Radio Technical Commission for Maritime Services (RTCM) is an international non-profit organization engaged in the standardization of radio-technical means for maritime navigation, communications, and related technologies. It was founded in the United States in 1947 and is headquartered in Washington, D.C.
The RTCM membership includes governmental and non-governmental organizations.
The international commission establishes rules for the [format] of data transmission (differential corrections) required when the consumer receiver operates in differential mode. [RTM 68-14-01]
Some of the standards developed by RTCM are used not only by maritime users but also by terrestrial and airborne users.
Special Committees
Active Special Committees (SC) of RTCM:
SC 101 — Digital Selective Calling (DSC) Joint Special Committee 101/110 — portable VHF radios equipped with GPS positioning system
SC 104 — transmission of corrections for Differential Global Navigation Satellite Systems (DGNSS). The standards of this committee are often applied for differential GPS and Real Time Kinematic (geodesy).
SC 109 — Electronic Charts
SC 110 — Emergency Position-Indicating Radio Beacons (EPIRB) and Personal Locator Beacons (PLB)
SC 117 — Interference of maritime communication systems in the VHF frequency band
SC 119 — Maritime Survivor Locator Devices
SC 121 — Automatic Identification Systems (AIS) and digital messaging
SC 123 — Short Digital Message Service VHF-FM
SC 127 — Enhanced Loran (eLoran)
SC 128 — Satellite Emergency Notification Device (SEND)
Related articles: ETSI — European Telecommunications Standards Institute.