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Why shouldn't it be possible to turn off only those satellites that are visible in a certain area? I don't see any argument in your favour.

• dogma1138 10y ago
  Satnav sattelites are not geosynchronous what are you going to do press on and off every time passes over? You do understand that satellites are not light bulbs right?
  • madez 10y ago
    Of course you could turn sending the signal on and off depending on the time or where they are.
    • dogma1138 10y ago
      A satellite is not a lightbulb.
      • Atheros 10y ago
        That's also not a counter argument. Radio transmissions can be turned on and off.
• robryk 10y ago
  Wouldn't this cripple the system over a much wider area than intended? The are from which a satellite in LEO is visible is ~5000km in diameter.
  • dogma1138 10y ago
    Galileo isn't in LEO https://en.wikipedia.org/wiki/Medium_Earth_orbit https://en.wikipedia.org/wiki/Medium_Earth_orbit but yes, shutting off the signal would mean that a radius of about 7000 (GPS sats can be seen across about 6500~ miles depending on the exact orbit and angle, Galileo will have more coverage since they are at a higher orbit, if you really want to know here is how you calculate it http://gis.stackexchange.com/questions/77651/how-to-find-ring-of-coverage-of-gps-satellite-on-wgs-84-ellipsoid http://gis.stackexchange.com/questions/77651/how-to-find-rin...) miles has no SatNav... Jamming can shut down GPS in any range from 10M to 100,000M turning the transmitters of effectively shuts down GPS to half the globe. ]