On Mon, May 02, 2016 at 07:08:07PM -0500, John Hasler wrote: > Ralph Sanchez writes: > > I guess a lot of those 2.1 million customers probably live in very > > rural areas where maybe other forms aren't available, or the cost to > > lay wire would be more then they have. My thinking is, we have GPS > > that works nearly (ok maybe not) everywhere you'd go and want > > internet, so why hasn't some billionaire or multi-billion or trillion > > dollar company decided to provide a wifi type service in the same way? > > GPS requires many orders of magnitude less bandwidth than does Internet > service. There is satellite Internet service and some people in remote > areas use it. However the present version has serious drawbacks. Elon > Musk plans to change that.
In particular, GPS is a one way service. Point your receiver at the sky, let it see several satellite's radio beacons. Each beacon emits a short pulse train encoding the satellite's position and a very accurate timestamp. Your receiver does the math and now knows where it is and what the time is. The total bandwidth from a satellite is just over 1 megabit per second. If it had to be shared among various receivers, it would be completely overwhelmed by demand. But as a broadcast signal, it is very effective. -dsr-