To accurately locate an object with radio waves, you need a very brief signal, ideally a pulse with sharp edges. A single frequency wave has very round edges and is not an ideal pulse for timing purposes. By mixing together many signals at various amplitudes, it is possible to create a very square signal with sharp edges. The squarer you need the pulse, the more frequencies you need to add. Very short pulses need to rise and fall nearly instantaneously in order to reach full amplitude. Therefore, the more accurately we need to time an event, the larger number of different frequencies (bandwidth) we need to use. For this reason and many others, ultra-wide band is the best modulation standard to perform localization.

We measure distances between two transceivers by computing the time it takes for a signal to perform a round trip. It requires a very precise time measurement, but we also have to deal with issues like clock instabilities. Our method to compute these distances is called two-way ranging.

Once you can measure distances, it is pretty straightforward to locate everything you want. A simple network of fixed trackers can apply basic triangulation to pin anything accurately on a 3-dimensional map. This is just one of many alternative methods…