LORAN : a hyperbolic radio-positioning system

As it is well known, LORAN is a radio navigation system by which hyperbolic lines of position are determined by measuring the difference in the times of reception of synchronized pulse signals from two fixed transmitters; by using two pairs of such transmitters an unlimited number of users can determine their own positions as the interception point between two such hyperbolic lines. In the standard use of LORAN systems there is a chain of fixed transmitters and the user, generally mobile, employs a receiver system to compute his own position.