Inmarsat C and Mini C terminals can receive broadcast messages known as Enhanced Group Calls (EGC). EGC is the system for broadcasting Maritime Safety Information (MSI) and SAR- related information messages to Inmarsat C and Mini C terminals, and supports two services: SafetyNET and FleetNET.
SafetyNET is the international service for the broadcast and automatic reception of maritime safety information (MSI) and SAR-related information via the Inmarsat EGC system.
SafetyNET receiving capability is part of the mandatory equipment required to be carried by certain ships in accordance with the provisions of the International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended.
It is used by, but not limited to, NAVAREA co-ordinators for NAVAREA warnings and other urgent safety-related information; national coordinators for coastal warnings and other urgent safety-related information (the world’s oceans are divided into 21 geographical sea areas, called NAVAREAs in which various governments are responsible for navigation and weather warnings); METAREA issuing services for meteorological warnings and forecasts METAREAs are sea areas for weather forecast broadcast); and MRCCs for shore-to-ship distress alerts, SAR information and other urgent safety-related information.
SafetyNET messages can be directed to all ships in an entire ocean satellite region, to fixed NAVAREAs/METAREAs, to user-defined circular and rectangular addressed areas and to coastal areas with safety, urgency or distress priority. Reception of messages with urgency and distress priority will set off audial and visual alarms on the terminal and these messages will automatically be printed out on SOLAS-compliant terminals.
All ships navigating inside the addressed areas will receive MSI automatically. To receive costal warnings, ships’ terminals should be set up accordingly.
FleetNET is a commercial service and allows information to be sent to a virtually unlimited number of predesignated mobile terminals simultaneously, irrespective of their position. To receive EGC FleetNET messages, ships should have an Enhanced Data ID (ENID) downloaded into the terminal by a FleetNET service provider, using a poll command. The service may be used by shipping companies, organisations distributing news, commercial weather providers, etc.
Inmarsat C data reporting and polling services
The data reporting service allows Inmarsat C and Mini C terminals to send short data reports, up to four data packets, to a shore-based authority or operational centre.
A typical data report could be a ship’s position report, sailing plan, or fisheries catch report – any data that can be encoded into data packets for the Inmarsat C system. One of the services to use data reporting and polling communication protocol is Long Range Identification and Tracking (LRIT) of ships, as required by the IMO.
Data reports may be sent from ships regularly, randomly or in response to a polling command from a shore-based operational centre. A typical polling command may instruct an Inmarsat C terminal to send a data report immediately or at a defined start time, with particular repetition intervals, to stop sending reports or to perform a defined task.
To transmit a data report, the MES should have Data Network ID (DNID) and Member number downloaded using polling command. Both are stored in the terminal’s memory.