AN/SPQ-11 Cobra Judy

The U.S. AN/SPQ-11 Cobra Judy was a solid-state, phased-array radar fitted on the USNS OBSERVATION ISLAND (TAGM-23) missile range instrumentation ship. The Navy ship operated in the Pacific, where the radar was employed to monitor the exo- and endo-atmospheric portions of Russian and Chinese ballistic missile test flights, to monitor compliance with strategic arms treaties. It was also used for research and development work, as well as supporting military weapons test programs.