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 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 2007 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 objectives of this mission are:

to secure the Galileo frequency allocations by providing a signal in space
on-board clock characterization
MEO radiation environment characterization
additional experimentation

The GIOVE-A and -B satellites are equipped with LLR arrays to provide precise orbit determination. Both routine SLR tracking and occasional campaigns with more intense tracking will be required. By June 2006, a sufficient number of receivers were deployed to allow ESA to begin microwave orbit determination. Therefore, an initial SLR tracking campaign began in June 2006 and lasted for eight weeks; further campaigns are planned for later in 2006. Predictions are based on these microwave-determined orbits; prediction accuracy is on the order of 30 meters. GIOVE-A tracking is comparable to GLONASS and GPS tracking (perhaps up to 40 percent more return energy than GPS).

A third satellite, GIOVE-A2, is under construction in 2007 for launch in the second half of 2008. The same company that built GIOVE-A will build this new satellite, basing its technology on that of GIOVE-A, with some enhancements.

Mission Instrumentation:

GIOVE-A has the following instrumentation onboard:

Phased array antenna of individual L-band elements
Signal generation units to create two representative Galileo signals
Two redundant rubidium atomic clock
Retroreflector array

Mission Parameters:

Galileo Parameters
	GIOVE-A (GSTB-V2/A)	GIOVE-A2	GIOVE-B (GSTB-V2/B)	Galileo
Sponsor:	EU/ESA	EU/ESA	EU/ESA	EU/ESA
Expected Life:	2 years	2 years	2 years	years
Primary Applications:	Positioning	Positioning	Positioning	Positioning
COSPAR ID:	0505101	TBD	0802001	TBD
SIC Code:	7001	TBD	7002	TBD
NORAD SSC Code:	28922	TBD	32781	TBD
Launch Date:	26-Dec-2005	Mid 2008	26-Apr-2008	2009
RRA Size:	308mm x 408mm x 48 mm	308mm x 408mm x 48 mm	305mm x 305mm x 42 mm	435mm x 540mm x 53mm
RRA Shape:	trapezoidal	trapezoidal	trapezoidal	trapezoidal
Reflectors:	76 corner cubes	76 corner cubes	67 corner cubes	78 corner cubes
Size of Reflector:	27 mm	27 mm	27 mm	27 mm
Orbit:	near-circular	near-circular	near-circular	near-circular
Inclination:	56 degrees	56 degrees	56 degrees	56 degrees
Altitude:	23,916 km	23,916 km	23,916 km	23,916 km
Eccentricity:	0.002	0.002	0.002	0.002

Additional Information:

Web sites:

Publications:

Appleby, G. and Gibbs, P. "First Laser Range Measurements to GIOVE-A", Inside GNSS, May/June 2006.
Falcone, M., Navarro-Reyes, D., Hahn, J., Otten, M., Piriz, R., Pearlman, M. "GIOVE's Track", GPS World, November 2006.
Schoenemann, E., Springer, T.A., Otten, M., Becker, M., Dow, J., "GIOVE-A Precise Orbit Determination from Microwave and Satellite Laser Ranging Data - First Perspectives for the Galileo Constellation and Its Scientific Use" (PDF paper | presentation), at Scientific and Fundamental Aspects of the Galileo Programme, Toulouse, France, October 2007.