GPS Block IIF

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GPS Block IIF
Navstar-2F.jpg
Artist's impression of a Block IIF GPS satellite in orbit
Manufacturer Boeing
Country of origin  United States
Operator US Air Force
Applications Navigation satellite
Specifications
Bus AS-4000
Design life 12 years
Launch mass 1,630 kilograms (3,590 lb)
Regime Semi-synchronous MEO
Production
Status Production Completed
Built 12
On order 0
Launched 7
Operational 7
First launch GPS IIF SV-1
28 May 2010, 03:00 UTC
← GPS Block IIR GPS Block IIIA

GPS Block IIF, or GPS IIF is an interim class of GPS satellite, which will be used to keep the Navstar Global Positioning System operational until the GPS Block IIIA satellites become operational. They are being built by Boeing, and will be operated by the United States Air Force following their launch by United Launch Alliance, using Evolved Expendable Launch Vehicles.[1] They will be the final component of the Block II GPS constellation to be launched. The spacecraft have a mass of 1,630 kilograms (3,590 lb) and a design life of 12 years. Like earlier GPS satellites, Block IIF spacecraft operate in semi-synchronous medium Earth orbits, with an altitude of approximately 20,460 kilometres (12,710 mi), and an orbital period of twelve hours.

The satellites will replace the GPS Block IIA satellites which were launched between 1990 and 1997 and were designed to last 7.5 years. Eleven of those satellites are still in use, including four that were launched in 1992.[2]

Because the Evolved Expendable Launch Vehicles are more powerful than the Delta II, which was used to orbit earlier Block II GPS satellites, they can place the satellites directly into their operational orbits. As a result, Block IIF satellites do not carry apogee motors. The original contract for Block IIF, signed in 1996, called for 33 spacecraft. This was later reduced to 12, and programme delays and technical problems pushed the first launch from 2006 to 2010.[3]

New characteristics[edit]

  • Broadcasting L5 "safety of life" navigation signal demonstrated on USA-203[2]
  • Broadcasting a new M-code signal[2]
  • Doubling in the predicted accuracy[4]
  • Better resistance to jamming[2]
  • Reprogrammable processors that can receive software uploads[2]
  • The first GPS satellites not to have Selective Availability hardware installed which degraded civilian accuracy when turned on in the original satellite fleet[2]

Launch history[edit]

This is a list of GPS Block IIF (Both launched & planned).

GPS Block IIF satellites
Satellite USA designation Launch Date
(UTC)
Rocket Launch Site Status Notes Ref.
GPS IIF-1 USA-213 28 May 2010, 03:00 Delta IV-M+(4,2), D349 Cape Canaveral SLC-37B In Service [4][5][6]
GPS IIF-2 USA-232 16 July 2011, 06:41 Delta IV-M+(4,2), D355 Cape Canaveral
(CC) SLC-37B
In Service [7]
GPS IIF-3 USA-239 4 October 2012, 12:10 Delta IV-M+(4,2), D361 CC SLC-37B In Service This launch came shortly before the 10th anniversary of the inaugural Delta IV launch. [8]
GPS IIF-4 USA-242 15 May 2013, 21:38 Atlas V 401, AV-039 CC SLC-41 In Service [9][10]
GPS IIF-5 USA-248 21 February 2014, 01:59 Delta IV-M+(4,2), D365 CC SLC-37B In Service [11]
GPS IIF-6 USA-251 17 May 2014, 00:03 Delta IV CC SLC-37B In Service [12]
GPS IIF-7 USA-256 2 August 2014, 03:23 Atlas V CC SLC-41 Launched [13][14]
GPS IIF-8 29 October 2014 Atlas V CC SLC-41 Planned [15]
GPS IIF-9 Delta IV Planned [13]
GPS IIF-10 Delta IV Planned [13]
GPS IIF-11 Planned
GPS IIF-12 Planned

See also[edit]

References[edit]

  1. ^ "Global Positioning System (GPS) IIF". Boeing. Retrieved 27 May 2010. 
  2. ^ a b c d e f "First Block 2F GPS Satellite Launched, Needed to Prevent System Failure". DailyTech. Retrieved 2010-05-30. 
  3. ^ Pike, John. "GPS Block II F". Globalsecurity.org. Retrieved 27 May 2010. 
  4. ^ a b "Mission Overview". Delta IV Launches GPS IIF SV-1. United Launch Alliance. Retrieved 27 May 2010. 
  5. ^ Tariq Malik (28 May 2010). "Air Force Launches Advanced New GPS Satellite". SPACE.com. 
  6. ^ "Delta IV Set to Launch GPS IIF SV-1". United Launch Alliance. Retrieved 27 May 2010. 
  7. ^ "United Launch Alliance GPS IIF-2". United Launch Alliance. Retrieved 16 July 2011. 
  8. ^ "United Launch Alliance GPS IIF-3". United Launch Alliance. Retrieved 8 October 2012. 
  9. ^ "ULA Atlas V sets sail with new GPS satellite". NASA Space Flight. 15 May 2013. Retrieved 15 May 2013. 
  10. ^ "Orbit Data and Resources on Active GNSS Satellites". GPS World. Retrieved 6 March 2014. 
  11. ^ "United Launch Alliance Successfully Launches 25th Delta IV Mission Carrying Global Positioning System Satellite for the U.S. Air Force". United Launch Alliance. Retrieved 6 March 2014. 
  12. ^ "Sixth GPS IIF Spacecraft Launches". Inside GNSS. Gibbons Media & Research LLC. Retrieved 17 May 2014. 
  13. ^ a b c "Boeing Satellite Launch Schedule". Boeing. Retrieved 17 May 2014. 
  14. ^ "Atlas V to Launch GPS IIF-7". United Launch Alliance. Retrieved 2 August 2014. 
  15. ^ "Atlas V successfully vaults satellite to orbit". Florida Today. Retrieved 5 August 2014.