The application of radio waves triggered a wholly new approach to navigation at sea. ‘The electronic age’ begins with Radio Direction Finding introduced at the start of the 20th century with radio beacons established to transmit signals, so that a direction-finding antenna could determine a bearing to a known transmitter on shore. Examples of this technology were the short-distance Decca Navigator System and Loran (long-range aids to navigation). Radio detecting and ranging (radar), using shortwave radio signals, is also discussed along with the development of the inertial navigation system. Global satellite navigation systems have transformed the art of navigation, yet there is no immediate prospect of old techniques being abandoned.
