Any modern radar system can find a needle in a haystack. But how do you find one in a stack of needles rocketing through space at hypersonic speeds?
To the people responsible for defending the U.S. and its allies from a ballistic missile attack, this type of problem isn’t a theoretical one. Real warheads could hide among countermeasures meant to confuse the radar.
“There are a lot of objects associated with a ballistic missile, and if you don’t know which one to hit, the only way to address that threat is to shoot an interceptor at each object,” said Adam Art, chief engineer for missile defense programs at Raytheon Integrated Defense Systems.
The technical term for using radar to distinguish a threat like a warhead from non-threats, such as countermeasures is discrimination.
“When there are multiple objects in a cluster, you have to determine which one is the lethal object,” said Chip Wolcott, Raytheon’s chief engineer for the AN/TPY-2 radar. “The radar does this and passes the information to the interceptor.”
Two Raytheon missile defense radars, both of which operate in the X-band of the radio-wave spectrum, have become synonymous with discrimination: the AN/TPY-2, a school-bus sized radar, and the Sea-based X-band radar, a converted offshore oil rig topped with a 10-story-high radar dome.
AN/TPY-2s are deployed around the world in sites that include Turkey, Japan and Guam.
“The AN/TPY-2 is so powerful that a radar could see a baseball being lofted into space from hundreds of miles away, and then direct a player where to stand in order to catch the ball,” said Fred Kramer, Raytheon’s AN/TPY-2 program director.
The company’s engineers and scientists are applying their expertise in discrimination to other frequencies beyond the X-band. Raytheon is incorporating discrimination capability into the Air and Missile Defense Radar (AMDR), a new S-band radar for the U.S. Navy.
“AMDR introduces new technologies, like gallium nitride-based semiconductors and modular hardware and software to create a highly scalable radar,” said Raytheon’s Jim Barry, technical director for Integrated Defense Systems’ Seapower Capability Systems business area.
Over more than four decades, the company has invested hundreds of millions of dollars to conduct focused research and development, create processes, develop tools and build a nation-wide manufacturing infrastructure, with one aim in mind – creating radars that provide the customer with cutting-edge discrimination capability.
The focus on discrimination matters.
Public U.S. intelligence reports estimate there are more than 6,300 ballistic missiles outside of U.S., Russian, Chinese and NATO control, with that number expected to grow to nearly 8,000 by 2020. The danger posed by those missiles is also growing, as they become more accurate and lethal, and capable of traveling over longer distances.
“People are in harm’s way from these threatening ballistic missiles, and as the threat evolves, it’s important we keep up with it,”Art said. “There’s no room for error here.”