A hyperbolic navigation system for measuring differences between distances from a radio receiver to three or more fixed transmitters of known geographic location. One type of Loran operates in a narrow band about 2 MHz; another in a narrow band about 100 kHz. The receiver's location is found to lie on a particular hyperbola like curve on the ellipsoid by measuring the difference in times of arrival of pulses sent synchronously from a single pair of transmitters. This curve is one of the two loci of all points whose distances from the two stations differ by the linear equivalent of the time interval measured. By measuring the time interval using a different pair of stations, a second hyperbola-like curve is determined. The receiver is therefore located at the intersection of these two curves. Note that each difference actually determines a pair of hyperbolas (i.e., a complete hyperbola of two branches.) However, one branch is usually too far distant from the approximately known location of the receiver to need consideration. Furthermore, it is usually on land.