Global Positioning System Guidance systems (Flight) 3 Navigation (Aeronautics) 3 Artificial satellites in navigation 2 Geodetic satellites 2 Remote sensing 2 Artificial satellites in surveying 1 Base measuring 1 Boats and boating 1 Congresses 1 Data processing 1 Electronic equipment 1 Electronics in navigation 1 Geodesy 1 Geographic information systems 1 Geographical positions 1 Hydrographic surveying 1 Instruments 1 Maritime collection 1 Meteorological optics 1 Photogrammetry 1 Refraction 1 Route surveying 1 Satellite geodesy 1 Security measures 1 Signal processing 1 Technique 1 Transit (Navigation satellite) 1 Transportation engineering 1