The Northrop Grumman RQ-4A Global Hawk is the modernest UAV of the USAF & the world. As part of the High Altitude Endurance (HAE) Advanced Concept Technology Demonstration (ACTD), the Global Hawk program began with both the Global Hawk and the Dark Star UAV programs in 1995.

The ACTD began under Defense Advanced Research Projects Agency management. October 1998, it was transitioned to the Air Force systems program office at Wright Patterson AFB. The Dark Star program was cancelled in January 1999.

In Sep 2011, The U.S. defense department started conversation with South Korea to deploy the RQ-4 Global Hawk surveillance drone near its border with North Korea. It is believed that this would enhanced view of North Korea and China. This aircraft's cameras and sensors are able to pick up target information well beyond the Yalu River, which is where border between North Korea and China lies.
  Related Aircraft:
Chinese J15, Chinese J20,
F-35 JSF, F/A-18E/F, EA-18G

The Global Hawk portion of the ACTD was conducted in three phases: design; development and test; and deployment and evaluation. The relative manufacturer are Electronic Systems (ES), Information Technology (IT), Integrated Systems (IS), Ship Systems and Component Technologies.

The deployment and evaluation phase was conducted between June 1999-June 2000, with the U.S. Joint Forces Command as the operational sponsor. The desired operational requirements were prioritized and each spiral will include those upgrades that available funding can afford. The full operational capability identified by the Air Force in the ORD will not be available until the second spiral or Block 10 systems are produced.

Global Hawk had its first flight in February 1998, and completed 58 sorties totaling 719.4 flight hours throughout the ACTD period. A crash in March 1999 destroyed air vehicle Number 2 and its sensor suite, and a runway incident in December 1999 damaged air vehicle Number 3 and destroyed the only other integrated sensor suite. Consequently, no EO/IR imagery was available during any warfighting exercises. A separate SAR sensor provided imagery. Flight-testing resumed in March with AV-01. The entire system re-deployed to Edwards AFB in June 2000.

22nd Apr 2001, the Global Hawk completed its pioneering flight from USA to Australia. Only few aircraft with pilot onboard can fly over the Pacific, such as the airliners as we know. This is the first time UAV do this thing. The long range makes sure that the Global Hawk can stay above the target area for 24 hours, proceeding non-stop surveillance. Both ground stations and a support package can be transported in one C-5 or two C-17s.

The vehicle itself needs no airlift: with a straight-line range of 13,500 nautical miles and endurance up to 38 hours, it can fly anywhere.

The Global Hawk is 44.4 ft. long, 15.2 ft height, wingspan 116.2 ft., Weight 25,600 lbs. The wingspan is similiar to the Boeing 747, so it is a very large UAV. It can carry over 7t fuel, maxium range 25945km, and is able to self-control over-continent flight for 41 hours. In another word, it can fly to 5556km away from the base, stay there for 24 hours 60000ft high. The flight control system contains GPS & INS, which insured auto takeoff & landing, as well as the whole flight process.

The RQ-4A reached at ceiling of 65125ft, and broke the jet UAV record of 31.5 hours mission flying. The original world record was held by Compass Cope-R UAV for 26 years.

The Global hawk can carry Electro-Optical (EO) / Infrared (IR) and Synthetic Aperture Radar (SAR) in the same time. The EO sensor operates in the 0.4 to 0.8 micron visible waveband and the 3.6 to 5 micron infrared band. The EO sensor incorporates a third-generation IR sensor and a Kodak digital charge coupled device (CCD) visible wavelength camera. The SAR system, with Moving Target Indicator (MTI) operates at X-band with a 600 MHz bandwidth and 3.5 kW peak power, can capture the 1 meter precision scroll photo, and 1ft precision photo for point-target investigation. When detecting the 20km/h to 200km/h moving target on the ground, the precision is about 7km. In one mission flight, the Global hawk can proceed extension area radar search and EO/IR photo capturing for 74,000 square kilometers, the minium CEP of the target positioning would be 20 meters. The SAR with a 1.2 meter antenna can penetrate the rain or cloud and be able to proceed continuous moving target surveillance.

The more advanced advantage of the Global Hawk is that linked with systems such as the Joint Deployable Intelligence Support System (JDISS) and the Global Command and Control System (GCCS), imagery may be transferred NRT to the operational commander for immediate use, such as targeting, warning, fast attack & re-attack and combat evaluation. And the RQ-4A is capable to fit for different communicaion and control systems of Army, Airforce or Navy. It can use broadband satellite communication as well as the line-of-sight data transmission. The broadband system is good support up to 274 megabits per second, but not currently supported, and 50 megabits per second by a Ku band SATCOM. Global Hawk also carries back-up datalinks.

Now each Global Hawk cost US$ 51.00 million. Since the USAF is to buy 66 RQ-4As, the price is expected to be US$ 20.00 million, comparing with U-2`s US$ 52.00 million price. Australia is to make a AU$ 250 million (US$ 130 million) order for Global Hawks in 2004 to 2005 financial year. The photo shows the range of RQ-4A deployed in Australia.

Disadvantages are inside the Global Hawk, too. The speed of it is too slow to escape from the hunting of the hi-speed fighters. The jet engine still produces some IR signal. That is why the Global Hawk is equiped with IR flares. The payload of it is 900kg, the capability for carrying equipments is limited.

In Sep 2011, The Air Guard announced that despite recent budget cut plan, they will continue to operate the Air Force’s combat UAVs, including MQ-1B. A few Air Guard squadrons have switched from operating F-16 fighters and KC-135 tankers, to fly MQ-1B Predator and MQ-1C Reaper combat UAVs.

The photo shows the air pressure while flying.

Rolls Roys AE3007 enjine.

The photo taken by SAR radar.

The following picture showed the advantage of IR sensor, the C-130 on the top right has just left the runway, but its shadow cool down the ground, so left a shadow in the IR photo.

The wonderful photo taken by EO, close to the best quality satellites.

The system of Global Hawk.

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