Guardrail Common Sensor (GR/CS) provides signals intelligence (SIGINT) collection and precision targeting that intercepts, collects and precisely locates hostile communications intelligence radio frequency emitters and electronic intelligence (ELINT) threat radar emitters. It provides near-real-time information to tactical commanders in the Joint Task Force Area supporting a full spectrum of operations (close-in and deep-look collections) with emphasis on indications and warnings.

GR/CS is a fixed-wing, airborne, SIGINT-collection and precision targeting location system. It collects low-, mid- and high-band radio signals and ELINT signals; identifies and classifies them; determines source location; and provides near-real-time reporting, ensuring information dominance to commanders. GR/CS uses a Guardrail Mission Operations Facility (MOF) for the control, data processing and message center for the system.

A standard system has RC-12 aircraft flying operational missions in single-ship or multiship operations. Up to three aircraft and systems simultaneously collect communications and electronics emitter transmissions and gather lines of bearing and time-difference-of-arrival data, which is transmitted to the MOF, correlated and supplied to supported commands via National Security Agency Net.


The warfighter will benefit from planned improvements through Guardrail modernization efforts, which support a full spectrum of operations, including:

  • Full motion video (FMV), precision geolocation subsystem and the Communications High-Accuracy Location Subsystem – Compact with increased frequency coverage and a higher probability to
    collect targets
  • Communications intelligence (COMINT) infrastructure and core COMINT subsystem provide a frequency extension and Enhanced Situational Awareness
  • A capability to process special high-priority signals through the high-end COMINT subsystems High Band COMINT and X-Midas
  • Ground processing software and hardware are being upgraded for interoperability with the Distributed Common Ground System – Army


  • Integrated COMINT and ELINT collection and reporting
    • Enhanced signal classification and recognition and precision emitter geolocation
      • Advanced integrated aircraft cockpit
        • Tactical Satellite Remote Relay System


  • FY13: RC-12 fleet was reduced to 38 aircraft; three RC-12X mission aircraft were fielded bringing the total of the modernized Guardrail fleet to 14
  • FY14: RC-12X FMV Prototype Flight Handling Qualities and Performance Flight Testing completed; eight RC-12 aircraft were deployed in support of Operation Enduring Freedom; these aircraft flew 6,721 hours and had an average mission-capable rate of 90.5 percent
  • FY15: Four RC-12 aircraft remained deployed in support of operations in Afghanistan


  • FY16: RC-12 fleet will be reduced to 19 aircraft (14 operational and 5 trainers) with the divestment of 6 RC-12K aircraft in accordance with the Army 2020 Intelligence, Surveillance and Reconnaissance Plan; RC-12X Autopilot replacement program scheduled to begin with the induction of the prototype aircraft; continue to support contingency operations in Afghanistan with four RC-12X aircraft
  • FY17: Field two FMV-capable systems and continue to support contingency operations




  • Northrop Grumman (Sacramento, CA)
  • L-3 Communications (Salt Lake City, UT)
  • Lockheed Martin (Owego, NY)
  • ArgonST (A Boeing Company) (Mountain View, CA)