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An Australian AN/TPS-77 in 2007
|Country of origin||United States|
|Type||Phased array Long-Range Radar System|
|Frequency||1215 to 1400 MHz (D/L)|
|Pulsewidth||51.2 / 409.6 μS|
|RPM||5 - 6 RPMs|
|Range||470 km (250 nmi)|
|Altitude||30.5 km (100,000 ft)|
|Azimuth||0.18° at 250 km|
|Elevation||-6° to +20°|
|Other Names||Seek Igloo, AN/TPS-77, AN/TPS-59, RRS-177, AMES Type 92|
The system is a low power (~20 kW), long range (200-250 nautical miles), L-band pencil beam, search radar with solid-state transmitters. System design includes a redundant architecture with computer software remote controlled and monitored operations to minimize manning requirements. It is typically also equipped with an identification friend or foe system using a second antenna on top.
The AN/FPS-117 is in use as part of the American-Canadian North Warning System of radars stretching across North America from Alaska, USA to Labrador, Canada. This North Warning System is designed to provide long-range detection and coverage for drug interdiction support and tactical command and control.
Implementation of the North Warning System has resulted in a reduction in Operations and Maintenance (O&M) spending by up to 50% compared to previous systems. Due to extreme northern locations of these radars, the physics of radiowave propagation in the 1215-1400 MHz frequency range is even more critical for target detection requirements.
The Air Force and the FAA also operate a limited number of AN/FPS-117 radars within the continental United States. The AN/FPS-117 radar is capable of randomly hopping among 18 channels in the 1215-1400 MHz band.
Originally selected for the Alaskan Air Command's SEEK IGLOO project, the radar was also picked to replace the United States Air Force's AN/FPS-67 radar at Berlin's Tempelhof Airport and was commissioned at Tempelhof in July 1984.
The RRP-117 version is a model which is being supplied to Germany with an offset input from Siemens in fixed-site applications.
In 2011, Lockheed Martin was awarded a contract to upgrade the radars to extend their operational lives through 2025.
- Canada - Used in North Warning System
- Estonia - Used in Baltic Air Surveillance Network 
- Germany - Uses German variant RRP-117
- Latvia - Used in Baltic Air Surveillance Network
- Lithuania - Used in Baltic Air Surveillance Network
- Saudi Arabia
- South Korea - Used on Ulleungdo Island to defend Liancourt Rocks from a territorial dispute with Japan, and on the Korean Demilitarized Zone.
- Singapore - Republic of Singapore Air Force
- United Kingdom
- United States - Used in North Warning System 
- AN/FPS-117 - Standard fixed version produced by Lockheed Martin.
- AN/TPS-77 - Transportable version produced by Lockheed Martin.
- RRP-117 - German fixed variant produced by Lockheed Martin, modified by Siemens to meet Luftwaffe requirements.
|Wikimedia Commons has media related to AN/FPS-117.|
- Lockheed Martin. "AN/FPS-117 LONG-RANGE AIR SURVEILLANCE RADARS" (PDF). Retrieved 2019-04-02.
- "AN/FPS-117". Radomes. Retrieved September 5, 2017.
- "AN/FPS Series". alternatewars.com. Retrieved 2013-10-13.
- "Lockheed Martin to Modernize 29 U.S. Air Force Early Warning Long-Range Surveillance Radars." Archived November 8, 2011, at the Wayback Machine Lockheed Martin, 7 November 2011.
- ""The Baltic Air Surveillance Network - BALTNET"". Archived from the original on 2008-06-03. Retrieved 2008-06-03.
- "Bundeswehr baut auf dem Flughafen Tempelhof (Bundeswehr is building at Tempelhof Airport)". Berliner Morgenpost. September 4, 2009. Retrieved September 4, 2017.
- "AN/FPS-117 Long Range Radar Upgrade". ASD News. December 26, 2008. Retrieved September 2, 2017.
- John Keller (December 12, 2012). "Lockheed Martin to continue project to upgrade AN/FPS-117 long-range surveillance radars". Military & Aerospace Electronics. Retrieved September 2, 2017.
- "RRP-117 "Seek Igloo"". Retrieved 2017-09-14.[dead link]