4 Msi Navarea Egc Safetynet Navtex)

MARITIME SAFETY INFORMATION

Hilmi ECE GMDSS Instructor Piri Reis University 1

Subjects:

MSI (NAVAREA , EGC, NAVTEX)


Maritime safety information (MSI) is defined asnavigational and meteorological warnings, meteorological

forecasts, and other urgent safety information of vital

importance to all ships at sea. It may also include

electronic chart correction data.

MSI is promulgated, transmitted, by a variety of means,using terrestrial and satellite communications. GMDSS

supports three independent systems for broadcasting

MSI:

NAVTEX

Inmarsat EGC system (SafetyNET)

HF Radio Telex (NBDP)

Radio telephony (Safety Messages)

2Hilmi ECE GMDSS Instructor Piri Reis University


The world is divided into 21 Navigational Areas

(NAVAREA) for the transmission of MSI. These are the

same as the Meteorological Areas (METAREA) into which

the earths navigable waters are sub-divided for thepurpose of MSI broadcasting. For each area, a NAVAREA

coordinator is assigned to coordinate the broadcasting of

navigational warnings, and a Meteorological Issuing

Service coordinates the meteorological information

throughout that area.




21 Different NAVAREAs in the GMDSS System



Metareas


The international establishment of this system was createdby the IMO and the International Hydrographic Organization(IHO), for the collection and distribution of MSI worldwide.This system is known as the World Wide NavigationalWarning Service (WWNWS).



The MSI service is an internationally coordinatednetwork of broadcast from official Information Providers, such as:

National Hydrographic Offices for navigational warnings & chart correction data

National Meteorological Offices for weather warnings and forecasts

Rescue Coordination Centers (RCCs) for shore to ship distress alerts

The International Ice Patrol for North Atlantic ice hazards


8EGC SafetyNET and FleetNET


Hilmi ECE GMDSS Instructor Piri Reis University


To ensure that the GMDSS Operator knows when toreceive MSI for a given area and subject, many MSIbroadcast are scheduled. All navigational warnings andmeteorological forecast are scheduled, whilemeteorological warnings and distress alerts areunscheduled broadcasts.

To be sure of receiving a scheduled MSI broadcast, thereceiver must be tuned to the appropriatechannel/frequency/satellite at the specific time.



A smaller number of MSI messages are transmitted asunscheduled broadcast. Unscheduled broadcast are sentout over entire regions to ensure that receiver will not missthe message. These types of message will set of somesort of alarm on the unit to alert the operator of theincoming message.

Not really considered the primary source of MSI. HF MSIrelies on the GMDSS operator to be aware of the time oftransmission and set the equipment to the receive modeand frequency for the broadcast.



HF MSI

Unlike the NAVTEX and SafetyNET systems (that haveprogrammable features so that they can be programmed forarea of operation, type of message desired, and even subareas with in a NAVAREA) HF MSI has no such features. Itwill receive and print any and all information received. Thismeans that a receiver left unattended can run through lots ofpaper and storage memory in the computer system.

The following eight (8) frequencies have been set up on aworldwide basis for transmission of HF MSI via NBDP:

4210 kHz 6314 kHz 8416.5 kHz 12579 kHz

16806.5 kHz 19680.5 kHz 22376 kHz 26100.5 kHz



SafetyNET is a service of INMARSATs Enhanced GroupCall (EGC) system. The EGC is a method used tospecifically address particular regions or ships. Its uniqueaddressing capabilities allow messages to be sent to allvessels in both fixed geographical areas or topredetermined groups of ships.

SafetyNET is an international direct-printing satellite basedservice for the promulgation of navigational andmeteorological warnings, distress alerts, forecasts, andother safety messages. It fulfills an integral rile in GMDSSas developed by the IMO. The ability to receive SafetyNETservice information will be generally necessary for all shipsthat sail beyond coverage of NAVTEX.


SafetyNET


SafetyNET can direct a message to a given geographicalarea based on EGC addressing. This is particularly useful

for messages, such as local storm warnings or a ship-to-

shore distress alert for which it would be inappropriate to

alert ships in an entire ocean region.

Scheduled broadcasts of MSI for a given NAVAREA/METAREA which is covered by more than one Satellite

Ocean Region are made only by a single designated

satellite. To receive scheduled broadcasts of MSI for that

NAVAREA/METAREA, the terminal must be logged in to

the designated satellite ocean region at the scheduled

time.



For a NAVAREA/METAREA which is covered by more thanone satellite ocean region, unscheduled broadcasts such asdistress alert relays and weather warnings, are made by allthe satellites that cover the area concerned.

For example, NAVAREA/METAREA I (the UK) is covered bythree satellite ocean regions. The AOR-W, AOR-E, and theIOR, but scheduled broadcasts of MSI are only made by theAOR-E.

The terminal must be logged into the AOR-E to receive thescheduled broadcasts. If logged into either of the other tworegions, it would not receive the scheduled broadcast, itwould not receive scheduled broadcast of MSI for this areaeven if the vessel were located in this region. It would,however, receive unscheduled broadcasts of MSI.



Selective reception of messages

x

x



Updating ships position

IMO requires Manual position update every 4

hours



NAVTEX is an international automatic direct printingservice for the promulgation of navigational andmeteorological warnings and urgent information to allships.

It provides a simple, low cost means for the automaticreception of MSI by narrow band direct printingtelegraphy.


NAVTEX



The GMDSS makes specific requirements with regard to radio

equipment, and ships must be able to carry out several different

functions, one of which is the ability to TRANSMIT and

RECEIVE Maritime Safety Information (MSI). They are

Navigational reports, Meteorological reports, Weather

Forecasts and Messages of General Importance


NAVTEX system could reach up to a distance 400 nm offshore.

24 NAVTEX stations in one NAVAREA.

The NAVTEX system is allocated three exclussive world-wide broadcast frequencies:

518 kHz

- Internatinal NAVTEX channel

490 kHz

- used for national broadcasts in local languages (i.e.: non-English)

4209.5 kHz

- allocated for national NAVTEX broadcasts 21Hilmi ECE GMDSS Instructor Piri Reis University


The 24 stations are divided into 4 groups consisting of 6 transmitting stations.

Every group is allowed one hour transmission time. (10mins/4 hours).

NAVTEX stations are geographically separated.

Every NAVTEX station has its own identification character (A-Z).



NAVTEX stations coverage is shown in the ITU List of Radio Determination and Special Service Stations.

The NAVTEX coordinator in each NAVAREA decides which MSI messages the system is to broadcast.



NAVTEX Stations WorldwideExperience has indicated that the tentatively required range of 250 to

400 nautical miles can often be attained by transmitted power in the

range between 100 and 1000 W during daylight with a 60% reduction

during night-time.


MARITIME SAFETY INFORMATION Coastguard

Buoyage authority Electronic Navaids Offshore Operator Government dept.

Ship reports NAVAREA co-

ordinator

National Coordinator

Ice Monitoring

meteorological offices

Initial distress message

Navigational warning

co-ordinator

Meteorological message co-

ordinator

SARco-ordinator

NAVTEX coordinator

Transmitter



Building up a NAVTEX message

------------------------------------------------------------

ZCZC B1 B2 B3 B4

Message Origin .

..

NNNN

-------------------------------------------------------------



Examples of station identifiers on the Coast of

Turkey are:


STATIONNAVTEX

CODEFREQ.

TRANSMISSION TIMELANGUAGE

STANBUL D 518 kHz 0030-0430-0830-1230-1630-2030 ENGLISH

SAMSUN E 518 kHz 0040-0440-0840-1240-1640-2040 ENGLISH

ANTALYA F 518 kHz 0050-0450-0850-1250-1650-2050 ENGLISH

ZMR I 518 kHz 0120-0520-0920-1320-1720-2120 ENGLISH

NAVTEX Stations ID. (B1)



STATIONNAVTEX

CODEFREQ. TRANSMISSION TIME

LANGUAG

E

STANBUL B 490 kHz 0010-0410-0810-1210-1610-2010 TRKE

SAMSUN A 490 kHz 0000-0400-0800-1200-1600-2000 TRKE

ANTALYA D 490 kHz 0030-0430-0830-1230-1630-2030 TRKE

ZMR C 490 kHz 0020-0420-0820-1220-1620-2020 TRKE

STANBUL M 4209.5 kHz 0200-0600-1000-1400-1800-2200 TRKE

Examples of station identifiers on the Coast of

Turkey are:

NAVTEX Stations ID. (B1)


A - Navigational warnings (Can not be rejected)

B - Meteorological warnings (Can not be rejected)

C - Ice reports

D - Search and rescue information (Can not be rejected)

E - Meteorological forecasts

F - Pilot service messages

G - Ais messages

H - Loran messages

I - Spare

J - SATNAV messages (related to Satellite navigation)

K - Other electronic NAVAID messages

L - Additional navigational messages (Can not be rejected)

V - Special services

W - Special services (possible other languages use)

X - Special services

Y- Special services

Z - No message on hand (to confirm there are no new messages)

NAVTEX Subject Indicators (B2)


------------------------------------------------------------

ZCZC GA20

ORKNEY ISLANDS

LOTHER ROCK RACON 58.44N 02.49W

TEMPORARILY OFF AIR

NNNN

-------------------------------------------------------------

------------------------------------------------------------

ZCZC GL67

RIGMOVE. SOUTHERN NORTHSEA.

CHARLES ROWAN AT 54-19N 02-07.7E

CANCEL THIS MESSAGE 121020 Z FEB 25

NNNN

-------------------------------------------------------------

------------------------------------------------------------

ZCZC PB68

NETHERLANDS COASTGUARD GALE

WARNING NR. 55 180630 FEB

DOVER THAMES SOUTH 8

OTHER DISTRICTS NO WARNINGS

NNNN

-------------------------------------------------------------



NAVTEX is a component of the WWNWS and isconsidered an essential element in GMDSS. Vesselsunder these regulations have been required to carryNAVTEX equipment since 1 August of 1993.

NAVTEX messages are broadcast on a single frequency of518 kHz, using the English language. Other frequenciessuch as 490 kHz were considered for local languageNAVTEX, but due to the extra cost of equipment, locallanguage is broadcast as a separate station identifier on518 kHz from the same station.

Plans also call for the use of a HF frequency of 4209.5 kHzfrom the same station



Nominated station within each NAVAREA transmit on a

time-sharing basis to eliminate mutual interference. All

necessary information is contained in each transmission.

The power of each transmitter is regulated in order to

avoid the possibility of interference between transmitters,

this is known as selective fading. The typical range of a

NAVTEX broadcast is approximately 200-400 nautical

miles.



All the NAVTEX broadcasts are formatted in the same way.Each message is preceded with ZCZC, which is the

phasing signal that enables the receiver to decode the

message correctly. A header, consisting of two letters and

two numbers, follows this signal.

Example: DE45

The first letter after the phasing signal indicates the identityof the transmitter that is sending the message. All

dedicated NAVTEX receivers can be programmed to

receive messages only from selected stations, known as

selective rejection of stations.



This is done by indicating to the receiver the letter of thestation(s) they are selected to reject. Stations identified bythe same letter are normally sited far enough apart toprevent reception of messages from the wrong one, orhaving interference between the two. As far as possible,stations are numbered A to Z going counter-clockwisedirection around each continent.


38

What do NAVTEX messages contain?

NAVTEX messages may include (A,B,C etc are called SubjectIndicators and denote the kind of message, eg, A is forNavigational warnings. The Subject indicators are unique).Categories A, B, D, & L cannot be rejected form the NAVTEXreceiver.

Category L, may be reject from some receiver, but should notbe.The receiver can be programmed to reject those categoriesthat are of little or no concern to the operator.

For example, if the vessel does not have Loran equipmentfitted, messages concerning the Loran system are of littleinterest and should be rejected to save on paper. Messagecategories A, B, D and L cannot be rejected and will always beable to receive these messages. This is to ensure that noimportant safety, weather, or distress alerts are missed.

Hilmi ECE GMDSS Instructor Piri Reis University

39

ZCZC DA52

ISTANBUL TURK RADIO

NAVTEX N/W NR : 126/05

SEA OF MARMARA

MAINTENANCE REPAIRMEN OF THE

UNDERWATER

CABLE WHICH IS AVAILABLE STUDIES WILL BE

CONDUCTED BETWEEN YALOVA AND ERENKOY

(40 4050N 2915 10E 40 50 05N 29 02 75E)

SEA OF MARMARA DURING 25 APR/6MAY 2005

WIDE BERTH REQUESTED

NNNN



The two numbers in the message header are the serialnumber of each individual message.

If the receiver is left on, it remembers which messages havebeen received.

Duplicate messages are not printed in order to conserve onpaper.

Any errors in the reception of the NAVTEX message text willshow up as a * and if an excess amount of errors arereceived receiver will give a corrupt message on theprinter.

The corrupt message will be received again on futurebroadcast, since the message header will not be stored inthe receiver.

This prevents important information from being missed dueto equipment or propagation problems.



NAVTEX receivers are also equipped with an alarm shouldSAR type messages be received, this is designed to be resetmanually by the operator. Most Units also have a self-testfacility. The manufacturers manual should explain itsprocedure. This test should be done on a weekly basis andthe results logged.

A majority of NAVTEX receivers employ the use of a thermalprinter for printing the data. This paper is the same materialas the old rolls of fax machine paper. So it is important tostore this paper away from excessive heat or light, whichcould dry out the chemicals in the paper. It is alwaysimportant to keep a good supply of paper for the NAVTEXreceiver.



If the NAVTEX receiver should fail, the NAVTEX messagecan be copied on a standard Telex (NBDP) terminal with its

receiver tuned to 518 kHz in MOD B COLFEC mode.

Remember that a GMDSS vessel must be able to receive

MSI at all time by one of the three methods (HF MSI,

SafetyNET or NAVTEX).


Some older models of NAVTEX

receiver had the capability to

receive weather faxes as well as

NAVTEX messages. These units

have a switch that would be

turned to select either Weather

fax or NAVTEX


During the Practical Competency of the NAVTEX unit,you will be required to program the unit for a particulararea.

You will be given an area with a list of stations andmessage categories to program into the unit.

Messages may be assigned one of three priorities:

VITAL - for immediate broadcast subject to avoiding anyinterference with other transmissions. The next

scheduled broadcast may be delayed to enable

transmission of the VITAL message. The message

number is generally 00.

IMPORTANT - for broadcast at the next available timewhen the frequency is unused

ROUTINE - for transmission at the next scheduled slot44Hilmi ECE GMDSS Instructor Piri Reis University


VITAL messages are reserved to important distressmessages. Both VITAL and IMPORTANT messages are

normally transmitted in the next time slot. Note that VITAL,

IMPORTANT or ROUTINE is not included in the message,

but just determines how the message is handled at the

transmitting end.




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