(U) Bi-static Geosynchronous/Medium Earth Orbit (GEO/MEO) Space-Based Radar (SBR)

(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) The Bi-static Geosynchronous/Medium Earth Orbit (GEO/MEO) Space-Based Radar concept has been developed by ESC.  The proposed system consists of three to four radar transmitter satellites at geosynchronous orbit, combined with 24-36 receiver satellites at MEO.  The theoretical coverage and control methods would be similar to those for a monostatic system.  However, due to the "fixed" locations of the GEO transmitters, the size of the antennas, and the revisit rates required, one transmit satellite would be dedicated to each theater of operation.  Orbital positions would be adjusted if necessary to provide appropriate instantaneous fields of regard.  The use of bi-statics requires fewer transmitters than the mono-static constellations, and would also allow for a lighter fleet of receiver satellites at MEO.  However, the bi-static approach would also result in a significant increase in signal processing to match filter the target return signals received at the MEO satellites, and polar coverage is not possible.  Thus the tradeoff between mono- and bi-static concepts is weight vs. signal processing power and flexibility.

Description: (U)
(U) A Bi-static GEO Space-Based Radar would include a constellation of 3-4 GEO transmitters equipped with an L-band radar for airborne warning and control missions which would require a 100 m dish that would weigh 30,000 lbs and require 20+ kw of power.  A Joint STARS-like radar in geosynchronous orbit would function in the S-band and would require a 25 m dish which would weigh 6,000 lbs and require 2 kw+ of power.

(U) The MEO receivers would include a constellation of 24-36 receivers at an altitude of 1600 km.  For AWACS-like missions, the MEO satellites would require a 35 x 35 m array weighing 10,000 lbs.  A Joint-STARS-like mission would require a 10 x 10 m receive array that would weigh 4,000 lbs.

User Impact: (U)
(U) None.

Programmatics: (U)
(U) Concept/Technology.
	(U) IOC: 10/1996 (1QFY1997).
	(U) FOC: 10/1999 (1QFY2000).
		(U)  The IOC is for road map purposes only and represents the possible program start date.  The anticipated IOC date for SBR is FY2020.  The 1997-2000 timeframe is planned for SBR concept analysis and technology risk reduction investment.  Around the year 2000, a decision will be made on which concept design to pursue, based on the available technology and technology trends.  Based on current trends in launch capability, it is projected that any concept considered will not be deployable prior to 2005.

(U) Organizations and Funding:
	(U) ESC: Funding Source.

Related Initiatives: (U)
(U) BI-STATIC GEO/UAV SBR, Future Space-Based Radar, MONO-STATIC SBR

Related Requirements: (U)
(U) None.

Related Categories: (U)
(U) SBR

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).)