I'm currently writing a book. In the book the main characters need to find the source of a signal but they can only use two primitive, non-directional receivers. I think it is possible to calculate the location providing they have access to a very accurate timebase which will tell them the time difference it takes the signal to reach the receivers. Each measurement would give them a plane in which the source should lie. After each measurement they move to a different location (at a considerable distance of the previous location). After two measurements they would have an line on which the source should be, the intersection between the two planes. Three measurements would give them the location of the source, the intersection between the line and the third plane. (assuming none of the planes are the same or parallel) Am i correct? And if so, how should the calculations be done. If not, is there an other way to do it with just time difference as data, f.e. using more receivers.