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GPS-3 Long Range Search Radar Set - A Long Range backup Search Radar set built by General Electric in the 1950s. This set consisted primarily of FPS-8 components and was considered a stripped down variant of the FPS-8.

GPS-3 Search Radar

Text Adapted from Mil-HDBK-162A 15 Dec 1965.

Radar Set GPS-3 is used to back-up the search function of a primary surveillance radar set. The GPS-3 equipment has a maximum target detection range of 220 nautical miles using normal video. The antenna reflector mounted on Tower AB-397/FPS-8 may be manually preset to the desired angle of vertical tilt and may be rotated in forward or reverse direction through 360 degrees in azimuth. The reflector may be scanned through any sector of 40 to 120 degrees with the center of the sector at any azimuth position.

This radar set includes a coherent video cancellation type of a range indicator, and a PPI for monitoring received target video or for general testing. The antenna circuits for IFF equipment are included in Radar Set GPS-3. The GPS-3 is composed of a surveillance radar set, Tower AB-397/FPS-8, and Radar Recognition Set UPX-6.

Either Arctic Tower AB-313/FPS-8 or Temperate Tower AB-397/FPS-8 is used with Radar Set GPS-3, depending upon environmental conditions. When the GPS-3 is used in an arctic installation, the power requirement is increased by 60 kilowatts by the addition of radome heat banks.

GPS-3 Search Radar Components.

GPS-3 Search Radar
Element Value Notes
Nomenclature GPS-3
Origins FPS-8
Manufacturer General Electric
Type Search
Number Made  ?
Frequency 1280-1350 mc
PRF 360 pps
Pulse Width 3 us
Rotation Speed 0-10 rpm
Transmitter Power 1 mw Peak
RF Power Source QK-358 Magnetron Tuneable
Range 220 nmi (Normal delay)
160 nmi (Normal no delay)
150 nmi (MTI)
Long Range
Accuracy .5 mi Range
.5 deg Azimuth
Altitude 40 k
Introduced 1954c
Power Requirements 120/208 vac, 60 cps, 3-ph, 4-wire
Temperate Tower - 16.9 kva
Arctic Tower - 76.9 kva

FPS-8/MPS-11/GPS-3 Antenna on Fixed Tower.

GPS-3 Components (edit list)
Component Model Quantity Height Width Deep Weight Notes
Modulator Group OA-414/FPS-8 1 55.5 24 24.5 578
Power Supply Group OA-412/FPS-8 1 65 30 28 1,160
Radar Transmitter T-370/FPS-8 3 57.5 32 24 578
Receiver Group OA-417/FPS-8 1 50.5 33.125 27 540
Radar Set Group OA-416/FPS-8 1 83.56 24 29 570
Radar Set Group OA-381/FPS-8 1 60.094 34.375 27.75 570
Indicator OA-99A/CPS-6B 1 42 21 43 419
Power Switchboard SB-245/FPS-8 1 62 20 22.625
Electrical Power Switching Group OA-415/FPS-8 1 60.5 25 32 760

See Also:


  • Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf, page 76.
  • MIL-HDBK-162A, 15 Dec 1965.


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