Extensively used low-frequency, high-power terrestrial navigation system

Might be phased out in favor of GPS, which is microwave-frequency, low power, and satellite

Might be modernized to complement GPS


24 USCG U.S. LORAN-C stations work in partnership with Canadian and Russian stations to provide coverage in Canadian waters and in the Bering Sea.

LORAN-C TD lines on P-Sea plot

Operational characteristics on the boat

LORAN-C provides better than 0.25 nautical mile absolute accuracy for suitably equipped users within the published areas. Users can return to previously determined positions with an accuracy of 50 meters or better using LORAN-C in the time difference repeatable mode.

Some chartplotters can use LORAN instead of GPS, or combine the two for greater accuracy

LORAN receivers usually have NMEA 0183 output

When the Global Positioning System (GPS) appeared in the1980s, with its positioning accuracy of tens of meters, many began to regard Loran-C as irrelevant. But others saw it as an essential source of position and time that could still be relied upon if GPS failed.

Joint use of LORAN and GPS


An advanced LORAN system can complement GPS

There are budget wars; some want to shut down LORAN and use just GPS.

eLoran is seen both as a complement and backup to GPS.

More accurate than LORAN-C with same or better accuracy

Precise enough to bring ships into harbor in low visibility

Complements GPS

Like GPS, a source of precision time and frequency reference

Technically different enough from GPS that environmental conditions, or sabotage, unlikely to affect both

High power transmission allows cheap receivers, even in the same box as GPS.

Will do some things GPS can't, such as acting as a static compass