The first Galileo navigation message was created by the navigation signal generator unit on board GIOVE-A, using content prepared by the GIOVE Mission Segment. This week-one navigation message was uplinked to GIOVE-A on 2 May from the Guildford ground station operated by Surrey Satellite Technology Ltd (United Kingdom) and then transmitted from the spacecraft to the users. The objective of the test was to demonstrate an end-to-end link between the Mission Segment and the user receivers. The navigation message is being generated for demonstration purposes only – no service guarantee is provided.
The complete radio transmission from GIOVE-A carries a navigation signal and a navigation message. The navigation signal contains the information needed to accurately measure the distance from the satellite to the user receiver. The navigation message provides the timing and spacecraft orbit data needed to calculate the time and exact position of the satellite. One of the main tasks of the GIOVE Mission Segment is the generation of this navigation message.
GIOVE Mission Segment
The GIOVE Mission Segment comprises two main elements, a world-wide network of 13 Galileo experimental sensor stations and the GIOVE Processing Centre (GPC) located at ESA’s European Space Research and Technology Centre (ESTEC) in Noordwijk, The Netherlands. The GPC is operated by European Satellite Navigation Industries (ESNIS) – the new name for Galileo Industries.
In order to generate the navigation message, the sensor stations track the signal-in-space from GIOVE-A and send the tracking information to the processing centre. The GPC computes, among other things, the precise satellite flight path and on-board clock model. It then generates a prediction of the orbital path and clock performance for the near-term future, which is the basis of the navigation message. Next, this message is transmitted to GIOVE-A which retransmits it to the user.
Aside from navigation message generation, the primary tasks of the GIOVE Mission Segment are performance characterisation of the on-board clocks, orbit modelling, and operations planning & telemetry analysis for the navigation payload.
Another validation step completed
On 12 January 2006, GIOVE A transmitted the first Galileo signals, thereby securing the frequencies allocated to Galileo by the International Telecommunication Union. Now, the transmissions are carrying a navigation message – this means that the satellite is providing information that is needed by a receiver to calculate its position.
Although the navigation message structure of GIOVE-A is slightly different, the GIOVE-A navigation transmissions are fully representative of those that will be sent by the operational Galileo system. The operating principles are identical and the achievement of the first navigation message is another important step in the validation of the Galileo system design.
Following this successful test, in the near future GIOVE-A will begin to continuously broadcast the navigation message, with the message content being updated whenever the satellite is visible from the Guildford uplink station. Additionally, the message content will be extended to include the time offset between GPS and the experimental Galileo system. Knowing this offset, the Experimental Galileo-GPS Time Offset (E-GGTO), will allow the user to build a position fix using GPS satellites and GIOVE-A.
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.
Dominique Detain | alfa
Fraunhofer FIT joins Facebook's Telecom Infra Project
25.10.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Stanford researchers create new special-purpose computer that may someday save us billions
21.10.2016 | Stanford University
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Life Sciences
25.10.2016 | Earth Sciences