AN/SPQ-11

The AN/SPQ-11 Cobra Judy was a PESA radar found on the USNS Observation Island (T-AGM-23) missile range instrumentation ship.

AN/SPQ-11

Close-up of the front of Cobra Judy radar, 1983.
Country of origin	United States
Introduced	1983
No. built	1
Type	Passive electronically scanned array radar
Frequency	2900–3100 MHz (E\F band)

Aft view of the USNS Observation Island showing the location of the Cobra Judy array.

It was used for space tracking, ballistic missiles tracking and other instrumentation. Cobra Judy was the Airforce code name for the afloat phased-array radar that was designed with a primary mission of monitoring Soviet missile tests and which operated in conjunction with land based phased-array radar Cobra Dane and Cobra Ball aircraft.^[1] Cobra Judy was replaced by the Cobra Judy Replacement (CJR) in April 2014.

In accordance with the Joint Electronics Type Designation System (JETDS), the "AN/SPQ-11" designation represents the 11th design of an Army-Navy electronic device for surface ship special radar system.^[2][3] The JETDS system also now is used to name all Department of Defense electronic systems.

Replacement

The Cobra Judy Platform, USNS Observation Island was taken out of service and stricken from the Naval Vessel Register March 31, 2014.^[4] On 31 March 2014, the Cobra Judy Replacement program, aboard USNS Howard O. Lorenzen (T-AGM-25) reached initial operational capability (IOC). According to the Naval Sea Systems Command (NAVSEA), the U.S. Air Force also assumed operational and sustainment responsibilities for the ship.^[5] The inertial navigation system for the antenna stabilization and alignment had been provided by iMAR Navigation.

See also

• Electronics portal

• USNS Observation Island (T-AGM-23)
• USNS Howard O. Lorenzen (T-AGM-25), platform for Cobra King, the Cobra Judy Replacement
• Cobra Dane
• Cobra Ball
• Cobra Eye
• List of radars
• List of military electronics of the United States