During its lifetime, the Joint Strike Fighter (JSF) will start operating routinely alongside unmanned combat aircraft. Unmanned vehicles will extend the reach of the fighter's sensors and weapons into heavily defended airspace no manned aircraft would venture near.
Unmanned combat air vehicles (UCAVs) are the next major step in the evolution of unmanned air vehicles (UAVs). Whether they will prove viable remains to be seen, but since Israel used them against Syrian air defences in Lebanon in 1983, unmanned aircraft have been a factor in warfare.
Israel has since developed increasingly sophisticated and internationally successful UAVs. Several highly classified programmes under way are proof of the importance given by its defence forces to unmanned platforms. "The UAV is moving in new directions," says Israel Aircraft Industries executive vice-president Ovadia Harari, forecasting that in 20 years unmanned aircraft will be able to perform "attacks on ground targets as their primary mission, with intelligence gathering as a secondary one".
Although the USA used remotely piloted vehicles successfully in Vietnam and experimented with them in the strike role, its record since has been, until recently, abysmal. Since the Vietnam War, says the US General Accounting Office, the Department of Defense has cancelled at least nine UAV programmes, spending over $4 billion in the process.
The biggest failures, each consuming $1 billion, were the Lockheed Aquila tactical UAV and a classified programme. Development of the Aquila, which began in 1979, was expected to take less than four years and cost little more than $120 million. Eight years and $1 billion later, the programme was cancelled when the delta-wing, pusher-propeller UAV failed operational testing.
A decade later, the TRW Hunter programme was terminated after costing $700 million, despite having the hallmarks of success - it was derived from a string of successful Israeli designs and its conventional runway operation avoiding the risky rail launch and net recovery that plagued the Aquila. But the Hunter was beset with operating problems and production was cancelled.
Costly cancellations
To the list of costly cancellations can be added Amber, Compass Cope, Compass Dwell, Condor, Medium-Range UAV and Raptor, plus many delayed and terminated programmes in Europe and elsewhere. That list makes it clear why so many are so sceptical about the future of unmanned systems.
But the tide may be turning, at least in the USA. Since 1994, when it introduced a strategy of demonstrating UAVs before committing to development and production, the Pentagon's success rate - or more precisely its "failure avoidance" rate - has improved. General Atomics' Predator was approved for production after prototypes were evaluated operationally in Bosnia, and it was used successfully over Kosovo - becoming the first US UAV to designate a target for a laser-guided bomb.
The new technology demonstration approach has led to the early termination of programmes, before too much money had been spent. After prototypes of Alliant Techsystems' Outrider tactical UAV failed to demonstrate the necessary military utility, the US Army re-opened the competition, while the US Navy and Marine Corps decided they would rather have a vertical take-off and landing UAV.
The biggest demonstration programme to date has had mixed results. Started by the US Defense Advanced Research Projects Agency (DARPA), the High Altitude Endurance (HAE) UAV programme set out to demonstrate a reconnaissance system comprising two complementary platforms: the "workhorse" Northrop Grumman (formerly Teledyne Ryan) Global Hawk and the stealthy Lockheed Martin/Boeing DarkStar.
Recognising that previous programmes had been hindered by the requirement that unmanned vehicles should be cheap and expendable, the HAE effort was intended to demonstrate sophisticated UAVs that would be "affordable and attritable" - in other words, capable enough to perform a valuable mission, but not so expensive that their loss would be catastrophic.
After the first prototype of the tailless, flying-wing DarkStar crashed on take-off because of flight control problems, a DARPA official joked: "We've demonstrated that it's attritable, now all we have to do is demonstrate it's affordable." It was not. The DarkStar programme was terminated early when it became clear the UAV could not be produced for the target $10 million unit price,
The more conventional Global Hawk has fared better, despite suffering its own crash, and has been approved to enter development. The success of the Global Hawk is a major reason for the renewed excitement surrounding UAVs and the main reason why US military planners are giving serious consideration to replacing, or at least complementing, manned aircraft with unmanned systems.
"UAVs are not for everything, and their utility varies with the level of technology that is in place at the time," says Maj Gen Bruce Carlson, USAir Force deputy chief of staff for operational requirements. "We used drones extensively during the 1960s, but they had very, very limited missions. They essentially went out in a straight line, did a couple of circles and came back, and they either crashed or we caught them in a net because we could never try to land them. Now, the indications are that we have made a jump in technology. We can get the reliability required and the precision necessary to consistently land them without crashing. Combine that with the fact that we've had a revolution in computer technology, where you can shrink the size of payloads, get them to the altitude and keep them up there for the duration we would like, it appears as though UAVs have a new set of utilities."
Technology leaps
Those new utilities, Carlson says, are in the high-altitude/long-endurance niche, and include intelligence, surveillance, reconnaissance and communications relay. "It will take more leaps in technology before we are ready for close air support with these things. I'm not sure that the army would be too keen about some guy in Colorado driving a drone that's going to drop 500lb [225kg] bombs 150m [490ft] from their position. We have to have another set of technologies to do that, and we're not there yet."
The US Air Force is ready to move ahead with the Global Hawk and to consider using the UAV as an adjunct, and in some cases an alternative, to manned platforms like the Lockheed U-2. "Global Hawk is a 'light' U-2," says USAF acquisition chief Lt Gen Gregory Martin. While the U-2 is more capable, there are only a limited number available, he says. As a result, the Global Hawk could be used to augment the U-2 and provide theatre commanders with round-the-clock surveillance coverage.
This would pave the way for the joint operation of manned and unmanned combat aircraft - seen as an essential requirement for any UCAV. The manned/ unmanned force mix is one of the crucial questions being considered under the European Future Offensive Air System (FOAS) programme.
The UK-led FOAS effort is acquiring technologies to be used in a replacement for Panavia Tornado and Dassault Mirage 2000 strike aircraft. This is expected to enter service around 2018-20. Study teams are looking at manned aircraft, unmanned air vehicles and conventional air-launched cruise missiles. The FOAS is expected to emerge as a manned aircraft, but is likely to be augmented in some way by unmanned platforms.
A range of unmanned vehicles is under study, from small surveillance UAVs to large autonomous UCAVs. Also under consideration is the possibility of switching the aircraft between manned and unmanned roles depending on the mission requirement.
BAE Systems is looking to develop a multinational technology demonstrator that would fly around 2005-6 and allow evaluation of manned and unmanned technologies. The FOAS force mix could be frozen by 2006-7.
This timescale will allow the Europeans to digest the results of a USUCAV technology demonstration before deciding on the correct mix of manned and unmanned platforms for the FOAS. Under the DARPA/USAF programme, Boeing is to conduct an end-to-end demonstration in 2001 of the lethal suppression of enemy air defences (SEAD) using autonomous UCAVs. This will be pivotal to the future of UCAVs.
The major issue emerging, in the FOAS studies as well as US work on UCAVs, concerns the level of autonomy the vehicle is allowed. Autonomy is important because it determines the degree to which the human operator must be involved in controlling the vehicle. This in turn, drives the sensor sophistication that must be on the vehicle, the communications connectivity that must be guaranteed and, ultimately, the degree of integration with manned aircraft that will be acceptable.
The vehicle is not seen as an issue, except perhaps in the packaging of sensors and systems. The flight control system in the DARPA UCAV demonstrator, for example, will be a development of that used in Boeing's X-36, a subscale model of a highly agile tailless fighter flown by NASA and the USAF in 1997-8. Technology for storing the vehicles until they are needed is also coming from other programmes.
"What is less well understood is the consequence of taking the man out of the cockpit," says Bob Frampton, head of UCAV research at the UK's Defence Evaluation and Research Agency (DERA). The major challenge, he believes, will be replicating man's intelligence and decision-making abilities in the UCAV through the use of robust software tools such as automatic target recognition.
Boeing's operational concept foresees SEAD UCAVs flying at the outskirts of a strike package, "miles and minutes, not feet and seconds" away from manned aircraft, and communicating with each other via line-of-sight links and with mission control by satellite communications. The unmanned vehicles would be controlled from the ground or a stand-off aircraft to avoid overloading the strike package crews.
When a UCAV detects an air-defence radar, it will ask the other vehicles to triangulate on the signal to locate the emitter. It will then shoot a synthetic-aperture radar image of the missile site, to defeat the standard defensive tactic of shutting down the emitter. The UCAV will then move in to drop precision-guided munitions on the target, coming back for a second pass to confirm the air-defence system has been disabled - risky and reckless actions for a manned aircraft.
The SEAD mission was selected, says DARPA programme manager Dr Larry Birckelbaw, because it is "very challenging, but technically feasible" for a UCAV. "If we can do SEAD, we can do fixed-target strike easily." Defence-suppression is also a mission for which there is no good solution today, he says. While the USAF's limited fleet of Lockheed Martin F-16CJs is severely stretched providing SEAD support for peacekeeping operations, a force of defence-suppression UCAVs could provide 24h-a-day coverage for extended periods with only limited manpower, DARPA believes.
Variable autonomy
The SEAD mission also allows DARPA to test its concept of "variable autonomy", in which the degree of self-determination the vehicle is allowed is decided by factors such as the quality of sensor data, the communications connectivity and the rules of engagement. Reactive SEAD, for example, in which the UCAV has to respond to "pop-up" targets, will require a greater degree of onboard self-awareness than pre-emptive SEAD, in which the vehicles are going against known targets.
Without some degree of autonomy, communications links and operators will become overloaded. Autonomy reduces the criticality of the uplinks and downlinks, minimises the amount of information that needs to be exchanged, and is central to DARPA's concept that one operator can control four UCAVs. "If the link is lost, we don't want the vehicle to circle [like a UAV]," says Birckelbaw.
Each vehicle will be able to tap into a wide range of networks and filter the offboard sensor data for relevant information. This will be combined with onboard sensor data and only that information required to provide the mission controller with adequate situational awareness will be returned. Given sufficient sensor data and robust communications links, the UCAV will have the autonomy to locate, identify and attack a target within the prevailing rules of engagement. But the human operator will always have executive control over weapons release, Birckelbaw stresses.
DARPA's aim is to conduct an end-to-end, "sensor to shooter" SEAD mission in which the UCAV demonstrators will be required to detect, identify and locate an air-defence target, attack with live weapons and verify the damage. While the scenario will not be fully reactive, the UCAVs will be required to show they can "respond to dynamic situations with acceptable human intervention".
If successful, the demonstration may spark serious interest in UCAVs - if only because of their affordability. In production, Boeing's air vehicle - a 6,800kg (15,000lb) gross-weight aircraft with 1,400kg payload and 1,100km (600nm) combat radius - is projected to cost under $10 million, a unit price less than one-third that of the JSF, with operating and support costs over 75% less.
How quickly the world will move towards unmanned combat aircraft remains to be seen. DARPA and the USAF are paving the way for a SEAD/ strike UCAV programme that could lead to a development start in 2005 and service introduction by 2010.
DERA's Frampton is more cautious, believing UCAVs should be introduced incrementally. While the initial laser-guided bombs were controlled by human operators, the latest stand-off weapons are autonomous once launched, he says, drawing a parallel with UAVs, which are widely accepted in the surveillance role but only now beginning to be used to designate targets for laser-guided bombs. The key to their acceptability in both roles, Frampton believes, is that "the man is still in the loop".
Overcoming mistrust of unmanned aircraft is a major challenge facing UCAV proponents. The issue is particularly relevant to future coalition operations, where UCAVs could be called upon to fly alongside aircraft from allies whose pilots have little or no experience of co-operating with unmanned vehicles.
UCAVs may not entirely replace manned aircraft, but could reduce the cost of future strike platforms by taking on the riskier missions that would otherwise drive the requirements. It is likely that UAVs and UCAVs will be used to help expand the capabilities of the JSF, perhaps avoiding the need to develop expensive upgrades.
Source: Flight International
