gps, global positioning system, tracker, satellite

GPS, GMDSS - Navigation tools for the Seafarer

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GPS, Global Positioning System

Dear Seafarer / visitor,

Have you wondered how the global positioning of a ship is determined? How do you ensure that you arrive at the right place?


If you want to determine where is North, South, East and West, the basic equipment to use is the compass. However, on board ship, the movement of the ship may play havoc on the accuracies of an ordinary compass.

Gyro-compasses that make use of rapidly spinning shafts are used to provide immunity from the movement of the ships.


A sextant is a compulsory piece of equipment carried by a ship. It is used to determine the angle of the sun relative to the horizon.

As you very well know, on the open sea, there are no landmarks that you can check your position. Knowing the local time, from clocks, you should be able to know at what angle the sun will be relative to the horizon.

With a bit of checking from published navigation charts (maps), you should be able to determine your global position anywhere in world.

It is not usable during cloudy weather when the sun is not visible.

Navigation Charts (maps)

These charts are invaluable to provide documented data on positioning. Various governmental bodies do hydrographic surveys that are published as navigation charts.

These will be plotted by navigators and helps to locate the exact position of the ship.


Since the invention of radio, ships have relied on Morse Code for communications. However, its use require skilled radio operators, which was quite difficult to find.

Various electronic systems like DECCA, and LORAN-C had also been used in navigation. Since the advent of satellite communication, these systems have either become obsolete or have found limited use.

The International Maritime Organization (IMO) has required ships to fit GMDSS equipment by 1999. This "Global Maritime Distress and Safety System" is based on a combination of satellite and terrestrial radio services.

The system can reliably perform the following functions:

  • Alerting (including position determination of the unit in distress)
  • Search and rescue coordination
  • Locating (homing)
  • Maritime safety information broadcast
  • General communications
  • Bridge-to-bridge communications


Global Positioning System or GPS has been developed to provide all-weather round-the-clock navigation both for military and civilian applications. Many recreational outdoor activities like boating, kayaking, hiking, fishing, hunting, camping, skiing, mountain climbing, exploring, has adopted GPS as an important piece of equipment for positioning and locating people.

Corporate fleet tracking of buses, lorries, trucks, taxis, cabs, automobiles, planes, aircraft, ferry and even ships can easily be made available economically and accurately. Applications like surveys, commercial fishing, mineral prospecting, air traffic management and many other uses have been suggested as commercial applications. The scientific community has also shown interest in GPS.

GPS users can easily create accurate digital maps from any scanned map or existing map database. And they can be used on PC, Pocket PC like iPAQ or Palm device O.S.3.5+

More information can be obtained at:

Global Positioning System


Marine navigation has come a long way. With satellite navigation fully available commercially, it would be an excellent idea to make full use of these advanced tools for our own business profit and recreational safety.

If you ever travel to remote areas and you want people to be able to locate you then think GPS, or Global Positioning System.



Marine Engineer World


P.S. We have located the perfect GPS for you here. If you venture into the vast open sea, your life may depend on using this GPS.

2003 Yoon Chee Tuck    Contact me

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