Triangulation: from 1 dimension to 3 dimensions
So we crafted these chips that can accurately measure distance between two points. It is like inventing an invisible ruler. Once this is done, the rest is simple geometry.
Distance measurement is like positioning in one dimension: you know the distance but not the direction of the device. Actually, you can draw a circle around you with the correct radius and the device could be anywhere on that circle.
Now, if you can get another measurement from another place, then you can draw a second circle and the device will be located at the intersection between these 2 circles. The process of comparing the two circles is called triangulation.
If you have only one reference, you can only do 1D positioning. If you have 2 reference points, you can do 2D positioning. Three or more reference points allow you to do 3D positioning with increasing accuracy as you add reference points.