See Einstein at work

Satellites move at high speed far above Earth, where gravity is weaker. According to Einstein's general theory of relativity, weaker gravity makes clocks run faster. According to his special theory of relativity, fast motion makes clocks run slower. It's hard to imagine, but time passes at a different rate aboard a satellite than on Earth! This dashboard shows live GPS or GLONASS satellites, depending on the receiver's current mode, and the calculated relativistic clock effects for the selected satellite.

Select a satellite from the sky plot or from the list below it.

Satellite type: Unknown Select type:
GNSS receiver Unknown
Location Bladel, Netherlands
Time --:--:--
View direction 247° WSW
Visible 0 satellites
Positioning 0 satellites

Selected satellite: No satellite selected

Waiting
Height above Earth
-- km
Approximate distance from receiver
-- km
Gravity at orbit
-- m/s²
Orbital speed
-- km/s
Height in sky
--° above the horizon
Azimuth
--°
Signal
-- dB-Hz
Used for positioning
Waiting

Relativistic time dilation

Gravity -- μs/day
Motion -- μs/day
Combined -- μs/day

Relativity correction needed

Sky plot    

Outer circle: horizon; center: points straight up from the receiver (zenith).