How does a GPS receiver determine its position?

A GPS receiver determines its position by calculating multiple ranges from at least four satellites. This process involves a method known as trilateration, where the receiver measures the distance to several satellites based on how long it takes for signals from those satellites to reach the receiver. Each satellite provides a spherical range of possible locations, and by determining the intersection of these spheres from multiple satellites, the GPS receiver can pinpoint its exact location in three-dimensional space (latitude, longitude, and altitude).

To achieve an accurate position fix, at least four satellites are typically required. With three satellites, the receiver can establish a two-dimensional position (lat and long), and the fourth satellite helps in determining altitude and correcting for any clock discrepancies between the satellite's atomic clock and the receiver's less accurate clock.

This method of position determination is essential for providing reliable and precise navigation information for aviation and many other applications.