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Geeky bit of fun

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Just posting this as a bit of fun. ;) It will be old news to some but for those who don’t know it’s can be fascinating.


Have you ever wondered where the satellites that drive your GPS are in relation to you? :laughing: Most GPS units will crudely show you using a diagrammatic sky chart e.g. my Garmin yellow eTrex has a Tracking Satellites page (in Advanced Sky View) which shows me which birds I am locked onto (they are numbered using their PRN codes) and where they are in the sky in relation to my position (see diagram below).


However if you want to see where they really are in relation to the earth, you can track them using NASA’s J-Track 3D. You can select the GPS satellites in the Java applet that pops up by using Satellite; Select. The PRN numbers should accord with the numbers your GPS e.g. GPS BIIA-10 (PRN32) is no 32 on your GPS unit.


You can also use the Real Time Satellite Tracking website to see what country they are currently over but bear in mind they are over 12K miles up! You can tell this site your location then click the Live In Your Sky ‘GPS SATELLITES’ link to shows you the GPS birds over a map of your part of the world – you can identify each one by double clicking on it - the info’ appears in the top right of the screen. Again it is the PRN number that relates to your GPS not the Navstar number.


I know this is very nerdy but quite good fun if you’ve not already discovered it. ;)


Enjoy :D



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Wow! This is amazing! I left my GPSr on the windowsill and checked the PRN numbers of the farthest satellites it picked up and found one was over Japan and another was off the coast of Chile! That's a pretty sensitive receiver! :D


It was also interesting to see the orbits of other satellites like the geostationary weather and TV ones. I didn't realise that Chandra's orbit was so elliptical either. Something to watch on rainy evenings. Better than Eastenders! :unsure: Thanks for the info Robin.


PS Glad to see Cleeve Hill Curious is back. B)

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