(U) PAVE Phased Array Warning System (PAWS) at Eldorado Air Force Station (AFS)

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)

Overview: (U)
(U) PAVE PAWS is an Air Force Space Command radar system operated by the 21st Space Wing for missile warning and space surveillance.  The PAVE PAWS radar located at Eldorado Air Force Station (AFS), TX, is one of four PAVE PAWS radars.  The other three are located at Beale Air Force Base (AFB), CA; Cape Cod AFS, MA; and Robins AFB, GA.  The Eldorado and Robins sites were placed in caretaker status by AFSPC in Sep 95, and are not performing their mission, although they could be quickly reconstituted.  

(U) PAVE is an Air Force program name, while PAWS stands for Phased Array Warning System. The radar is used primarily to detect and track sea-launched and intercontinental ballistic missiles (SLBM and ICBM).  The system also has a secondary mission of earth orbiting satellite detection and tracking. Information received from the PAVE PAWS radar systems pertaining to SLBM, ICBM and satellite detection is forwarded to Space Command's Missile Warning and Space Control Centers at Cheyenne Mountain AFB, CO. Data is also sent to the National Military Command Center (NMCC) and the U.S. Strategic Command (USSTRATCOM).

Description: (U)
(U) The PAVE PAWS (Phased Array Warning System) at Eldorado AFS provided the Southwest segment of the U.S. PAVE PAWS network.  The PAVE PAWS radar provides warning and attack assessment of SLBM and ICBM attacks against North America and provides support to the Space Surveillance Network.  The PAVE PAWS Southwest site is a two-faced phased array radar run by the 8th Space Warning Squadron located at Eldorado AFS, TX.  The system reached IOC on November1986, and was placed in caretaker status on 3 Sep 95.  It is currently not providing data to the ITW/AA architecture.  All equipment, including both faces, are scheduled to be removed from the site in FY99 to support the Clear Radar Upgrade (CRU). 

(U) The unique aspect of this radar system is the dual-faced phased array antenna technology. This system differs from a mechanical radar, which must be physically aimed at an object in space to track or observe it. The phased array antenna is in a fixed position and is part of the exterior building wall. Phased array antenna aiming, or beam steering is done rapidly by electronically controlling the timing, or phase of the incoming and outgoing signals.  Controlling the phase through the many segments of the antenna system allows the beam to be quickly projected in different directions. This greatly reduces the time necessary to change the beam direction from one point to another, allowing almost simultaneous tracking of multiple targets while maintaining the surveillance responsibility. 

(U) The large fixed antenna array using its beam focusing improves system sensitivity and tracking accuracy.  A phased array antenna, as any other directional antenna, receives signals from space only in the direction in which the beam is aimed. The maximum practical deflection on either side of antenna center of the phased array beam is 60 degrees. This limits the coverage from a single antenna face to 120 degrees. To provide surveillance across the horizon, the building housing the entire system and supporting antenna arrays is constructed in the shape of a triangle. The two building faces supporting the arrays, each covering 120 degrees, are therefore be able to monitor 240 degrees.  The array faces are also tilted back 20 degrees to allow for an elevation deflection from three to 85 degrees above the horizon. The lower limit provides receiver isolation from signals returned from ground clutter and for environmental microwave radiation hazard protection of the local area.  

(U)  The radar system is capable of detecting and monitoring a great number of targets that would be consistent with a massive SLBM attack. The system rapidly discriminates between vehicle types, calculating their launch and impact points in addition to the scheduling, data processing and communications requirements. The operation is entirely automatic, requiring people only for monitoring, maintenance, and as a final check the validity of warnings. Three different computers communicating with each other form the heart of the system, which relays the information to Cheyenne Mountain AFB.  

User Impact: (U)
(U) To be supplied.

Programmatics: (U)
(U) Operational.
	(U) Termination: 01/2010 (2QFY2010).
		(U)  The termination date for the PAVE PAWS radars corresponds with the operation of the Long Range Dual Band Transportable Radar.

(U) Organizations and Funding:
	(U) AFSPC.
	(U) Air Force.

Related Initiatives: (U)
(U) None.

Related Requirements: (U)
(U) None.

Related Categories: (U)
(U) PAVE PAWS

Road Map Placements: (U)
(U) SURVEILLANCE AND WARNING.

Lead Office: (U)
(U) Air Force.

Date of Information: (U)
21 November 1997

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)