Up to early March 2008, GIOVE-B underwent final testing at the European Space Agency’s research and technology centre (ESTEC) in Noordwijk, the Netherlands. On March 5, media representatives had the unique opportunity to visit the satellite as part of an in-depth GIOVE-B and Galileo background briefing at ESTEC. It was the last opportunity for the public to see GIOVE-B before it was shipped to the launch base at Baikonur.

An earlier cornerstone of European GNSS, and the first-ever Galileo satellite, GIOVE-A was placed in orbit on December 28, 2005, enabling Galileo signal broadcasts for frequency filing and experimentation. GIOVE-A has also allowed testing of the basic navigation technologies, like signal generation and clock stability, that are now fully demonstrated to be within expectations.

GIOVE-B will continue the validation of these basic technologies. The new satellite will fly a new type of frequency reference, based on the passive hydrogen maser principle, complemented by two on-board rubidium clocks based on the design already flown on GIOVE-A. This clock is expected to provide the most stable timing reference ever in space. GIOVE-B will also broadcast the new multiple binary offset carrier (MBOC) signal resulting from a number of extensive interactions with our U.S. GPS colleagues on compatibility and interoperability. With the wide frequency range covered (E1, E5, E6), GIOVE-B will be the best navigation satellite put into orbit so far, providing major opportunities for early confirmation of Galileo system performance.

During the operation of the GIOVE satellites, the GIOVE Processing Centre at ESA ESTEC will play a fundamental role in risk mitigation continuing the assessment of navigation performance (including navigation message generation and broadcast to users) and validation and associated operational aspects, validation of critical in-orbit technologies, end-to-end analysis of the Galileo signal-in-space, assessment of Galileo receiver performance, validation of ground algorithm prototypes, and overall performance.

Integrating and testing GIOVE-B has been and is quite a challenge, and the effort required has been exceptional, far beyond predictions, but the collaboration in the team has always been excellent, and this experience will surely pave the way for the next Galileo phases.In the Galileo Project, we all have very high expectations of GIOVE-B and we are all anxiously looking forward to exercising its capabilities in orbit. In parallel, the ESA Project is approaching Galileo segments critical design reviews in the coming months. The next four Galileo satellites are scheduled for launch beginning of 2010.

JÖRG HAHN (right) is navigation systems engineer for the ESA Galileo Project Office. He received his Ph.D. in engineering sciences from the University of the Federal Armed Forces, Germany. He is a member of GPS World’s Advisory Board.

VALTER ALPE (left)  is the satellites infrastructure manager for the ESA Galileo Project, focusing on the GIOVE-A and GIOVE-B projects.