Encyclopedia Astronautica
Galileo Navsat

Galileo Navsat
Galileo Navsat
Credit: ESA
European navigation satellite. Operational, first prototype launched 2008.04.26, GIOVE B. Galileo was Europe's own global navigation satellite system, providing a highly accurate, guaranteed global positioning service under civilian control.

Despite potential budget overruns and schedule delays, it was considered a strategic necessity, providing Europe with a navigation system for critical applications not subject to control by the Americans (GPS) or Russians (GLONASS). At the same time Galileo would be inter-operable with both GPS and GLONASS.

A user would be able to take a position with the same receiver from any of the satellites in any combination. By offering dual frequencies as standard, however, Galileo would deliver real-time positioning accuracy down to the meter range, which was unprecedented for a publicly available system.

It would guarantee availability of the service under all but the most extreme circumstances and would inform users within seconds of a failure of any satellite. This would make it suitable for applications where safety was crucial, such as running trains, guiding cars and landing aircraft.

The first experimental satellite, part of the so-called Galileo System Test Bed (GSTB) was to be launched in mid-2005. However the project reached almost immediate budget overruns. The objective of this experimental satellite was to characterize the critical technologies, which were already under development under ESA contracts. Thereafter up to four operational satellites would be launched in the timeframe 2005-2006 to validate the basic Galileo space and related ground segment. Once this In-Orbit Validation (IOV) phase had been completed, the remaining satellites would be installed to reach the Full Operational Capability (FOC) in 2008.

The fully deployed Galileo system was to consist of 30 satellites (27 operational + 3 active spares), positioned in three circular Medium Earth Orbit (MEO) planes in 23616 km altitude above the Earth, and at an inclination of the orbital planes of 56 degrees with reference to the equatorial plane. Once this was achieved, the Galileo navigation signals would provide a good coverage even at latitudes up to 75 degrees north, which corresponds to the North Cape, and beyond. The large number of satellites together with the optimization of the constellation, and the availability of the three active spare satellites, would ensure that the loss of one satellite had no discernible effect on the user.

Two Galileo Control Centers (GCC) would be implemented on European ground to provide for the control of the satellites and to perform the navigation mission management. The data provided by a global network of twenty Galileo Sensor Stations (GSS) would be sent to the Galileo Control Centers through a redundant communications network. The GCC's would use the data of the Sensor Stations to compute the integrity information and to synchronize the time signal of all satellites and of the ground station clocks. The exchange of the data between the Control Centers and the satellites would be performed through so-called up-link stations. Five S-band up-link stations and 10 C-band up-link stations would be installed around the globe for this purpose.

As a further feature, Galileo would provide a global Search and Rescue (SAR) function, based on the operational Cospas-Sarsat system. To do so, each satellite would be equipped with a transponder, which would be able to transfer the distress signals from the user transmitters to the Rescue Co-ordination Centre, which would then initiate the rescue operation. At the same time, the system would provide a signal to the user, informing him that his situation had been detected and that help was under way. This latter feature was new and was considered a major upgrade compared to the existing system, which did not provide a feedback to the user.

First Launch: 2008.04.26.
Last Launch: 2011.10.21.
Number: 3 .

More... - Chronology...

Associated Countries
See also
  • Soyuz The Russian Soyuz spacecraft has been the longest-lived, most adaptable, and most successful manned spacecraft design. In production for fifty years, more than 240 have been built and flown on a wide range of missions. The design will remain in use with the international space station well into the 21st century, providing the only manned access to the station after the retirement of the shuttle in 2011. More...

Associated Launch Vehicles
  • Soyuz Russian orbital launch vehicle. The world's first ICBM became the most often used and most reliable launch vehicle in history. The original core+four strap-on booster missile had a small third stage added to produce the Vostok launch vehicle, with a payload of 5 metric tons. Addition of a larger third stage produced the Voskhod/Soyuz vehicle, with a payload over 6 metric tons. Using this with a fourth stage, the resulting Molniya booster placed communications satellites and early lunar and planetary probes in higher energy trajectories. By the year 2000 over 1,628 had been launched with an unmatched success rate of 97.5% for production models. Improved models providing commercial launch services for international customers entered service in the new millenium, and a new launch pad at Kourou was to be inaugurated in 2009. It appeared that the R-7 could easily still be in service 70 years after its first launch. More...
  • Soyuz FG Uprated Soyuz booster designed for high performance Russian government missions and delivery of Soyuz and Progress spacecraft to the International Space Station. Upgraded engines, modern avionics, reduced non-Russian content. Unknown differences to Soyuz ST. More...

Associated Manufacturers and Agencies
  • ESA European agency overseeing development of rockets and spacecraft. European Space Agency, Europe. More...

  • European Space Agency web site, Web Address when accessed: here.

Associated Launch Sites
  • Baikonur Russia's largest cosmodrome, the only one used for manned launches and with facilities for the larger Proton, N1, and Energia launch vehicles. The spaceport ended up on foreign soil after the break-up of Soviet Union. The official designations NIIP-5 and GIK-5 are used in official Soviet histories. It was also universally referred to as Tyuratam by both Soviet military staff and engineers, and the US intelligence agencies. Since the dissolution of the Soviet Union the Russian Federation has insisted on continued use of the old Soviet 'public' name of Baikonur. In its Kazakh (Kazak) version this is rendered Baykonur. More...

Galileo Navsat Chronology

2008 April 26 - . 22:16 GMT - . Launch Site: Baikonur. LV Family: R-7. Launch Vehicle: Soyuz FG. LV Configuration: Soyuz-FG/Fregat.
  • GIOVE B - . Mass: 530 kg (1,160 lb). Nation: Europe. Agency: Starsem. Class: Navigation. Type: Navigation satellite. Spacecraft: Galileo Navsat. USAF Sat Cat: 32781 . COSPAR: 2008-020A. Apogee: 23,244 km (14,443 mi). Perigee: 23,104 km (14,356 mi). Inclination: 56.0000 deg. Period: 842.60 min. Second European Galileo navigation system test satellite. The booster placed the Giove/Fregat stack on a suborbital trajectory. The Fregat stage then burned to enter a a 170 km parking orbit. The stage burned at least twice more before releasing the satellite into its operational orbit.

2011 October 21 - . 10:30 GMT - . Launch Site: Kourou. Launch Complex: Kourou ELS. LV Family: R-7. Launch Vehicle: Soyuz-2-1B.
  • Galileo-PFM - . Nation: Europe. Class: Navigation. Type: Navigation satellite. Spacecraft: Galileo Navsat. USAF Sat Cat: 37846 . COSPAR: 2011-060A. Apogee: 23,307 km (14,482 mi). Perigee: 23,234 km (14,436 mi). Inclination: 54.7000 deg. Period: 846.80 min. Summary: First Galileo navigation satellites launched to establish an autonomous European navigation satellite constellation. First Soyuz booster launch from the new Ensemble de Lancement Soyuz pad in Kourou..
  • Galileo-FM2 - . Nation: Europe. Class: Navigation. Type: Navigation satellite. Spacecraft: Galileo Navsat. USAF Sat Cat: 37847 . COSPAR: 2011-060B. Apogee: 23,274 km (14,461 mi). Perigee: 23,228 km (14,433 mi). Inclination: 54.7000 deg. Period: 845.90 min.

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