2023 GNSS in Review


As we close out 2023, we wanted to review some of the key Global Navigation Satellite System (GNSS) developments from the past year.

GPS Continues March to Modernization

The United States Space Force kicked off the year with the launch of GPS III Space Vehicle 06, the 18th modernized GPS satellite supporting the civilian L5 and military M-Code signals.1 The next launch, also a GPS III design, is not expected until 2024.

Space Force closed the year by assigning missions in the National Security Space Launch (NSSL) Phase 2 Launch Service Procurement contract.2 In the next two to three years, United Launch Alliance and SpaceX will each launch a GPS III mission. SpaceX will also launch a GPS IIIF, or GPS III Follow-on, mission. GPS IIIF is a new design that improves navigation, performance, and resilience while adding novel capabilities like on-orbit servicing and Search and Rescue (SAR) distress beacons.

A mid-year report from the General Accounting Office reviewed the GPS Modernization program.3 The report recommended that the Space Force establish a firm requirement to expand the GPS constellation to 27 M-Code capable satellites. Otherwise, the program may not be able to secure sufficient funding to support the necessary development.

The report’s authors also questioned the Space Force’s development of a new handheld receiver without commitments from the Army or Marine Corps. Finally, the report noted already-announced delays to the Next-Generation Operational Control Segment (OCX) due to software development challenges, training concerns, pandemic-related schedule compression. Space Force expects delivery of the OCX Blocks 1 and 2 by the end of 2023. GAO expressed concerns about the tight development schedule, but had no recommendations.

Europe’s Galileo Program Evolves

Europe’s Galileo program continues to iterate its relatively new GNSS service. At the beginning of the year, the European Union Agency for the Space Programme (EUSPA) announced the initial availability of Galileo’s High Accuracy Service.4 The new service will provide accurate positioning within 25 centimeters.

In August, the Galileo Open Service began transmitting an upgraded I/NAV message.5 This upgraded signal will significantly reduce Time to First Fix, especially for users in harsh environments. EUSPA testing campaigns will help receiver manufacturers implement the I/NAV improvements.

The European Geostationary Navigation Overlay Service (EGNOS) added new capabilities when a payload hosted on EUTELSAT’s Hotbird 13G geostationary satellite began transmitting EGNOS V3 test signals.6 This enhanced augmentation service will provide more accurate GPS and Galileo positioning for European aviation, rail, and other transport nodes.

Several expansions to Galileo’s ground segment in 2023 will improve service levels and lay the groundwork for future modernization. Galileo Sensor Stations (GSS) check the constellation’s accuracy and signal quality and help refine satellite orbits. A new GSS established in France’s Territory of the Wallis and Futuna Islands will improve Galileo’s performance in the southern hemisphere.7 A new SAR Reference Beacons (REFBE) site in Greenland will enhance Galileo’s Search and Rescue Service in the North Atlantic.8 Finally, a new Telemetry, Tracking, and Control (TT&C) facility at Europe’s launch site in Kourou, French Guiana, will prepare the ground segment for the Galileo constellation’s expansion and modernization.9

Disruptions in Europe’s launch sector forced the European Commission in July to sign contracts with SpaceX for Galileo launches in 2024.10 Russia’s invasion of Ukraine ended Europe’s use of the Soyuz vehicle, a late 2022 launch failure grounded the Vega C vehicle, and development delays pushed Ariane 6’s debut into 2024. SpaceX will launch two Galileo satellites in April and another two in July on its Falcon 9 rocket.

Ten current-generation satellites remain to be launched over the next few years. However, the development of Galileo Second Generation (G2G) satellites has already begun. In mid-2023, the European Space Agency signed the final contracts to begin G2G’s in-orbit development phase.11

Other Positioning Systems

China and Russia made incremental changes to their positioning systems. China’s Beidou GNSS became fully operational last year. May’s launch of Beidou-3 G4 marked the first backup and replenishment satellite.12 A geostationary satellite, Beidou-3 G4 will provide positioning services to China and surrounding regions.

In August, Russia launched its first GLONASS-K2 satellite.13 Ten years behind schedule, the new design introduces changes to GLONASS civilian signals to bring performance in line with competing services. The K2 design also reduces Russia’s dependence on international procurement and sanctions related to its invasion of Ukraine.

International GNSS Adoption Continues

In March, the Council of the International Civil Aviation Organization (ICAO) issued new standards for the use of GNSS in international aviation.14 Previous standards only supported the American GPS constellation’s L1 signal. Adding Galileo, GLONASS, and Beidou to the standard will guide the aviation industry as it adopts dual-frequency multi-constellation GNSS-based navigation.

What’s Ahead in 2024

According to GAO’s report, OCX’s ground segment modernization will reach initial operating capacity next May, a thirteen-month delay from the original April 2023 target. Space Force plans operational acceptance sometime in 2025. The Block III satellites will continue to provide basic M-Code access, but military GPS users will not have access to its full capabilities until OCX is operational.

Currently, Galileo’s constellation consists of four satellites built to the In-Orbit Validation (IOV) design and twenty-two based on the Full Operational Capacity (FOC) design. The decision to use a non-European launch provider for next year’s launches will keep the transition of Galileo’s space segment to the FOC design on track.


  1. Maddie Saines, “GPS III SV06 launched,” GPS World, January 18, 2023.
  2. Final GPS III Missions, First GPS IIIF Satellites Part of SSC’s Latest Launch Assignments,” Inside GNSS, November 5, 2023.
  3. GPS Modernization: Space Force Should Reassess Requirements for Satellites and Handheld Devices,” United States Government Accountability Office, June 2023.
  4. Galileo High Accuracy Service goes live,” European Union Agency for the Space Programme, January 24, 2023.
  5. I/NAV improvements are now available to all Galileo Open Service users,” European Union Agency for the Space Programme, August 18, 2023.
  6. EGNOS latest payload becomes operational ahead of V3 Service,” European Union Agency for the Space Programme, June 5, 2023.
  7. New Galileo Sensor Station up and running in South Pacific,” European Union Agency for the Space Programme, May 5, 2023.
  8. New site in Greenland to enhance Galileo SAR,” European Union Agency for the Space Programme, May 31, 2023.
  9. New Galileo station goes on duty,” European Space Agency, July 24, 2023.
  10. SpaceX to Launch Galileo Satellites Next Year,” Inside GNSS, October 24, 2023.
  11. Galileo Second Generation enters full development phase,” European Space Agency, June 1, 2023.
  12. Adrian Beil, “Beidou-3 G4 gets launched and Chinese Raptor gets tested, as it receives its own name,” NASA Spaceflight, May 17, 2023.
  13. Maddie Saines, “Russia launches Glonass-K2 No. 13,” GPS World, August 25, 2023.
  14. GNSS milestone achieved as ICAO Council adopts new dual-frequency multi-constellation standards,” International Civil Aviation Organization, March 23, 2023.

December 8, 2023