A2AD – anti-access/area-denial
ABSAA – Airborne Sense and Avoid
AESA – Active Electronically Scanned Array Radar
ASIC – Aviation Security Identification Card
AUDS – Anti-UAV Defence System
AUV – Autonomous Underwater Vehicle
BVLOS – Beyond Visual Line Of Sight
C-UAV (or C-UAS) – Counter UAV (or Counter UAS)
DAA – Detect And Avoid (same idea as Sense and Avoid)
DARPA – Defense Advance Research Project Agency
DEM – Digital Elevation Modelling
Drone – Popularized to mean any unmanned aerial vehicle
FPV – First Person View [or Video], also called Remote Video Piloting (RVP)
GIS – Geographic Information System
GBSAA – Ground Based Sense and Avoid
GNSS – Global Navigation Satellite System
HACMS – High Assurance Cyber Military Systems (a DARPA secure software drone program)
HALE – High Altitude Long Endurance (See MALE)
HAPS – High Altitude Pseudo-Satellite, such as the Astrium Zephyr.
ISR – Intelligence, Surveillance, Reconnaissance
LAR – Lethal Autonomous Robot
MALE – Medium Altitude Long Endurance (See HALE)
NAS – National Airspace System
NDVI – Normalized Difference Vegetation Index
NPRM – Notice of Proposed Rulemaking
NUAV – Nano Unmanned Air Vehicles
RPA – Remotely Piloted Aircraft
RPAS – Remotely Piloted Aircraft System
RPV – Remotely Piloted Vehicle
RVP – Remote Video Piloting, also called First Person View (FPV)
SAA – Sense And Avoid
SAR – Synthetic Aperture Radar. Also Search and Rescue
SFOC – Special Flight Operations Certificate (Canadian)
sUAS – small Unmanned Aerial System
TCAS – Traffic Collision Avoidance System
UAS – Unmanned Aircraft System, which includes the aircraft plus the associated ground personnel and systems. Also, the gender-neutral Unoccupied Aircraft System.
UAV – Unmanned Aerial Vehicle (a powered aircraft without an onboard pilot)
UCAS – Unmanned Combat Aircraft System
UCLASS – Unmanned Carrier-Launched Surveillance & Strike aircraft proposed for the US Navy
UGV – Unmanned Ground Vehicle
UOC – Unmanned Operator Certificate
USV – Unmanned Surface Vehicle
UUV – Underwater Unmanned Vehicle
UxS – Used by NOAA for unmanned systems
VLOS – Visual Line-of-Sight