The Decca Navigator was a radio navigation system developed in the 1940s, primarily used for maritime navigation. It utilized a network of shore-based transmitters to provide accurate positioning information to ships at sea. By measuring the time it took for radio signals to travel from the transmitters to the receiver on the vessel, navigators could determine their location with greater precision than traditional methods. This system was particularly popular among commercial shipping and fishing industries until the advent of more advanced technologies like GPS. Despite its decline in use, the Decca Navigator played a significant role in improving maritime safety and navigation during its time.