Four Galileo Spacecraft Ordered

[zavvy]

<b>Four Galileo Spacecraft Ordered </b><br /><br />LINK<br /><br />The Galileo satellite navigation system took another important step forward on Tuesday with the go-ahead being given to build its first four spacecraft. <br /><br />The satellites will be launched in 2008 with the whole constellation of 30 expected in orbit by the decade's end. <br /><br />The "authorisation to proceed" came with the signing of a 150m-euro contract between the European Space Agency (Esa) and Galileo Industries. <br /><br />The latter has been charged with building the system's infrastructure. <br /><br />Galileo will be compatible and interoperable with the US Global Positioning System (GPS), improving the accuracy and reliability of navigation and timing signals received across the planet. <br /><br />On the move <br /><br />The new constellation will be a joint venture between Esa and the European Union (EU). <br /><br />On 10 December, EU transport ministers gave their approval to the project. Tuesday's preliminary contract signed in Paris for the so-called In-Orbit-Verification-Phase is the next step. <br /><br />It will see not only the construction of the first spacecraft but the building of ground station facilities to operate them. <br /><br />A full contract, worth more than a billion euros, should be signed next year; and this will clear the way for the whole constellation to be put in orbit. <br /><br />"After extensive discussions, this authorisation to proceed enables us, at last, to get started on building the Galileo satellites," said Evert Dudok, from EADS Astrium, the major shareholder company in the Galileo Industries consortium. <br /><br />"By the end of the decade, a global independent satellite navigation system, under civil control, will be available to all." <br /><br />The new European constellation is expected to drive a multi-billion-euro industry in which receivers find their way into many more markets

 

[Leovinus]

I thought GPS was already accurate down to a few inches. We have to hurl 30 more satellites up there to improve that? <div class="Discussion_UserSignature"> </div>

 

[zavvy]

<font color="yellow">I thought GPS was already accurate down to a few inches.</font><br /><br />The US Military owns GPS and they have 'confusing' standards .. (they changed the code so that it was less effective for civilians...)

 

[najab]

><i>I thought GPS was already accurate down to a few inches.</i><p>Differential GPS is accurate down to inches, but that requires access to the military 'high precision' signals, and a transmitter at a known location on the ground. Regular civilian GPS is accurate to between 3 and 30 metres depending on where in the coverage area you are (how many satellites you can see).</p>

 

[nacnud]

The 'how many satellites you can see' is the main thing here as built up areas can disrupt the signals, plus GPS is getting so important that it’s nice to have more than one operator available.