Improved United Kingdom Air Defence Ground Environment

The Improved United Kingdom Air Defence Ground Environment, normally shortened to either UKADGE or IUKADGE, was the Royal Air Force's (RAF) ground-controlled interception system covering the British Isles during the 1990s. It consisted of a number of ground-based radar sites, links to airborne early warning aircraft and Royal Navy ships, a telecommunications system to send digital data and voice communications on a protected network, and processing systems based on VAX-11/780 computers.

Source: Wikipedia — Improved United Kingdom Air Defence Ground Environment (CC BY-SA 4.0)