THE ROLE OF
NAVIGATION IN THE FIELD OF AVIATION
For any pilot of an aircraft or a captain of a ship it would be extremely difficult to plan his journey unless he is a good navigator. We will mainly concentrate on the part of navigation related to the field of aviation. This abstract will contain the basics of navigation. For details about any field in navigation in depth please do mail me to ‘remanth_reddy@yahoo.co.in’.
The earth is not a true sphere but is flattened slight at the poles. The more correct description of its shape may be an ellipsoid. In air it is very important to know your position on the ground and also the path you are following. For this we depend on maps and charts. There are many methods of describing position used in aviation:
* Place name.
* ICAO And IATA codes, for example EGLL for London, hearthrow(ICAO) and LHR(IATA).
* Bearing and
distance from a stated position.
*
Latitudes and longitudes.
Latitude and
longitude is a very precise method of describing a point any where on the earth. To use this method it is necessary to know about latitudes and longitudes. Latitudes are imaginary lines drawn parallel to the equator. The equator is taken as a reference for latitudes. Equator is taken as the 0
degree and north and south poles are taken as 90 degree latitudes respectively. Longitudes are lines joining the north and south poles. These are also called meridians. The
meridian which pass through the Greenwich near England is the reference meridian and it is taken as the 0 degree longitude. And the anti meridian of this is taken as the 180 degree longitude the meridians are named both east and west of Greenwich meridian starting from the 0 degree to 180 degree. This network which is formed by the latitudes and the longitudes is called as graticule. After knowing the imaginary network called graticule, and for using this to plot a place or finding the distance between two points on earth we should know how to read a map. A
map is a representation on a flat sheet of the earth’s graticule of meridians and parallels. For this the earth has to be scaled down to the required size so that it becomes model or reduced earth. this reduced earth would be practically a perfect tool for measuring distances and the paths. From this reduced earth maps will be projected for this there are two methods, the standard Mercators projection and the lambert’s conformal conic projection. There are other methods too but are not in use at present. Now by using these maps it would be easy to find the path and distance. By joining the two points on the map which represent the two places on the earth we will get the path which the aircraft should travel this is called the track. And by back scaling the distance on the map we will get the actual distance. To plot a point on the earth it would be very easy using a map. To get this point on the map the longitude and the latitude which are passing through this point are taken and the point could be found out.
The navigators in air also use various instruments like the magnetic compass, the radio aids etc for navigating through air. The modern aircrafts are equipped with more sophisticated equipment which would help the pilot in navigation. The ADF(Automatic Direction Finder), VOR(Very high frequency Omni direction Range) are some of the equipments used for instrument flying.
The radio aids also play a very important role in navigation. The Air Traffic Controllers(ATC) will give all the information for the pilot to make his flight more safer and comfortable. They also give information on the current weather and the visibility over an airfield which would make a pilots job more easy.
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