AN/APS-20

rdf:langString AN/APS-20

rdf:langString AN/APS-20

rdf:langString AN/APS-20 at the Museum of Science and Industry in Manchester

rdf:langString United States

rdf:langString S Band , plus L and X Band

rdf:langString against surface ships,

rdf:langString The AN/APS-20 was an airborne early warning, anti-submarine, maritime surveillance and weather radar developed in the United States in the 1940s. Entering service in 1945, it served for nearly half a century, finally being retired in 1991. Initially developed at Massachusetts Institute of Technology (MIT) under Project Cadillac, the radar was developed to be carried by aircraft to extend the sensor range of ships by placing a radar at altitude. Although developed for carrier-borne operation, first being installed in the single-engined General Motors TBM-3W Avenger, it was also used in larger four-engined airframes, the last being a fleet of Avro Shackleton AEW.2 which were converted from maritime patrol aircraft. Similarly, although developed for detecting aircraft, it saw extensive service in anti-submarine and maritime patrol roles and was one of the first radars to be used in researching extreme weather like hurricanes by agencies like the Environmental Science Services Administration (ESSA). As well as the United States, the radar was used by a large number of services in other countries, including the French Navy, Japan Maritime Self-Defense Force (JMSDF), Royal Air Force (RAF) and Royal Canadian Air Force (RCAF). Early versions of the radar could see a low-flying aircraft at 65 nautical miles (120 km; 75 mi) and a ship at 200 nautical miles (370 km; 230 mi). This was improved, so that later versions had a range against aerial targets of 115 nautical miles (213 km; 132 mi).