Does GPS use theory of reletivity?

Question

I read on multiple website including wikipedia that GPS uses theory of reletivity because the clocks in the satellites slow down. Is this true? And what exactly causes the clocks on the sattelites to slow down?

Answer 1

yes, it's true. Without compensating for the effects of relativity the gps satellite clocks drift about 45 microseconds a day from ground based clocks, that doesn't sound like much, but it translates into an error of about 10km distance pr day calculating your position. It is caused by the satellites being in orbits high above the earth, where the curvature of spacetime due to the earth's mass is less than it is at the earth's surface.

Answer 2

Both General and Special Relativity affect the timing of the global GPS system .



Special Relativity concerns speed and General Relativity concerns gravity .



First of all , speed . . . ( Special Relativity )



Basically , the faster you travel compared to another object / person , the slower the passage of time will be for you



Secondly , Gravity . . . ( General Relativity )



Basically , the closer you are to the centre of mass of an object , the greater the acceleration you feel , so , an object on the surface of a planet will be accelerated faster than an object in orbit around that planet .



When you put these two relativistic laws together you get something quite unique .



First off with Special relativity , in this case , the time on the GPS system will 45 miliseconds slower per 12 hour period compared to a surface based clock .



Secondly , with General relativity , the clock on the GPS system will be 7 miliseconds FASTER , because they are further away from the centre of mass than a clock on the surface of the Earth .



The net effect is that the clock on a GPS system satellite is 38 miliseconds slower per 12 hours than a clock on the surface of the Earth .

Answer 3

The satellites are orbiting the earth at fairly brisk speeds, completing a 72,000 km orbit roughly twice a day. We are moving pretty fast too, due to the orbit and rotation of the planet, but because we and the clocks aboard the satellites are moving at different speeds, we experience relativistic time dilation to a different degree than the satellites do.



GPS position tracking is absolutely reliant on accurate timing, so the clocks in the satellites need to be compensated to account for relativity in order for the signal they generate to be useful to us on the surface of the planet.

Answer 4

Have you read about governing signals, three types of frequencies, transponders on board and so on? Do not miss it any more. Attentivly read about satellites paying attention to very space systems have being expluatated formerly as well. As conclusion it will be JPS system.

Answer 5

It's true.



A GPS satellite is essentially an atomic clock. 24 hours a day, 365 days a year, each satellite broadcasts the current time.



Now, your unit listens to the broadcasts - and, since the signal travels at a finite speed (about 186,282 miles/second), the times it hears doesn't agree - and, to figure out where you are on the Earth, it calculates the differential in time signals, and uses that to pinpoint you.



Now - there are two things affecting the GPS satellites.... first, the *closer* you are to a gravitational source, the *slower* time moves for you. So, for you and I, here on the Earth's surface, time is passing *slightly* slower than it is for the 6 guys on the space station. It's not much of an effect - but, over days and weeks, it can mean an error measured in miles when considering GPS.

The second effect is called "Frame dragging" and it has to do with the Earth's rotation. Since Earth is a gravitational source, and since it rotates, it kind of 'drags' space with it as it turns. The satellites need to account for this slight effect as well.

Answer 6

very much so.



the satellites are moving at a significant speed with respect to an observer on earth, and they are at a different gravitational potential. so their clocks are set to 10.22999999543 mhz, received as 10.23 mhz on earth.