• The first Unmanned Aircraft – Curtiss N9
   
• First pilotless aircraft capable of carrying explosives to its target
   
• Built by Elmer Sperry & Peter Cooper Hewitt for the US Navy during WW-I
   
• Some of the technology in this remotely controlled plane was inspired from ‘tele-automation’, a technology used to control under-water torpedoes in 1893.
   
• Other aircrafts that were subsequently built for the military to serve as an ‘aerial torpedo’ were the Liberty Eagle, TDN-1 ‘assault drone

Fig. 1 Curtiss N9

Fig. 2 Liberty Eagle

Fig. 3 TDN-1 ‘Assault Drone’

• Initial designs by the wright brothers were difficult to control.
   
• They were attributed for developing the widely used Three-axis control (Yaw/Pitch/Roll) for heavier than air piloted.
   
• Another famous scientist of that time, Dr. Samuel P. Langley dedicated his efforts in accomplishing stable manned flights. But failed to succeed despite receiving grants from the government and the military.
   
• Some areas that saw significant development were optimized structures, aerodynamics, control surfaces, lifting wing configuration

Fig. 7 Wright Flyer

Fig. 8 Langley Aerodrome No. 6 by Dr. Langley

• Several inventions contributed to the development of remotely piloted aircrafts a.k.a Unmanned aircrafts / Drones.
   
• Prior to the invention of aircrafts, discopvery of radio waves and its use for transmitting wireless signal led to invention of what was then called as “Teleautomation”.
   
• Underwater torpedos were invented in 1898 to guide explosives to enemy ships using teleautomation.
   
• Another technology that was specifically designed for torpedoes was the ‘three-axis gyro’ by Elemer Sperry.
   
• These underlying technologies allowed Sperry to perfect his design of the first reliable mechanical autopilot.

Fig. 9 Toy boat driven by Teleautomation by Nikola Tesla

Fig. 10 Three-axis mechanical gyroscope

• According to Federal Aviation Administration (FAA) - An unmanned aircraft system is an unmanned aircraft and the equipment necessary for the safe and efficient operation of that aircraft.
   
• An unmanned aircraft is a component of a UAS.
   
• All aircrafts operated without the possibility of direct human intervention from within or on the aircraft are classified as Unmanned Aircraft Vehicle (UAV). (Public Law 112-95, Section 331(8)).

Fig. 11 Fixed wing CTOL* (Left) & multi-rotor VTOL** (Right) UAS platforms

*Conventional Take-Off & Landing
** Vertical Take-Off & Landing

• To understand the foundational building block of UAS one requires  understanding of foundational information on vehicle control, stabilization and sensor design
   
• Methods of control utilized in a UAS can be broadly classified into:
  • Manual Control – This allows a skilled UAS pilot to precisely manipulate the flight path and predictable outcome of a UAV
  • Stabilized Control – This allows an operator to precisely manipulate an aircrafts position through an onboard autopilot on the UAV. The level of autonomy for the UAV is higher in this case.
  • Automated Control – This control scenario requires the least amount of operator control. Through use of software a complete mission is planned ahead of deployment and the complete control is taken over by ground control software and onboard autopilot.

Fig. 12 Different levels of UAS Autonomy

• Payload is defined as the total weight a UAV can carry. It does not include the weight of the platform itself.
   
• Type of payloads can vary depending upon platforms mission objectives. Typically, they are used for data collection such as images, videos, temperature, co-ordinates etc.
   
• Typical payloads used on UAV are:
  • Electro-optical Imaging Sensors
  • Visible RGB Sensors
  • IR (Infrared) Sensors
  • LiDAR (Light Detection & Ranging) Sensors
  • SAR (Synthetic Aperture Radar)

• Software is a key components of any UAS system irrespective level of autonomy the UAV has.
   
• Onboard autopilot, ground-based data processing and many other functions today are fulfilled by software.
   
• Typical softwares that are today commercially available are:
  • UAS fleet management software
  • Analytical photogrammetry software
  • Change detection and machine learning
  • Computer vision softwareAutonomous flight path planning software
  • Autopilot software
  • Sensor Data asset management

Fig. 18 UAV flight path planning User Interface