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List of GPS satellites

From Wikipedia, the free encyclopedia

Samples of three GPS satellites' orbits over a five-year period (2013 to 2018)
  USA-242 ·   USA-239 ·   USA-151 ·   Earth

As of 15 August 2023, 83 Global Positioning System navigation satellites have been built: 31 are launched and operational, 3 in reserve or testing, 42 are retired, 2 were lost during launch, and 1 prototype was never launched. 4 Block III satellites have completed construction and have been declared "Available For Launch" (AFL). The next launch is GPS III SV07, originally scheduled for June 2024, currently NET January 2025.

The constellation requires a minimum of 24 operational satellites, and allows for up to 32; typically, 31 are operational at any one time. A GPS receiver needs four satellites to work out its position in three dimensions.[1]

SVNs are "space vehicle numbers" which are serial numbers assigned to each GPS satellite. PRNs are the "pseudo-random noise" sequences, or Gold codes, that each satellite transmits to differentiate itself from other satellites in the active constellation.

After being launched, GPS satellites enter a period of testing before their signals are set to "Healthy". During normal operations, certain signals may be set to "Unhealthy" to accommodate updates or testing. After decommissioning, most GPS satellites become on-orbit spares and may be recommissioned if needed. Permanently retired satellites are sent to a higher, less congested disposal orbit where their fuel is vented, batteries are intentionally depleted and communication is switched off.[2]

Satellites

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Satellites by launch date

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  1. ^ Length Of Service in days. Includes testing period(s).

Satellites by block

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Block Launched Operational Testing/
Reserve
Unhealthy Retired Launch
Failures
Manufacturer Remarks
Block I 11 0 0 0 10 1 Rockwell International
Block II 9 0 0 0 9 0 Rockwell International One unlaunched prototype
Block IIA 19 0 0 0 19 0 Rockwell International
Block IIR 14 7 2 0 4 1 Lockheed Martin
Block IIRM 8 7 1 0 0 0 Lockheed Martin
Block IIF 12 11 0 0 1 0 Boeing
Block III 6 6 0 0 0 0 Lockheed Martin
Block IIIF 0 0 0 0 0 0 Lockheed Martin
Total 78 31 3 0 42 2
(Last update: October 2, 2024)

Orbital slots (by SVN)

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Refer to GPS Constellation Status for the most up-to-date information.

As of 10 August 2023
Slot Plane
A B C D E F
1 65 56 57 61 69 70
2 52 62 66 73 55
3 64 44 72 45 50 68
4 48 58 53 67 51 74
5 71 59 78 76
6 79 77 75 43
Block IIR IIRM IIF III

Numbers in parentheses refer to non-operational satellites.

Once launched, GPS satellites do not change their plane assignment but slot assignments are somewhat arbitrary and are subject to change.

PRN status by satellite block

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As of 23 August 2023, 31 of 32 PRNs are in use; PRN 01 is unassigned. Two additional satellites are designated as on-orbit spares.

PRN 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 --
IIR O S O O S O O O O
IIRM O O O O O O O S
IIF R O O O O O O O O O O O
III O O O O O O
Legend:
  • O – Operational
  • T – Testing in preparation for operation
  • S – On orbit Spare
  • U – Unhealthy and unusable
  • R – Retired

PRN to SVN history

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This section is for the purpose of making it possible to determine the PRN associated with a SVN at a particular epoch. For example, SVN 049 had been assigned PRNs 01, 24, 27, and 30 at different times of its lifespan, whereas PRN 01 had been assigned to SVNs 032, 037, 049, 035, and 063 at different epochs. This information can be found in the IGS ANTEX file[permanent dead link], which uses the convention "GNN" and "GNNN" for PRNs and SVNs, respectively. For example, SVN 049 is described as:

BLOCK IIR-M         G01                 G049      2009-014A TYPE / SERIAL NO    
  2009     3    24     0     0    0.0000000                 VALID FROM          
  2011     5     6    23    59   59.9999999                 VALID UNTIL         
BLOCK IIR-M         G24                 G049      2009-014A TYPE / SERIAL NO    
  2012     2     2     0     0    0.0000000                 VALID FROM          
  2012     3    14    23    59   59.9999999                 VALID UNTIL         
BLOCK IIR-M         G24                 G049      2009-014A TYPE / SERIAL NO    
  2012     8     9     0     0    0.0000000                 VALID FROM          
  2012     8    22    23    59   59.9999999                 VALID UNTIL         
BLOCK IIR-M         G27                 G049      2009-014A TYPE / SERIAL NO    
  2012    10    18     0     0    0.0000000                 VALID FROM          
  2013     5     9    23    59   59.9999999                 VALID UNTIL         
BLOCK IIR-M         G30                 G049      2009-014A TYPE / SERIAL NO    
  2013     5    10     0     0    0.0000000                 VALID FROM          

whereas for PRN 01 the following excerpt is relevant:

BLOCK IIA           G01                 G032      1992-079A TYPE / SERIAL NO    
  1992    11    22     0     0    0.0000000                 VALID FROM          
  2008    10    16    23    59   59.9999999                 VALID UNTIL         
BLOCK IIA           G01                 G037      1993-032A TYPE / SERIAL NO    
  2008    10    23     0     0    0.0000000                 VALID FROM          
  2009     1     6    23    59   59.9999999                 VALID UNTIL         
BLOCK IIR-M         G01                 G049      2009-014A TYPE / SERIAL NO    
  2009     3    24     0     0    0.0000000                 VALID FROM          
  2011     5     6    23    59   59.9999999                 VALID UNTIL         
BLOCK IIA           G01                 G035      1993-054A TYPE / SERIAL NO    
  2011     6     2     0     0    0.0000000                 VALID FROM          
  2011     7    12    23    59   59.9999999                 VALID UNTIL         
BLOCK IIF           G01                 G063      2011-036A TYPE / SERIAL NO    
  2011     7    16     0     0    0.0000000                 VALID FROM          

A table extracted out of the ANTEX file is made available by the Bernese GNSS Software.

Planned launches

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Block III

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Date Rocket Launch site Satellite SVN Remarks
January 2025 Vulcan Centaur VC2S[108] CCSFS SLC-41 GPS III SV07 Sally Ride 80 Space vehicle manufacturing contract awarded February 2013.[109] It was in assembly in December 2018.[110]

Declared "Available for Launch" on 20 May 2021.[111][112]

TBD 2025[113][114][115] Vulcan Centaur VC2S CCSFS SLC-41 GPS III SV08 Katherine Johnson 81 Space vehicle manufacturing contract awarded February 2013.[109] The satellite was named "Katherine Johnson" in June 2020 following its successful core mate assembly.[116]

Declared "Available for Launch" on 10 June 2021.[111]

End of 2025[117] Vulcan Centaur VC2S CCSFS SLC-41 GPS III SV09 Ellison Onizuka 82 Space vehicle manufacturing contract awarded September 2016.[118]

Declared "Available for Launch" on 23 Aug 2022.[117]

2026[119] Falcon 9 Block 5 CCSFS, SLC-40 GPS III SV10 Hedy Lamarr 83 Space vehicle manufacturing contract awarded September 2016.[118] Component build up stage as of June 2021.[120] Component deliveries continuing through May 2022.[121]

Declared "Available for Launch" on 08 Dec 2022.[122]

Block IIIF

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See also

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References

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