From: glen herrmannsfeldt on 18 May 2010 14:25 In sci.physics Tony M <marcuac(a)gmail.com> wrote: (Snip on GPS and GR) > The satellite clock is compensated for GR effects. The story I heard was that the GPS system was built with an option to do the GR correction, initially turned off. It didn't take long to determine that it needed to be on. -- glen
From: Androcles on 18 May 2010 15:13 "glen herrmannsfeldt" <gah(a)ugcs.caltech.edu> wrote in message news:hsum2s$c0o$2(a)speranza.aioe.org... > The story I heard was that the GPS system was built with an > option to do the GR correction, initially turned off. > It didn't take long to determine that it needed to be on. > > -- glen The story I heard was that the GPS system was built with an option to do the GR correction, initially turned on. It didn't take long to determine that it didn't matter if it was on or off, the GPS receiver doesn't have an atomic clock and is only accurate to 15 metres horizontally and 40 meters vertically, hopeless for landing an aircraft 100 feet below ground but ok for finding the bus stop. http://www8.garmin.com/aboutGPS/waas.html Perhaps you shouldn't listen to fairy tales.
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