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).


-Road Map
-Text Version

Overview (U):

(U) The COBRA JUDY System is a deployed and operational data collection sensor that consists of an S-band phased array and an X-band dish radar. The radars are permanently mounted aboard a U.S. Navy Ship, the USNS Observation Island. The system's primary mission is to collect precise data against strategic ballistic missiles to verify several United States arms control treaties. A secondary mission is to collect data for United States missile development and theater missile defense systems testing. The system is capable of worldwide deployment.

Description (U):

(U) The system collects dual frequency (S- and X-band), high precision metric and signature data on targets of interest. The S-band radar uses a mission profile to perform surveillance (target detection and acquisition), tracking, object classification, and wide or narrow band data collection. A wide repertoire of transmitter waveforms is available to aid in target discrimination and analysis. The X-band radar can perform wide band data collection on manually designated objects from the S-band radar.

(U) The S-band phased array consists of 12,288 active independent antenna elements. The S-band radar has a 45-degree maximum instantaneous field of view. The phased array is mounted in one face of a nearly cubical (30-foot) rotating turret that houses the transmitter, microwave circuits, and the inertial navigation unit. The S-band transmitter is composed of 16 broadband Traveling Wave Tube (TWT) power amplifiers.

(U) The X-band radar is composed of a 30 foot parabolic dish, horn and subreflector mounted on a pedestal. Some of the X-band electronics, including the TWT Power amplifiers, are in the on-mount room and are fed by flexible cables from equipment located on a lower deck of the ship.

(U) The S-band and X-band radars are controlled by a single CYBER 170 mainframe computer system. A second CYBER is available as backup. The CYBERs are of 1973 vintage. To ensure future system sustainability and maintainability, much of COBRA JUDY's data processing and RF subsystem equipment is scheduled to be replaced with modern (COBRA GEMINI) technologies during FY98-02.

(U) Mission data is provided to the National Air Intelligence Center (NAIC) for reduction and analysis.

User Impact (U):

(U) Data from the system will be used by all military services, the Ballistic Missile Defense Organization (BMDO), and the Arms Control and Disarmament Agency (ACDA).

Programmatics (U):

(U) Operational.

(U) Organizations and Funding:

Images (U):

(U) None.

Related Initiatives (U):
LRDBTRLong Range Dual Band Transportable Radar (LRDBTR)
This Table Is Unclassified.

Related Requirements (U): None.

Related Categories (U):
Ground-Based WarningGround-Based Warning Sensors
This Table Is Unclassified.

Road Map Placements (U):

This Table Is Unclassified.

Requirements, Funding and Additional Hotlinks (U):

(U) None.

Lead Office (U):


(U) DoD: ACDA, Pentagon, Washington, DC
(U) Service Staff: HQ USAF/XOI, Pentagon, Washington, DC
(U) Major Command: HQ/AIA, Kelly AFB, San Antonio, TX
(U) Program Management: HQ/AIA, Kelly AFB, San Antonio, TX

Point of Contact (U):

(U) Maj Donald Landing, ESC, Open Phone: None..

Date Of Information (U):

(U) 11 October 1997


(U) For comments/suggestions contact: Office of the National Security Space Architect (NSSA), 571-432-1300.

(U) Road Map Production Date: 23 June 2001

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).