Sir Robert Watson-Watt (1892-1973), British physicist and pioneer of radar. Watson-Watt worked at the Meteorological Office and later became head of the National Physical Laboratory at Teddington. During World War I he worked on radio location of thunder-storms. In 1935 he proposed the development of radio detection and ranging (RADAR) system for aircraft location. Bursts of radio waves transmitted from the radio station were reflected by aircraft giving the distance and position displayed on an oscilloscope. The system was important in the defence of Britain in World War II, and has become an invaluable tool in detecting objects beyond visual range.