Galileo

Jump to: Mission Objectives, Mission Instrumentation, Mission Parameters, Additional Information

Mission Photos:

Courtesy of ESA

Mission Objectives:

Galileo is a satellite radio navigation system initiative launched by the European Union and the European Space Agency. Galileo consists of a constellation of 30 satellites (27 operational satellites plus 3 satellites in reserve) and ground stations providing position information to users in many sectors (transportation, social services, justice system, custom services, public works, search and rescue, etc.). Two experimental spacecraft will be launched in 2005 and 2008 as part of the Galileo System Test Bed V2: GIOVE-A (Galileo In-Orbit Validation Element, formerly GSTB-V2/A) and GIOVE-B (formerly GSTB-V2/B).

The main objectives of the Galileo system are:

• Provide global navigation satellite system specifically for civilian purposes
• Generate new, large markets and provide the critical advance in technology for Europe and its partners
• Provide global Search and Rescue (SAR) function

The Galileo system consists of global, regional and local components. The global component consists of the satellites and ground segment. The regional component consist of a number off External Region Integrity Systems (ERIS) implemented to obtain higher integrity services independent of the Galileo system. Local components may be deployed for enhancing the performance of Galileo locally. These will enable higher performance such as the delivery of navigation signal in areas where the satellite signals cannot be received.

All Galileo satellites will be equipped with LLR arrays to provide precise orbit determination. Both routine SLR tracking and occasional campaigns with more intense tracking will be required. Laser tracking of Galileo will be comparable to GLONASS and GPS tracking (perhaps up to 40 percent more return energy than GPS).

Mission Instrumentation:

Galileo will have the following components:

• Satellite components:
1. L-band antenna for transmitting navigation signals
2. Search and rescue (S&R;) antenna to pick up distress signals
3. C-band antenna to receive signals from up-link stations
4. Two S-band antennas for transmiting housekeeping data and receiving control commands
5. IR Earth sensors for spacecraft pointing
6. FSS sun sensors for spacecraft pointing
7. Laser retro-reflector array for orbit determination
8. Space radiators for heat exchange
• Interior payload:
1. Passive maser clock
2. Rubidium clock
3. Clock monitoring and control unit
4. Navigation signal generator
5. Remote terminal unit
• Interior service module:
1. Solar array drive mechanism (SADM)
2. Gyroscopes
3. Reaction wheels
4. Magneto bar
5. Power conditioning and distribution unit
6. On-board computer

Mission Parameters:

Additional Information:

• ESA Galileo Home Page
• First Galileo satellite launch
• European Union Galileo Home Page
• European GNSS Agency
• Inside GNSS Galileo section

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Author: Mark Torrence
Maintained by: Carey Noll