Joint Surveillance System

The former J-31 San Pedro JSS ARSR-1 radar site, California
USAF Battle Control System operators monitor the skies from the floor of the program's Eastern Air Defense Sector location.

The Joint Surveillance System (JSS) is a joint United States Air Force and Federal Aviation Administration system for the atmospheric air defense of North America. It replaced the Semi Automatic Ground Environment (SAGE) system in 1983.