PAUL LEWIS / WASHINGTON DC
Unmanned combat vehicles are in their infancy, but a USArmy/DARPA programme aims to make unmanned rotorcraft the rulers of future battlefields
The Afghanistan conflict has provided a fertile proving ground for new weapons technology, especially in advancing the cause of armed unmanned air vehicles (UAVs). Less than nine months after the first missile firing from the General Atomics RQ-1B Predator against the Taliban, the US Army, in partnership with the Defense Advanced Research Projects Agency (DARPA), kick-started the Unmanned Combat Armed Rotorcraft (UCAR) programme. Four competing industry teams have been awarded concept development contracts that may open the door to the most far-reaching advance in army aviation since the helicopter made its combat debut in the Korean War more than 50 years ago.
From DARPA's narrow technology perspective, the UCAR represents the next evolution in UAV capability, building on the ability of the Northrop Grumman RQ-4A Global Hawk to fly autonomously from point to point to develop a system of systems that will plug into the army's Objective Force of tomorrow. The UCAR programme, furthermore, is an extension of the DARPA/US Air Force Unmanned Combat Air Vehicle (UCAV) programme, with its focus of proving single operator and multiple vehicle operations; and the DARPA/US Navy's planned naval UCAV-N demonstration, with the added complexity of shipboard launch and recovery.
Next level
"UCAR goes to the next level in that it will have to operate in an environment that is much more complex than either Global Hawks or UCAVs in that we envisage them operating in the low-altitude environment typical to the army," says Don Woodbury, DARPA UCAR programme manager. The vehicle will not only have to prove its battlefield survivability. To past muster with the army warfighters, a UCAR will need to demonstrate interoperability with other manned and unmanned assets on the ground and in the air, be affordable to operate as well as to buy, be autonomous in mission planing and collaborative operations and prove lethal in its ability to identify and destroy targets in real time.
The US Army is taking a conservative approach to fielding a UCAR, assuming DARPA can prove that the technology works and is of operational value. The army, anxious not to undermine the $6.6 billion being pumped into development of the tandem-seat Boeing Sikorsky RAH-66 Comanche helicopter, views armed UAVs in the near term as adjuncts to manned systems; in the mid-term as semi-autonomous assets working to pre-determined algorithms; and in the long-term as vehicles performing autonomous missions from start to finish - but not before 2020-25 and not without human oversight.
Col Waldo Carmona, commander of the US Army's Aviation Applied Technology Directorate (AATD), says: "The challenge from a technology standpoint is going to be autonomy. Everybody says 'fully autonomous' very cavalierly, which really means the ability to execute a mission without any input from anyone, make decisions, learn from your environment and then decide what to do considering the environment has changed. We're not really going to do that with UCAR. It's going to be semi-autonomous, using a decision-aided technology that we developed for RPA [rotorcraft pilot's associate] to help it be smart, but we're still going to have people in the loop."
DARPA and the army have mapped out a four-phase UCAR demonstration programme spread over eight years. The aim is to finish up with a system mature enough to make the transition to full-scale system development and demonstration (SDD). Phase One started in May with the award of four $3 million contracts to Boeing; Lockheed Martin and partner Bell Helicopter; Northrop Grumman; and Sikorsky teamed with Raytheon. The 12-month effort is focused on architecture development, trade studies, risk reduction and conceptual design and capability definition, and will conclude with the downselect of two contractors to go forward into Phase 2.
"As is typical in many DARPA programmes we've not given them a laundry list of requirements. They instead have top-level objectives, wide open trade space and have been told to come back and help us understand what they can offer," says Woodbury. The non-tradable requirements boil down to four stipulations: that a UCAR be capable of global operations; be safe to operate over populated areas; can be commanded and controlled from the air and ground; and use JP8 fuel. A UCAR must operate alongside the Boeing AH-64 Apache and the Comanche, which dictates a vertical take-off and landing design, although not necessarily a helicopter. Canard rotor wing, tiltrotor or even a liftfan design are all possibilities.
The nine-month Phase 2 will end with a preliminary design review and the selection of a single contractor to proceed to Phase 3, which will last for two and a half years and entail producing and flying two demonstrators by early 2006.
Technology challenge
The challenge will then be to convince the army that the UCAR's capabilities are compelling enough to move forward into development and construction of a more operationally relevant B-model to demonstrate individual systems capabilities. The intent is to mature the UCAR to technology readiness level (TRL) 7, rather than the more usual DARPA practice of TRL 5 or 6, with the objective of passing UCAR to the army in fiscal year 2009 to begin SDD.
"What the army has asked DARPA to do with the programme is unique in that we'll continue to work with them to mature the system capability to a point where it will make it into the acquisition environment, without further maturation by the service," says Woodbury. The army in return has committed up front to share the $500 million cost of completing the full demonstration. This approach is not without risk in that, unlike the joint strike fighter, there is not enough money to fly more than one demonstrator. It assumes the system will work to the US Army's satisfaction without having to resort to a new analysis of alternatives and a new procurement competition.
While the USAF has retroactively put a plan in place to transition UCAV from the Boeing X-45A/B demonstrators to A-45 initial operational system in the 2008 timeframe, the parallel UCAV-N programme has run aground. At issue are US Navy concerns about selecting between the Boeing X-46 and Northrop Grumman X-47 demonstrators for flight testing ahead of a separate service analysis of alternatives and open-tender procurement of an operational system.
The army wants myriad questions answered, among them: what kind of capability will UCARs bring to the battlefield? How will the system be managed? Will there be a multirole UCAR or mission-dedicated platform addressing the need for attack, reconnaissance, targeting or communications relay?
"The requirements process needs to see and understand what UCAR brings to the table. We need to have technology that is relevant to the warfighter and, as a concept, provides enough of a leap forward in capability," says Carmona.
AATD will support DARPA through its Airborne Manned/Unmanned System Technology and Hunter Stand-off Killer Team demonstrations. The latter teams UAVs such as the Hunter with the AH-64D and Sikorsky UH-60 Army Airborne Command and Control System (A2C2S) to extend situational awareness and "shooter eyes on target". UAV target data will be datalinked via the A2C2S to a USN Boeing F/A-18 and downloaded to a GPS-guided munition. AATD is also planning related flight experiments with the Sikorsky Cypher shrouded-rotor UAV, Bell Eagle Eye tiltrotor UAV and Northrop Grumman RQ-8A Fire Scout helicopter UAV.
DARPA has outlined a number of key technological challenges that need to be addressed by the teams for a UCAR to work successfully. The system must be able to work autonomously at low level and survive, and the technology must be affordable from a procurement, operational and support (O&S) and combat attrition standpoint. It must achieve a substantial improvement in target identification and recognition and be capable of dynamic mission replanning.
Low flying
Woodbury defines low level as anything between nap of the earth and 500ft (150m), a far lower than today's UAVs can fly. This brings challenges of working with other UAVs and manned machines in close confines, in addition to those of avoiding terrain and man-made obstacles such as buildings and powerlines. DARPA is looking at a mix of passive terrain and situation awareness aids, as well as adaptation of existing active avoidance system solutions. The UCAR must be also capable of collaborative autonomous operations at low level, with minimal human input.
"What we're trying to do is break the tether, but keep the man in the loop for tasking and weapon release. Apart from these critical functions, controllers would be relieved of detail tasks and put in supervisory positions. We are taking the man out of the middle and will have UCARs perform on their own or together, exchanging data and figuring out between themselves how best to execute a mission. A UCAR also must have the capability to replan missions where something goes wrong, where an asset is lost or there is a tactical information update," says Woodbury.
Key enabling technology to allow the UCAR to work is target identification with at least two to three times the range of current systems to give a controller a positive enough picture of an acquired target to authorise weapons release and to exploit fully a missile's stand-off range. Initial acquisition will likely be with a multi-spectral fusion of onboard and offboard distributed sensor data, be that visual, infrared, radar, laser detection and ranging and/or acoustic.
DARPA is planning for modular plug and play sensors, payloads capable of accommodating current air-launched missiles, rockets and guns. UCAR will also be integrated into the planned DARPA/US Army NetFires system. Margin for growth will have to be built into the UCAR design in turns of available power and payload volume and weight. "UCAR will be around for 20-30 years and we're likely to have directed energy weapons in that time," says Woodbury.
Stealth or low observability has not been specifically mandated as a requirement, but DARPA has made a high degree of battlefield survivability against a diverse set of air defence and small-arms threats a must, with the emphasis being on tactics, techniques and procedures. There must also be a quantum leap forward in terms of non-combat attrition rates, which have traditionally hovered around 100 UAVs for every manned platform. The ultimate goal is to improve system reliability to the point where the US Federal Aviation Administration will approve the operation of UCARs in controlled airspace.
Balanced against all this is the fundamental need for the UCAR to be affordable, with the goal of keeping within 20-40% of the flyaway cost of the Comanche and achieving a 50-80% reduction in O&S costs compared to today's Apache, through a greatly reduced support footprint. "We're in the $4-8 million flyaway cost range. That's the vision, but not a requirement, we're placing before contractors. We've given the teams relatively aggressive O&S cost goals in that an 80% reduction takes us below the operating cost of a commercial aircraft that doesn't have weapons or sensors," says Woodbury.
The UCAR advances unmanned air vehicles one step further towards artificial intelligence and a world of possibilities that hitherto has been confined to realm of science fiction. This raises questions which technology alone cannot address, but which require doctrinal answers on what is and is not politically permissible with robotic weapons. "Today, there is no reason why we can't fly combat air patrols with UAVS, but ideologically we're not ready for Judge Dredd," says Carmona.
Source: Flight International
