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More about Satellite Applications 
Galileo will be Europe's own global navigation satellite system, providing a highly accurate, guaranteed global positioning service under civilian control. It will be inter-operable with GPS and GLONASS, the two other global satellite navigation systems. A user will be able to take a position with the same receiver from any of the satellites in any combination. 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. It 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 crucial, such as running trains, guiding cars and landing aircraft.The first experimental satellite, part of the so-called Galileo System Test Bed (GSTB) will be launched in the second semester of 2005. The objective of this experimental satellite is to characterize the critical technologies, which are already under development under ESA contracts. Thereafter up to four operational satellites will be launched in the timeframe 2005-2006 to validate the basic Galileo space and related ground segment. Once this In-Orbit Validation (IOV) phase has been completed, the remaining satellites will be installed to reach the Full Operational Capability (FOC) in 2008. The fully deployed Galileo system consists of 30 satellites (27 operational + 3 active spares), positioned in three circular Medium Earth Orbit (MEO) planes in 23616 km altitude above the Earth, and at an inclination of the orbital planes of 56 degrees with reference to the equatorial plane. Once this is achieved, the Galileo navigation signals will provide a good coverage even at latitudes up to 75 degrees north, which corresponds to the North Cape, and beyond. The large number of satellites together with the optimisation of the constellation, and the availability of the three active spare satellites, will ensure that the loss of one satellite has no discernible effect on the user. Two Galileo Control Centres (GCC) will be implemented on European ground to provide for the control of the satellites and to perform the navigation mission management. The data provided by a global network of twenty Galileo Sensor Stations (GSS) will be sent to the Galileo Control Centres through a redundant communications network. The GCC’s will use the data of the Sensor Stations to compute the integrity information and to synchronize the time signal of all satellites and of the ground station clocks. The exchange of the data between the Control Centres and the satellites will be performed through so-called up-link stations. Five S-band up-link stations and 10 C-band up-link stations will be installed around the globe for this purpose. As a further feature, Galileo will provide a global Search and Rescue (SAR) function, based on the operational Cospas-Sarsat system. To do so, each satellite will be equipped with a transponder, which is able to transfer the distress signals from the user transmitters to the Rescue Co-ordination Centre, which will then initiate the rescue operation. At the same time, the system will provide a signal to the user, informing him that his situation has been detected and that help is under way. This latter feature is new and is considered a major upgrade compared to the existing system, which does not provide a feedback to the user.
What is EGNOS? "When you get a GPS navigation signal, how do you know you can trust it?" asks Laurent Gauthier, the EGNOS project manager at the European Space Agency. "EGNOS will tell you whether you can trust the signal. It will tell you that you are at a particular spot with a high degree of certainty and definitely within an area enclosed by a circle with the spot at the centre. In effect, it will give you your position and say by how much it could be out." EGNOS is Europe's first venture into satellite navigation. It will augment the two military satellite navigation systems now operating, the US GPS and Russian GLONASS systems, and make them suitable for safety critical applications such as flying aircraft or navigating ships through narrow channels. 
Consisting of three geostationary satellites and a network of ground stations, EGNOS will achieve its aim by transmitting a signal containing information on the reliability and accuracy of the positioning signals sent out by GPS and GLONASS. It will allow users in Europe and beyond to determine their position to within 5 m compared with about 20 m at present.EGNOS is a joint project of the European Space Agency (ESA), the European Commission (EC) and Eurocontrol, the European Organisation for the Safety of Air Navigation. It is Europe’s contribution to the first stage of the global navigation satellite system (GNSS) and is a precursor to Galileo, the full global satellite navigation system under development in Europe. EGNOS will become fully operational in 2004. In the meantime, a test signal, broadcast by two Inmarsat satellites, allows potential users to acquaint themselves with the facility and test its usefulness.
About Telecommunications / Planning for the future / A global trendsetter Communications is the new fashion. And in a fast-moving world of telecommunications, internet and multimedia business the latest trends are all important – yesterday's technology is quickly superseded. That's why ESA's latest telecommunications programme aims to set the pace – keeping European business and industry right at the forefront of the information age. The global telecommunications market is a huge, multi-billion Euro business. So for European operators there's no room for complacency. Modern business needs the ability to adapt and respond quickly to changing market conditions. Nowhere is this more so than in the telecommunications marketplace. ESA's 21st century telecommunications strategy has therefore been developed with this in mind. It is designed to adapt to changing circumstances and trends, whilst at the same time acting as a catalyst for the imagination, allowing the conception and development of new technologies. This bold vision has been brought together under a set of programme lines which allow a quick response to the needs of industry. The Telecommunications programme includes a wide range of activities – from analysing the performance of the global telecommunications market and studies on how to compete, to full development of new systems and technology-orientated activities. Each programme line has a distinct purpose and diverse goals. This allows for different levels of participation and accommodates market driven motivation:
Programme development Activities are designed to germinate ideas and concepts that will determine the key areas of development and form the seeds of future telecommunications technologies and services. Programme development therefore covers overall strategy, including the analysis of short and long-term requirements of industry, users and operators. It is designed to keep ESA's telecommunications programme on the pulse of exactly what is happening on a global scale. Typical activities therefore include market studies, system and services requirement studies, liaison with satellite and service operators, general monitoring, and providing a lead in the standardisation of services and systems. More far-sighted studies focus on futuristic technologies and system concepts. Support provided by Programme development includes evaluation of new system concepts, technologies and frequency bands, and their impact on the system concepts to which they may be applied. Some of the long-term initiatives will be followed up by specific technology developments.
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Developed by Ewapps S.A. | |
| This project is being implemented with the financial support of the European Union. |
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