Global Maritime Distress Safety
System
The Global Maritime Distress
Safety System (GMDSS) is an internationally agreed-upon set of safety
procedures, types of equipment, and communication protocols used to increase
safety and make it easier to rescue distressed ships, boats and aircraft. GMDSS
consists of several systems, some of which are new, but many of which have been
in operation for many years. The system is intended to perform the following
functions: alerting (including position determination of the unit in distress),
search and rescue coordination, locating (homing), maritime safety information
broadcasts, general communications, and bridge-to-bridge communications.
Specific radio carriage requirements depend upon the ship's area of operation,
rather than its tonnage. The system also provides redundant means of distress
alerting, and emergency sources of power. Recreational vessels do not need to
comply with GMDSS radio carriage requirements, but will increasingly use the
Digital Selective Calling (DSC) VHF radios. Offshore vessels may elect to equip
themselves further. Vessels under 300 Gross tonnage (GT) are not subject to
GMDSS requirements.
Components of GMDSS The main
types of equipment used in GMDSS are:
Emergency Position-Indicating
Radio Beacon (EPIRB) Cospas-Sarsat is an international satellite-based search
and rescue system, established by Canada, France, the United States, and
Russia. These four countries jointly helped develop the 406 MHz Emergency Position-Indicating
Radio Beacon (EPIRB), an element of the GMDSS designed to operate with
Cospas-Sarsat system. These automatic-activating EPIRBs, now required on SOLAS
ships, commercial fishing vessels, and all passenger ships, are designed to
transmit to alert rescue coordination centers via the satellite system from
anywhere in the world. The original COSPAS / SARSAT system used Polar orbiting
satellites but in recent years the system has been expanded to also include 4
geostationary satellites. Newest designs incorporate GPS receivers to transmit
highly accurate positions (within about 20 metres)of the distress position. The
original COSPAS / SARSAT satellites could calculate EPIRB position to within
about 3 nautical miles (5.6 km) by using Doppler techniques. By the end of
2010 EPIRB manufacturers may be offering AIS (Automatic Identification System)
enabled beacons. The service-ability of these items are checked monthly and
annually and have limited battery shelf life between 2 to 5 years using mostly Lithium
type batteries. 406 MHz EPIRB's transmit a registration number which is linked
to a database of information about the vessel.
NAVTEX Navtex is an
international, automated system for instantly distributing maritime safety
information (MSI) which includes navigational warnings, weather forecasts and
weather warnings, search and rescue notices and similar information to ships. A
small, low-cost and self-contained "smart" printing radio receiver is
installed on the bridge, or the place from where the ship is navigated, and
checks each incoming message to see if it has been received during an earlier
transmission, or if it is of a category of no interest to the ship's master.
The frequency of transmission of these messages is 518 kHz in English, while
490 kHz is sometime used to broadcast in a local language. The messages
are coded with a header code identified by the using single letters of the
alphabet to represent broadcasting stations, type of messages, and followed by
two figures indicating the serial number of the message. For example: FA56
where F is the ID of the transmitting station, A indicates the message category
Navigational warning, and 56 is the consecutive message number.
Global Maritime Distress Safety
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Inmarsat Satellite systems operated
by the Inmarsat, overseen by IMSO, International Mobile Satellite Organization
are also important elements of the GMDSS. The types of Inmarsat ship earth
station terminals recognized by the GMDSS are: Inmarsat B, C and F77. Inmarsat
B and F77, an updated version of the now redundant Inmarsat A, provide
ship/shore, ship/ship and shore/ship telephone, telex and high-speed data
services, including a distress priority telephone and telex service to and from
rescue coordination centers. Fleet 77 fully supports the Global Maritime
Distress and Safety System (GMDSS) and includes advanced features such as
emergency call prioritisation. The Inmarsat C provides ship/shore, shore/ship
and ship/ship store-and-forward data and email messaging, the capability for sending
preformatted distress messages to a rescue coordination center, and the
Inmarsat C SafetyNET service. The Inmarsat C SafetyNET service is a
satellite-based worldwide maritime safety information broadcast service of high
seas weather warnings, NAVAREA navigational warnings, radionavigation warnings,
ice reports and warnings generated by the USCG-conducted International Ice
Patrol, and other similar information not provided by NAVTEX. SafetyNET works
similarly to NAVTEX in areas outside NAVTEX coverage. Inmarsat C equipment is
relatively small and lightweight, and costs much less than an Inmarsat B or
F77. Inmarsat B and F77 ship earth stations which require relatively large
gyro-stabilized uni directional antennas; the antenna size of the Inmarsat C is
much smaller and is omni directional. Under a cooperative agreement with the
National Oceanic and Atmospheric Administration (NOAA), combined meteorological
observations and AMVER reports can now be sent to both the USCG AMVER Center,
and NOAA, using an Inmarsat C ship earth station, at no charge. . SOLAS now
requires that Inmarsat C equipment have an integral satellite navigation
receiver, or be externally connected to a satellite navigation receiver. That
connection will ensure accurate location information to be sent to a rescue
coordination center if a distress alert is ever transmitted. Also the new LRIT
long range tracking systems are upgraded via GMDSS Inmarsat C which are also
compliant along with inbuilt SSAS, or Ship Security Alert System. SSAS provides
a means to covertly transmit a security alert distress message to local
authorities in the event of a mutiny, pirate attack, or other hostile action
towards the vessel or its crew.
High Frequency A GMDSS system may
include High Frequency (HF) radiotelephone and radiotelex (narrow-band direct
printing) equipment, with calls initiated by digital selective calling (DSC).
Worldwide broadcasts of maritime safety information can also made on HF
narrow-band direct printing channels.
Search and Rescue Locating device
{{Main|Seartion range between these devices and ships, dependent upon the
height of the ship's radar mast and the height of the Search and Rescue
Locating device, is normally about 15 km (8 nautical miles). Once detected
by radar, the Search and Rescue Locating device will produce a visual and aural
indication to the persons in distress.
Global Maritime Distress Safety
System 3
Digital Selective Calling The IMO
also introduced Digital Selective Calling (DSC) on MF, HF and VHF maritime
radios as part of the GMDSS system. DSC is primarily intended to initiate
ship-to-ship, ship-to-shore and shore-to-ship radiotelephone and MF/HF
radiotelex calls. DSC calls can also be made to individual stations, groups of
stations, or "all stations" in one's radio range. Each DSC-equipped
ship, shore station and group is assigned a unique 9-digit Maritime Mobile
Service Identity. DSC distress alerts, which consist of a preformatted distress
message, are used to initiate emergency communications with ships and rescue coordination
centers. DSC was intended to eliminate the need for persons on a ship's bridge
or on shore to continuously guard radio receivers on voice radio channels,
including VHF channel 16 (156.8 MHz) and 2182 kHz now used for distress,
safety and calling. A listening watch aboard GMDSS-equipped ships on
2182 kHz ended on February 1, 1999. In May 2002, IMO decided to postpone
cessation of a VHF listening watch aboard ships. That watchkeeping requirement
had been scheduled to end on 1 February 2005. IMO and ITU both require that the
DSC-equipped MF/HF and VHF radios be externally connected to a satellite
navigation receiver (GPS). That connection will ensure accurate location
information is sent to a rescue coordination center if a distress alert is transmitted.
The FCC requires that all new VHF and MF/HF maritime radiotelephones type
accepted after June 1999 have at least a basic DSC capability. VHF digital
selective calling also has other capabilities beyond those required for the
GMDSS. The Coast Guard uses this system to track vessels in Prince William
Sound, Alaska, Vessel Traffic Service. IMO and the USCG also plan to require
ships carry a Universal Shipborne Automatic Identification System, which will
be DSC-compatible. Countries having a GMDSS A1 Area should be able to identify
and track AIS-equipped vessels in its waters without any additional radio
equipment. A DSC-equipped radio cannot be interrogated and tracked unless that
option was included by the manufacturer, and unless the user configures it to
allow tracking. GMDSS telecommunications equipment should not be reserved for
emergency use only. The International Maritime Organization encourages mariners
to use GMDSS equipment for routine as well as safety telecommunications.
GMDSS sea areas GMDSS sea areas
serve two purposes: to describe areas where GMDSS services are available, and
to define what radio equipment GMDSS ships must carry (carriage requirements).
Prior to the GMDSS, the number and type of radio safety equipment ships had to
carry depended upon its tonnage. With GMDSS, the number and type of radio
safety equipment ships have to carry depends upon the GMDSS areas in which they
travel. In addition to equipment listed below, all GMDSS-regulated ships must
carry a satellite EPIRB, a NAVTEX receiver (if they travel in any areas served
by NAVTEX), an Inmarsat-C SafetyNET receiver (if they travel in any areas not
served by NAVTEX), a DSC-equipped VHF radiotelephone, two (if between 300 and
less than 500 GRT)or three VHF handhelds (if 500 GRT or more), and two
9 GHz search and rescue radar transponders (SART).
Sea Area A1 An area within the
radiotelephone coverage of at least one VHF coast station in which continuous
digital selective calling (Ch.70/156.525 MHz) alerting and radiotelephony
services are available.Such an area could extend typically 30 nautical
miles (56 km) to 40 nautical miles (74 km) from the Coast Station.
Sea Area A2 An area, excluding
Sea Area A1, within the radiotelephone coverage of at least one MF coast
station in which continuous DSC (2187.5 kHz) alerting and radiotelephony
services are available.For planning purposes this area typically extends to up
to 180 nautical miles (330 km) offshore during daylight hours,but would
exclude any A1 designated areas.In practice,satisfactory coverage may often be
achieved out to around 400 nautical miles (740 km)
Global Maritime Distress Safety
System 4
offshore during night time...
Sea Area A3 An area,excluding sea
areas A1 and A2, within the coverage of an INMARSAT geostationary satellite.
This area lies between about latitude 76 Degree NORTH and SOUTH,but excludes A1
and/or A2 designated areas.Inmarsat guarantee their system will work between 70
South and 70 North though it will often work to 76 degrees South or North.
Sea Area A4 An area outside Sea
Areas A1, A2 and A3 is called Sea Area A4. This is essentially the polar
regions, north and south of about 70 degrees of latitude, excluding any A1 or
A2 areas.
GMDSS radio equipment required
for U.S. coastal voyages Presently, until an A1 or A2 Sea Area is established,
GMDSS-mandated ships operating off the U.S. coast must fit to Sea Areas A3 (or
A4) regardless of where they operate. U.S. ships whose voyage allows them to
always remain within VHF channel 16 coverage of U.S. Coast Guard stations may
apply to the Federal Communications Commission for an individual waiver to fit
to Sea Area A1 requirements. Similarly, those who remain within 2182 kHz
coverage of U.S. Coast Guard stations may apply for a waiver to fit to Sea Area
A2 requirements.
History Since the invention of
radio at the end of the 19th century, ships at sea have relied on Morse code,
invented by Samuel Morse and first used in 1844, for distress and safety
telecommunications. The need for ship and coast radio stations to have and use
radiotelegraph equipment, and to listen to a common radio frequency for Morse
encoded distress calls, was recognized after the sinking of the liner RMS
Titanic in the North Atlantic in 1912. The U.S. Congress enacted legislation
soon after, requiring U.S. ships to use Morse code radiotelegraph equipment for
distress calls. The International Telecommunications Union (ITU), now a United
Nations agency, followed suit for ships of all nations. Morse encoded distress
calling has saved thousands of lives since its inception almost a century ago,
but its use requires skilled radio operators spending many hours listening to
the radio distress frequency. Its range on the medium frequency (MF) distress
band (500 kHz) is limited, and the amount of traffic Morse signals can carry is
also limited. Not all ship-to-shore radio communications were short range. Some
radio stations provided long-range radiotelephony services, such as radio
telegrams and radio telex calls, on the HF bands (3-30 MHz) enabling worldwide communications
with ships. For example, Portishead Radio, which was the world's busiest
radiotelephony station, provided HF long-range services.[1] In 1974, it had 154
radio operators who handled over 20 million words per year.[2] Such large
radiotelephony stations employed large numbers of people and were expensive to
operate. By the end of the 1980s, satellite services had started to take an
increasingly large share of the market for ship-to-shore communications. For
these reasons, the International Maritime Organization (IMO), a United Nations
agency specializing in safety of shipping and preventing ships from polluting
the seas, began looking at ways of improving maritime distress and safety
communications. In 1979, a group of experts drafted the International
Convention on Maritime Search and Rescue, which called for development of a
global search and rescue plan. This group also passed a resolution calling for
development by IMO of a Global Maritime Distress and Safety System (GMDSS) to
provide the communication support needed to implement the search and rescue
plan. This new system, which the world's maritime nations are implementing, is
based upon a combination of satellite and terrestrial radio services, and has
changed international distress communications from being primarily ship-to-ship
based to ship-to-shore (Rescue Coordination Center) based. It spelled the end
of Morse code communications for all but a few users, such as amateur radio
operators. The
Global Maritime Distress Safety
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GMDSS provides for automatic
distress alerting and locating in cases where a radio operator doesn't have
time to send an SOS or MAYDAY call, and, for the first time, requires ships to
receive broadcasts of maritime safety information which could prevent a distress
from happening in the first place. In 1988, IMO amended the Safety of Life at
Sea (SOLAS) Convention, requiring ships subject to it fit GMDSS equipment. Such
ships were required to carry NAVTEX and satellite EPIRBs by 1 August 1993, and
had to fit all other GMDSS equipment by 1 February 1999. US ships were allowed
to fit GMDSS in lieu of Morse telegraphy equipment by the Telecommunications
Act of 1996.
Licensing of operators National
maritime authorities may issue various classes of licenses. The General Operator’s
Certificate is required on SOLAS vessels operating also outside GMDSS Sea Area
A1, while a Restricted Operator’s Certificate is needed on SOLAS vessels
operated solely within GMDSS Sea Area A1, Long Range Certificate may be issued,
and is required on non-SOLAS vessels operating outside GMDSS Sea Area A1, while
a Short Range Certificate is issued for non-SOLAS vessels operating only inside
GMDSS Sea Area A1. Finally there is a Restricted radiotelephone operator's
certificate, which is similar to the Short Range Certificate but limited VHR
DSC radio operation. Some countries do not consider this adequate for GMDSS
qualification. In the United States four different GMDSS certificates are
issued. A GMDSS Radio Maintainer's License allows a person to maintain,
install,and repair GMDSS equipment at sea. A GMDSS Radio Operator's License is
necessary for a person to use required GMDSS equipment. The holder of both
certificates can be issued one GMDSS Radio Operator/Maintainer License.
Finally, the GMDSS Restricted License is available for VHF operations only
within 20 nautical miles (37 km) of the coast. To obtain any of these
licenses a person must be a U.S. citizen or otherwise eligible for work in the
country, be able to communicate in English, and take written examinations
approved by the Federal Communications Commission. Like the amateur radio
examinations, these are given by private, FCC-approved groups. These are
generally not the same agencies who administer the ham tests. Written test
elements 1 and 7 are required for the Operator license, and elements 1 and 7R
for the Restricted Operator. (Passing element 1 also automatically qualifies
the applicant for the Marine Radiotelephone Operator Permit, the MROP.) For the
Maintainer license, written exam element 9 must be passed. However, to obtain
this certificate an applicant must also hold a General radiotelephone operator
license (GROL), which requires passing commercial written exam elements 1 and 3
(and thus supersedes the MROP). Upon the further passing of optional written
exam element 8 the ship radar endorsement will be added to both the GROL and
Maintainer licenses. This allows the holder to adjust, maintain, and repair
shipboard radar equipment.[3] Until March 25, 2008 GMDSS operator and maintainer
licenses expired after five years but could be renewed upon payment of a fee.
On that date all new certificates were issued valid for the lifetimes of their
holders. For those still valid but previously issued with expiration dates, the
FCC states: Any GMDSS Radio Operator's License, Restricted GMDSS Radio
Operator's License, GMDSS Radio Maintainer's License, GMDSS Radio
Operator/Maintainer License, or Marine Radio Operator Permit that was active,
i.e., had not expired, as of March 25, 2008, does not have to be renewed.[4]
Since an older certificate does show an expiration date, for crewmembers
sailing internationally it may be worth paying the fee (as of 2010 it was $60)
to avoid any confusion with local authorities. Finally, to actually serve as a
GMDSS operator on most commercial vessels the United States Coast Guard
requires additional classroom training and practical experience beyond just
holding a license.[5]
Global Maritime Distress Safety
System 6
Source • GMDSS Home Page [6] •
http:/ / www. gmdss. com. au/
References [1] Johnson, B (1994).
"English in maritime radiotelephony". World Englishes 13 (1): 83–91.
doi:10.1111/j.1467-971X.1994.tb00285.x. [2] "The story of Portishead
Radio: Long range maritime radio communications: 1920–1995" (http:/ / jproc.
ca/ radiostor/ portis1. html). 2001-04-06. . Retrieved 2008-01-09. [3] FCC -
Commercial Radio Operator Licenses (http:/ / wireless. fcc. gov/ commoperators/
) [4] Commercial Radio Operator License Program: Term of Licenses (http:/ /
wireless. fcc. gov/ commoperators/ index. htm?job=terms_license) [5] GMDSS
Training and Certification (http:/ / www. navcen. uscg. gov/ pdf/ gmdss/
taskForce/ Training_and_Certification_of_GMDSS_Radio_Operators. pdf) [6] http:/
/ www. navcen. uscg. gov/ ?pageName=GMDSS
External links • COSPAS-SARSAT
system home page (http:/ / www. cospas-sarsat. org/ ) • Search And Rescue
Satellite Aided Tracking (SARSAT) (http:/ / www. sarsat. noaa. gov/ ) • FCC -
Commercial Operator Licenses: Examinations (http:/ / wireless. fcc. gov/ commoperators/
exam. html) Federal Communications Commission (FCC) • FCC - GMDSS Radio
Maintainer's License (DM) (http:/ / wireless. fcc. gov/ commoperators/ dm.
html) FCC • FCC - GMDSS Radio Operator's License (DO) (http:/ / wireless. fcc.
gov/ commoperators/ do. html) FCC • FCC - Ship Radar Endorsement (http:/ /
wireless. fcc. gov/ commoperators/ sre. html) FCC • FCC - Commercial Operator
Licenses: Examination Question Pools (http:/ / wireless. fcc. gov/
commoperators/ eqp. html) FCC • GMDSS Ship Inspection Checklist (http:/ / www.
fcc. gov/ eb/ ShipInsp/ gmdss_checklist. pdf) FCC • "CCIR 493-4 HF Selcall
Information Resource" (http:/ / hflink. com/ selcall). HFLINK. 2010.
Retrieved 2010-01-10. • GMDSS Test box for MF/HF/VHF GMDSS equipment with DSC (http:/
/ gmdsstesters. com/ content/ view/ 2/ 6/ lang,en/ ) • GMDSS Training
Simulators (http:/ / www. buffalocomputergraphics. com/ content/ pages/ gmdss)
Article Sources and Contributors
7 Article Sources and Contributors
Global Maritime Distress Safety
System Source: http://en.wikipedia.org/w/index.php?oldid=406084688
Contributors: Alikaalex, Alkano, Amakuru, ArnoldReinhold, Arsenikk,
Baleywik, Betacommand, Bluelip, Bobo192, CKA3KA, Cheyne, Christian75,
CosineKitty, Davandron, Davidcannon, Denelson83, E Wing, EAA, Editus Reloaded,
Erkan Yilmaz, Esh, Eswar 09, Fumph, GCW50, Gaius Cornelius, Glane23, Glrx, Good
Olfactory, Ground Zero, Harthacnut, Hashemi sa, Haus, Hcberkowitz, Hede2000,
Hunturk, Icselectronics, JS747, Joseph Solis in Australia, Karada, Kharker, Leeyc0,
Lightmouse, Mark.murphy, MechBrowman, Melad malak, MichaK, Mild Bill Hiccup,
MrVibrating, Muhandes, Neparis, Neurolysis, Nigelj, Njd27, Nsevs, Papo77,
Paul1337, Pjmarkert, Queenmomcat, Radiojon, Rich Farmbrough, Richard Weil,
Riddley, Sam Hocevar, Sharkford, Shraktu, Spitfire, Stereorock, Syrthiss,
Tabletop, TastyPoutine, The Anome,
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