Page 56 - Basics of Electrical, Electronic and Communication

16.5. Navigational aids and systems 315

16.5 Navigational aids and systems

Navigation is the process of finding and controlling the movement of
a vehicle from one place to another. The position of an aircraft or ship
can be found by using radio navigational aids. This is achieved by
the installation of radio transmitters and receivers at known locations
on the earth’s surface as well as at aircraft or ship which will work
in conjunction with those on earth. Navigational aids include bouys,
beacons, lightships, radio beacons, fog signals etc.

Navigational aids

• Bouys are floating objects anchored at bottom. Their shape and
colour convey the message how to navigate around them.

• Beacons are structures permanently fixed to sea bed or land

Electronic navigation systems

• Instrument Landing System (ILS)
Some applications related to remote sensing and military, air-
crafts are controlled without pilots in it. ILS enables take off,
flying and landing with the electronic systems on ground and air
borne.

• Ground Controlled Approach (GCA)
GCA is a system which assists the pilot to take off, fly and land
the aircraft. This helps the pilot to land the aircraft even in haz-
ardous atmospheric conditions such as fog, haze, snow, rain etc.

• Radio Direction Finder (RDF)
RDF is used to find the direction of radio signal source. Di-
rection of the electromagnetic signal is detected by the direc-
tional antenna. This over the horizon system helps the navigat-
ing ships.

• Long Range Navigation (LORAN)
It is a terrestrial navigational system using low frequency radio
transmitters that use the time interval between the radio signals

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