1. (surveillance) Ability of a system to distinguish between two or more targets in close proximity to each other both in range and bearing (azimuth).
2. (AIS) A number of units or digits to which a measured or calculated value is expressed and used.
1. ICAO (2004) doc. 9684 Manual of the Secondary Surveillance Radar (SSR) Systems
2. ICAO (2010) Official definition, ANNEX 15 Aeronautical Information Services