What is a UAV?
UAV stands for “Uninhabited Aerial Vehicle”. The term refers to any aircraft that can fly without an on-board crew. This could be as simple as a radio control link to the ground with a pilot controlling the aircraft, or as complex as an on-board autopilot with programmed mission parameters.
There is no “typical” UAV aircraft: UAVs can be large or small, fixed wing or rotor craft, and can be used for diverse mission parameters. The image below emphasizes the diversity of such aircraft.
The term UAS, or “Unmanned Aircraft System” refers to the UAV aircraft, and the associated systems required to fulfill the intended mission. These systems include a payload (for example, monitoring equipment), a ground control station, a radio interlink, and other related systems such as launch platforms.
What advantages do UAVs have over standard piloted aircraft?
Consider a typical forest survey performed using a fixed wing aircraft. To perform the survey, the aircraft must fly in a fixed grid pattern similar to below:
These missions require the pilot to maintain a precise heading, altitude, and speed, and to turn on the grid pattern at a precise time and location. This is very mentally and physically draining for a pilot, especially when considering this grid pattern must often be maintained for hours at a time. Data collecting flights, then, must be kept relatively short to prevent risk to the pilot, resulting in either a compromise in data resolution (i.e. wider grids), or a compromise in time to complete the mission (i.e. perform the mission over multiple days). Obviously this is not optimal.
Compare this to an autonomous UAS performing the same mission. Using an autopilot board, the UAS can be pre-programmed to follow specific waypoints on a grid (using on-board GPS tracking), maintain a specific altitude above ground (using a laser rangefinder or similar), and maintain a specific airspeed (using measured airspeed data). It can even be pre-programmed to take off and land autonomously! The entire mission is pre-programmed on the aircraft, and can be completed, under optimal conditions, without any input from the pilot.
The advantages of a UAS over a classically piloted aircraft, then, are clear. Dependence on pilot fatigue is completely eliminated: the pilot becomes an on-ground overseer, who only needs to intervene under abnormal circumstances or emergency situations. The mission can be completed in a shorter amount of time, with a higher data resolution, compared to a manned aircraft since the mission can continue as long as the aircraft can. Finally, risk to the pilot is completely eliminated since he or she is no longer on-board the aircraft.