Uplink stations galileo biography

There is lot more to Galileo than just its satellites in space. A global ground network is essential to ensure the continued reliability of the time and positioning information embedded within the signals from orbit. Satellite navigation relies on the receiver deriving the time and point in space that a signal was transmitted to an extremely high level of accuracy.

This information is embedded within the satellite signal itself. A second's clock error would put users km off target. However, when the navigation system of a satellite is not in operation during launch and early orbit operations or during a contingency use of the common standard TTC modulation allows non-ESA TTC stations to be used.

The GMS is responsible for the determination and uplink of navigation data messages needed to provide the navigation and timing data. For this purpose, it uses a global network of Galileo Sensor Stations GSS [1] to monitor the navigation signals of all satellites on a continuous basis, through a comprehensive communications network using commercial satellites as well as cable connections in which each link is duplicated for redundancy.

The results of these computations for each satellite are up-loaded into that satellite nominally every minutes using a scheduled contact via a Mission Up-link Station. These transmissions are controlled by highly stable atomic clocks on board the satellites. The satellites will be spread evenly around each plane and will take about 14 hours to orbit the Earth.

Uplink stations galileo biography

Two satellites in each plane will be a spare; on stand-by should any operational satellite fail [4]. Its basic functions are:. The Galileo Ground Segment constitutes the major system element controlling the entire constellation, the navigation system facilities and the dissemination services. The Galileo user segment is composed of Galileo receivers.

Their main function is to receive Galileo signals, determine pseudoranges and other observablesand solve the navigation equations in order to obtain their coordinates and provide a very accurate time. The Galileo navigation Signals are transmitted in the four frequency bands indicated in next figure. These four frequency bands are the E5a, E5b, E6 and E1 bands.

They provide a wide bandwidth for the transmission of the Galileo Signals. By offering dual frequencies as standard, however, Galileo will deliver real-time positioning accuracy down to the metre range, which is unprecedented for a publicly available system. Galileo will guarantee availability of the service under all but the most extreme circumstances and will inform users within seconds of a failure of any satellite.

This will make it suitable for applications where safety is critical, such as controlling trains and landing aircraft. The objective of this mission was to characterise and validate the critical technologies required for Galileo, which were developed under ESA contracts. GIOVE-A results are largely in line with specifications, which gives good confidence for the future of the programme and shows that Galileo is on the right track.

This mission will continue the work started by GIOVE-A, using a satellite more closely representative of the design of those planned for the operational Galileo constellation.