INMARSAT’s Role in the Global Maritime Distress and Safety
System (GMDSS INMARSAT)
The introduction
of the Global Maritime Distress and Safety System (GMDSS) on 1 February 1992
marked the most important change in maritime safety since the advent of radio
in 1899. The proven benefits of satellite communications, with high reliability,
simple operation and multi-modal capabilities, cannot be ignored and are,
in fact, being enthusiastically welcomed on ships of all kinds for their business
and social features, as well as the serious business of distress and safety
communications.
Beginning 1 February 1992, the use of
modern satellite technology has resulted in a total transformation of the
maritime distress communications system. Whereas the old system for maritime
distress and safety communications relied primarily on the capability of a
ship in distress to alert only other ships for assistance, the GMDSS emphasizes
the ability to alert shore-based search and rescue authorities, in addition
to shipping in the immediate vicinity, in order to achieve co-coordinated
assistance and rescue operations.
The GMDSS is
a better, simpler and more efficient distress and safety communications system.
It relies heavily on well-proven automation and makes extensive use of Inmarsat's
satellites for rapid and reliable communications. The GMDSS applies to all
cargo ships of 300 tonnes gross tonnage and upwards and to all passenger ships
on international voyages subject to the SOLAS 1974 Convention, as amended.
GMDSS provision
via Inmarsat maritime safety services is shown in diagram A below:
Inmarsat's
key role in the GMDSS can be summarized as follows:
• Inmarsat
provides the space segment necessary for instant and reliable distress and
safety satellite communications for the maritime community.
•
Inmarsat offers three satellite communications systems, designed to provide
most of the gmdss medium- and long-range functions: Inmarsat‑A, Inmarsat‑B
and Inmarsat-C.
• Inmarsat
also provides a valuable distress alerting facility through Inmarsat-E, which
is an L-band Emergency Position Indicating Radio Beacon (epirb).
DISTRESS ALERTING:
SHIP-TO-SHORE
Inmarsat‑A/B:
Initiated at
the press of a dedicated button on the vessel's Ship Earth Station (SES),
distress alerts are given priority access in the Inmarsat system. The distress
alert is then routed, usually automatically, through an Inmarsat Land Earth
Station (LES) to an associated Rescue Coordination Centre (RCC) ashore.
Inmarsat-C:
Also initiated
at the press of a button, a distress alert from the vessel's SES ensures the
highest priority for automatic routing through the Inmarsat system to an RCC.
Inmarsat-E:
“Any delay
in receiving a distress alert can mean the difference between rescuing survivors
and recovering bodies”
(Steve Huxley,
GMDSS District Staff Officer, Falmouth MRCC)
An Inmarsat
L-band satellite EPIRB is an alternative means for sending the distress alert.
EPIRB transmissions can be initiated manually when the EPIRB is out of the
cradle, remotely from a remote control unit (RCU) when the EPIRB is in the
cradle, or automatically when the EPIRB floats free if a ship sinks. The time
taken from transmitting an Inmarsat-E distress alert and its receipt at an
RCC is typically less than one minute.
DISTRESS ALERTING:
SHORE-TO-SHIP
Initiated by
RCCs ashore, ships are alerted through automatic receipt of distress alert
relays transmitted via the International SafetyNET Service of the Enhanced
Group Call (EGC) capabilities of the Inmarsat-C system. Ordinary telex group
calls to Inmarsat-A or -B SESs can also be used to supplement this.
SEARCH AND
RESCUE COORDINATION COMMUNICATIONS
Inmarsat terminals
on board ships can be utilised for originating and receiving communications
with other ships involved in distress incidents and for communications with
RCCs. When multiple ships are involved, the EGC system is advantageous for
operational updates and planning actions from RCCs.
DISSEMINATION
OF MARITIME SAFETY INFORMATION
Navigational
and meteorological information is transmitted from ships to shore authorities
through the Inmarsat-A, -B or -C systems. Shore authorities in hydrographic,
meteorological and search and rescue offices initiate maritime Safety Information
(MSI). Messages are entered into the International SafetyNET Service for transmission
to ships through the EGC system, with the appropriate priority.
GENERAL RADIOCOMMUNICATIONS
Virtually all
of the telecommunications services found in offices ashore are available to
and from ships equipped with Inmarsat SESs. This results in ships having
capabilities for high quality, reliable and automatic communications via voice,
facsimile, telex, data, high-speed data and E-mail. These capabilities can
be used for obtaining advice and assistance from experts ashore in efforts
to solve problems before they develop into emergency situations.
A series of
2-digit service codes has been established to make it faster for ships to
make connections for a number of special purposes, both safety and routine.
Of these, there are six (6), which are specifically for safety services and
provide a rapid connection to an RCC, meteorological office, hydrographic
office, ship reporting centre or medical centre.
Satellite communications
via Inmarsat bring rapid and reliable communications to the aid of seafarers
- to help them avoid danger and to provide a means for summoning assistance
when all else fails. The ability to communicate with a vessel anywhere in
the world, at any time of day or night will appeal to all owners/operators
of ships. The ability to immediately contact an RCC or technical experts
ashore for assistance will, on the other hand, appeal to all seafarers. For
all parties, the availability of a reliable and flexible system for both safety
and commercial communications is the ultimate bonus.
International
Maritime Satellite Organization (INMARSAT)
Before
1984, most ships could not communicate with each other although they could
receive a distress alert. At that time, the range of transmission on MF was
only 150 miles so that ships beyond this distance from the nearest coastal
station, it is essentially a ship-to-ship distress system
The advent
of satellite communication led the IMO to commence a study of maritime satellite
communication with assistance from the International Radio Consultative Committee
(CCIR) of ITU in 1972.
In 1976,
IMO adopted the Convention on the Establishment of the International Maritime
Satellite Organization (INMARSAT). In 1979, the Convention entered into force
and INMARSAT became operational.
Also in
1979, the International Conference on Maritime Search and Rescue adopted the
International Convention on Maritime Search and Rescue, 1979 (1979 SAR Convention),
with the ultimate objective to establish a global plan for maritime search
and rescue based on a framework of multilateral or bilateral agreements between
neighbouring states on the provision of SAR services in coastal and adjacent
ocean waters to achieve co-operation and mutual support in responding to distress
incidents.
With the
assistance of ITU, CCIR, other international organizations such as the World
Meteorological Organization (WMO), the International Hydrographic Organization
(IHO), INMARSAT and the COSPAS-SARSAT partners, IMO developed and proved the
various equipment and techniques used in the global maritime distress and
safety system (GMDSS). The ITU also established the appropriate regulatory
framework for the implementation of the GMDSS.
INMARSAT
became a limited company in April 1999 and serves a broad range of markets.
Starting with a user base of 900 ships during the early 1980s, it now supports
links for telephone, facsimile and data communications at up to 64 kbits/s
to more than 210,000 ships, vehicles, aircrafts and portable terminals.
The Inmarsat-E
System
The
Inmarsat-E system provides global maritime distress alerting via Inmarsat
satellites operating at L-Band. Distress alerts transmitted from Inmarsat-E
Emergency Position Indicating Radio Beacons (EPIRBs) are relayed through
Inmarsat satellites to dedicated receiving equipment located at four Land
Earth Stations (LESs):
•
Raisting, Germany
•
Niles Canyon, USA
•
Perth, Australia; and
• Goonhilly,
UK.
The distress
alert transmitted by an EPIRB will always be received by two LESs in each
ocean region, giving 100 percent duplication for each ocean region in case
of failures or outages associated with any of the LESs. Table below shows
the relationship between the satellites, the Inmarsat LESs and their associated
maritime rescue co-ordination centre (MRCC).
|
Atlantic
Ocean Region–East (AOR-E)
|
Atlantic
Ocean Region-West (AOR-W)
|
|
Goonhilly
LES
Falmouth
MRCC
|
Niles
Canyon LES
United
States Coast Guard
|
|
Raisting
LES
Bremen
MRCC
|
Goonhilly
LES
Falmouth
MRCC
|
|
|
|
Pacific
Ocean Region (POR)
|
Indian
Ocean Region (IOR)
|
|
Perth
LES
Canberra
MRCC
|
Raisting
LES
Bremen
MRCC
|
|
Niles
Canyon LES
United
States Coast Guard
|
Perth
LES
Canberra
MRCC
|
The Inmarsat-E
system was first proposed in the 1970’s and the concept was developed and
tested in the 1980’s. Pre-operational service began in the Atlantic Ocean
Region East (AOR-E) in 1993. Full, global operation began in January 1997.
The Inmarsat-E system was runner-up in the safety section of the Seatrade
Awards in 1998.
Inmarsat-E
EPIRBs are approved by the IMO as complying with the requirements within
the GMDSS to have a satellite EPIRB fitted.
After
activation, there is a two-minute wait, during which an audible and visual
signal in the EPIRB warns that a distress alert is about to be sent. This
allows for the cancellation of inadvertent manual activation and thereby
reduces the chance of a false alert being sent. Then, once the GPS position
is confirmed within the integral GPS receiver, the distress alert is transmitted.
Because the
Inmarsat-E EPIRB will always be in view of at least one Inmarsat geostationary
satellite, and does not have to wait for an orbiting satellite to come into
view, the time taken from the transmission of a distress alert to reception
at the MRCC is within five minutes and typically less than one minute.
Following
reception of the distress alert, it is immediately and automatically forwarded
by an X.25 link to the associated Maritime Rescue Co-ordination Centre (MRCC)
so that appropriate action can be taken.
The Inmarsat-E
system supports "Float Free" EPIRBs that incorporate the following
features:
•
Global Positioning System (GPS) position, accurate to within 200 metres;
•
automatic activation when the EPIRB is released by "Floating free";
•
remote activation and information input from optional remote control unit
on the vessel’s bridge;
•
high intensity, low duty cycle strobe light.
•
optional Search and Rescue Radar Transponder (SART);
•
optional 121.5MHz locator beacon.
The size of the EPIRB is between 220mm
and 700mm high and weighs about 1200g, (depending on manufacturer and model).
Examples are shown below
Mk.IV
Inmarsat-E EPIRB (also available with integrated SART) from Fastnet GmbH
(Right)
Global-3
Inmarsat-E EPIRB from navtec GmbH (Left)
The EPIRB
may be activated in any of three ways:
1.
From an optional remote control unit on the bridge or the conning position
of the vessel, when the EPIRB is in its cradle;
2.
Manually, by using a switch on the side of the equipment if the EPIRB has
been carried into the survival craft; or
3.
Automatically, as soon as the EPIRB has been released by immersion in water
(hydrostatic release).
The carriage
of a satellite EPIRB is required on SOLAS ships by the GMDSS and this requirement
came into effect on 1 August 1993.
GMDSS regulations
apply to all vessels of over 300 gross registered tonnes and all passenger
vessels engaged on international voyages. However, distress incidents occur
on small craft not covered by GMDSS regulations, such as pleasure craft
etc., much more frequently than on larger vessels.
Although
such vessels may use the GMDSS approved models, there are also non-GMDSS
versions of the Inmarsat-E EPIRB available. Both types of Inmarsat-E EPIRB
will enable them to transmit distress alerts and obtain the services of
rescue authorities much faster and more reliably than by conventional means.
The picture below shows a typical non-GMDSS
Inmarsat-E EPIRB:
DAS-30A non-GMDSS
Inmarsat-E EPIRB from Fastnet GmbH
Registration
It is imperative
that owners of all Inmarsat-E EPIRBs register them with Inmarsat, giving
details of the vessel or craft on which they are installed, as soon as possible
after installation. MRCCs hold details of all registered Inmarsat-E EPIRBs
and as the position contained in the distress alert is accurate to within
200 metres, Search and Rescue (SAR) authorities can be alerted and start
to take appropriate action within minutes.
The registration
database held at Inmarsat is replicated at each of the Inmarsat-E associated
MRCCs and is keeps updated