ARGUS drone

ARGUS Drones are small, disc-like, one meter wide aerial Drones equipped with ARGUS detection systems, which stay aloft by a single shrouded rotor. They are also equipped with targeting computers and one or more Lancet Micro-missiles. Their function was to detect and occaisionally destroy explosives on motorways and in buildings.

They are likely named after Argus Panoptes of Greek Mythology, a giant with a hundred eyes and servant of Hera. It killed the bull that ravaged Arcadia, which is also the name of a UNSC colony world, Arcadia.