Between the GPS systems start of operations in 1994, and today, what kind of difference in time would the satellites' internal clocks have as compared to clocks on Earth?
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"...An error of a billionth of a second in time corresponds to an error in location of 1 foot.
GPS is one of the first operating systems, excluding high-energy accelerators, that has important effects from relativity. When the first satellite was launched in 1997 there was still a lot of controversy about the Einstein’s theory of Special and General Relativity. First satellite contained the first Cesium clock to be placed in the orbit and there was a lot of people who doubted that relativity effects are real. A frequency synthesizer was build into satellite clock system so that after launch, if it proved to be that clock would run at the rate predicted by the General Relativity, it could be turned on to bring clocks in the coordinate rate necessary for operation. The clock on board was operated for about 20 days without turning on the synthesizer and the frequency measure during that interval was 442.5 parts in 1012 faster then the clocks on the ground. If no correction would of took place this would resulted in error of about 38,000 nanoseconds per day. The frequency predicted by General Relativity was only within 3.97 parts of 1012 which was within accuracy capabilities of orbiting clock. It is not easy right now to perform relativity tests using GPS because satellite clocks are actively corrected to within 1 microsecond of Universal Coordinated Time...."
http://www.phy.syr.edu/courses/PHY312.03…
GPS is one of the first operating systems, excluding high-energy accelerators, that has important effects from relativity. When the first satellite was launched in 1997 there was still a lot of controversy about the Einstein’s theory of Special and General Relativity. First satellite contained the first Cesium clock to be placed in the orbit and there was a lot of people who doubted that relativity effects are real. A frequency synthesizer was build into satellite clock system so that after launch, if it proved to be that clock would run at the rate predicted by the General Relativity, it could be turned on to bring clocks in the coordinate rate necessary for operation. The clock on board was operated for about 20 days without turning on the synthesizer and the frequency measure during that interval was 442.5 parts in 1012 faster then the clocks on the ground. If no correction would of took place this would resulted in error of about 38,000 nanoseconds per day. The frequency predicted by General Relativity was only within 3.97 parts of 1012 which was within accuracy capabilities of orbiting clock. It is not easy right now to perform relativity tests using GPS because satellite clocks are actively corrected to within 1 microsecond of Universal Coordinated Time...."
http://www.phy.syr.edu/courses/PHY312.03…
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The GPS clocks would be off by about 38 microseconds per day. That adds up to 0.0139 seconds per year, or 0.257 seconds since the start of December 8, 1994. That would correspond to a distance error of over 77,000 km.
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about 0.01 seconds
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Time? Not a lot. Distance? Enough to get you lost.