LORAN (Long Range Navigation) is a radio-based navigational aid first used during World War II to locate ships and planes with greater accuracy than could be achieved with conventional techniques. LORAN determines location by comparing accurately-synchronized powerful radio pulses originating from different reference transmitter sites. Pulses from nearby transmitters arrive earlier than pulses from distant transmitters since radio signals travel at a constant speed.

At least three different LORAN signals must be received to determine latitude and longitude. In practice, the distance to more than the minimum three LORAN signals increases accuracy<.

The first LORAN systems were in use before computers were sophisticated enough to perform the complex calculations needed to process the timing comparisons. Early LORAN installations required highly-skilled operators to interpret the radio pulses. A half century later technical innovations eliminated the need for much of the skill once required to use LORAN for navigation.

LORAN...