The first unmanned aircraft was the Hewitt-Sperry Automatic Airplane from 1917, its was simply guided by an autopilot as the Kettering Bug, from 1918 and the RAE Larynx (Long Range Gun with Lynx engine) from 1925. The first system as we currently know was the De Havilland DH-82B Queen Bee, from 1932, considered the "mother of all drones"  

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"Drone" is a generic word used for unmanned aircraft however the ICAO stated as official the acronysms RPA (Remotely Piloted Aircraft), i.e. the aircraft itself, and RPAS (Remotely Piloted Aircraft System), RPA + ground equipments as antennas and control station