Navigation is the discipline of directing the motion of a craft from one place to another along a desired route. There are four methods of navigation used depending on what level of technology is available to the navigator, namely: navigation by pilotage, astronomical navigation, navigation by dead-reckoning and radionavigation.

Navigation by pilotage involves the navigator fixing his location by observing a landmark and comparing it with his map. Celestial navigation is focused on observing the heavens to determine the apparent elevation of a certain celestial body (uses a sextant) and noting the time during which the measurement was made. With the knowledge of time zones and spherical trigonometry, the position of the craft can be fixed. Navigation by dead-reckoning involves the use of mechanics to analyze the speed and direction of the craft with a pre-determined previous position to find its new position. Radio navigation employs the use of electronic devices that are in contact to known land earth transceivers that works in conjunction with the craft. For an aircraft, there are some useful electronic radio navigation aids that helps it travel safely.

Automatic direction finder is an aid used for automatic determination of relative bearing to a transmitting radio station or non-directional beacon. With ADF, the ground station transmits an amplitude modulated signal in an omnidirectional pattern. The receiver at the aircraft receives the transmitted signal in a combined loop-and-sense antenna whose output is calculated to give the relative bearing.

Low Range Radio Altimeter measures the absolute aircraft height above the terrain. It works much similar like a sonar which involves sending , in this case, an RF signal directly down and waits for the reflected signal. The echo will always be originating from the surface and thsu by dividing the time it takes for the echo to be detected by two results for the signal to reach the ground. Since signal speed is a constant, thus the altitude can be calculated. The range of this system is 2500 ft.

Posted 2010-12-14 and updated on Dec 14, 2010 2:06pm by crisd

Be the 1st to write comments on this issue and make it a threaded topic!!
Name : ZIP(optional) :
Please DO NOT use html tags or links.


Since 2010 by Noel Allosa