Third Galileo Satellite Transmits Test Signals
December 4, 2012

ESA’s Third Galileo Satellite Transmits Test Signals

Lee Rannals for — Your Universe Online

The European Space Agency's (ESA) Third Galileo satellite has sent its first test navigation signals back to Earth, and has broadcasted signals across all three Galileo bands.

The pair of Galileo satellites launched this fall join two others that were launched in October 2011. The first set have reached their final orbital position and are in the middle of testing. The third satellite, known as FM3, transmitted its first navigation signal in the E1 band last Saturday.

Since its first transmission, FM3 has delivered signals across Galileo bands E5 and E6 as well. Band E1 is a freely available Open Service band, interoperable with GPS.

The Galileo satellite system is designed to provide highly accurate timing and navigation services to users around the world. Testing is being carried out in addition to the standard satellite commissioning to confirm that the critical navigation payloads have not been degraded from launch.

The satellites are being watched from Galileo´s Oberpfaffenhofen Control Centre near Munich in Germany, and their navigation payloads are overseen by Galileo´s Mission Control Centre in Fucino, Italy.

“This marked the very first time that a Galileo payload was activated directly from ESA´s Redu centre in Belgium,” Marco Falcone, overseeing the campaign effort as Galileo´s System Manager, said in a statement.

Redu is specially equipped for Galileo testing with an S-band antenna to upload commands and receive telemetry from the satellite. The site also has an L-band dish to monitor the shape and quality of navigation signals at high resolution.

“We have now established an end-to-end setup in Redu that allows us to upload commands generated from Fucino´s Galileo Control Centre to the satellite payload whenever the satellite passes over the station, while at the same time directly receiving the resulting navigation signal through its main L-band antenna," Falcone said.

The Galileo satellites take about 14 hours to orbit the planet, and they typically come into view of Redu between three to nine hours each day. The satellites are floating at an altitude of about 14,400 miles.

The fourth Galileo flight model, FM4, launched alongside FM3 back on October 12, was carried into space by a Russian Soyuz launcher. Both satellites have joined their 2011 launch counterparts and are now in operational orbit. FM4 is set to begin transmitting test navigation signals later this month. The first two satellites have already passed their in-orbit testing.