OX-60 Beacon Interrogator

Cooperative Surveillance

The OX-60 is a secondary (beacon) system collocated with the 12 joint-use FPS-117 long-range primary radars in Alaska and 1 joint-use FPS-117 in Hawaii. It is used to interrogate transponder-equipped aircraft, receive aircraft identification, determine aircraft position, and forward the information to appropriate U.S. Department of Defense (DoD) and FAA air traffic control (ATC) automation systems.

The BAE Systems (formerly GEC-Marconi Hazeltine/Marconi Aerospace Systems) IFF interrogator OX-60/FPS-117 is the beacon interrogator group for the AN/FPS-117 minimally attended radar. The OX-60 is a 370 km system with receiver sidelobe suppression and interrogator sidelobe suppression. It is capable of interlacing Modes 2, 3/A, C, and 4 and parallel processing the replies. The system is all solid state and to meet the requirements of a minimally attended site, it is designed in a redundant, automatic switch over configuration. The equipment consists of a control processor, two processors, signal data and two receiver/transmitters which provide a mean time between failure value of in excess of 118,000 hours. The automatic fault test and isolation is extensive and under the control of an 8086 microprocessor. Self-test of the beacon system is carried out on a continuous basis and consists of both a local circuits self-check as well as a full test accomplished by the generation of simulated targets. This function occurs in parallel to normal operation and is completely transparent to it. Once a fault has been detected the microprocessor goes into a fault-isolation function to isolate the fault automatically to a single or group line-replaceable unit. A status message is then passed to the computer indicating which module is at fault and needs to be replaced. This automatic fault isolation reduces mean time to repair and simplifies maintenance procedures.