PAUL LEWIS / WASHINGTON DC
Northrop Grumman to address control conundrum as part of latest Global Hawk development plans
The challenge of conducting unmanned air vehicle (UAV) operations in civil controlled airspace is one of the main goals facing Northrop Grumman under a newly awarded $147 million contract to begin development of the next Spiral 3 version of the RQ-4A Global Hawk for the US Air Force.
"A key performance parameter for Global Hawk is to operate in all classes of airspace and to do that elements of the global air traffic management [GATM] system are being incorporated as part of Spiral 3. We're ploughing new ground and because of the size and robustness of this vehicle we have the ability to carry equipment not used in other UAVs," says Alfredo Ramirez, Northrop Grumman Global Hawk chief engineer.
New equipment will include a civil-certificated GPS satellite navigation system embedded in the RQ-4A's navigation system, controller-pilot datalink communications and automatic dependent surveillance (ADS). Global Hawk is already equipped with a traffic collision avoidance system and Mode S transponder, but for situation awareness and not automatic avoidance manoeuvres.
The ground control station (GCS) will be equipped with 8.33kHz-spacing VHF radios for voice communications with civilian air traffic control (ATC) via the UAV and an Inmarsat satellite communications relay. ADS-A data on the UAV's identification, location and heading will be similarly relayed to ATC. While Global Hawk is often restricted to operating at 50,000ft (15,250m) or higher and making spiral take-off and landings to avoid civil air traffic, Spiral 3 will be capable of transiting through GATM airspace.
Other Spiral 3 work will include evaluating and selecting alternative mission packages, including radio frequency signals intelligence (SIGINT) and making initial open- system computing provision for the future Multi-Platform Radar Technology Insertion Programme due in Spiral 4 in 2007-8. The first Spiral 3/Lot 3 production vehicle is scheduled to fly and be delivered by late 2005. Spiral 5 in 2008-9 will include more SIGINT and a new common datalink.
As well as hosting Spiral 3 systems, Lot 3 vehicles will also be the first incorporating structural changes developed as part of Spiral 2. This includes a 0.9m (3ft) fuselage extension, a new 39.6m span wing and a 27kVA generator replacing the existing 10kVA system.
The changes provide a one-third increase in payload to 1,360kg (3,000lb). Northrop Grumman has decided against winglets, which would provide additional range and endurance, but is keeping them as an option (Flight International, 18-24 February).
The USAF has postponed indefinitely a planned deployment to Germany and demonstration of a Global Hawk equipped with an EADS electronic intelligence(ELINT)package. The air force says there are no available UAVs for the demonstration as the result of the military build-up in the Gulf. Following the delivery last month of the seventh development vehicle and the loss of three earlier demonstrators there are now four RQ-4As flying. The ELINTpackage is part of the Northrop Grumman/EADS EuroHawk proposal.Source: Flight International
