"ILS (Instrument Landing System)." . . "Navigation." . . "Radarnavigation." . . "Sekundær Radar." . . "Elektronisches Gerät." . . "DME (Distance Measuring Equipment)." . . "Ground- Controlled Approach (GCA)." . . "Radionavigation." . . . . . . . . . . . . . . . . . . . . . . "Electronic navigation" . "Electronic navigation"@en . . . . . . "Pan American Navigation Service." . . "LORAN (Long Range Navigation)." . . "Weems System of Navigation." . . "Decca." . . "GCA." . .