> How does a GPS receiver figure its distance from a GPS satellite? (Q0111)
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?