Air Traffic Control. The ground-based personnel and equipment concerned with controlling and monitoring air traffic within a particular area.

Aerial Photography - a blanket term for all photography taken from a UAV in flight.

Air Navigation Order - an Act of Parliament detailing the law as it relates to Civil Aviation in the UK

Altitude Above Ground Level

Aerodrome

Autonomous Collision Avoidance System - this allows the drone to detect obstacles and reroute or hold position in order to avoid them.