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The two BMEWS (Ballistic Missile Early Warning System) are collateral sensors in the SSN’s network and are essentially larger versions of the PAVE PAWS. Located at Fylingdales in Britain (54.36˚N, 0.67˚W) and Thule in Greenland (76.57˚N, 68.32 W˚), these radars’ primary mission is early warning of ballistic missile attack. The radar in Greenland has two faces, providing 240˚ degree azimuthal coverage, while the radar in Britain has three faces, providing 360˚ coverage. Both of these radars have received upgrades that allowed them to be incorporated into the United States’ ground-based national missile defense (GMD) system.
Each radar face is bore-sited at 20˚ above the horizon, and can provide elevation coverage from 3˚ to 85˚. Each octagonal BMEWS radar face has a diameter of about 25.6 m and contains 2,560 active transmit/receive modules (the total number of elements, including passive ones, is 3584). Each face has a peak power of 850 kw and an average power of 255 kw (corresponding to a duty factor of 0.3). The radar’s beam width is about 2.0˚
The BMEWS transmit/receive modules have a maximum duty factor of 30% and can produce pulses with lengths between 0.25 and 16 msec. The BMEWS radars use pulse lengths of 0.3 and 6 (typical) msec. in search and pulse lengths between 1 and 16 msec. in track. Search bandwidth is 0.3 MHz (Britain) and 0.6 MHz (Greenland) and track bandwidths are 5-10 MHz respectively. The radars operate using a 54 msec. resource periods.
BMEWS Performance Claims
3,000 nmi range coverage.
 Cohen, “Pulse Compression in Radar Systems,”; F. Shackford, Technical Seminar.
 Shackford, Technical Seminar. It is unclear if this applies to BMEWs or PAVE PAWS or both, but is consistent with the 16 msec. maximum pulse length and a 30% duty factor of BMEWS.
 Shackford, Technical Seminar.
This post originally was made by George Lewis and is used with permission.