Northrop Grumman RQ-4 Global Hawk facts for kids
Quick facts for kids RQ-4 Global Hawk |
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| An RQ-4 Global Hawk flying in 2007 | |
| Role | Unmanned surveillance and reconnaissance aerial vehicle |
| National origin | United States |
| Manufacturer | Northrop Grumman |
| First flight | 28 February 1998 |
| Introduction | November 2001 |
| Status | In service |
| Primary users | United States Air Force NASA NATO |
| Produced | 1998–present |
| Number built | 42 RQ-4Bs as of FY2013 |
| Program cost | US$10 billion (USAF cost through FY2014) |
| Unit cost | US$131.4M (FY13) US$222.7M (with R&D) |
| Developed into | Northrop Grumman MQ-4C Triton |
The Northrop Grumman RQ-4 Global Hawk is a high-altitude, remotely-piloted surveillance aircraft introduced in 2001. It was initially designed by Ryan Aeronautical (now part of Northrop Grumman), and known as Tier II+ during development. The RQ-4 provides a broad overview and systematic surveillance using high-resolution synthetic aperture radar (SAR) and electro-optical/infrared (EO/IR) sensors with long loiter times over target areas. It can survey as much as 40,000 square miles (100,000 km2) of terrain per day, an area the size of South Korea or Iceland.
The Global Hawk is operated by the United States Air Force (USAF). It is used as a high-altitude long endurance (HALE) platform covering the spectrum of intelligence collection capability to support forces in worldwide military operations. According to the USAF, the superior surveillance capabilities of the aircraft allow more precise weapons targeting and better protection of friendly forces.
Cost overruns led to the original plan to acquire 63 aircraft being cut to 45, and to a 2013 proposal to mothball the 21 Block 30 signals intelligence variants. The initial flyaway cost of each of the first 10 aircraft was US$10 million in 1994. By 2001, this had risen to US$60.9 million (~$90.2 million in 2021), and then to $131.4 million (flyaway cost) in 2013. The U.S. Navy has developed the Global Hawk into the MQ-4C Triton maritime surveillance platform. As of 2022, the U.S. Air Force plans to retire its Global Hawks in 2027.
Contents
Design
Overview
The Global Hawk UAV system comprises the RQ-4 air vehicle, which is outfitted with various equipment such as sensor packages and communication systems; and a ground element consisting of a Launch and Recovery Element (LRE), and a Mission Control Element (MCE) with ground communications equipment. Each RQ-4 air vehicle is powered by an Allison Rolls-Royce AE3007H turbofan engine with 7,050 lbf (31.4 kN) thrust, and carries a payload of 2,000 pounds (910 kilograms). The fuselage uses aluminum, semi-monocoque construction with a V-tail; the wings are made of composite materials.
There have been several iterations of the Global Hawk with different features and capabilities. The first version to be used operationally was the RQ-4A Block 10, which performed imagery intelligence (IMINT) with a 2,000 lb (910 kg) payload of a synthetic aperture radar (SAR) with electro-optical (EO) and infrared (IR) sensors. Seven A-model Block 10s were delivered and all were retired by 2011. The RQ-4B Block 20 was the first of the B-model Global Hawks, which has a greater 3,000 lb (1,400 kg) payload and employs upgraded SAR and EO/IR sensors. Four Block 20s were converted into communications relays with the Battlefield Airborne Communications Node (BACN) payload.
The RQ-4B Block 30 is capable of multi-intelligence (multi-INT) collecting with SAR and EO/IR sensors along with the Airborne Signals Intelligence Payload (ASIP), a wide-spectrum SIGINT sensor. The RQ-4B Block 40 is equipped with the multi-platform radar technology insertion program (MP-RTIP) active electronically scanned array (AESA) radar, which provides SAR and moving target indication (MTI) data for wide-area surveillance of stationary and moving targets.
Since the RQ-4 is capable of conducting sorties lasting up to 30 hours long, scheduled maintenance has to be performed sooner than on other aircraft with less endurance. However, since it flies at higher altitudes than normal aircraft, it experiences less wear during flight.
System and ground facilities
Raytheon's Integrated Sensor Suite (ISS) consists of the following sensors:
- a synthetic aperture radar (SAR)
- electro-optical (EO)
- thermographic camera (IR)
Either the EO or the IR sensors can operate simultaneously with the SAR. Each sensor provides wide area search imagery and a high-resolution spot mode. The SAR has a ground moving target indicator (GMTI) mode, which can provide a text message providing the moving target's position and velocity. Both SAR and EO/IR imagery are transmitted from the aircraft to the MCE as individual frames, and reassembled during ground processing. An onboard inertial navigation system, supplemented by Global Positioning System updates, comprises the navigational suite.
The Global Hawk's camera is capable of identifying objects on the ground as small as 30 cm (12 in) in diameter from 20 km (66,000 ft) in the air.
The Global Hawk is capable of operating autonomously and "untethered". A military satellite system (X Band Satellite Communication) is used for sending 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 within line-of-sight of compatible ground stations. For dense flight areas the autonomous navigation is switched off and the RQ-4 is remote controlled via the satellite link by pilots on the ground who are supplied with the same instrument data and who carry the same responsibilities as pilots in crewed planes.
The ground segment consists of a Mission Control Element (MCE) and Launch and Recovery Element (LRE), provided by Raytheon. The MCE is used 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 GPS 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.
Sensor packages
Radar
The Global Hawk carries the Hughes Integrated Surveillance & Reconnaissance (HISAR) sensor system. HISAR is a lower-cost derivative of the ASARS-2 package that Hughes developed for the U-2. It is also fitted to the US Army's de Havilland Canada RC-7B Airborne Reconnaissance Low Multifunction (ARLM) crewed aircraft, and is being sold on the international market. HISAR integrates a SAR-MTI system, along with an optical and a thermography imager.
All three sensors are controlled and their outputs filtered by a common processor and transmitted in real time at up to 50 Mbit/s to a ground station. The SAR-MTI system operates in the X band in various operational modes; such as the wide-area MTI mode with a radius of 62 mi (100 km), combined SAR-MTI strip mode provides 20 ft (6.1 m) resolution over 23 mi (37 km) wide sections, and a SAR spot mode providing 6 ft (1.8 m) resolution over 3.8 square miles (9.8 square kilometers).
In July 2006, the USAF began testing the Global Hawk Block 30 upgrades in the Benefield Anechoic Facility at Edwards AFB. Upgrades include the Advanced Signals Intelligence Payload, an extremely sensitive SIGINT processor. and a specialist AESA radar system, the Multi-Platform Radar Technology Insertion Program, or MP-RTIP. In 2010, Northrop disclosed the sensor capabilities of the new Block 40 aircraft, including the MP-RTIP radar, emphasising surveillance over reconnaissance.
On 14 April 2014, a Block 40 Global Hawk completed the first Maritime Modes program risk-reduction flight to enhance the Air Force's maritime surveillance capabilities. Maritime Modes is made up of a Maritime Moving Target Indicator and a Maritime Inverse synthetic aperture radar (MISAR) that function together to provide ISR information on vessels traveling on the water's surface. During the 11.5-hour flight off of the California coast, the MISAR collected data on over 100 items of interest. Maritime Modes is planned to be integrated with the RQ-4B's existing MP-RTIP radar to detect and produce synthetic aperture radar imagery of ground vehicles.
In November 2015, Northrop Grumman selected the Garmin International GSX 70 weather radar to be installed on Air Force Global Hawks. The GSX 70 is designed to provide operators with real-time weather information, offering horizontal scan angles of up to 120 degrees for better visibility into the strength and intensity of convective activity and a vertical scanning mode to analyze storm tops, gradients, and cell buildup activity. It also has a Turbulence Detection feature to identify turbulence in air containing precipitation and other airborne particulates and Ground Clutter Suppression that removes ground returns from the display so operators can focus on weather. Installation is expected to begin in early 2016. Installation of weather radars on the Global Hawk fleet completed in late 2019.
Visible light/infrared
The visible and infrared imagers share the same gimballed sensor package, and use common optics, providing a telescopic close-up capability. It can be optionally fitted with an auxiliary SIGINT package.
Variants
- RQ-4A
- Initial production version for the USAF, 16 built.
- RQ-4B
- Improved version with increased payload, wingspan increased to 130.9 ft (39.9 m) and length increased to 47.7 ft (14.5 m). Due to the increased size and payload the range is reduced to 8,700 nmi (16,100 km).
- RQ-4D Phoenix
- NATO Alliance Ground Surveillance (AGS).
- RQ-4E Euro Hawk
- Version for the Bundeswehr based on RQ-4B and equipped with an EADS reconnaissance payload for SIGINT. Germany canceled its order in May 2013; it received one of five Euro Hawks originally ordered.
- For USN Broad Area Maritime Surveillance (BAMS) role; previously known as the RQ-4N; 4 ordered, 68 total planned.
- EQ-4B
- Equipped with the Battlefield Airborne Communications Node (BACN) system.
- KQ-X
- Proposed autonomous tanker variant.
- Model 396
- Scaled Composites and Northrop Grumman also offered an armed, 50% smaller version of the RQ-4A, known as the Scaled Composites Model 396, as part of the USAF Hunter-Killer program. The aircraft was rejected in favor of the MQ-9 Reaper.
Specifications (RQ-4B Block 30/40)
Data from Northrop Grumman USAF
General characteristics
- Crew: 0 onboard (3 remote: Launch and Recovery Element (LRE) pilot; Mission Control Element (MCE) pilot and sensor operator)
- Capacity: 3,000 lb (1,360 kg)
- Length: 47.6 ft (14.5 m)
- Wingspan: 130.9 ft (39.9 m)
- Height: 15.3 ft (4.7 m)
- Empty weight: 14,950 lb (6,781 kg)
- Gross weight: 32,250 lb (14,628 kg)
- Powerplant: 1 × Rolls-Royce F137-RR-100 turbofan engine, 7,600 lbf (34 kN) thrust
Performance
- Maximum speed: 391 mph (629 km/h; 340 kn)
- Cruise speed: 357 mph (575 km/h; 310 kn)
- Range: 14,155 mi; 22,780 km (12,300 nmi)
- Endurance: 34+ hours
- Service ceiling: 60,000 ft (18,000 m)
- Lift-to-drag: 33
See also
