How many GPS satellites are needed to produce the most accurate position solution?

To achieve the most accurate position solution using GPS technology, a minimum of four satellites is required. This is because GPS positioning relies on a technique called trilateration, which requires a minimum of three satellites to determine a two-dimensional position (latitude and longitude) and a fourth satellite to obtain an accurate altitude (elevation) coordinate.

The use of four satellites allows the GPS receiver to simultaneously calculate the position in three-dimensional space and correct for any discrepancies in time measurements between the satellites and the receiver. Each GPS satellite continuously transmits signals that include its location and the precise time the signal was sent. The receiver calculates how long it took for each signal to arrive, which, combined with the known speed of light, allows it to determine how far away each satellite is.

Thus, when four satellites are utilized, they provide enough information to resolve any potential errors and refine the accuracy of the position solution, enhancing both the precision of the location and the reliability of the navigation data.