Knowing the distances to three stations is enough to find a hidden position
GPS receives only information from several satellites about "how many kilometers away I am from each satellite." How can it determine an exact position from that information alone? This time, the real position is hidden. Using only the distance values and the circles below, drag the blue dot to the true position.
Principle: Any point at distance r_A from station A can lie anywhere on a circle centered at A with radius r_A. Do the same for stations B and C. There is exactly one point where all three circles intersect, and that point is the hidden position.
🔍 Distance to the hidden position (given values)
To A -To B -To C -
Drag the blue dot to where the three circles intersect
💡 Real GPS calculates distance from the time difference in satellite signals arriving (speed of light × elapsed time). Three satellites can determine position; a fourth also allows the exact time to be determined.