Published on November 5, 2007
Global Maritime Distress and Safety System (GMDSS): Global Maritime Distress and Safety System (GMDSS) By S. M. Challo, Radiocommunication Bureau 2000 General concept of GMDSS: General concept of GMDSS Application: Application The GMDSS applies to vessels subject to the SOLAS Convention - that is: Commercial vessels of 300 Gross Registered Tons (GRT) and above and all passenger vessels, engaged on international voyages. The GMDSS became mandatory for such vessels as from February 1, 1999. Commercial vessels under 300 GRT, or those above 300 GRT engaged on domestic voyages only are subject to the requirements of their Flag State. Some Flag States have incorporated GMDSS requirements into their domestic marine radio legislation - however many have not. GMDSS: Implementation Calendar: GMDSS: Implementation Calendar 1.7.1991: Entry into force of the Radio Regulations (gradual implementation of GMDSS) 1.2.1992: Entry into force of the 1988 Amendments to SOLAS Convention (IMO) specifying (for SOLAS ships): new ships built after 1.2.1992: SART and two-way VHF RTF apparatus for survival craft; After 1.8.1993: all ships with NAVTEX receiver and S-EPIRB; Slide5: After 1.8.1993: all ships with NAVTEX receiver and S-EPIRB; After 1.2.1995: all ships will have to carry at least one radar capable of operating in the 9 GHz band, and SART and two-way VHF RTF apparatus for survival craft ; new ships built after 1.2.1995 must comply with all applicable GMDSS requirements After 1.2.1999: all ships must comply with the GMDSS Functional requirements : Functional requirements The GMDSS regulations (chapter IV of the International SOLAS Convention), require that every GMDSS equipped ship shall be capable of; transmitting ship-to-shore Distress Alerts by at least two separate and independent means, each using a different radio communication service; receiving shore-to-ship Distress Alerts; transmitting and receiving ship-to-ship Distress Alerts; transmitting and receiving search and rescue co-coordinating communications; transmitting and receiving on-scene communications; Slide7: transmitting and receiving locating and homing signals; receiving maritime safety information; transmitting and receiving general radiocommunications relating to the management and operation of the vessel; transmitting and receiving bridge-to-bridge communications. Equipment vs. Operational requirements : Equipment vs. Operational requirements The major difference between the GMDSS and its predecessor systems is that the radio communications equipment to be fitted to a GMDSS ship is determined by the ship's area of operation, rather than by its size. Because the various radio systems used in the GMDSS have different limitations with regards to range and services provided, the new system divides the world's oceans into 4 areas: Slide9: Area A1 lies within range of shore-based VHF coast stations (up to about 50 nautical miles); Area A2 lies within range of shore based MF coast stations (excluding A1 areas) (up to about 150 nautical miles); Area A3 lies within the coverage area of Inmarsat communications satellites (excluding A1 and A2 areas - approximately between latitude 70 degrees north to latitude 70 degrees south); and Area A4 comprises the remaining sea areas outside areas A1, A2 and A3 (the polar regions). GMDSS communication systems: GMDSS communication systems The GMDSS utilizes both satellite and terrestrial radio systems as appropriate: Sea Area A1 (short range) - VHF is used to provide: 1) DSC alerting on CH-70, 2) Distress and Safety voice communications on CH-16. Sea Area A2 (medium range) – MF Frequencies are used to provide : 1) DSC alerting, 2) Distress and safety communications on voice and NBDP. Sea Areas A3 and A4 (long range) - HF &/or SES are used to provide: 1) alerting, 2) Distress and Safety communications both voice and NBDP. GMDSS: Ship equipment carriage requirements : GMDSS: Ship equipment carriage requirements A1 A2 A3 A4 VHF equipment S-EPIRB or VHF EPIRB MSI receiver VHF and MF equipment S-EPIRB MSI receiver VHF, MF and HF or satellite equipment S-EPIRB MSI receiver VHF, MF and HF equipment 406 MHz S-EPIRB MSI receiver Shore infrastructure: Shore infrastructure Each signatory country to the SOLAS Convention (basically, all of the world's major shipping nations) is obliged to enforce the appropriate carriage of GMDSS radio equipment and service documents by vessels sailing under their national flag; and also to provide suitable GMDSS shore-based infrastructure, including Coast radio stations, RCC and Search and Rescue units. However, the shore based infrastructure may be provided in conjunction with neighboring states, as appropriate. Maritime Mobile Service Identities (MMSI): Maritime Mobile Service Identities (MMSI) All DSC equipment is programmed with a unique nine digit identification number, known as a Maritime Mobile Service Identity (MMSI). The MMSI is sent automatically with each and every DSC transmission made. Maritime Identification Digits (MID): Maritime Identification Digits (MID) Maritime Identification Digits (MID) The first three digits of the MMSI are known as the Maritime Identification Digits (MID). The MID represents the country of registration (FLAG) of the vessel. MID's are allocated on an international basis by the ITU, in much the same way as the international series of call-sign prefixes are. N A V T E X: N A V T E X Introduction The NAVTEX system is used for the automatic broadcast of localized Maritime Safety Information (MSI) using Radio Telex, NBDP. The system operates on the Medium wave Frequency band. The system range is generally about 200 or so nautical miles from the transmitter. Slide16: Major service areas of NAVTEX coverage include the Mediterranean Sea, the North Sea, coastal areas around Japan and areas around the North American continent. The NAVTEX system is designed to be used in GMDSS Sea Area A2, and is utilized mainly by those countries with relatively small areas of coastline and/or sea areas to cover. Frequency of operation: Frequency of operation The NAVTEX system has been allocated three broadcast frequencies: 518 kHz - the main NAVTEX channel 490 kHz - used for broadcasts in local languages (i.e.: non-English) 4209.5 kHz - allocated for NAVTEX broadcasts in tropical areas - not used at the moment. Slide18: In real terms, 518 kHz is the only NAVTEX channel used - this means that all broadcasts from stations within the same NAVAREA must be coordinated (IMO) on a time sharing basis to eliminate interference. In addition, power outputs from each station are adjusted to control the range of each broadcast. This is particularly important during night-time hours, as Medium Frequencies tend to travel further after dark. CONCLUSIONS: CONCLUSIONS Unprecedented international cooperation over a period of about 10 years, involving IMO, ITU, IHO, WMO, INMARSAT and the COSPAS-SARSAT partners, has resulted in the maritime community being provided with an integrated distress and safety system The provision of appropriate international regulations concerning the operation and implementation of the system has been successfully completed Slide20: The implementation of the system and its efficient operation would considerably depend upon the establishment of shore based facilities by the Members and proper network arrangements that will include: maritime satellite and terrestrial radio services between the coast and ships, connections between coast stations and CES and RCCs, telecommunication interconnections between RCCs.