SSTL completes Galileo in-orbit test campaign

09 September 2008, 10:16am

Guildford, 9th September 2008

SSTL has completed an in-orbit test campaign analysing signals from the new GIOVE-B satellite for ESA. The results suggest that GIOVE-B is operating well and in turn validates technologies integral to the EU-funded Galileo Satellite Navigation project.

"Having conducted several in-orbit test campaigns for GIOVE-A, ESA invited the SSTL team to support their GIOVE-B in-orbit test campaign. We are delighted to contribute to this further Galileo milestone," commented Elizabeth Rooney, SSTL's GIOVE project manager.

During May and June SSTL's Galileo team processed data acquired by the Science and Technology Facilities Council (STFC) at its 25m dish in Chilbolton to analyse the centre frequency, signal power and structure of all three Galileo signals. The team validated the in-orbit signals, which met expectations and correlated with ground tests before launch.

In addition to the Galileo Binary Offset Carrier (BOC) signals transmitted by GIOVE-A, GIOVE-B is successfully transmitting the new multiplexed binary offset carrier (MBOC) signal in line with the EU-US agreement reached in 2007. The new signal supports efforts towards Galileo-GPS cooperation.

Additional test results also indicate that the new hydrogen maser atomic clock onboard GIOVE-B is working correctly. The maser promises better long term stability and improved accuracy compared to the rubidium clock on board GIOVE-A.

Following the GIOVE-B campaign, SSTL retested GIOVE-A for ESA. The results confirm that GIOVE-A is still performing as it should five months into its mission extension. The satellite, which was built by SSTL, has been broadcasting navigation signals almost continuously since January 2006.

This campaign further extends SSTL's expertise on the Galileo programme, which was demonstrated by the provision of the first Galileo satellite, GIOVE-A, in 2005, which secured the frequencies for the European programme and has since been continuously providing Galileo signals. SSTL has recently offered ESA a reliable and cost effective approach to the further deployment of Galileo based on these successful programmes.

Rooney supports ESA's investment in Chilbolton, "The STFC's 25m dish provides excellent signal to noise ratio. This was further improved by the ESA and BNSC funded fast feed changer that allows fast changeover
between customers."

Over the coming months SSTL intends to perform analysis of the data collected by the Standard Radiation Environment Monitor (SREM) device on
board the GIOVE-B spacecraft in conjunction with the Surrey Space Centre (SSC) to characterise the little known Medium-Earth Orbit (MEO). It is hoped that GIOVE-B will provide data to complement and expand upon
results from GIOVE-A, which was the first European satellite to operate in MEO.

SSTL

Geo: International