How the Predator UAV Works

**A.Rafay** · 07-29-2012 10:46 AM

Predator Unmanned Aerial Vehicle.

These high-tech aircraft, controlled by a crew miles away from the dangers of combat, are capable of reconnaissance, combat and support roles in the hairiest of battles. In a worst-case scenario, if a Predator is lost in battle, military personal can simply "crack another one out of the box" and have it up in the air shortly -- and that's without the trauma of casualties or prisoners normally associated with an aircraft going down.

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

+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:
1.Synthetic Aperture Radar (SAR) Antenna
2.Inertial Navigation System/GPS
3.Ku-Band Satellite Communications Antenna
4.Video Cassette Recorder
5.GPS Antennas (Left and Right)
6.APX-100 Identification Friend or Foe Transponder
7.Ku-Band Satellite Communications Sensor Processor Modem Assembly
8.C-Band Upper Omnidirectional Antenna Bracket
9.Forward Fuel Cell Assembly
10.Aft Fuel Cell Assembly
11.Accessory Bay
12.Engine Cooling Fan
13.Oil Cooler/Radiator
14.914F Engine
15.Tail Servo (Left and Right)
16.Battery Assembly #2
17.Power Supply
18.Battery Assembly #1
19.Aft Equipment Bay Tray
20.Secondary Control Module
21.Synthetic Aperture Radar Processor/AGM-114 Electronics Assembly
22.Primary Control Module
23.Front Bay Avionics Tray
24.ARC-210 Receiver/Transmitter
25.Flight Sensor Unit
26.Video Encoder
27.De-ice Controller
28.Electro-Optical/Infrared Sensor/AN/AAS-52(V)1 Electronics Assembly
29.Front Bay Payload Tray
30.Ice Detector
31.Synthetic Aperture Radar (SAR) Receiver/Transmitter
32.Nose Camera Assembly

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.

Predator RQ1 uses some of the most sophisticated monitoring equipment available today:
+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.
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.

Behind The Wheel

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.

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.

I wish Pakistan Could also make these kind of drones operated via Satellite.

**A.Rafay** · 07-29-2012 07:47 PM

**gambit** · 07-29-2012 08:31 PM

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.

For the above four basic communication architectures, the US have experience in all of them.

Direct -- The simplest and low latency architecture. Unfortunately, this architecture cannot be for beyond line-of-sight (LoS) missions, which include obstructions from natural to manmade. The higher the UAV traffic in terms of quantity of aircrafts and the data transfer from them, the greater the hardware capability in order to maintain distinct communication lines for each UAV in this traffic. If there is to be aircraft-to-aircraft communication, it would be a pseudo link because the central command module must monitor and route all such signals that are intended for aircraft-to-aircraft communication. There are no real direct aircraft-to-aircraft links. This make a multi-UAVs cooperative environment either impossible or at best highly inefficient.

Satellite -- The best geographical coverage but high latency architecture due to distance between UAV and satellite. This architecture demands the best possible UAV technology in terms of individual autonomy because of the high latency. Real time two-way command-control protocols must have dedicated antennas and communication pathways discrete from data storage that are for later transfer. Because this architecture demands the highest possible UAV technology in terms of individual autonomy, said demand naturally leans towards true real time aircraft-to-aircraft communication and cooperative operations.

Cellular -- The most mobile and lowest latency architecture. This architecture is line-of-sight (LoS) only, just like Direct. The difference is that the command-control protocol can be and usually is parceled out to physically distinct and mobile command-control stations. This architecture offers the lowest latency because of this mobility when a UAV detects the nearest command-control station and connect, however, in the event these discrete command-control stations may not be interconnected themselves, there must be operational provisions built into the UAV in the event of unexpected mission parameters changes. Engaging in evasive maneuvers is one such unplanned mission parameter. The greater the quantity and geographical dispersal of command-control stations, aka topology, the higher the integrity of network connections and reliability of data transfer as long as LoS is maintained at all times. True real time aircraft-to-aircraft communication and cooperative operations are possible with supporting technological sophistication in terms that each UAV being intelligent enough to prioritize commands from ground controllers versus cooperative operations requests from other UAVs, in other words, whose signals takes priority, ground or other UAVs. There is a difference between a command versus a request for cooperation. The latter is optional in response but the UAV must be intelligent (programmed scenario sophistication) enough to distinguish out that difference.

Mesh -- The most complex architecture and the most demanding in term of overall technology. The greater the mission scope, as in civilian versus military, the greater that demand. Aircraft-to-aircraft communication technology and capable is mandatory. It is not a hybrid of any of the other three architectures but a totality of all of them.

https://www.hsaj.org/?special:fullarticle=0.3.3

... meshed airborne communication is feasible and that meshed networking architectures will provide the needed communication for a large number of highly mobile and small aircrafts.

In a mesh network, each UAV should be a working data node as well as being highly autonomous as possible. Each UAV must be capable of recognizing when there is a request for cooperative operations versus when there is a request for simply being a data relay. Because each UAV is a mobile data node as well as an independent and autonomous entity, LoS is crucial between these mobile stations in order for the entire network to function at maximum efficiency.

The UAV mesh architecture is adopted from the computer networking industry.

Mobile ad hoc network - Wikipedia, the free encyclopedia

A mobile ad-hoc network (MANET) is a self-configuring infrastructureless network of mobile devices connected by wireless. ad hoc is Latin and means "for this purpose".

Each device in a MANET is free to move independently in any direction, and will therefore change its links to other devices frequently. Each must forward traffic unrelated to its own use, and therefore be a router. The primary challenge in building a MANET is equipping each device to continuously maintain the information required to properly route traffic. Such networks may operate by themselves or may be connected to the larger Internet.

For military operations over hostile territory where ground control stations are either denied or limited, the meshed UAVs will be able to provide real time observation over said territory without putting human operators in danger. Ironically, command latency can be a high risk despite a high number of meshed UAVs in the area because the command signals may have to be passed through multiple relay nodes and any of them may be under evasive maneuvers or the entire network is under adversarial EM interference, aka 'jamming'. This mean the meshed UAVs network owner must be tolerant of delays in data transfer, especially if the data transfer mode involve a 'ferry' instead of a 'retransmit' and the modes selection authority is given to the UAVs themselves.

In data trafficking, a 'retransmit' is when a data station continuously transfer any input while a 'ferry' is when the entire packet of information is physically stored while the mobile data node searches for the nearest and strongest relay station to offload. This can affect 'time sensitive' operations. More complex data transfer laws can be written to allow a data ferry to parcel out its store as opportunities presented but this will of course increase the technological demand on transmitter components.

My personal experience have been with Cellular in weapons testing and development a looooong time ago.