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Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
navigation satellites have been built: 31 are launched and operational, 3 are unhealthy or in reserve, 41 are retired, 2 were lost during launch, and 1 prototype was never launched. 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.
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SVNs are "space vehicle numbers" which are serial numbers assigned to each GPS satellite. PRNs are the "pseudo-random noise" sequences, or
Gold code
A Gold code, also known as Gold sequence, is a type of binary sequence, used in telecommunication ( CDMA) and satellite navigation ( GPS). Gold codes are named after Robert Gold. Gold codes have bounded small cross-correlations within a set, which ...
s, 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.
Satellites
Satellites by launch date
Satellites by block
Orbital slots (by SVN)
Refer t
GPS Constellation Statusfor the most up-to-date information.
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
, 31 of 32 PRNs are in use; PRN ''28'' is unavailable. Three additional satellites, including one not assigned a PRN, are designated as on orbit spares.
PRN to SVN history
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 th
IGSANTEX
tp://igs.org/pub/station/general/igs14.atx file 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 mad
available
by th
Bernese GNSS Software
Planned launches
Block III
Block IIIF
See also
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List of Beidou satellites
This is a list of past and present satellites of the BeiDou/Compass navigation satellite system. , 44 satellites are operational: 7 in geostationary orbits (GEO), 10 in 55° inclined geosynchronous orbits (IGSO) and 27 in Medium Earth orbits ...
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List of Galileo satellites
This is a list of past and present satellites of the Galileo navigation system.
As of August 2022, 28 Galileo (4 IOV "In Orbit Validation" and 24 FOC "Full Operational Capability") satellites have been launched. The 2 GIOVE prototype vehicles ...
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List of GLONASS satellites
, 144 GLONASS navigation satellites have been launched, of which 132 reached the correct orbit and 23 are currently operational.
Satellites
GC number (Ground Control number, Russian: системный номер, номер по наземн ...
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List of NAVIC satellites
References
External links
Boeing Delta launch scheduleUnited States military launch recordNAVCEN GPS Constellation StatusUNB GPS Constellation Status*
tp://ftp.agi.com/pub/Catalog/Almanacs/SEM/GPSData.txt AGI-CSSI GPS Constellation Status
{{GPS satellites
Global Positioning System
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
*