What does 3D trilateration determine about a location?

3D trilateration is a method used to determine the precise location of a point in three-dimensional space based on distance measurements from at least three, and preferably four, reference points (usually satellites in the case of GPS). When employing 3D trilateration, the process calculates the intersection of spheres whose radii are determined by the distances to the satellites.

In this method, three satellites provide their relative distances to a receiver. The intersection of the spheres created by these distances yields a specific point on the Earth's surface, which includes both the horizontal position (latitude and longitude) and altitude (elevation). Therefore, the location determined by 3D trilateration is not merely the altitude or distance to one satellite but a comprehensive geographic location that accounts for all three dimensions.

This choice captures the essence of 3D trilateration perfectly, as the intersection of the data provided by three satellites indeed determines the position on the Earth's surface in a 3D context.