trilateraation

Trilateration is a method for determining the location of a point by using the measured distances to three other known points. Unlike triangulation, which uses angles, trilateration relies solely on distance measurements. Imagine three spheres, each with a radius equal to the measured distance from one of the known points to the unknown point. The intersection of these three spheres will define the location of the unknown point. In two dimensions, the intersection of three circles will yield either zero, one, or two possible locations. In three dimensions, the intersection of three spheres typically results in a single point, though ambiguities can arise in certain geometric configurations. This technique is widely used in various fields, including global navigation satellite systems (GNSS) like GPS, where receivers calculate their position by measuring the time it takes for signals from multiple satellites to arrive. The travel time of the signal, combined with the known speed of light, allows for the calculation of the distance to each satellite. Other applications include surveying, underground utility locating, and even some methods of astronomical observation.