Recent success spurs US Department of Defense to seek $1.1 billion to boost programmes for air force, army and navy

As the US military starts to digest the lessons from the Afghanistan conflict, it is clear that unmanned air vehicles have emerged as clear winners from the war on terrorism. This is reflected by the US Department of Defense's recently proposed fiscal year 2003 budget, which is seeking more than $1.1 billion to accelerate development and deployment of a number of critical systems for the USA's air force, army and navy.

The success of the General Atomics RQ-1A Predator, armed with little more than a pair of Lockheed Martin AGM-114 Hellfire, has underlined the potential of an armed UAV. While the near-term demand for extra firepower will be met by the larger turboprop-powered Predator B, longer-term planning focuses on purpose-built unmanned combat air vehicles for the air force (UCAV-AF) and navy (UCAV-N). The former has progressed the furthest and, with the first of two Boeing X-45A demonstrators due to fly soon, the USAF wants to field 14 UCAVs by FY08 to begin an operational assessment.

Mike Heinz, vice president of Boeing's recently created Unmanned Systems business unit, says: "It's always a challenge to accelerate a programme by a year or two, but we're getting a head start by having the engineering in place to start designing the X-45B vehicle in advance of the plan. We've the ability to start getting ready the additional laboratories necessary to finish the A-vehicle and developmental flight testing, and commence work on the B-vehicle in parallel with that."

The three follow-on X-45B demonstrators will more closely resemble the initial Block 10 UCAV-AF planned for 2008, with an increased 8.5t maximum take-off weight, 63% larger wing area, and the integration of low-observable (LO) features (Flight International, 18-31 December 2001). Boeing is seeking a more powerful 7,000lb-thrust- (31kN) class turbofan and reviewing responses to its recent request for proposals (RFP) for the UCAV radar, electro-optical/infrared sensor and electronic warfare (EW) suite. "We'll be selecting partners in the next three months," adds Heinz.

UCAV-N is one step behind UCAV-AF, with the USN still to choose between the Boeing X-46 and competing Northrop Grumman X-47 as the basis for a full-up demonstrator. RFP submissions are due shortly with selection expected in early summer. The navy's roadmap calls for the deployment of an operational vehicle aboard an aircraft carrier around 2015, but this schedule is being reviewed and could be accelerated.

UCAV-N faces altogether different challenges from its air force counterpart. "I think the focus of the next phase will be on convincing everyone that you have an autonomous vehicle capable of coming aboard an aircraft carrier with only small dispersions," says Heinz.

Whereas the USAF's immediate mission focus is on suppression of enemy air defences, the USN is looking to UCAV-N initially to provide an intelligence, surveillance and reconnaissance capability, with armed strike following around 2020. The USN's requirement for operation up to 12h at extended distances over hostile territory drives the need for improved survivability, something that until now has not been afforded high priority.

"Historically, the loss rate for UAVs is over 100 times that of manned aircraft and, although in Afghanistan these are not people driven, sooner or later losses mount," says Neil Kacena, Lockheed Martin deputy advanced development programmes.

The key ingredients for battlefield survivability are LO, EW and balancing the need to gather intelligence with controlling signal emissions. Future UAVs, UCAVs and what Lockheed Martin is terming unmanned reconnaissance air vehicles (URAV) will draw on the pool of technology developed by the Skunk Works and Boeing's Phantom Works for the Joint Strike Fighter. This will include clear radomes capable of supporting very wide bandwidths and LO sensor apertures, as well as seals and leading-edge treatment.

If UCAV/URAVs are to be fully exploited, they must also be made an integral part of the evolving network-centric architecture. The use of RQ-1As in Afghanistan, in conjunction with Lockheed Martin AC-130 gunships, has provided a sneak preview of what could be possible in a future system-of-systems environment. "There is a time-critical chain of find, fix, target, track, engage and assess," says Kacena, which entails not only locating a target, but optimising a real-time response that might include jamming or a suppression of enemy air defences strike.

This is driving a need for real-time mission planning, with which Lockheed Martin is already experimenting using the navy's P-3 Hairy Buffalo testbed and an F-117 simulator equipped with an in-flight planner to do in four seconds what had previously taken 12h. Both Heinz and Kacena agree the recent conflict has also highlighted the need for an extended endurance vehicle that would be able to dwell over a battlefield and continually stare rather than periodically pass over.

Whether this could be fulfilled by a Northrop Grumman RQ-4A Global Hawk derivative, or whether a new system would be required, more along the lines of the Air Force Research Laboratory's Sensor Craft concept, remains to be seen.

Source: Flight International