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JSS Ajo and the JSS radar/comms system in a nutshell

Last modified: 11 Mar 2020

Country: United States    Region: Arizona

Latitude: 32° 25' 50" N     Longitude: -113° 3' 18" E

Area use / Military Branches: JSS radar & comms


Grid 3225'50.11"N 11256'41.20"W Joint Surveillance System radar
Q. What is Joint Surveillance System:(JSS)?
A. JSS is a joint USAF/FAA radar network.providing communication and radar data to both FAA and USAF control centers.. JSS has been activated in 1983 replacing the former Semi Automatic Ground Environment (SAGE) system.

Q How is it working?
A. The FAA equipment is a mixture of Air Route Surveillance Radar (ARSR) 1, 2, and 3 systems. The USAF equipment are Air Route Surveillance Radar Model 4 (ARSR-4).radars providing air defense and air traffic control for the continental United States, Guam, and Hawaii. These are epuipped with UHF ground-air-ground (G/A/G) transmitter/receiver (GATR) facilities and several sites have VHF radios as well. The GATR facility provides radio access to fighters and Airborne early warning and control (AEW&C) aircraft from the Sector Operations Control Centers (SOCC).

Q. What is a Sector Operations Control Center?
A. A SOCC is responsible for collecting and analyzing all radar data in its sector. Based on its data it commands and controls the airdefence assets in its sector which may be deployed to counter threats.

JSS radars transmit data to the SOCCs who then forward tracks of interest to the CONUS ROCC and NORAD. Radar and track data are sent through landlines as TADIL-B data and through HF links as TADIL-A data. Both links are provided by the Radar Data Information Link (RADIL). CONUS SOCCs communicate with the CONUS ROCC and NORAD by voice and data landline circuits.

This location is former AFS Ajo (1953-1970). Activated 1958 with 612th Aircraft Control & Warning Sqn being assigned to the new station by the 34th Air Division. Initially, 612th AC&W Sqn operated AN/FPS-20A and AN/FPS-6 radars and functioned as a Ground-Control Intercept (GCI) and warning station. As a GCI station, the squadron's role was to guide interceptor aircraft toward unidentified intruders.
1961 Ajo AFS joined the Semi Automatic Ground Environment (SAGE) system, feeding data to DC-21 at Luke AFB, Arizona. After joining, the squadron was redesignated 612th Radar Squadron (SAGE) and 1963 the site was redesignated NORAD ID Z-181.
612th Radar Squadron deactivated 1970.
Site reactivated as a JSS facility operating as an ARSR-4 radar and a communications site for the Barry M. Goldwater USAF Range. The former USAF site also hosts an Air Combat Maneuvering Instrumentation (ACMI) antenna on top the old AN/FPS-26 radar tower.

The other JSS radars in the state of Arizona are Humboldt Mtn (closed 2000) at grid 3358′53″N 11147′53″W and Seligman at 3521′10″N 11256′59″W (ARSR-4 radar)

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