Does GPS really need relativity?

A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day. Relativity is not just some abstract mathematical theory: understanding it is absolutely essential for our global navigation system to work properly!

Why do GPS clocks need to be corrected using the general theory of relativity?

The correction is needed because of a combination of effects on the satellite clock due to gravitational frequency shift and second-order Doppler shift, which vary due to orbit eccentricity.

Is time relativity proven?

Physicists have verified a key prediction of Albert Einstein’s special theory of relativity with unprecedented accuracy. Experiments at a particle accelerator in Germany confirm that time moves slower for a moving clock than for a stationary one.

How does special relativity affect GPS clock frequency?

Special Relativity Effect on GPS Clock Frequency Because a clock on the satellite is moving relative to the same clock on the earth, the clock on the satellite appears to run slower than the same clock on earth.

What does Global Positioning System tell us about relativity?

You can find out about this in great detail in the excellent summary over here: What the Global Positioning System Tells Us about Relativity? General Relativity predicts that clocks go slower in a higher gravitational field. That is the clock aboard the GPS satellites “clicks” faster than the clock down on Earth.

How does the rate of drift on a clock work?

Everyday clocks such as wristwatches have finite precision. Eventually they require correction to remain accurate. The rate of drift depends on the clock’s quality, sometimes the stability of the power source, the ambient temperature, and other subtle environmental variables.

What does 10km / day drift mean in GPS?

If you look at the wikipedia page about GPS and relativistic corrections, they make it clear that this 10km/day drift applies to the ‘pseudoranges’ – the initial distance calculated between the receiver and each satellite.