Enhanced Group Call (EGC)
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Contents
Overview
The Enhanced Group Call (EGC) service is a part of the GMDSS for the transmission of maritime safety information (MSI) in areas where the NAVTEX service is not available. These messages could be e.g. Navigational warnings, Meteorological warnings, Meteorological forecasts and Search And Rescue messages.
The EGC service uses the Inmarsat C system for broadcasting these messages. The Enhanced Group Call (EGC) service is used for the transmission of messages to a group of ships or to ships in a specified area via the Inmarsat satellites.
For the reception of EGC messages an Inmarsat C terminal will be used. A printer will be connected to this terminal for printing the received messages. These messages will also be stored in a log file on the terminal and can be displayed on the terminal screen.
Performance standards, testing standard & carriage requirement
Performance standards
- Resolution MSC 306(87) applies to EGC equipment installed on/after 1 July 2012
- Resolution A.664(16) applied to EGC equipment installed before 1 July 2012
Testing standard
- IEC 61097-4 - Global maritime distress and safety system (GMDSS) - Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC) equipment - Operational and performance requirements, methods of testing and required test results
Carriage requirement
- Under the GMDSS, ships over 300 GT and all passenger vessels on international voyages must carry an Inmarsat EGC receiver if engaged on voyages in any area of Inmarsat coverage where MSI services not provided by NAVTEX or HF NBDP.
How it works
The MSI provider determines which receivers or ships are to receive the message by including identifying information, such as the NAVAREA or METAREA number, circular or rectangular geographical area, coastal warning area for which the MSI is intended. On some models identification of NAVAREA/METAREA where the ship is navigating is done automatically. Individual EGC receivers can be programmed (setup) to use identification to select additional EGC messages along with some mandatory MSI addressed to areas where the ship is, and to reject some messages that are not required for the planned voyage.
Based on this selective capability, the EGC system supports two services:
- The EGC SafetyNET service, which allows the ship’s operator to program EGC receiver with main (on some models) and/or additional NAVAREAs/METAREAs, geographical areas or coastal warning areas for which MSI will be received and the categories of coastal warnings required
- The EGC FleetNET service, a commercial service, where individual EGC receivers are programmed from a shore by a poll command to store an EGC Enhanced Network IDentification (ENID) code or group ID, which is used to receive only messages intended for ships belonging to this group, such as a fleet or national flag, or subscribers to an information service.
EGC receiver types
EGC SafetyNET (and FleetNET) broadcasts are received using Inmarsat C or Inmarsat mini-C maritime terminals of different classes. Class 2 and 3 models provide EGC capability in addition to shore-to-ship and ship-to-shore messaging capability; class 0 are self-contained EGC receivers only. It should be noted that not all these models meet GMDSS requirements and not all non-GMDSS models support reception of MSI.
Typical system components
- Component 1
- Component 2...
Detailed requirements
MSC.306(87)
| 1. Introduction | 1.1 | The EGC equipment to be used in the GMDSS should comply with the general requirements set out in the annex to Assembly resolution A.694(17); relevant IEC standards (IEC 61097-4 and IEC 60945) and the following minimum performance requirements |
|---|---|---|
| 1.2 | The equipment should be capable of producing a printed copy of received information. Received EGC messages may be stored for later printing with an indication to the operator that the message has been received, except for the vital messages referred to in paragraph 3.2 which should be printed out upon receipt | |
| 1.3 | The EGC installation may be either separate or combined with other installations | |
| 2. Technical requirements | The equipment should be type-approved by Inmarsat and should comply with the environmental conditions and electromagnetic compatibility requirements specified in IEC 60945 | |
| 3. Operation | 3.1 | The equipment should provide a visual indication that the ship's position has not been updated during the last 12 h. It should only be possible to reset this indication by revalidating the ship's position |
| 3.2 | Means should be provided to enter the ship's position and current and planned NAVAREA/METAREA codes manually so that area group calls can be received. Means should also be provided to enter current and planned coastal warning service coverage areas and different classes of messages. Optionally, the ship's position, as determined by the navigational equipment, may be entered automatically and the NAVAREA/METAREA code automatically derived therefrom | |
| 3.3 | Provision should be made for a specific aural alarm and visual indication at the position from which the ship is normally navigated, to indicate receipt of a distress or urgency priority EGC message. It should not be possible to disable this alarm and it should only be possible to reset it manually and only from the position where the message is displayed or printed | |
| 3.4 | The equipment should indicate when it is not correctly tuned or synchronized to the EGC carrier | |
| 3.5 | Any message should be printed regardless of the character error rate of its reception. The equipment should print a low line mark if a character is received corrupted | |
| 3.6 | Acceptance or rejection of service codes should be under the operator's control except that equipment should always receive navigational warnings, meteorological warnings and forecasts, search and rescue information and shore-to-ship distress alerts, which are directed to a fixed or absolute geographical area within which the ship is operating | |
| 3.7 | Means should be provided to prevent the re-printing of a message once it has been received without error | |
| 3.8 | The printing device should be capable of printing at least the standard International Alphabet Number 5 (IA5) character set. Other character sets are optionally used according to ISO 20223 standards or CCITT Recommendation T.61 | |
| 3.9 | The printing device should be able to print at least 40 characters per line | |
| 3.10 | The signal processor and printing device should ensure that if a word cannot be accommodated in full on one line, it should be transferred to the next line. The printing device should automatically feed five lines after completing the printed messages | |
| 3.11 | A local audible alarm should be sounded to give advanced warning of the printing device "paper low" condition. It should not be possible to confuse the sound of the "paper low" alarm with that of the distress or urgency alarm caused by the reception of a distress or urgency priority message | |
| 4. Sources of energy | 4.1 | The EGC equipment should normally be powered from the ship's main source of electrical energy. In addition, it should be possible to operate the EGC equipment, and all other equipment necessary for its normal functioning, from an alternative source of energy |
| 4.2 | Changing from one source of supply to another, or any interruption of up to 60 seconds' duration of the supply of electrical energy, should not require the equipment to be manually re-initialized and should not result in loss of received messages stored in the memory | |
| 5. Antenna siting | 5.1 | Where an omni-directional antenna is used, it is desirable that the antenna be sited in such a position that no obstacle likely to degrade significantly the performance of the equipment appears in the fore and aft directions down to -5° and in the port and starboard directions down to -15° |
| 5.2 | Where a stabilized directive antenna is used, it is desirable that the antenna be sited in such a position that no obstacle likely to degrade significantly the performance of the equipment appears in any azimuth down to -5° | |
| 5.3 | For omni-directional antennas, objects, especially those within 1 m of the antenna, which cause a shadow sector of greater than 2°, are likely to degrade significantly the performance of the equipment | |
| 5.4 | For directive antennas, objects, especially those within 10 m of the antenna, which cause a shadow sector of greater than 6°, are likely to degrade significantly the performance of the equipment | |
