The USAF has learnt, through sometimes bitter experience, that however good a design looks on paper, it’s only by actually building, flying and thoroughly testing a design that its true capability can be determined. In recent years this practice has been used to good effect for a number of manned aircraft was also used in the development of the Dark Star and Global Hawk UAVs. Even though the Global Hawk has just begun full-scale production and entry into service and the Dark Star has evolved into a larger ‘black’ UAV, the Air Vehicles Directorate element of the Air Force Research Laboratory (AFRL) at Wright-Patterson Air Force Base, Ohio has already begun developing the concept of a next-generation advanced UAV to replace these vehicles.
Throughout the remainder of this decade the AFRL will investigate a wide variety of the latest sensors, communications links, air vehicle components and propulsion systems and consider how they can all be incorporated into the concept of a next generation long-range high-altitude ISR UAV – known as SensorCraft. When and if it finally enters service, this cutting-edge vehicle will carry an integrated mix of radar, cameras, ELINT equipment and data links, whilst orbiting a battlefield at 65,000ft for between 60-80hrs at around 350kts, gathering intelligence and passing it onto supporting elements in near real-time.
For the design of SensorCraft the traditional design process has been reversed. In previous UAV designs the vehicle has been constructed and then the sensors have been incorporated into the available space. In SensorCraft the optimum mix of sensors will be determined and then the vehicle design moulded around the systems, with sensor apertures embedded in the fuselage as necessary. This unusual approach to UAV design has already resulted in some radical proposals; in particular, a diamond shaped structure that would facilitate sensor coverage. Another proposal is for a flying-wing design, not dissimilar to the B-2 Spirit stealth bomber along with a large U-2 style design with a 200ft wing-span and an endurance of 60hrs.
Particular attention is being paid to the sensors planned for this UAV and they will probably operate on a wide variety of frequencies, such as VHF to allow foliage penetration and X-band for improved image resolution, as well as hyperspectral and passive sensors. There’s even as possibility that the vehicle will be able to operate in a bistatic mode, allowing for passive operations, and be equipped with active countermeasures. As technology advances, this next generation Global Hawk could well have a combined Air and Ground Moving Target Indicator (AGMTI) built into an Active Electronically Scanned Array (AESA) giving it the air-to-air capability of an E-3D AWACS together with the air-to-ground function of the E-8 JSTARS.
The SensorCraft concept will allow the ARFL to establish how evolving technologies develop and enable the programme to determine if they can eventually mature into a viable UAV. The ARFL aim to launch an aircraft programme around 2010 and the eventual system could enter service around 2020.