Space satellites guide cruise missle attack on Gaddafi
WIRED.CO.UK
By Noah Shachtman
March 22, 2011
When the US military wanted to take out Muammar Gaddafi’s air defense systems, it unleashed a barrage of 122 Tomahawk cruise missiles. But these munitions aren’t like most others in the American arsenal.
Smart, maneuverable, able to see its surroundings and shift to new targets mid-flight, the newest Tomahawks are closer to the unmanned planes flying over Afghanistan than to the weapons they fire. In some ways, the Tomahawk is the drone’s suicidal cousin: a robotic aircraft, packed with explosives, that has no intention of ever coming home.
When officers get ready to shoot off a Tomahawk, “they are basically planning a flight for a little aeroplane,” one Navy official tells Danger Room. “It’s got stubby little wings — but is is an unmanned aerial vehicle.”
The next-gen Tomahawks — known as “Block IVs” — start their flights out just like other missiles, launched from ships or subs. But after 12 seconds of flight, things change. The Tomahawk starts to fly horizontally, skimming above the ocean at a height of less than 15 metres to avoid enemy radar.
GPS waypoints keep the missile on track until it makes landfall. Then, a Tercom (Terrain Contour Matching) system kicks in. too. Using a radar altimeter, the Tomahawk Tercom checks its height, and matches that altitude against a database of satellite and overhead imagery, to make sure the missile is headed in the right direction and at the right height.
Once the Tomahawk’s target is in sight, the missile can dart in for the attack. A Digital Scene-Mapping Area Correlator (“dee-smack” in military jargon) matches a stored picture of the target to the missile’s last sight, to make sure the two match.
Or, the missile can wait a while. The Tomahawk’s controller can give it a new route, telling the Tomahawk to circle around in the air, lingering until an enemy pops up its head. Then comes the strike. …
Read on: www.wired.co.uk/news/archive/2011-03/22/drones-suicidal-cousins