AN/GSA-51 Radar Course Directing Group

The Burroughs AN/GSA-51 Radar Course Directing Group was a United States Air Force air defense command, control, and coordination system, part of the Semi-Automatic Ground Environment system. It was intended to replace vacuum tube IBM AN/FSQ-7 Combat Direction Centrals. Developed under Electronic Systems Division's 416M Program,^[1]: 241 in 1962 Burroughs "won the contract to provide a military version of its D825" modular data processing system^[2] for the AN/GSA-51 to be used at "BUIC II radar sites"^[3] (follow-on to the initial Back-Up Interceptor Control System, BUIC)^[4]: 10 BUIC II was 1st used at North Truro Z-10 in 1966,^[3] and the Hamilton AFB BUIC II was installed in the former MCC building.^[5]

The first D825 computer was originally built for the Navy Research Laboratory with a designation of AN/GYK-3(V).^[6] The D825 contained between one and four 48 bit central processor/arithmetic units, up to 16 memory modules and up to 20 IO modules.^[7][8] The BUIC systems used "two computer modules, six memory modules and three input/output modules".^[7] The computer was designed for high availability and could still operate if any one of its modules failed.^[6]

In accordance with the Joint Electronics Type Designation System (JETDS), the "AN/GSA-51" designation represents the 51st design of an Army-Navy electronic device for ground special auxiliary system. The JETDS system also now is used to name all Department of Defense electronic systems.