Always knowing and letting know where you are
For ships, knowing their exact position at all times is essential, and communicating that position can be vital in case of emergency. In the past, in case of serious difficulty, crews had to establish their exact position and communicate it by radio or telegraphy to other ships or shore-based centres in order to call for assistance. It was a system open to breakdown or that might provide incomplete or erroneous information.
The IMO (International Maritime Organization) is the specialized UN (United Nations) agency with responsibility for the safety and security of shipping. Of particular importance to IMO is the International SOLAS (Safety of Life at Sea) Convention, the first version of which was adopted in 1914, as a direct result of the sinking of the Titanic. The disaster represents the best known early example of a distress signal being sent via wireless telegraphy using Morse code.
Search and rescue on an international scale
In 1979 IMO adopted the International Convention on Maritime Search and Rescue (SAR) so that, no matter where an accident occurred at sea, the rescue of persons in distress would be coordinated by a SAR organization and, when necessary, by co-operation between neighbouring SAR organizations. The convention includes recommendations on establishing ship reporting systems for SAR purposes.
Recognizing that satellites would play an important role in SAR operations at sea, IMO established the International Maritime Satellite Organization, known today as Inmarsat, to provide emergency maritime communications. This led to IMO's member states adopting the basic requirements ofGMDSS as part of SOLAS, and which is an essential tool for SAR.
In agreement with IMO, which recognized the IEC's expertise in the electrotechnical domain, IECTC 80: Maritime navigation and radiocommunication equipment and systems, took on the role of producing International Standards for GMDSS.
Multiple standards for an integrated system
GMDSS is an international integrated communications system that uses safety systems based around different communications technologies. It is intended to perform many functions including signalling distress and coordinating SAR operations. It should ensure that no ship in distress can disappear without trace.
Under the GMDSS obligations, all cargo ships over 300 gross registered tonnes and all passenger vessels on international voyages have been required, since August 1993, to be equipped with satellite EPIRBs (emergency position-indicating radio beacons) and NAVTEX (Navigational Telex) receivers to automatically receive shipping safety information for navigational, SAR and meteorological warnings and urgent information. More equipment has been added since.
In order to cover different areas and ranges, GMDSS relies on MF/HF/VHF (medium/high/very high frequency) radio and on satellite-based communications, the latter via COSPAS/SARSAT, the international satellite-based SAR distress alert detection and information distribution system, and Inmarsat systems.
Inmarsat provides ship-to-shore, ship-to-ship and shore-to-ship voice, data and telex services that require different equipment and terminals.
TC 80 prepares the IEC 61097, Global maritime distress and safety system (GMDSS) series of standards for the various components of the system. Eleven standards have been published so far covering all aspects and technologies of GMDSS. One standard concerning NAVTEX equipment was released in January 2012. Two more, dealing with operational and performance requirements for Inmarsat ship earth stations, are at the FDIS (Final Draft International Standard) stage.
Latest standards for Inmarsat services
Satellite communications in all domains are constantly evolving to provide new and better services that then drive the need for new standards and the development of existing ones, as the latest FDIS documents that deal with Inmarsat components show.
The third edition of IEC 61097-4 covers Inmarsat-C SES (ship earth station) and Inmarsat EGC (enhanced group call) equipment. This is able to receive multiple-address messages and is designed for use in GMDSS and LRIT (long-range identification and tracking) applications.
The standard lists all non-operational and operational requirements as well as the technical characteristics and methods of testing for both types of equipment.
The first edition of IEC 61097-15 details the operational requirements as well as the technical characteristics and methods of testing for Inmarsat FB500 SES. These are stations “capable of transmitting and receiving distress and safety communications, initiating and receiving distress priority calls and transmitting and receiving general radiocommunications, using radiotelephony (voice)” for use in the GMDSS.
These new standards enhance and expand the capabilities of the Inmarsat element of GMDSS.
Evolutionary system requiring constant updating
The 61097 series of standards for GMDSS are based on IMO resolutions defining equipment performance standards for all components of the system. IMO is constantly reviewing these and adding new ones as more requirements are identified, particularly concerning security and piracy and increased interest in shipping traffic in polar regions, with the unique navigational and SAR concerns specific to these areas.
With the constant quest for increased safety and security at sea and as the system evolves to deal with the emergence of new risks, TC 80 is set to have a busy agenda in the future, producing updated and, when needed, new, standards for the GMDSS.