got a boost after the Iraq invasion in 2003, which was followed by a growing amount of urban fighting. This created the need for an AH-64 that could hover at 800 meters (2,500 feet) altitude (safe from most small arms fire) and use its high resolution sensors to see who was doing what for out to eight kilometers (five miles) away. Arrowhead could do that, and now all AH-64s have Arrowhead, and many transport helicopters are getting it as well, to make night flying safer.

Over a decade earlier, the army developed another advanced fire control system for their AH-64s, Longbow. But this system was designed for the original mission; flying at higher altitudes, looking for and destroying distant enemy armored vehicles. The Longbow allowed the AH-64 to go after armored vehicles at night and in bad weather. In the past, potential American enemies practiced moving their armor at night and bad weather, to avoid helicopters armed with long range missiles (like Hellfire or TOW). Longbow was doubly lethal because it was designed to avoid giving away its position when using its radar. AH-64s also had electronic countermeasures. Arrowhead, on the other hand, made night and bad weather deadly for enemy troops thinking they could sneak through urban areas unobserved. Longbow could not spot these guys, but Arrowhead could, and did, except in some low light conditions. But with VNsight, that is no longer a problem.

The 7.5 ton AH-64D carries a pilot and a weapons officer, as well as up to 16 Hellfire missiles (plus the 30mm automatic cannon). Sorties average three hours. The AH-64 can operate at night and has a top speed of 260 kilometers an hour.