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Canadian Coast Guard |
| Search and Rescue |
Search and Rescue
Global Maritime Distress and Safety System (GMDSS)
Download the document in [pdf 1.8MB] What is GMDSS?The Global Maritime Distress and Safety System (GMDSS) is a new international system using improved terrestrial and satellite technology and ship-board radio systems. It ensures rapid alerting of shore-based rescue and communications authorities in the event of an emergency. In addition, the system alerts vessels in the immediate vicinity and provides improved means of locating survivors. GMDSS was developed through the International Maritime Organization (IMO) and represents a significant change in the way maritime safety communications are conducted. While it is mandatory for all ships subject to the International Convention for the Safety Of Life At Sea (SOLAS) (cargo ships 300 gross tons or greater and all passenger vessels, on international voyages), GMDSS will impact on all radio-equipped vessels, regardless of size. All SOLAS ships will be required to fully comply with GMDSS by February 1, 1999. Why GMDSS?GMDSS was developed to SAVE LIVES by modernizing and enhancing the current radiocommunications system. By utilizing satellite and digital selective calling technology, GMDSS provides a more effective distress alerting system. It improves the current system by:
GMDSS EquipmentDigital Selective Calling (DSC)The traditional marine radio (VHF/MF/HF) has been enhanced with the addition of a feature known as DSC. This feature enables vessels to automatically maintain the required watch on distress and calling channels instead of the current aural listening watch. A DSC receiver will only respond to the vessel's unique Maritime Mobile Service Identity number (MMSI#), similar to a telephone number, or to an "All Ships" DSC call within range. Once contact has been made by DSC, follow-up communications take place by voice on another frequency. Satellite CommunicationsThe Inmarsat satellite network provides global communications, except for the polar regions. In areas without any VHF or MF DSC shore facilities, Inmarsat A, B or C terminals are used for distress alerting and communications between ship and shore. Inmarsat provides an efficient means of routing distress alerts to Search and Rescue (SAR) authorities. Emergency Position Indicating Radiobeacon (EPIRB)GMDSS makes use of the COSPAS-SARSAT Satellite System which provides global detection of 406 Megahertz (MHz) EPIRBs. These beacons are small, portable, buoyant, and provide an effective means of issuing a distress alert anywhere in the world. Float free EPIRBs (class 1) have been required on most Canadian commercial vessels 20m or more in length since 1989, and are highly recommended for all vessels. Owners must register these EPIRBs in the national beacon database (1-800-727-9414).
406 MHz COSPAS/SARSAT EPIRB Search And Rescue Transponder (SART)SARTs are portable radar transponders used to help locate survivors of distressed vessels, which have sent a distress alert. They are detected by radar and therefore operate in the same frequency range as radars carried onboard most vessels. SARTs transmit in response to received radar signals and show up on a vessel's radar screen as a series of dots, accurately indicating the position of the SART. In the event that a ship must be abandoned, SARTs should be taken aboard survival craft.
SART dots on radar screen
Examples of SARTs Maritime Safety Information (MSI)Maritime Safety Information broadcasts, which comprise distress alerts, SAR information, navigational and weather warnings, as well as forecasts, can be received in three different ways in GMDSS:
GMDSS Sea Areas - InternationalAlthough ship-to-ship alerting is still an important function in GMDSS, the emphasis is on two way communications between ships and shore facilities. All GMDSS ships must be capable of communicating with the shore and transmitting a distress alert by two different means. The equipment carried by a GMDSS ship is therefore determined by its area of operation and the availability of shore-based communications services. There are four "Sea Areas" defined internationally in the GMDSS: Sea Area A1 Within range of shore-based VHF DSC coast station (40 nautical
miles) GMDSS Sea Areas - CanadaIn Canada, as a result of consultations with the Canadian marine industry, it has been decided to implement sea areas A1 on the east and west coasts. Outside of A1 will be an A3 sea area with an A4 sea area in the Arctic. Consideration was given to the implementation of an A2 sea area, but due to budgetary constraints and the marine industry's preference for sea areas A1 and A3, sea area A2 is not being planned at this time nor are sea areas for the Great Lakes and St Lawrence River. On Canada's east and west coasts, VHF DSC implementation is scheduled to begin in 1998 to cover the busiest areas. Full implementation, similar to today's VHF coverage, is planned to be completed in 2002. A1 sea areas will be declared as shore facilities are provided. In the Canadian Arctic, communications will be augmented by providing HF DSC and NBDP services planned for February 1, 1999, at which time, sea area A4 will be declared.
Vessel ComplianceGMDSS requirements for all SOLAS ships on international voyages have been established by the IMO. February 1, 1999 is the date set for full compliance. Requirements for Canadian commercial vessels, not subject to SOLAS, are currently being developed in consultation with the marine industry through the Canadian Marine Advisory Council (CMAC). The carriage of GMDSS equipment on pleasure craft will not be mandatory, however, it is recommended that they carry GMDSS equipment as applicable to their area of operation. Also, for additional safety, vessels equipped with Global Positioning System (GPS) or LORAN-C are encouraged to connect this equipment to DSC and/or satellite communications equipment capable of transmitting a pre-formatted distress alert. Communications Between GMDSS Vessels & Non-GMDSS VesselsAfter February 1,1999, GMDSS ships will be maintaining an automated listening watch on VHF DSC ch 70 and MF DSC 2187.5 kHz. This will create the situation, during the transition to GMDSS, where vessels fitted with traditional, non-GMDSS radio equipment, may have difficulties alerting or contacting a GMDSS ship. The Coast Guard is addressing this by monitoring both GMDSS and traditional distress frequencies during the transition. Although the final date for the cessation of mandatory watchkeeping on VHF ch 16 by SOLAS ships is under review by the IMO, all vessels should fit VHF DSC as soon as practicable to keep the transition period short. Canadian Coast Guard Marine Communications and Traffic Services (MCTS) CentresTo help ease the transition to GMDSS and bridge the communication gap between the two systems, Canadian Coast Guard MCTS Centres will continue to monitor VHF ch 16 and MF 2182 kHz, the current distress and safety channels, until 2003. Once Canada's sea areas have all been implemented, lower cost DSC equipment is available, and it is determined that these services are no longer required, these listening watches will be discontinued. To supplement the broadcasting of Maritime Safety Information (MSI) on NAVTEX and INMARSAT EGC, MCTS Centres will continue safety broadcasts using the existing VHF continuous marine broadcast system. Canadian Rescue Co-ordination Centres (RCC) and Maritime Rescue Sub-Centres (MRSC)Canadian RCCs and MRSCs will continue to receive distress alerts transmitted by vessels and relayed via MCTS or satellite. When a GMDSS distress alert is received, the centre must re-issue an "all ships" broadcast in the vicinity so that vessels in the immediate area are aware and can respond. Search and Rescue will task aircraft and vessels at this time. If a distress alert is sent in error, the Coast Guard MCTS Centre or RCC/MRSC should be notified immediately so that these resources can be "stood-down". Operator ProficiencyA major concern for the marine community is the number of false alerts that are being experienced on some GMDSS sub-systems, especially DSC and INMARSAT-C. Since the large percentage of false alerts is attributed to a lack of operator proficiency, it is especially important that operators of GMDSS fitted vessels receive instruction in the proper operation of their GMDSS equipment. Instruction is currently available through various training institutes across Canada. There are two GMDSS operator certificates issued by Canada: General Operators Certificate (GOC) - Required on most compulsory fitted GMDSS vessels operating outside sea area A1. This certificate involves a two week training course including a written and practical exam. Restricted Operators Certificate (ROC) with Maritime Qualification - Basic certificate for operators of compulsory fitted GMDSS vessels operating in an A1 sea area. It is also recommended for operators of GMDSS equipment on voluntary fitted vessels. This certificate is obtained by successfully completing an approved written exam. This information was compiled in 1997 by the Canadian GMDSS Working Group in cooperation with the RCC Halifax GMDSS Implementation Team under the authority of the Canadian Coast Guard - Rescue, Safety and Environment Response Directorate and the Marine Communications and Traffic Services Directorate and by Transport Canada - Marine Safety. Photographs have been reproduced from the IMO publication "GMDSS Handbook" with the kind permission of the International Maritime Organization. More information can be obtained by contactingTransport Canada - Marine Safety Regional Offices |
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