From scepticism to Sine Quan Non.

The military drone arena is progressing rapidly, in terms of both technological capability and the dollar value of the business. According to the US Department of Defense "UAV Roadmap 2002-2027", about now we should expect to see (for example) a diesel-powered tactical drone fielded, and one that is inaudible beyond 150 metres. Its sensor payload should be capable of identifying individuals at 7.5 km, and within two years it should be able to detect targets hidden under trees. Its datalink should be able to relay the entire comint spectrum in real time. The following report summarises recent developments in each drone category.

The first drones were targets for air defence systems, and this category remains a significant part of the aerospace business. At the lower end, lightweight piston-engined drones such as the Eads-Cac Fox TS1 and TS3 still serve in the development of short-range air defences and in the training of operators (although they no longer seem to be strongly promoted by Eads).

The latest propeller-driven target produced by Meggitt Defence Systems is the 210 kg Voodoo, powered by a 108 kW engine. However, sales continue with the 17-year old, 95 kg Banshee, equipped with a 18.6 or 37 kW engine, as evidenced by an order in 2004 by the Finnish Armed Forces. Over 5000 Banshees have been sold to 40 countries. In 2001 it was announced that Meggitt and Cobham (which includes FR Aviation) were forming a joint venture, Integrated Target Services, to provide a complete solution to aerial target needs.

The mother of all jet-powered target drones was the Ryan (later Teledyne Ryan Aeronautical, now part of Northrop Grumman Integrated Systems) Model 147, which in 1948 won a contest that resulted in the AQM/BQM-34 Firebee and led to the production of over 7000 units. For the 2003 invasion of Iraq, five Firebees (two were ground-launched and three air-launched from the sole surviving US Navy DC-130A) were equipped with GPS navigation and used to drop chaff over Baghdad. Interestingly, this project is reported to have been a by-product of a Special Operations Command investigation into the use of drones to resupply otherwise inaccessible ground units.

From the 1960s the Firebee was supplemented in US Navy service by the same company's BQM/MQM-74, named Chukar in the export market. Over 7500 have been produced. The BQM-74E version was introduced into service by the Navy in 1993 is currently being produced at a rate of ten per month and a further contract for an additional 60 have been awarded in April 2005 to the tune of $48.2 million with an option for another 60 for delivery in 2007. In December 2003 the service awarded Northrop Grumman a contract to upgrade its BQM-34 Firebee fleet with the control and guidance system of the BQM-74E Chukar. The BQM-74F is an extensively redesigned development, with longer range and an increased speed (Mach 0.92) and manoeuvrability. Its maiden flight is planned for the latter half of 2005.

The US Army's equivalent of the Firebee and the Chukar is the Raytheon/ Composite Engineering MQM-107A Streaker, a 664-kg ground-launched drone with a 4.43 kN Microturbo Tri-60 engine. Since 1977 the service has used it in the development, testing and training of crews for the Patriot, Pac-3, Improved Hawk and Stinger air defence systems. Since 1984 the US Air Force has used the MQM-107B in air-to-air firings of the Sidewinder, Sparrow and Amraam missiles. The latest version is the MQM107E, for which a contract was placed in 1994 with Tracor, which is now part of BAE Systems.

In July 2002 the Composite Engineering Skeeter was selected by the US Air Force as the basis for its next generation BQM-167A Air Force Subscale Aerial Target (Afsat), to replace the BQM-34A and MQM-107D/E. The Skeeter had flown in 2001, and the BQM-167A had its maiden flight on 8 December 2004. It will provide a maximum speed of Mach 0.91 and cruise at an altitude between 20 ft and 50,000 ft. CEi is producing 50 per year under a seven-year US Air Force contract. Boeing is reported to be studying a BGM-167 multi-role derivative, weighing around 900 kg in ground-launched form, and carrying (for example) two Hellfire missiles or an electronic attack payload.

The latest European subsonic targets include the Dornier-Eads single-engined Do-DT25 and twin-jet Do-DT35 drones, both of which completed qualification trials in 2004. The German armed forces will use both types in the training of Stinger, Roland and Patriot units. Meanwhile, Galileo Avionica is developing the jet-powered Locusta mini-target to be released from a primary target drone such as the Meteor Mirach 100. The 20 kg Locusta is proposed as a secondary target for use with air defence systems that are intended to destroy with a direct hit.

Supersonic Targets

The US Navy's standard high altitude supersonic target is the air-launched, non-reusable, rocket-propelled Raytheon/ Composite Engineering AQM-37. The original AQM-37A weighed 256 kg at launch and was capable of climbing to 80,000 ft. The AQM-37C weighs 280 kg and reaches 100,000 ft. The latest AQM-37D is capable of Mach 4.6 at 115,000 ft. The series is employed by the US Navy to simulate supersonic and ballistic missile threats, and has been exported to France, Israel, Italy and Britain. Over 5000 AQM-37s have been produced, and the AQM-37C/D is still enjoying limited production for the US Navy.

For several years the US Navy has had a requirement for a target to represent the Raduga 3M80/82 Moskit (SS-N-22 Sunburn) anti-ship missile in testing the Evolved Sea Sparrow and Standard Missiles. The Moskit has a range of 120 km and a cruise speed of Mach 2.5. In June 2000 Orbital Sciences was awarded the EMD (Engineering and Manufacturing Development) contract for the Supersonic Sea-Skimming Target (SSST) system.

The resulting GQM-163A Coyote is launched by a tandem rocket booster from a Standard Missile, and powered by a solid-fuel ducted rocket developed by Atlantic Research. It is designed to cruise for 100 km at Mach 2.5 at a height of 16 ft, and then descend to 13 ft for the 20 km terminal phase, which is flown at Mach 2.3. It is capable of 13.9-G manoeuvres. The avionics are derived from those of the Raytheon AQM-37D target. The first flight by one of six test vehicles took place on 18 May 2004. The contract included options on a further 90 operational systems through 2006.

The project that lost to the Coyote was a Boeing proposal to develop an extended-range version of the MA-31 target variant of the Zvezda-Strela (later Tactical Missiles Corp) Kh-31A air-launched anti-ship missile. This has been in service with the Russian Air Force since 1988, and is capable of Mach 2.5 at sea level.

The 600 kg MA-31 target first flew in 1996, and Boeing has delivered at least 61 to the US Navy. There are reports of a further 41 being negotiated.

The US Navy is studying target systems for testing the Raytheon SM-6 Extended Range Active Missile, emulating the threat posed by the two-stage Novator 3M54E (SS-N-27), which has already been exported. This has a range of up to 220 km, largely cruising subsonically at low level. For the 20 km terminal phase it pops up to check the target position, then detaches a rocket-powered 'dart', which attacks the ship at Mach 2.9 and a height of less than 30 ft.

Decoys

The air-launched decoy drone is an important element in reducing the effectiveness of air defence systems. The leader in this field was Brunswick Defense, which developed the Samson swing-wing glide vehicle. This was license manufactured by Israel Military Industries (IMI) in the early 1980s, and around 2000 Samsons were supplied to the US Navy by Brunswick. The improved ADM-141A Tald (Tactical Air-Launched Decoy) was then produced for the US Navy, entering service in 1987. Brunswick subsequently left the decoy business, and from 1996 the Tald became the responsibility of Israel Military Industries. The Tald has a gliding range of up to 100 km, and over 100 Talds were used in the 1991 Gulf War. The United Kingdom may acquire some surplus US Navy Talds for use on the Harrier GR7/9.

The ADM-141D Improved Tald (Itald) has a 0.79 kN Teledyne Continental J700-CA-400 turbojet, and a range of up to 280 km. It first flew in 1996, and the F/A-18 can carry up to 20 units. The chaff-dispensing version weighs 172 kg and the jammer 181 kg. IMI is upgrading US Navy stocks of around 6000 Talds to Itald standard and has recently teamed with Northrop Grumman to further develop the concept.

In 2003 the US Air Force selected Raytheon for its low-cost Miniature Air-Launched Decoy (Mald), which is currently in the SDD (System Development and Demonstration) phase. It is due to fly in 2006 and will be used initially on the F16 and B-52. The Maid is a swing-wing 115-kg air vehicle with a 0.67 kN Hamilton Sundstrand TJ-150 engine, which was made possible by Darpa's Sengap (Small Engine Advanced Program). It is to cruise at Mach 0.91 at 40,000 ft and provoke 'double-digit' air defence systems (i.e., SA-10 and above) into disclosing their positions. Unit cost is required to be less than $ 125,000. Low-rate initial production is to start in 2007 and deliveries should be completed by 2011. In 2004 the US Air Force decided to support an electronic attack version, the Mald-J, equipped with a jammer.

Micro

In 1995 Darpa began funding studies of micro air vehicles (dubbed Mavs), defined as having a wingspan of less than 15 cm and a weight of less than 100 gram. One of the main beneficiaries was AeroVironment, which in August 2000 demonstrated the 80 gram Black Widow, which was powered by a lithium battery and capable of downlinking real-time colour video. The company subsequently demonstrated its Microbat ornithopter weighing less than 15 gram, and in August 2003 achieved a duration of 107 minutes with its Wasp drone powered by a lithiumion battery. It has a span of 33 cm and a weight of 170 gram. In March 2003 AeroVironment flew its 38 cm, 170 gram Hornet, the first powered solely by a hydrogen fuel cell. Hydrogen is carried in the form of pellets, which produce the gas when in contact with water, and oxygen is collected from the airflow over the wing.

America leads in the micro field, but several other countries are also involved. At the start of 2003 Israel Aircraft Industries made its first flight with the Mosquito 1, which has a span of 34 cm and a weight of 250 gram. It has since flown up to 40 min with a video camera. The larger Mosquito 1.5 weighs close to 400 gram and has improved avionics and an endurance of about 60 min.

Darpa's Mav programme usefully encouraged development of very light equipment components, but it is still not clear if micros have any practical military role, bearing in mind their sensitivity to wind and their invisibility.

One way to achieve a useful time-on-station (e.g. 20 min) is to develop a 'perch-and-stare' design, which suggests a helicopter, a ducted fan or an entomopter (insect-like winged device), innovative work in the rotary-wing field includes the US Naval Research Laboratory Samara, which employs two single-blade contra-rotating rotors that are stopped to form a fixed wing in forward flight. For entomopters, work has been done by the Georgia Tech Research Institute on a reciprocating chemical muscle (RCM).

In discussing Raytheon's May work, company representatives at Farnborough in 2004 spoke of a back-packable flying wing design of 30 to 40 cm span (i.e., over twice the span in the Darpa definition), requiring at least a year of further development work. Eight to ten would be used simultaneously by a platoon. European interest in this area is evidenced by the .53 kg, 49-cm span Carolo, being developed by Mavionics under Rheinmetall funding.

In late 2004 the US Army announced a May competition with cash prizes, specifying a maximum dimension of 20 cm, a maximum weight of 150 grams, and a 30-minute endurance at 500 metres radius. The drone is required to be capable of a 1000 ft ceiling, autonomous operation beyond line-of-sight and to be quieter than 60 dB. It must also survive 37 km/hr gusts and use a launch device weighing less than two kg.

Mini

Whatever the future for micros, there appear to be better short-term prospects for somewhat larger (though man-portable) mini-drones that are either ground-launched, or deployed in-flight from larger drones or manned aircraft.

The air-launched category is exemplified by the NRL-developed 26.8-kg, piston-engined, folding-wing Finder (Flight-Inserted Detector Expendable for Reconnaissance), which has been released from a General Atomics Predator-A. It is envisaged that a drone such as the Finder could be used for atmospheric sampling in an area contaminated by chemical agents, either passing sensor data back to Predator for onward transmission or taking samples for later analysis by ground forces. The Finder has an endurance of two hours at 90 km radius.

The Raytheon SilentEyes is an unpowered mini-drone, designed to perform bomb damage assessment (BDA) after being ejected rearwards from an ALE-50 countermeasures dispenser. The SilentEyes has an unfolded span of 0.7 metres, and a glide ratio of nine-to-one. It descends at around 1000 ft/min, transmitting near real-time (NRT) video. Raytheon has built about 20, and it was first released from a light aircraft over Nellis AFB, Nevada, in September 1999. The US Air Force has funded trials of the release from a Predator-B, and the first took place over Edwards AFB, California, in July 2004.

In larger categories, there is a tendency to overlap with air-to-surface missiles. The Boeing Dominator project envisages an expendable drone weighing less than 50 kg, with an unfolded span of 3.7 metres, launched from a stealth aircraft. Dominators would be released in salvoes of three or four at high altitude, merging into swarms of up to 24 vehicles. Each would carry three warheads, initially in the form of Skeet anti-armour devices. Two warheads would be released in flight and the third used in a terminal dive.

Hand-Launched

The operational leader in the field of hand-launched reconnaissance drones was the battery-powered, 4.5 kg AeroVironment FQM-151 Pointer, which has a wingspan of 2.74 metres and an endurance of 60 minutes. It first flew in 1986 and has been used by the US Army and Marine Corps since 1989. The Pointer was employed in the 1991 Gulf War and has subsequently seen service with the US Navy. The AeroVironment Raven is described as a smaller cousin, weighing only 2.3 kg, although maximum endurance is 90 minutes. It first flew in 2001, and 185 have been produced for US Special Forces and the US Army for assessment in Afghanistan and Iraq. Based on this experience, the US Army now plans to competitively purchase 600 to 1100 small drones for wider use.

Israeli interest in drones of around Pointer size is demonstrated by a series of recent projects. Elbit Systems is now marketing the hand-launched Skylark IV, which weighs 4.5 kg, and has a 2.0 metre wingspan and an endurance of 90 minutes. The Skylark has been chosen by the Israeli Defense Force (IDF) to fulfil its mini-drone requirement (deliveries began on 31 March 2005). It was reportedly the only contender capable of routinely landing within five metres of the operator, a feat that is achieved by means of a deep-stall terminal descent, impacting on its ventral airbag.

Israel's Aeronautics Defense Systems Orbiter is a flying wing design with a launch weight of 6.5 kg, a span of 2.2 metres and an endurance of 90 minutes. The IAI Malat division has recently unveiled its Bird Eye 500, which has a weight of 5.0 kg, a span of 2.0 metres and a 60-minute endurance. It may be hand- or bungee-launched. IAI's I-See appears to be a rival to the Skylark IV and Orbiter, with a reported weight of 7.5 kg and a span of 2.9 metres. Aimed more at law-enforcement, the IAI Bird Eye 100 is a low-cost 1.3 kg air vehicle with a span of 85 cm and an endurance of 60 minutes.

In Germany, EMT (which also manufactures the Luna that has seen extensive use in Kosovo) has recently received an order for 115 Aladin electrically powered mini systems with deliveries to start in August 2005. Each system comprises two aircraft for one portable station.

South Korea's Remo Eye 006 has a launch weight of 6.0 kg and an endurance of over 90 minutes. It is marketed by Ucon Systems, which also owns the rights to the Korea Aerospace Research Institute Durumi or Remo Eye 015, reportedly based on the Aerosonde. The Durumi's maximum fly-off weight is 15 kg.

Bungee-launch

The Dragon Eye was designed to meet a US Navy/Marine Corps requirement named Interim Small Unit Remote Sensing System (I-Surss). It weighs 2.04 kg and has a span of only 1.15 metres. It is bungee launched, powered by two electric motors and has a maximum endurance of one hour. Recovery is by means of an autopilot-commanded deep stall, leading to a steep descent. A version with an extended span of 1.6 metres has an endurance of 90 minutes. The Dragon Eye first flew in 2000, and AeroVironment is now under contract to produce 342 systems (with 1026 air vehicles) in a five-year programme for the US Marine Corps. A possible US Navy version has been referred to as Sea All (Airborne Lead Line).

In broadly the same weight category, the Lockheed Martin Desert Hawk was developed by the US Air Force Electronic Systems Center to meet a 1999 US Central Command requirement. This aimed to improve base security in overseas deployments, patrolling not only perimeters but also runway approach and departure paths. Formally designated Force Protection Aerial Surveillance System, the Desert Hawk is battery powered and bungee launched, and can be operated from a 100-metre square clearing. The system has six air vehicles. The drone, developed from the Lockheed Martin Sentry Owl, weighs 2.26 kg and has a span of 1.22 metres.

US Army Plans

Current US Army thinking on the smallest practical mini-drone to provide reconnaissance, surveillance and target acquisition is illustrated by its Class I UAV requirement. This describes a "backpackable vtol" drone weighing less than 6.8 kg, with an endurance of 60 minutes. A complete system with two air vehicles and a control unit is to weigh 18.15 kg or less. In the Army's Future Combat System, each of 48 planned Unit of Action will have 69 Class I systems, each with two air vehicles representing a total of 6624 drones.

In January 2005 Honeywell (with AAI as airframe subcontractor) announced that it had begun testing a 33 cm ducted-fan Mav under Darpa funding and that prototype systems would be delivered to the US Army three months later for evaluation in Class I. A heavy fuel engine version will be available from 2006. The Honeywell micro has a gross weight of 5.7 kg, giving a system weight of less than 18 kg. It is inaudible (60 dB) at 100 metres.

It may be useful at this point to digress and outline the remainder of the Future Combat System family of drones. The following stage is the Class II, a company-level, vehicle-mounted vtol air vehicle that can be carried by two soldiers and that has an endurance of 120 minutes and a radius of 16 km. With 36 two-vehicle systems per Unit of Action, the US Army presumably envisages 3456 Class II drones. In December 2004 Darpa awarded contracts to develop prototype Class II ducted-fan air vehicles to Aurora Flight Sciences, BAE Systems and Honeywell International. Aurora's GoldenEye team includes Northrop Grumman and General Dynamics Robotic Systems.

Each Class II prototype is required to have a "dry weight" (a term normally referring to an engine without accessories) of less than 50.8 kg, an endurance of two hours and a range of "tens of kilometres". It is to use advanced heavy fuel propulsion and acoustic signature-reduction. Advanced sensors are to provide situational awareness and target designation. It will have non-line-of-sight networked communications and a collision-avoidance system.

The initial six-month contracts are to be followed by a nine-month phase for "up to two" contractors, and a third of 33 months for one contractor, leading to the SDD phase. As the Future Combat System lead integrator, Boeing will manage the Class II programme.

The battalion-level Class Ills will have a six-hour endurance and a 40 km radius of action. In addition to the RSTA facilities of Class I and II, they will provide communications relay, NBC detection and meteorological data. They must be able to operate without a conventional airfield. With a single four-vehicle system per Unit of Action the Army must expect to buy 192 Class III drones.

The AAI RQ-7B Shadow 200 has been selected as the baseline Class lie but Teledyne Brown Engineering is proposing a Prospector derivative of the 161 kg Rheinmetall Defence Electronics KZO (previously Brevel) with a heavy fuel engine. The KZO entered service with the German Army in late 2004. Teledyne is also reported to be interested in Rheinmetall's Taifun attack drone, to be renamed Thunder in US marketing.

The improved RQ-7B began rolling off the AAI production line in August 2004, using the same 28.3 kW engine as the RQ-7A (the US Army's current standard Tuav), but with an increased span (4.27 metres) and gross weight (170.5 kg). Maximum endurance is extended from five to more than seven hours. The RQ-7 is launched from a rail and makes a parachute-arrested landing. AAI also markets the 201 kg (RQ-2B Pioneer-size) Shadow 400, reportedly sold to the South Korean Navy, and the 265 kg Shadow 600 which has an endurance of 12 to 14 hours and has been sold to Romania and Turkey.

The brigade-level Class IV UAV will likewise operate without an airfield, but it will have much longer endurance (18 to 24 hours) and radius (75 km). With eight systems per Unit and four air vehicles per system, the US Army market potential is for 1152 Class IV drones. The Northrop Grumman RQ-SB Fire Scout has been selected to fulfil this role.

However, Boeing is promoting--at least as an interim Class IV--an Unmanned Little Bird (ULB) based on the MD Helicopters MD530E which offers commonality with the AH-6J and MH-6J used by US Special Operations Command. The ULB first flew on 8 September 2004. Boeing entered the unmanned helicopter field only months earlier in taking over Frontier Systems, which had developed the Maverick unmanned version of the Robinson R22. Boeing now provides product support for Mavericks operated by the US Special Operations Command.

In a similar category, the US Army is using the Science Applications International (Saic) Vigilante 502, an unmanned version of the two-seat Light's American SportsCopter Ultrasport 496. The Vigilante has fired Hydra 70 rockets, but it has now been equipped with nuclear/chemical agent detection sensors for service in Iraq.

Precision Recovery

Launching a drone by hand or bungee is a simple and reliable procedure, but appropriate only in the context of slow-flying lightweight vehicles that are launched horizontally. There is clearly scope for launching a somewhat heavier, faster drone using the energy stored in a chemical propellant, but one without the vehicular demands of a launch rail.

Rafael has now developed its Skylite (formerly Skylark) system in which a drone with folding aerofoil surfaces is shoulder-launched from a reusable canister, somewhat like a lightweight surface-to-air missile. In a crowded urban environment it can be launched vertically.

It is recovered by flying it into a net, the procedure used in shipboard operations with the IAI/AAI Pioneer, which was given an automatic take-off and landing capability in 1997.

The current Israeli emphasis on precision recovery is also evident in the case of the much larger IAI Malat I-View, which was designed for battlefield operation, is launched by catapult and recovered automatically by means of a guided parafoil. It has a span of 5.7 metres, a maximum take-off weight of 125 to 165 kg and an endurance of up to six hours and a range of up to 80 km.

An improved I-View has been proposed by IAI, teamed with Boeing Australia, to meet the Australian Army's JP149 requirement. This would have a 6.7-metre wing and a 250 kg gross weight, allowing payload to be increased from the standard 30 kg to 80 kg. Other JP149 contenders include the AAI Shadow, Elbit Hermes 180 and the ATE Vulture, deliveries of which began to the South African National Defence Force in February 2005.

One of the principal examples of fully automated recovery is the Ranger Autoland Precision Sensor (Raps), which continuously monitors drone position by means of a TV camera and laser ranger and transmits the data to the ground control station. The Ruag Aerospace Ranger lands on skids, eliminating the need for a runway. It has a maximum weight of 275 kg with a 45 kg payload. Wingspan is 5.71 metres. The Ranger has a 31.5 kW engine, which gives it an endurance of six hours. The maximum operating range is rated at 150 km. The responsibility for the Ranger product support has now been transferred from Oerlikon Contraves (formerly the prime contractor) over to Rheinmetall-Detec.

Small But Persistent

Drones have the potential to provide more persistent surveillance than a manned aircraft. Of the tactical designs so far discussed only the 26.8 kg NRL Finder, with a flight time of ten hours, falls into this category.

Lightweight designs providing a high endurance/weight ratio include the 25 kg Dara Aviation D-1 with an endurance of 20 hours and the 18 kg Boeing/Insitu ScanEagle; capable of over 15 hours. The ScanEagle has been assessed in the context of road convoy protection with the First Marine Expeditionary Force in Iraq, logging some 2400 flight hours in the process. In April 2005, the Navy placed a $14.5 million contract for an undisclosed number of systems that will be deployed from ships. The ScanEagle is being further developed toward a 30-hour endurance target.

In broadly the same class, the 9.0 kg Silver Fox manufactured by Advanced Ceramics Research has already performed flights of 17.5 hours and is now being developed toward reaching 24 hours. It was known earlier as the Smart Warfighter Array of Reconfigurable Modules (Swarm), the concept being to fuze sensor data from multiple drones. It has been used by the US Marine Corps in Iraq as a larger complement for Dragon Eye. The longest endurance so far achieved in the small drone category is the 40 hours of the 15 kg Aerosonde Mk III.

Recognising the shortage of drones in the small payload, long endurance class Northrop Grumman is working with Swift Engineering to develop the Killer Bee, a flying wing with a two-metre span and a 3.2 kg payload, capable of flights of 30 hours. Rather than having folding wings the Killer Bee is designed to be stackable and bungee-launched from the back of a Humvee. It is also designed to be highly stable and to survive launches at relative airspeeds up to 550 km/hr, allowing it to be tossed out of the back of a transport, or pylon-mounted (inverted for positive separation) under the wing of a turboprop trainer.

Other Tactical Developments

In addition to the AAI Shadow 200 discussed earlier, the US Army still operates the much heavier (725.7 kg) twin-engined Northrop Grumman RQ-5A Hunter, which is due to be replaced by the Extended-Range/Multi-Purpose (ER/ MP) drone. The ER/MP is a division-level asset providing surveillance (twelve hours on station at 300 km) and satcom relay, with some ground attack capability. A minimum warload of 180 kg is required, which would be ample for two Hellfire missiles. Reports suggest that at least 60 air vehicles will be required, with IOC around 2009.

In January 2005 the Army gave two teams the go-ahead to start comparative trials with a view to the SDD contract for ER/MP being awarded the following April. One team is led by Northrop Grumman Integrated Systems and includes IAI and Aurora Flight Sciences. The resulting Model 397 Hunter II is based on the IAI Heron, but would use the ground control station of the existing Hunter. The Hunter II, characterised as a Medium Altitude, Medium Endurance (Mame) drone, made its first flight on 27 December 2004. By mid-March 2005 the bird had logged 50 flight hours in 14 flights. It also demonstrated its automatic take-off and landing capabilities by day and night (see Northrop Grumman's photograph in title picture) as well as its ability to perform missions at a range of over 300 km and remain aloft for more than twelve hours. The second team, led by General Atomics and including AAI and Sparta, has already demonstrated the Warrior, which is basically a Predator with a heavy fuel engine. The US Army is evaluating the General Atomics I-Gnat-ER as a potential Hunter replacement.

One of the principal lessons learned in formulating requirements for drones is that there is no substitute for operational experience. Around 450 drones of at least twelve different types have been employed by the US services in Iraq and Afghanistan. Recent additions include the BAI Aerosystems Tern, a 65 kg vehicle with a 3.45-metre span and an endurance of five hours. The Tern has been tested by US Navy Special Forces in Afghanistan. This experience is hopefully providing some basis for future rationalisation via the Pentagon Joint UAV Planning Task Force.

Some European services also have operational experience with drones; beginning with Kosovo in 1999 when the Bombardier/Dornier CL-289 was deployed by France and Germany, the BAE Systems Phoenix by Britain and the Sagem Crecerelle by France. The Phoenix is due to be replaced from late 2006 by the Thales Defence Watchkeeper system, based on the WK180 and WK450 drones, a.k.a, the Elbit/Silver Arrow Hermes 180 and 450. Recent reports indicate that only the Hermes 450 will be employed.

The Crecerelle was further developed into the 250 kg Sperwer, which has been ordered by Canada, France, Denmark, Greece, the Netherlands and Sweden (as the Ugglan). The German Army deployed the EMT Luna in 2000 to Kosovo and later to Afghanistan. The Italian Air Force has deployed its Predators to Iraq, and British (RAF) personnel form part of the US-led Joint Predator Task Force operating these drones in Afghanistan and Iraq.

The Canadian Army purchased the Sperwer through Oerlikon Contraves Canada, signing the contract for an initial four aircraft (with an option on two more) in September 2003. The CU-161 Sperwer was deployed to Afghanistan from the following November until July 2004, when the ground equipment and the surviving four drones were returned to Canada (two were lost in landing accidents). Although the Canadians appear to have been satisfied with their night-time imagery, the standard Sperwer was not designed for the hot/high operational environments in Afghanistan. Sagem has since switched production to the 350 kg Sperwer-B (formerly Sperwer-LE), with span increased from 4.2 to 6.2 metres and endurance up from eight to twelve hours.

The 138 kg Yakovlev Pchela-lT (TV camera only) is believed to have been used operationally in Chechnya in the Kulon Stroy-P reconnaissance system. One system with twelve drones was sold to North Korea before the system entered Russian service in mid-1997. The all-weather Pchela-1K with flir and low-light TV (Stroy-PD system) has recently been certificated, and has been offered to India with the Smerch-M artillery rocket system. The Kulon Stroy-PB is a short-range system based on the lightweight (25 kg) Osa drone. Filling the niche between the 20 km normal operating radius of the Osa and the 60 to 70 km of the Pchela, the 50 kg Lutch 9M62 Tipchak has a nominal radius of 40 km, which is adequate for conventional artillery.

The Russian Air Force makes more use of high-performance jet-powered reconnaissance drones than its Western counterparts. The Tupolev Tu-143 Reis has been exported to Syria, and the 1400 kg Reis-D is now being marketed in ground-launched form, weighing 1600 kg with booster. Tupolev has reportedly completed trials of the 3000 kg Tu-300 Korshun, which is basically a reconnaissance drone but can carry an external warload of 1000 kg.

Drone development is also proceeding apace in areas of the world not traditionally associated with this type work. A good example is provided by Advanced Target Systems in Abu Dhabi that unveiled its Yabhon-M observation drone (also refer to the ground station and engine section of this survey). The company's experience so far has been limited to targets drones, but with the Yabhon-M. The focus was on sophistication, with ample use of composites and a biplane (canard) configuration for added stability. It is tail-less with winglets at the tip of a high-aspect delta wing blended into a lift-contributing fuselage. This observation drone should take to the air by the time these lines are read. The engine initially was to be a Limbach, but this has since changed.

With a 25 kg payload, the S-100 can carry out six-hour missions. Like its predecessor, the aircraft takes off and lands autonomously and has a redundant inertial and satellite navigation system. It has a maximum take-off weight of 200 kg for an empty weight of 97 and a dash speed of 220 km/hr, although cruise speed for best endurance is around 100 km/hr.

Schiebel in Austria was hitherto better known for its mine detection systems before developing its autonomous flight Camcopter with a view to providing a platform for, amongst other more classical missions, mine field and ordnance survey. Since its appearance in the late 1990s, the Camcopter has made a tremendous technological leap and was also highlighted at Idex, by the United Arab Emirates Armed Forces. The current development is known as the Camcopter S-100 and boasts a neatly streamlined carbon-fibre fuselage and structure (monocoque). Modern materials are also found in the rotor hub which is made of titanium. Power, like the designers of the aircraft, comes from Austria in the form of a single rotor 55 hp Diamond AE50R rotary engine (used in powered gliders) and so does the transmission, made by Pankl.

Schiebel has already chalked up orders for about 100 units. Production is now starting for deliveries to the Emirates and other customers.

New roles for drones are also being explored. The US Army has tested the use of the Shadow 200 to deliver emergency medical supplies to high-threat areas, using a streamlined container with lattice-type stabilising fins, a braking parachute and a crushable nose. The system is known as Quick-Meds (medical emergency delivery system) and a later version will have GPS guidance operating the fins for semi-precise delivery. The baseline version weighs only 9.0 kg, but can be scaled up to 90 kg.

Shipboard Operations

The use of drones from ships began in the 1960s with the Gyrodyne QH-50 torpedo-platform, of which some 780 were produced. The system was withdrawn due to operational problems, including a high accident rate. More recently Eads-Dornier proposed to develop the QH-50 as a radar platform for German Navy corvettes, but this Seamos programme was terminated in 2002.

Suddenly it appears that all the leading navies need shipboard drones, and the only serious contenders are the Northrop Grumman RQ-8B Fire Scout helicopter and the Bell Eagle Eye tilt-rotor vehicle. The RQ-8A first flew in May 2002. The Fire Scout was originally turned down by the US Navy, then selected by the US Army in 1428 kg RQ-SB form as its Class IV vehicle. Seven have been ordered for evaluation. However, in 2003 the US Navy selected the RQ-8B for its Littoral Combat ship (LCS), of which 30 to 50 are planned, with three drones per ship. The Fire Scout is powered by a 313 kW Rolls-Royce 25C20W.

Also in 2003, the US Coast Guard selected the 1360 kg Eagle Eye for its Deepwater programme, citing its high dash speed (370 km/hr, compared to 230 km/hr for the RQ-8B) and anticipated better deck handling. The resulting HV-911D is due to fly in early 2006. The US Marine Corps decided to buy eight Eagle Eyes for evaluation, its high speed offering the prospect of it acting as armed escort for the V-22. Bell is now teamed with Lockheed Martin, AAI and Textron Systems on developing and marketing the Eagle Eye, and with Sagem and Rheinmetall on a European version. The Eagle Eye is powered by a single P&WC PW200/55.

Males

The Medium Altitude, Long Endurance (Male) category is dominated by General Atomics Aeronautical Systems (GA-ASI) products, but other companies are striving to gain a foothold in this sector, which combines effectiveness with affordability.

The lower end is represented by the 748 kg GA-ASI I-Gnat with a 60 kW Rotax engine, a 40-hour endurance and a ceiling of 30 000 ft. A new rival (recently exhibited in India) is Israel's 800 kg Aeronautics Defense Systems Dominator with a 120 kW engine, which affords it a higher transit speed.

As sold to the US Army for evaluation in the ER/MP context, the GA-ASI Army I-Gnat has been given the 73.5 Rotax 914 of the Predator-A and a similar gross weight of 1043 kg. The PredatorA finally achieved IOC with the US Air Force on March 1, 2005. In 2004 Dencl unveiled its 1000 kg Batcleur, which may use the Rotax 914 or the Subaru EA-82T. So far the principal rival to the Predator-A has been the 1100 kg IAI Heron, which has been tested with a 134 kW Volkswagen diesel in place of the standard 73.5 kW Rotax. The Heron has been sold to the Indian Army and forms the basis for the Eads Eagle 1, which was selected for use by a joint French/Dutch unit. The Eagle I is seen as an interim system, pending the availability of a new Euromale around 2011. At the upper end of this class, the 1650 kg Elbit Hermes 1500 is the subject of a turnkey services contract with the Israeli defence ministry, reportedly involving the use of highly classified sensors.

Turboprop engines make possible much higher weights and altitudes. The IAl Heron TP flew in late 2004, but at 3500 kg is still much lighter than the 4536 kg GA-ASI Predator-B. The latter has now been developed into the 4990 kg Predator-B-ER, with additional fuel, increased span and a ventral 360-degree radar. Earlier known as the Mariner, the latter first flew in March 2004, and is now being promoted jointly with Lockheed Martin in the context of the US Navy Broad Area Maritime Surveillance (Barns) programme.

The latest study in the context of Males is the Northrop Grumman Model 395 (see our cover) based on the Rutan-designed Scaled Composites Proteus aeroplane. The latter has been used in recent tests at Nellis Air Force Base to verify the behaviour of the platform whilst carrying and releasing 500-pound inert general-purpose bombs. The idea is to turn the very stable Proteus into the Model 395 with as little airframe alterations as possible. With an external payload of two tandem underbelly weapons the aircraft would be able to fly at 40,000 feet on a 16-hour mission. With no crew on board, the cabin offers ample space for missions other than bombing, and accommodate synthetic aperture radar as well as elint and sigint gear.

Hales

The leader in the High Altitude, Long Endurance (Hale) category is the Northrop Grumman RQ-4 Global Hawk. Production is now switching from the 12,111-kg RQ-4A to the stretched 14,628-kg RQ-4B, which will form around half of the US Air Force fleet. The RQ-4B has also been selected, alongside the A321, for the Nato AGS (Alliance Ground Surveillance) programme. It is anticipated that five RQ-4Bs will be converted to Eurohawk standard by Eads to meet a German Navy requirement for sigint aircraft to replace the Atlantic in that role. There appears to be a ready market for the Global Hawk, especially in ocean surveillance, despite its high price.

In US Air Force service, the RQ-4 has been complemented in high threat areas by one or two examples of a stealthy Lockheed Martin drone. In the international market the RQ-4B may face competition from a less expensive jet-powered GA-ASI Predator, and from a projected Gulfstream RQ-37 development of the G550 business jet.

Combat Drones

In October 2003 the Darpa/US Air Force Ucav and Darpa/USN Ucav-N programmes were combined in Jucas (Joint Unmanned Combat Air System) to demonstrate the feasibility of using drones in the Sead, electronic attack, surveillance and strike roles. Responsibility for Jucas was assigned to Darpa, which within a year had placed five-year contracts with Boeing ($767 million) and Northrop Grumman ($1.0 billion) to each produce three demonstrators and conduct a two-year operational assessment.

The Boeing X-45C is a 16,555-kg drone with a single 48.9 kN General Electric F404-GE-102D engine. The Northrop Grumman X-47B is much heavier, grossing around 19,000 kg, and powered by a single 64.9 kN Pratt & Whitney F100-PW-220U. Both are due to fly in 2007, and are designed to achieve an endurance of 50 hours with multiple in-flight refuelings.

However, hopes of a truly joint programme have been hit by a Pentagon decision in December 2004 to reassign Jucas responsibility from Darpa to the US Air Force, which has taken over the funding for FY2006. In addition, the US Air Force is now pressing for a much heavier operational aircraft, weighing around 45 tonnes with a bomb load of at least 4.5 tonnes, compared to the two tonnes specified for Jucas. In essence, the US Air Force is saying it needs an aircraft that is too heavy to operate from a carrier (which is limited to around 33 tonnes).

Predictably, Britain hopes to join the Jucas programme, while the other leading European nations (France, Germany, Italy, Spain, Sweden and Switzerland) plan to co-operate on the French-led five-tonne Neuron demonstrator, which is hoped to fly in 2009. This programme has not stopped interim national projects, such as Italy's Alenia Sky-X Ucav and Sweden's 55 kg Saab Aerosystems Filur stealth demonstrator, both of which are due to fly before the end of 2005. The Sky-X is powered by a 4.23-kN Microturbo Tri 60-5/268, and the diminutive Filur by a 0.23-kN AMT Olympus-HP. Its flight data will be exploited as part of the European Neuron think-tank led by Dassault Aviation.

Sensors

A recent report by the US Government Accountability Office (GAO-05-395T, published 9 March 2005) states that the operational capability of some drones is now out of step with that of their sensors. There are lightweight radars that can see through the worst atmospheric conditions, including sandstorms, although crosswinds, icing and other unfavourable condition may ground their platforms.

The most effective sensors are naturally at the heavy end of the spectrum, and carried by the larger drones. The current fit for the RQ-4A Global Hawk is the responsibility of Raytheon and is known as the Integrated Sensor Suite (ISS). It consists of a synthetic aperture radar (Sat), a Kodak digital CCD camera and a third-generation infrared sensor. The unnamed long-range, all-weather, high-resolution Sar is similar to the Asars-2 used in the U-2. In the wide area search mode it covers a ten-kilometre-wide swath parallel to the flight path and offset by 20 to 200 km, with a resolution of one metre. In the spot mode, it covers a two-kilometre square with a resolution of 0.3 metres.

The ISS radar also has an MTI (Moving Target Indicator) facility, which was first developed for ground use, and only later for maritime operations, at the time of the Australian demonstration. Threshold speed for MTI is four knots (9.25 km/hr). The radar normally operates in an interleaved MTI/Sar mode. Inverse Sar operation can be employed to generate an image of a target, a ship for example, by virtue of its rolling and pitching motion. The antenna looks to only one side of the aircraft at a time, scanning a 90-degree arc. It can cover more than 100,000 square kilometres in a single RQ-4 sortie.

Whereas the current ISS-Sar is mechanically scanned in elevation, the MP-Rtip (Multi-Platform Radar Technology Insertion Program) being introduced with the RQ-4 Spiral Four has an active, electronically scanned array (Aesa), scanning electronically in both azimuth and elevation. It will also be capable of simultaneous operation in multiple modes, and the antenna will be rolled through 180 degrees to switch from scanning one side to the other. MP-Rtip will also provide improvements in range and resolution, and an MTI function against air targets for use in cruise missile defence. It currently appears that the RQ4B with the new radar will lose the EO and infrared sensors.

Northrop Grumman is the prime contractor for MP-Rtip, but Raytheon is providing hardware and software for the programme, which will also include radars for the E-10A. The MP-Rtip radar is modular, being 1.5 metres long and costing $ six million as applied to the RQ-4B, and 6.1 metres and $54 million for the E-10A.

The three-year Phase I risk-reduction programme for MP-Rtip began in December 2000, and all modes had been demonstrated in laboratory tests with a prototype by the end of July 2004. The six-year, $888 million Phase II (SDD) contract was awarded in April 2004, requiring the production of six radars, including three for the RQ-4B. The Global Hawk radar is due to be flown below a Northrop Grumman-owned Scaled Composites Proteus in October 2006 and it will fly on an RQ-4 in late 2007 or early 2008. Production deliveries of the MP-Rtip radar will begin in 2010, including twelve for Global Hawk.

In the Nato AGS programme, Global Hawks will initially have the MP-Rtip radar as fitted to US Air Force aircraft, but they will later be equipped with the Transatlantic Collaboration AGS Radar (Tcar), combining US and European technology. Tcar is the responsibility of the Northrop Grumman-led Tips (Transatlantic Industrial Proposed Solution) team, which includes Eads, Galileo Avionica, General Dynamics Canada, Indra and Thales, and has workshare agreements with the Czech Republic and Hungary. The Tips was selected by Nato in April 2004 to provide the radar for AGS. The first Tcar is due to be delivered in late 2007.

Several other types of Sar have already been applied to drones. For example, Northrop Gruman has its own 75 kg Tesar (Tactical Endurance Sar), which is produced for the Predator. The 82-kg Telephonics APS-143B OceanEye was developed for detecting, tracking and identifying small targets in severe maritime environments. It has been fitted to the GA-ASI Altair demonstrator that was used to represent the company's projected Mariner in over-water trials from US, Canadian and Australian bases. Maximum range is over 370 km. Operating modes for the OceanEye include inverse synthetic aperture radar, maritime MTI and air-to-air MTI.

The IAI/Elta EL/M-2055 is capable of both Sar and ground MTI. It is currently available in lightweight (36 kg) form for tactical drones such as the IAI Searcher II and Elbit/Silver Arrow Hermes 450, and in a heavier (66 kg) variant for Male drones such as the IAI Heron and Eads Eagle 1.

One of the lightweight Sars is the 52-kg General Atomics APY-8 Lynx, which was developed by the US Department of Energy's Sandia National Laboratories and is now operational on the I-Gnat. In stripmap mode it covers a swath ten kilometres wide, with a maximum range of 87 km at three metres resolution in dry air, or 54 km at 30 cm resolution. In rain, the maximum range is reduced to 33 km at 30 cm resolution. In spotlight mode with ten centimetres resolution it has a maximum range of 39 km in dry air and 28 km in rain.

The Lynx is a payload growth option for the RQ-8B, as is the even lighter (26 kg) Northrop Grumman Tuavr (Tactical UAV Radar); derived from the Tesar. The Tuavr has been tested on the Hunter but was designed primarily for the Shadow 200.

Turning to other types of sensor, the standard fit for the Predator is Raytheon's AAS-52 multi-spectral targeting system. Its 46-cm-diameter turret weighs 59 kg and is designed for an airspeed of 650 km/hr. The AAS-52 combines infrared and EO, laser ranging and target designation for laser-guided munitions and Hellfire missiles.

Other leaders in this field include Flir Systems, with the StarSafire III and Brite Star turrets, and the new Ultra8500. L-3 Wescam produces the 21-kg Model 12DS (dual sensor) for the RQ-2B, combining a thermal imager and a colour daylight TV camera with a 20x zoom lens. The MX-12 turret weighs less than 25 kg but houses four sensors; typically a colour daylight camera, an infrared camera with three-step zoom, a laser illuminator and a laser rangefinder. The new MX-15D houses six sensors, including a laser designator.

Israel's leaders are Elbit Systems' El-Op and IAI's Tamam division. El-Op's Compass IV turret is used (for example) on the Hermes 450s flown by the US Department of Homeland Security. Tamam makes the Pop (Plug-in Optronic Payload) used on the Shadow 200. and the Mosp and Moked families of sensor turrets.

inputs from Eric H. Biass