Saturday, 13 August 2016

ASCI 530: Unmanned Aerospace System (Discussion: 1.6 - Research: History of UAS)

Introduction
In the thirteen century, Chinese invented gun powder and used them to launch rockets in the battlefield. The rockets had little or no control and followed a ballistic trajectory. At that time, it was a powerful weapon to eliminate enemies. On the other hand, the modern definition of aircraft refers to an object that must generate aerodynamic lift and can be controlled. In turn, the kite would probably fit the definition of the first UAV. In 1883, Douglas Archibald attached an anemometer to the line of a kite and measured wind velocity at altitudes up to 1,200 ft. He also attached cameras to kites in 1887, providing one of the world’s first reconnaissance UAVs (Fahlstrom & Gleason, 2012).
AQM-34 Ryan Firebee (Pre- 1970s)
During Vietnam War, one of the most popular military UAVs was AQM-34 Ryan ‘Firebee’, they were deployed mainly for reconnaissance missions. The air vehicles were usually air launched from C-130’s and recovered by parachute (Fahlstrom & Gleason, 2012). Early versions were programmed to fly a pre-programmed route and take still-photographs. More than 1,000 AQM-34 Ryan ‘Firebee’ flew in excess of 34,000 operational surveillance missions over Southeast Asia during the war, deploying from Japan, South Vietnam, and Thailand. They flew daytime and nighttime surveillance, leaflet-dropping missions, and surface-to-air missile radar detection over North Vietnam and southeast China. (Lloyd, 2016). The ‘Firebee’ was radio controlled and flown within the range of line-of-sight.
Following are the general characteristics and performance specifications of Firebee (Global Security, 2016):
·         Crew: None
·         Length: 22 ft 10 in (7.00 m)
·         Wingspan: 12 ft 10 in (3.91 m)
·         Empty weight: 1,500 lb (680 kg)
·         Gross weight: 2,500 lb (1,135 kg)
·         Power plant: 1 × Continental J69-T-29A, 1,700 lbf  (7.6 kN) each
·         Maximum speed: 710 mph (1,140 km/h)
·         Endurance: 1 hours 15 min
·         Service ceiling: 60,000 ft (18,300 m)
Predator (Current)
With the advancement of technologies and satellite navigation, UAVs can fly long distances from their bases, loiter for extended periods to perform surveillance functions. They are designed to carry weapons in significant quantities. Currently, the ‘Predator’ is the most popular military UAV manufactured by General Atomic. Currently, the unmanned aircraft are deployed by the U.S. Air Force, U.S. Department of Homeland Security, NASA, the Royal Air Force, the Italian Air Force, the French Air Force, and the Spanish Air Force for intelligence, surveillance and reconnaissance missions (General Atomic Aeronautical, 2016).
The size of MQ-1 Predator A is larger than a light single-engine private aircraft with following specifications:
·         Wingspan of 17 m (55 ft)
·         Length of 8 m (26 ft).
·         Ceiling: 7,620 m or 24,521 ft
·         Cruising speed: 220 km/h (119 knots)
·         Internal payload of 200 kg (441 lb)
·         External payload (hung under the wings) of 136 kg (300 lb)

The predator provides real-time surveillance using high-resolution video, infrared imaging, and synthetic aperture radar. Moreover, it achieves longer endurance about 40 hours and remains on station for 24 hours, 925 km (575 mi) from the operating base. The GPS and inertial systems provide navigation, and the control is via satellite (Fahlstrom & Gleason, 2012).
Conclusion
The development of UAV in the future is encouraging in view of the advancement of communication technology utilizing satellite. The system enable two-way communications and control beyond line-of-sight. The Global Positioning System (GPS) technology provides accurate and precise location and position of unmanned vehicle systems. The target or destination can be programmed accurately in order to fly from one waypoint to another. More powerful and affordable micro-controller enable complex tasks and maneuvering pattern possible. Current micro electro-mechanical systems (MEMS) found in gyroscopes, inertial measurement units (IMUs), and accelerometers have dramatically revolutionize the industry.  Also, the development of lithium polymer battery, which provides larger capacity and longer endurance widen the future frontier of UAVs.



Reference
Fahlstrom, P. G., & Gleason, T. J. (2012). Introduction to UAV Systems. West Sussex: John Wiley & Sons Ltd.
General Atomic Aeronautical. (2016, July 02). Predator B RPA. Retrieved from http://www.ga-asi.com/predator-b
Global Security. (2016, Aug 13). AQM-34N Firebee. Retrieved from http://www.globalsecurity.org/intell/systems/aqm-34n-specs.htm
 Lloyd, P. A. (2016, 8 12). The Use of Drones During The Vietnam War. Retrieved from http://peteralanlloyd.com/general-news/the-use-of-drones-during-the-vietnam-war/


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