No it isn't - in this case triangulation is the correct technique. Trilateration is when you measure distances. For instance, locating the epicenter of an earth

No it isn't - in this case triangulation is the correct technique. Trilateration is when you measure distances. For instance, locating the epicenter of an earthquake is done by comparing the time at which various waves arrive, and making calculations based on the known speeds of those waves. Doing that with the speed of light at terrestrial distances is very tough and will be prone to inaccuracies and large errors. Instead, you measure the angles at which the signal is strongest, and that is triangulation.