The trailer-mounted radar is a "phased array" type - it scans the sky with a narrow beam which flicks between thousands of locations each second.

BBC: Fact file: Patriot missile defence

Pulsars are a special type of neutron star that rotates rapidly, emitting a beam of high-energy that spins much like the bulb in a lighthouse.

MSN: Runaway star may be fastest pulsar yet - Technology & science - Space - Space.com | NBC News