3 ms·
Talk about deployment hell - puts things into perspective: "to counteract the General Relativistic effect once on orbit, they slowed down the ticking frequency
by hoggle 12y ago
Talk about deployment hell - puts things into perspective:
"to counteract the General Relativistic effect once on orbit, they slowed down the ticking frequency of the atomic clocks before they were launched"
The mind boggles.
It makes me uneasy that we only have this single system though (the effects of a GPS failure would be quite severe I guess). Do the people behind GPS collaborate with the Galileo folks?
Thanks a lot for the submit, now I need to find a good book on the history behind the GPS!
- jupiter 12y agoThere is http://en.wikipedia.org/wiki/GLONASS http://en.wikipedia.org/wiki/GLONASS
- timthorn 12y agoThere are multiple GNSS platforms - not just GPS & Galileo, but also GLONASS, Compass, IRNSS, and others. Some receivers are multi-system capable, such as: http://www.u-blox.com/en/gps-chips/stand-alone-gps-chips/ubx-g7020-ctktka.html http://www.u-blox.com/en/gps-chips/stand-alone-gps-chips/ubx...
- tomfanning 12y agoAnd the iPhone, Samsung Galaxy and others, at least assisted GPS + GLONASS http://en.wikipedia.org/wiki/GLONASS#Receivers http://en.wikipedia.org/wiki/GLONASS#Receivers
- CWuestefeld 12y agoGiven that 4 satellites are necessary for a fix, are such receivers able to mix-and-match satellites, say, three GPS satellites and one GLONASS satellite?
- agos 12y agoThe system is a bit more redundant now: there are now 32 satellites, and on average 9 are visibile from any point.
- anrope 12y agoThere used to be a terrestrial radionavigation system called Loran-C that could be used for positioning and timing, but it was decommissioned in 2010. Loran-C was a high-power, low-frequency signal as opposed to the very-low-power, high-frequency signal of GPS. This made Loran-C less susceptible to jamming. It was a nice backup. http://en.wikipedia.org/wiki/Loran-C http://en.wikipedia.org/wiki/Loran-C