LORAN - Interpreting Loran Measurements

Early LORAN operation required the use of a previously-prepared map, covered with curved lines that corresponded to various distance differences from sets of received signal sources. The early LORAN devices indicated which map lines to use, the operator found the point on the map where the lines intersected to learn the location.

The latest versions of LORAN C receivers no longer require the use of a special map to determine location. These updated units contain a more sophisticated computer that calculates longitude and latitude directly, displaying in a format that does not need interpretation.

The LORAN C receiver automatically tunes first one then another and another of as many LORAN signals that can be received well enough to provide good data. After a short calculation delay the latitude and longitude is displayed.

As an illustration of the great locating accuracy achieved by LORAN C systems, commercial fishers sometimes use LORAN C when looking for buoys marking submerged crab traps left unattended in the open ocean.