attack submerged submarines, where before only surfaced submarines could be detected. However, according to the latest reports on the history U.S. Navy periscope detection the first minimal possibilities for periscope detection appeared only during 50's and 60's and the problem was not completely solved even on the turn of the millennium. In addition, radar could detect the submarine at a much greater range than visual observation, not only in daylight but at night, when submarines had previously been able to surface and recharge their batteries safely. Centimetric contour mapping radars such as H2S, and the even higher-frequency American-created H2X, allowed new tactics in the strategic bombing campaign. Centimetric gun-laying radars were much more accurate than older technology; radar improved Allied naval gunnery and, together with the proximity fuze, made anti-aircraft guns much more effective. The two new systems used by anti-aircraft batteries are credited with destroying many V-1 flying bombs in the late summer of 1944. British Army During Air Ministry RDF development in Bawdsey, an Army detachment was attached to initiate its own projects. These programmes were for a Gun Laying (GL) system to assist aiming antiaircraft guns and searchlights and a Coastal Defense (CD) system for directing coastal artillery. The Army detachment included W. A. S. Butement and P. E. Pollard who, in 1930, demonstrated a radio-based detection apparatus that was not further pursued by the Army. When war started and Air Ministry activities were relocated to Dundee, the Army detachment became part of a new developmental centre at Christchurch in Dorset. John D. Cockcroft, a physicist from Cambridge University, who was awarded a Nobel Prize after the war for work in nuclear physics, became Director. With its greater remit, the facility became the Air Defence Research and Development Establishment (ADRDE) in mid-1941. A year later, the ADRDE relocated to Great Malvern, in Worcestershire. In 1944, this was redesignated the Radar Research and Development Establishment (RRDE). Transportable Radio Unit While at Bawdsey, the Army detachment developed a Gun Laying ("GL") system termed Transportable Radio Unit (TRU). Pollard was project leader. Operating at 60 MHz (6-m) with 50-kW power, the TRU had two vans for the electronic equipment and a generator van; it used a 105-ft portable tower to support a transmitting antenna and two receiving antennas. A prototype was tested in October 1937, detecting aircraft at 60-miles range; production of 400 sets designated GL Mk. I began in