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.

It was used for space tracking, ballistic missiles tracking and other instrumentation. Cobra Judy was the sea component of the COBRA program for monitoring missile launches and outer space. Cobra Judy was replaced by the Cobra Judy Replacement (CJR) in April 2014.

Classification of radar systems
Under the Joint Electronics Type Designation System (JETDS), all U.S. military radar and tracking systems are assigned a unique identifying alphanumeric designation. The letters “AN” (for Army-Navy) are placed ahead of a three-letter code.
 * The first letter of the three-letter code denotes the type of platform hosting the electronic device, where A=Aircraft, F=Fixed (land-based), S=Ship-mounted, and T=Ground transportable.
 * The second letter indicates the type of equipment, where P=Radar (pulsed), Q=Sonar, and R=Radio.
 * The third letter indicates the function or purpose of the device, where G=Fire control, Q=Special Purpose, R=Receiving, S=Search, and T=Transmitting.

Thus, the AN/SPQ-11 represents the 11th design of an Army-Navy “Ship-mounted, Radar, Special Purpose” electronic device.

Replacement
The Cobra Judy Platform, USNS Observation Island (T-AGM-23) was taken out of service and stricken from the Naval Vessel Register March 31, 2014. 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. The inertial navigation system for the antenna stabilization and alignment had been provided by iMAR Navigation.