Galileo Satellite European satellite navigation system-Galileo has passed a historic milestone, with the first determination of a groun...
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| Galileo Satellite |
A minimum of four satellites is required to make a position fix in three dimensions. The first two were launched in October 2011, with two more following a year on.
This first position fix of longitude, latitude and altitude took place at the Navigation Laboratory at ESA’s technical heart ESTEC, in Noordwijk, the Netherlands on the morning of 12 March, with an accuracy between 10 and 15 metres – which is expected taking into account the limited infrastructure deployed so far.
The €5 billion project is named after the Italian astronomer Galileo Galilei. The system consists of a network of 30-satellite with 27 operational and three active spares.
This fix relies on an entirely new European infrastructure, from the satellites in space to the two control centres in Italy and Germany linked to a global network of ground stations on European territory.
With only four satellites for the time being, the present Galileo constellation is visible at the same time for a maximum two to three hours daily. This frequency will increase as more satellites join them, along with extra ground stations coming online, for Galileo’s early servicest o start at the end of 2014.
With the validation testing activities under way, users might experience breaks in the content of the navigation messages being broadcast. In the coming months the messages will be further elaborated to define the ‘offset’ between Galileo System Time and Coordinated Universal Time (UTC), enabling Galileo to be relied on for precision timing applications, as well as the Galileo to GPS Time Offset, ensuring interoperability with GPS. In addition, the ionospheric parameters for single frequency users will be broadcast at a later stage.
Aim of Galileo is to provide a high-precision positioning system upon which European nations can rely, independently from the Russian GLONASS , US GPS , and Chinese Compass systems, which can be disabled in times of war or conflict.
Galileo is intended to provide horizontal and vertical position measurements within 1 meter precision, and better positioning services at high latitudes than other positioning systems.
