Scientific Frontline® Mission News / GIOVE-A Test Campaign Completed

Mission News / GIOVE-A

GIOVE-A Test Campaign Completed

Friday, August 17, 2007

Chilbolton Observatory

The 25 meter antenna at the Chilbolton Observatory of the Rutherford Appleton Laboratory

Credits: ESA / RAL

The test campaign using the large antenna at Chilbolton Observatory to analyzes the navigation signals transmitted by GIOVE-A, the first Galileo satellite, has been successfully completed.

Following its launch from Baikonur Cosmodrome on 28 December 2005, GIOVE-A began transmitting navigation signals on 12 January 2006. Analysis of these signals has involved several facilities, including the Navigation Laboratory at ESA's European Space Research and Technology Center (ESTEC), in the Netherlands, the ESA ground station at Redu, in Belgium, and the Rutherford Appleton Laboratory (RAL) Chilbolton Observatory in the United Kingdom.

Chilbolton's 25-meter antenna made it possible to acquire the signals from GIOVE-A and analyses them in detail to verify their conformance with the Galileo system specification.

Analysis of the signals has allowed some adjustments to be made, re-programming the spacecraft's navigation signal generation unit to compensate for changes to the signals introduced by the amplifier that boosts them for transmission to Earth and by a filter that protects adjacent frequency bands from interference.

To achieve the correct solution, the calibrated Chilbolton station was used to receive the signals from GIOVE-A. ESA's Navigation Laboratory processed the resulting data. The signal generator manufacturer, TAS (France), calculated the new settings for the unit. Finally, the satellite manufacturer, Surrey Space Technology Limited (SSTL) uploaded the new values to the payload using their ground station at Guildford, in the United Kingdom.

Thanks to the cooperation of a large international team, GIOVE-A is now transmitting optimized signals. Research and testing continues and manufacturers are using the signals as they develop the receivers that users will need when Galileo enters operational service.

Galileo is a joint initiative between ESA and the European Commission. When fully deployed in the early years of the next decade, it will be the first civilian positioning system to offer global coverage.

Source: ESA