Upgrades
The Thule and Fylingdales sites were upgraded with phased array radars in the 1990s. BMEWS 3, located in RAF Fylingdales, was upgraded by Raytheon/Cossor AeroSpace and Control Data Corporation at a cost of US $100M. The new antenna was a three-faced phased array antenna providing 360 degrees of coverage. The embedded computer was a CDC-Cyber running JOVIAL. The Clear, Alaska, site was upgraded in 2001 with a PAVE PAWS radar that was originally located at Eldorado Air Force Station, Texas. The phased array radars operate in the 420-450 MHz (UHF) frequency range.
Along with the PAVE PAWS radar sites at Cape Cod Air Force Station on Cape Cod, Massachusetts41°45′09″N 70°32′19″W / 41.7524°N 70.5386°W / 41.7524; -70.5386, Beale Air Force Base, California39°08′10″N 121°21′02″W / 39.1361°N 121.3506°W / 39.1361; -121.3506 and the PARCS radar at Cavalier AFS, North Dakota48°43′29″N 97°53′59″W / 48.7246°N 97.8998°W / 48.7246; -97.8998, the BMEWS sites provide continual ground-based missile warning for the United States and Canada, with satellite surveillance as a secondary role.
Read more about this topic: Ballistic Missile Early Warning System