The DRADIS console descends from a cylinder during combat operations like a periscope on a submarine. Despite its name, the DRADIS console allows officers to monitor not only DRADIS contacts, but other navigational and tactical information on the battlestar as well.
A Cylon transponder is placed on the base of the console in an attempt by a Cylon agent to track Galactica in the latter events of the genocidal attack on the Colonies (Miniseries). The transponder is removed and, with a second copy, later used in operations to infiltrate Cylon ships and occupied territories (Kobol's Last Gleaming, Part II).
Like its counterpart technology, RADAR (RAdio Detection And Ranging), the name DRADIS is an acronym. It is never stated in the series what the letters stand for.