How GPS Works

Related Terms

• GPS satellite
• GPS receiver

Help Us Grow

link to us | request a link
contribute content

How does a GPS receiver figure its distance from a GPS satellite?

Yeah, the home page did kind of gloss over a few details. Let's back up and take a closer look, starting with some basic physics:

• [distance] = [speed] * [travel time]

We know [speed] because GPS signals are electromagnetic waves, which travel at light speed (approximately 300,000,000 meters per second).

We can figure [travel time] by comparing [time sent] and [time received].

• Each GPS satellite has an on-board clock and includes [time sent] in the the signal it broadcasts.

• A GPS receiver also keeps track of time, which gives [time received]

• [Travel time] is the difference between these times.

Piece of cake! Right?

See Also

• How does GPS "triangulation" work?