Introduction.

On modern sea-going vessels there are a number of electronic navigation systems and equipment which are designed to assist the navigator to navigate his vessel safely. They are:

1. The gyro compass.
2. Ship’s log.
3. Echo sounder (depth recorder).
4. Radar.
5. Automatic radar plotting assistant (ARPA).
6. Automatic identification system (AIS).
7. Global positioning system (GPS).
8. Electronic chart display and information system (ECDIS).
9. Radio direction finding system (Marine radio beacons).
10. Hyperbolic radio navigation system.

Whilst it is not intended to cover the above equipment/systems in great technical detail, the principles on which they operate and a broad description of each will be discussed. The last item on the above list has been included, although few vessels actually still use the system these days or are fitted with the specific equipment.