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www.telegraph.co.uk said:
A new Nasa map of the universe, calibrated using mysterious quasars a billion times brighter than the Sun, is being used to guide drivers’ satnav systems.
The GPS technology behind satnavs work in the same way as sailors navigating by the stars – they use seemingly fixed landmarks to establish the position of the satellites, and then the GPS receiver works out its position using its distance from the satellites.
Dr Chopo Ma of Nasa's Goddard Space Flight Center, says: "For GPS to work, the orbital position, or ephemeris, of the satellites has to be known very precisely.
However, the “fixed landmarks” that the sailors used, the stars, are not fixed at all, but moving at hundreds of thousands of miles an hour – as is the Earth.
Read more...
The GPS technology behind satnavs work in the same way as sailors navigating by the stars – they use seemingly fixed landmarks to establish the position of the satellites, and then the GPS receiver works out its position using its distance from the satellites.
Dr Chopo Ma of Nasa's Goddard Space Flight Center, says: "For GPS to work, the orbital position, or ephemeris, of the satellites has to be known very precisely.
However, the “fixed landmarks” that the sailors used, the stars, are not fixed at all, but moving at hundreds of thousands of miles an hour – as is the Earth.
Read more...
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