European GNSS, operated under an EU program. For UAS, Galileo—like other GNSS systems—can provide positioning and timing data for navigation and tracking, among other things.

Collective term for satellite-based navigation systems (e.g., GPS, Galileo) that provide position/time data. GNSS is the basis for many UAS navigation and monitoring functions.

Principle of collision avoidance through active visual search for conflicting traffic, provided that visual flight conditions exist. For UAS, this is supplemented by remote pilot/observer and/or technical means, depending on the operation.

Ability/systems to detect other traffic and obstacles and avoid conflicts – as a technical supplement/alternative to "see and avoid," particularly relevant for BVLOS.

Collective term for technologies that make an aircraft electronically "visible" (e.g., ADS-B, FLARM, Remote ID). SORA cites increased detectability as a recommended risk mitigation measure.

Surveillance technology in which aircraft automatically transmit their identity, position, and other data (e.g., via GNSS). ADS-B is used for airspace surveillance and situational awareness (ADS-B Out/In), among other things.

Altitude relative to mean sea level. Often used in aviation for airspace and obstacle reference and can differ significantly from AGL.

Altitude measurement relative to the local terrain surface. AGL is practical for UAS because many operating limits (e.g., 120 m) refer to altitude above ground level.

Official notification regarding the establishment, status, or change of aviation-related facilities, services, procedures, or hazards, the timely knowledge of which is essential for flight operations.

Government publication containing aeronautical information of permanent importance for air navigation (e.g., structures, procedures, aerodromes).