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RQ-4 Global Hawk

The RQ-4 Global Hawk is an unmanned aerial vehicle (UAV) used by the US Air Force. It is a theater commander's asset to satisfy broad area coverage and deep target surveillance and reconnaissance shortfalls. The Global Hawk air vehicle is to provide high resolution Synthetic Aperture Radar (SAR) and Electro-Optical/Infrared (EO/IR) imagery at long range with long loiter times over target areas. Potential missions for the Global Hawk cover the spectrum of intelligence collection capability to support joint combatant forces in worldwide peace, crisis, and wartime operations. These systems will support the in-theater CINC in precision engagement and full-dimensional protection through information superiority.

USAF Global Hawk unmanned
reconnaissance aircraft.

Larger version

The Global Hawk UAV system comprises an air vehicle segment consisting of air vehicles with sensor payloads, avionics, and data links; a ground segment consisting of a Launch and Recovery Element (LRE), and a Mission Control Element (MCE) with embedded ground communications equipment; a support element; and trained personnel.

The Integrated Sensor Suite (ISS) consists of a synthetic aperture radar (SAR), electro-optical (EO), and infrared (IR) sensors. Either the EO or the IR sensors can operate simultaneously with the SAR. Each of the sensors provides wide area search imagery and a high-resolution spot mode. The SAR has a ground moving target indicator (GMTI) mode. GMTI data are transmitted as a text product providing moving target location and radial velocity. Both SAR and EO/IR imagery are processed onboard the aircraft and transmitted to the MCE as individual frames. The MCE can mosaic these frames into images prior to further dissemination.

Navigation is via inertial navigation with integrated Global Positioning System updates. Global Hawk is intended to operate autonomously and "untethered" using a satellite data link (either Ku or UHF) for sending sensor data from the aircraft to the MCE. The common data link can also be used for direct down link of imagery when the UAV is operating within line-of-sight of users with compatible ground stations.

The ground segment consists of an MCE for mission planning, command and control, and image processing and dissemination; an LRE for controlling launch and recovery; and associated ground support equipment. (The LRE provides precision differential global positioning system corrections for navigational accuracy during takeoff and landings, while precision coded GPS supplemented with an inertial navigation system is used during mission execution.) By having separable elements in the ground segment, the MCE and the LRE can operate in geographically separate locations, and the MCE can be deployed with the supported command's primary exploitation site. Both ground segments are contained in military shelters with external antennas for line-of-sight and satellite communications with the air vehicles.

The "R" is the Department of Defense designation for reconnaissance; "Q" means unmanned aircraft system. The "4" refers to it being the fourth of a series of purpose-built unmanned reconnaissance aircraft systems. See also RQ-1 Predator, RQ-2 Pioneer, RQ-3 Dark Star, RQ-5 Hunter, RQ-6 Outrider, and RQ-7 Shadow.

General Characteristics

  • Ceiling: 19.8km
  • Endurance: 24-36 hours
  • Length: 13.4m
  • Weight: 11,600kg
  • Wingspan: 35.4m
  • Velocity: 250kph (cruise); 636kph (max)

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