Satellite Slots In Space



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  • Recent Developments

Who Has Satellites In Space

The Space Network List (SNL) is a list of basic information concerning planned or existing space stations, earth stations and radio astronomy stations. It includes sections on Advanced Publication Information, coordination requests, notifications, Plans information and their related processing backlog. Ovzon ordered Ovzon-3 in December from Space Systems Loral — a satellite Wahlberg said will be around 1,000 kilograms. Ovzon has six orbital slots, and anticipates putting a satellite in. Ment of slots in the GEO belt through the International Telecommunications Union (ITU). Today, any compa-ny or nation planning to launch a satellite to GEO must apply to the ITU for an orbital slot, and popular regions over North America, Europe, and eastern Asia have be-come so congested that few or no slots are left for new entrants to the.

The GPS space segment consists of a constellation of satellites transmitting radio signals to users.

The United States is committed to maintaining the availability of at least 24 operational GPS satellites, 95% of the time.

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To ensure this commitment, the Air Force has been flying 31 operational GPS satellites for the past few years.

Constellation Arrangement

GPS satellites fly in medium Earth orbit (MEO) at an altitude of approximately 20,200 km (12,550 miles). Each satellite circles the Earth twice a day.

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Enlarge
Expandable 24-Slot satellite constellation, as defined in the SPS Performance Standard.

The satellites in the GPS constellation are arranged into six equally-spaced orbital planes surrounding the Earth. Each plane contains four 'slots' occupied by baseline satellites. This 24-slot arrangement ensures users can view at least four satellites from virtually any point on the planet.

The Air Force normally flies more than 24 GPS satellites to maintain coverage whenever the baseline satellites are serviced or decommissioned. The extra satellites may increase GPS performance but are not considered part of the core constellation.

Current and Future Satellite Generations

The GPS constellation is a mix of old and new satellites. The following table summarizes the features of the current and future generations of GPS satellites, including Block IIA (2nd generation, 'Advanced'), Block IIR ('Replenishment'), Block IIR-M ('Modernized'), Block IIF ('Follow-on'), GPS III, and GPS IIIF ('Follow-on').

SatelliteLearn about GPS modernizationView full-size images<-- Drag table to scroll -->
Legacy SatellitesModernized Satellites
Block IIABlock IIRBlock IIR-MBlock IIFGPS III/IIIF
0
operational
8
operational
7
operational
12
operational
3
operational
  • Coarse Acquisition (C/A) code on L1 frequency for civil users
  • Precise P(Y) code on L1 & L2 frequencies for military users
  • 7.5-year design lifespan
  • Launched in 1990-1997
  • Last one decommissioned in 2019
  • C/A code on L1
  • P(Y) code on L1 & L2
  • On-board clock monitoring
  • 7.5-year design lifespan
  • Launched in 1997-2004
Learn more about GPS IIR at af.mil
  • All legacy signals
  • New military M code signals for enhanced jam resistance
  • Flexible power levels for military signals
  • 7.5-year design lifespan
  • Launched in 2005-2009
Learn more about GPS IIR-M at af.mil
  • All Block IIR-M signals
  • Advanced atomic clocks
  • Improved accuracy, signal strength, and quality
  • 12-year design lifespan
  • Launched in 2010-2016
Learn more about GPS IIF at af.mil
  • All Block IIF signals
  • Enhanced signal reliability, accuracy, and integrity
  • 15-year design lifespan
  • IIIF: laser reflectors; search & rescue payload
  • First launch in 2018
Learn more about GPS III at af.mil

As of November 13, 2020, there were a total of 30 operational satellites in the GPS constellation, not including the decommissioned, on-orbit spares.

Recent Developments

Space Satellite Viewing

GPS III

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  • Nov 5, 2020: The Space Force and its partners successfully launched the fourth GPS III satellite into orbit.
    View Space Force news release
  • Jun 30, 2020: The Space Force successfully launched the third GPS III satellite into orbit.
    View Space Force news release
  • Mar 2020: The Space Force accepted control of the second GPS III satellite.
    View Space Force news release
  • Aug 2019: The Air Force successfully launched the second GPS III satellite into orbit.
    View AF news release

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Learn more about GPS III from the prime contractor (lockheedmartin.com)

GPS IIIF ('Follow-On')