Long Range Identification and Tracking. A ship reporting system requiring ships to automatically transmit their identity, position and date/time at 6–hour intervals, as part of Maritime Domain Awareness, by contracting Governments under SOLAS.

Lower Sideband mode of emission. A form of single sideband emission, where only the lower sideband is transmitted.

Metre. Unit of length.

Distress Alerts, navigational warnings, meteorological warnings and forecasts and other important safety information for ships.

Modernised Australian Ship Tracking and Reporting System (replaces AUSREP).

Maritime Communications Station. Another term for a coast station.

A Mobile Earth Station in the Inmarsat system, which includes mobile, land, ship and airborne Inmarsat terminals. On a ship it is more commonly referred to as a Ship Earth Station (SES).

Meteorological Area: A meteorological service area with area limits similar to NAVAREA’s in the WWNWS.

Medium Frequency (300 to 3 000 kHz).

Medical and First Aid Guide. Part of the International Maritime Dangerous Goods Code.