Flying Bots: Predator

Reconnaissance plays a key role in military planning -- drones help military commanders keep track of their own troops and also spot enemy troops that might be waiting to ambush U.S. soldiers.

Photo courtesy U.S. Air Force
MQ-1 Predator UAV

Flying robots like the Predator provide constant real-time data on troop movements, enemy locations and weather. In at least one case, a flying robot did a lot more than just spot the enemy: Predators can be fitted with Hellfire missiles, and when one of these Air Force drones spotted an anti-aircraft gun in southern Iraq in March 2003, it used one of the Hellfires to take it out [ref].

Photo courtesy U.S. Air Force
The MQ-1 Predator Hunter/Killer is equipped with two Hellfire missiles and a targeting system.

To learn much more about the Predator, see How the Predator UAV Works.

Today's military robots are limited in their autonomy and their range. They are essentially tethered to human controllers. The Defense Advanced Research Projects Agency (DARPA), the U.S. government entity that funds and develops new technologies for military use, recently held a widely publicized robot race to see how far along robot AI had come. It turns out that AI is still pretty limited -- not a single robot completed the course. So even as the abilities of robots increase, it seems that for the foreseeable future, a human soldier will still be required at the control unit.

Under the Hood

The Predator UAV is a medium-altitude, long-range aircraft that operates much like any other small plane.

Photo courtesy U.S. Air Force
An airman works on the Predator's Rotax 914 engine.

A Rotax 914, four-cylinder, four-stroke, 101-horsepower engine, the same engine type commonly used on snowmobiles, turns the main drive shaft. The drive shaft rotates the Predator's two-blade, variable-pitch pusher propeller. The rear-mounted propeller provides both drive and lift. The remote pilot can alter the pitch of the blades to increase or decrease the altitude of the plane and reach speeds of up to 135 mph (120 kts). There is additional lift provided by the aircraft's 48.7-foot (14.8-meter) wingspan, allowing the Predator to reach altitudes of up to 25,000 feet (7,620 meters). The slender fuselage and inverted-V tails help the aircraft with stability, and a single rudder housed beneath the propeller steers the craft.

The fuselage of the Predator is a mixture of carbon and quartz fibers blended in a composite with Kevlar. Underneath the fuselage, the airframe is supported by a Nomex, foam and wood laminate that is pressed together in layers. Between each layer of laminate, a sturdy fabric is sandwiched in to provide insulation to internal components. The rib work of the structure is built from a carbon/glass fiber tape and aluminum. The sensor housing and wheels are also aluminum.

The edges of the wings are titanium and are dotted with microscopic weeping holes that allow an ethylene glycol solution to seep out of internal reservoirs and breakdown ice that forms on the wings during flight.

The Predator UAV uses run-of-the-mill mechanical systems. A 3-kilowatt starter/alternator supplies the craft's electronics with power; this is supplemented with auxiliary battery power. Forward and aft fuel tanks house rubberized fuel bladders that are easy to fill through gas caps located at the top of the fuselage. An operator starts the engine by attaching the umbilical cord of a Starter/Ground Power Cart to the aircraft's starter-control connector, located in the ground panel on the outside of the plane. An operator stops the engine by hitting a kill switch just behind one of the wings on the side of the plane.

For the Engine

The Predator's two fuel tanks combined carry up to 600 pounds of 95-octane to 100-octane reciprocating aircraft engine fuel.

The Predator uses 7.6 liters of standard motor oil for lubrication.

In addition to venting, conventional automotive antifreeze is used to cool the engine.

Two 8-pound, 14-amp-hour Ni-Cad battery packs are housed in the fuselage for backup power in case the engine or alternator fails.

A Look Inside the Predator

As an aircraft, the Predator UAV is little more than a super-fancy remote-controlled plane. But this simple design lends itself well to the Predator's intended functions. Below you can see the placement of components:

Image courtesy AFCESA

Synthetic Aperture Radar (SAR) Antenna
Inertial Navigation System/GPS
Ku-Band Satellite Communications Antenna
Video Cassette Recorder
GPS Antennas (Left and Right)
APX-100 Identification Friend or Foe Transponder
Ku-Band Satellite Communications Sensor Processor Modem Assembly
C-Band Upper Omnidirectional Antenna Bracket
Forward Fuel Cell Assembly
Aft Fuel Cell Assembly
Accessory Bay
Engine Cooling Fan
Oil Cooler/Radiator
914F Engine
Tail Servo (Left and Right)
Battery Assembly #2
Power Supply
Battery Assembly #1
Aft Equipment Bay Tray
Secondary Control Module
Synthetic Aperture Radar Processor/AGM-114 Electronics Assembly
Primary Control Module
Front Bay Avionics Tray
ARC-210 Receiver/Transmitter
Flight Sensor Unit
Video Encoder
De-ice Controller
Electro-Optical/Infrared Sensor/AN/AAS-52(V)1 Electronics Assembly
Front Bay Payload Tray
Ice Detector
Synthetic Aperture Radar (SAR) Receiver/Transmitter
Nose Camera Assembly

Spy in the Sky

The RQ-1 is the reconnaissance version of the Predator UAV. The letter 'R' is the U.S. Defense Department signature for an aircraft designated for reconnaissance. 'Q' is a designation for unmanned or automated weapons or vehicles.

The simple and lightweight design of the Predator's fuselage allows it to carry a payload of up to 450 pounds (204 kg) in addition to the weight of its 100-gallon (378.5-liter) fuel tank. This large fuel tank and the nice gas mileage afforded by the Predator's light weight are great assets for a reconnaissance aircraft. The Predator can stay in the air monitoring enemy positions for up to 24 hours fully loaded.

Photo courtesy U.S. Air Force
The RQ-1 uses a set of nose cameras to "see" on missions.

The RQ-1 uses some of the most sophisticated monitoring equipment available today:

Photo courtesy U.S. Air Force
An airman cleans the lens pilots use to fly the MQ-1 Predator.

Full-color nose camera that the pilot uses primarily to navigate the craft
Variable aperture camera (similar to a traditional TV camera) that functions as the Predator's main set of "eyes"
Variable aperture infrared camera for low-light and night viewing
Synthetic aperture radar (SAR) for seeing through haze, clouds or smoke

Every camera in the plane's forward bank can produce full-motion video and still-frame radar images.

The RQ-1 can give real-time imagery of the enemy position to a command post well before the first troops or vehicles arrive. This kind of information allows field commanders to make quick and informed decisions about troop deployment, movements and enemy capabilities. Of course, the greatest advantage of using the Predator is that it has all the advantages of a traditional reconnaissance sortie without ever exposing the pilot to a hostile environment.

In Battle

The only thing better than having a robotic airplane assist forces in making decisions about how to fight a battle is to have a robotic airplane actually fight the battle for you. That is where the Predator UAV MQ-1 Hunter/Killer comes into play. Replacing the camera array with the Multispectral Targeting System (MTS) and loading the Predator with two Hellfire missiles transforms this battlefield spotter into a deadly automated combatant. The 'M' in MQ-1 is the Defense Department designation for multipurpose aircraft; by adding the MTS and Hellfire missiles to the Predator, it truly becomes a multifunctional battle aircraft.

Photo courtesy U.S. Air Force
The MQ-1 Hunter/Killer awaits orders.

The MTS includes the AGM-114 Hellfire missile targeting system, electro-optical infrared system, laser designator, and laser illuminator. All of these components give the Predator and its operators multiple ways to acquire a target in any combat environment. The Predator fires a laser or infrared beam from the MTS ball located near the nose of the plane. This laser can be used in two ways:

The beam lands on the target and pulses to attract the laser seekers at the end of each Hellfire missile.
The on-board computer uses the beam to makes calculations about trajectory and distance.

Sensors bundled in the MTS also calculate wind speed, direction, and other battlefield variables to gather all of this data into a firing solution. This process is known as "painting the target." Once a target is painted, the MQ-1 can unleash its own missiles to destroy the target or send the firing solution to other aircraft or ground forces so they can destroy it.

Photo courtesy U.S. Air Force
A Predator MQ-1 comes in for a landing after firing one of its Hellfire Missiles

Predator Utility

The battlefield effectiveness of the MQ-1 has been tested in several recent conflicts, including those in Afghanistan, Bosnia, Kosovo, Iraq, and Yemen.

The Predators have flown into combat alongside manned warplanes, have provided air support to ground forces, and have attacked areas where enemy air defenses have not been fully suppressed. They could also be used in areas that are traditionally too dangerous to send in manned aircraft, such as open ocean environments or biologically or chemically contaminated environments. And even loaded with the MTS, the Predator MQ-1 is capable of effective battlefield reconnaissance.

Photo courtesy U.S. Air Force

Perhaps the most infamous use for the combat version of the Predator is in stealthy aerial assassinations. On February 7, 2002, the CIA used an armed Predator to attack and destroy a convoy of SUVs transporting suspected al Qaeda terrorists. On November 3, 2002, the CIA used a Predator to launch a Hellfire missile into a car in Yemen, killing Qaed Senyan al-Harthi, the al-Qaeda leader thought to be responsible for the bombing of the USS Cole. Though this application of the Predator is rare, none of these missions would have been possible using conventional methods without risking the lives of U.S.

Behind The Wheel

According to the U.S. Defense Department, "The Predator is a system, not just an aircraft." This is because of the unique way the Predators are deployed and controlled.

A fully operational system consists of four Predators (with sensors), a ground control station (GCS) that houses the pilots and sensor operators, and a Predator primary satellite-link communication suite.

On the ground, there are the techs and support personnel normally associated with aircraft. The whole show takes about 82 personnel to run successfully. This fully integrated team is capable of using the four aircraft for 24-hour surveillance within a 400-nautical-mile radius of the ground control station.

The Predator can run autonomously, executing simple missions such as reconnaissance on a program, or it can run under the control of a crew. The crew of a single Predator UAV consists of one pilot and two sensor operators. The pilot drives the aircraft using a standard flight stick and associated controls that transmit commands over a C-Band line-of-sight data link. When operations are beyond the range of the C-Band, a Ku-Band satellite link is used to relay commands and responses between a satellite and the aircraft. Onboard, the aircraft receives orders via an L-3 Com satellite data link system. The pilots and crews use the images and radar received from the aircraft to make decisions about controlling the plane.

Predator aviators have described piloting the aircraft as flying an airplane while looking through a straw. This is quite a change from driving a conventional aircraft from the cockpit. Predator pilots have to rely on the onboard cameras to see what's going on around the plane. For the crew, it's a trade-off between the disadvantage of limited visibility and the definite plus of personal safety.

On The Road

One of the greatest things about the Predator system is that the whole thing is fully transportable. The aircraft breaks down into six pieces that are transported in a huge crate called the coffin. The coffin contains:

The fuselage
Wings
Tail surfaces
Landing gear
The propulsion system
Two payload/avionics bays

The largest component in the system is the GCS. The GCS has wheels that allow it to be rolled onto transports. The Predator primary satellite link consists of a 20-foot (6.1-meter) satellite dish and support equipment. This can also be broken down. The coffin, GCS, and satellite link all fit in the cargo hold of a C-130 Hercules or C-141 Starlifter. This is how they are moved around from mission to mission. Once on site, a single Predator can be reassembled by a crew of four in under eight hours.

Photo courtesy U.S. Air Force
A fully assembled Predator ready for flight

The flexibility and ease of transport designed into the system allows personnel to rapidly deploy an entire four-aircraft Predator system anywhere in the world. Currently, the 11th and 15th Reconnaissance Squadrons, Indian Springs Air Force Auxiliary Field, oversee all Predator operations.

The Future

New variations on the Predator are being created to expand its capabilities. By modifying the airframe and expanding the wing span to 86 feet (26 meters), they will be able to fly the new Predator variations at up to 50,000 feet (15,240 meters). The new model is called the MQ-9 Altair. It will be used during peace time for scientific and atmospheric research. The U.S. Navy and Coast Guard will have their own versions of the new Predator that are used for surveillance and reconnaissance.

The Predator is not the only UAV deployed by the U.S. military. The RQ-2 Pioneer, RQ-3 Dark Star, RQ-4 Global Hawk, RQ-5 Hunter, RQ-6 Outri der, and RQ-7 Shadow have all been used in a reconnaissance capacity since the early 1990s. The Predator and its variations are, however, the only UAVs with a combat role and the UAVs most capable of flying into battle alongside manned warships.

Photo courtesy U.S. Air Force

With the proliferation of remotely-operated and automated combat units, the trend in military technology seems to be moving toward missions carried out by automated warriors, with the flesh-and-blood controllers battling safely from behind computer terminals. For more information on the Predator and other remotely-controlled aircraft, check out the links on the next page.

Wednesday, August 5, 2009

Predator UAV