North Warning System The North Warning System ( NWS ) is a joint United States and Canadian radar system for the atmospheric air defense of North America . It provides surveillance of airspace from potential incursions or attacks from across North America ' s polar region . It replaced the Distant Early Warning Line system in the late 1980s . Overview . The NWS consists of both long range AN / FPS - 117 and short range AN / FPS - 124 surveillance radars , operated and maintained by the North American Aerospace Defense Command ( NORAD ) . The Alaska Regional Operations Control Center ( ROCC ) at Elmendorf AFB , Alaska controls the stations in Alaska ; the Canada East and Canada West Regional Operations Control Centres ( ROCCs ) at CFB North Bay , Ontario control the stations in Canada . ROCC information is then passed to the NORAD Combat Operations Centre ( COC ) at Colorado Springs , Colorado . History . The Distant Early Warning Line , constructed in the late 1950s , was reaching obsolescence in the 1980s . With the signing of North American Air Defence Modernization agreement at the " Shamrock Summit " between Prime Minister Mulroney and President Reagan in Quebec City on 18 March 1985 , the DEW Line began its eventual upgrading and transition becoming the North Warning System ( NWS ) of today . The NWS began limited operation in 1988 with the commissioning and acceptance of the three newly constructed east coast sites BAF - 3 Brevoort Island , Nunavut , LAB - 2 Saglek , and LAB - 6 Cartwright both in Labrador . Throughout the late 1980s and early 1990s , new NWS LRR radars replaced former DEW Line sites . DEW sites that weren ' t transitioned to North Warning operation were eventually closed down . The official activation of the NWS and inactivation of the DEW Line took place on 15 July 1993 . The bi - national North Warning System Office ( NWSO ) is located in Ottawa , Ontario and staffed with both Canadian and American military and civilian personnel . Manned sites are operated by the Royal Canadian Air Force . Logistical and maintenance support for the NWS is supplied by the Air Force Materiel Command of the United States Air Force , located at Ogden Air Logistics Center ( OO - ALC ) , Hill Air Force Base , Utah . Site remediation . The former DEW Line sites were operated using practices and materials accepted by the environmental standards of the time . With their closure and many of them rebuilt as NWS sites , a clean - up project was undertaken to remove surplus infrastructure , treat chemically contaminated soils , and stabilize landfill sites . The clean - up was designed to keep chemical contamination from the DEW Line sites out of the Arctic food chain , and ensure that the sites are restored to an environmentally safe condition . In 1989 , the Canadian Department of National Defence ( DND ) started investigating the environmental conditions of the DEW Line sites and commenced clean - up work at two sites in 1996 . The clean - up of 21 sites is scheduled to be completed in 2013 . Currently , 14 sites have been cleaned up and the remaining seven are on - going in Nunavut . Stations . The NWS consists of 15 long - range radar s ( 11 in Canada , of which 8 were DEW Line sites ) and 39 short - range radars ( 36 in Canada ) . The system forms a long and wide " tripwire " stretching from Alaska to southern Labrador . Minimally - attended NWS Long Range Radar AN / FPS - 117 radar sites shaded in blue . Distant Early Warning Line sites not included . The following table lists the DEW Line sites not included in the NWS . Most of these sites not included were Intermediate sites closed in 1963 when declared obsolete . The stations consisted of a module train , a warehouse , a vehicle garage , an Inuit house , POL ( " P " etroleum , " O " il , " L " ubricant ) tanks and a continuous wave radar tower . Others were some Auxiliary sites that were replaced with new NWS stations . DEW Line stations in the Aleutian Islands of Alaska were inactivated due to budget reductions in 1969 . Stations in Greenland and Iceland were transferred to the USAF Air Forces Iceland in 1980 . The primary DEW line radars were the Raytheon AN / FPS - 19 long lange L - Band search radar in Canada and Alaska at main and auxiliary sites ; Bendix AN / FPS - 30 at the four Greenland " DYE " radar stations . Motorola AN / FPS - 23 short range search radar was installed at the Intermediate sites , used as fillers to cover any Long Range Radar surveillance gaps .