Radio fix
Encyclopedia
In telecommunication
and position fixing
, the term radio fix has the following meanings:
Compare triangulation
.
A single transmitter can be used to give a line of position (LOP) of the craft. The (true) bearing to the station from the plane, TB or QUJ, is composed of the planes true heading, TH, plus the relative bearing, RB, of the station. The bearing of the plane from the station (QTE) is found by adding 180° to the QUJ figure.
The line of position is then the line of bearing QUJ (i.e. from the station to the plane) passing through the station.
For the diagram on the right, we have:
A radio fix on two stations can be found in exactly the same way. The intersection of the two position lines gives the position of the plane. For the diagram on the right, the LOPs are found as before:
Remembering that the LOPs pass through their respective stations, it is now simple to find the location of the aircraft.
Remember too, that bearings and direction are given/recorded with respect to True North and to Magnetic North. Values used by mobile stations usually need to be converted from Magnetic to True. (Fixed stations are expected to use True).
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
and position fixing
Position fixing
Position fixing is the branch of navigation concerned with the use of a variety of visual and electronic methods to determine the position of a ship, aircraft or person on the surface of the Earth.These techniques include:...
, the term radio fix has the following meanings:
- The locating of a radioRadioRadio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
transmitter by bearings taken from two or more direction findingDirection findingDirection finding refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication...
stations, the site of the transmitter being at the point of intersection.
- The location of a ship or aircraft by determining the direction of radio signals coming to the ship or aircraft from two or more sending stations, the locations of which are known.
Compare triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
.
Obtaining a Radio Fix
The line of position is then the line of bearing QUJ (i.e. from the station to the plane) passing through the station.
For the diagram on the right, we have:
A radio fix on two stations can be found in exactly the same way. The intersection of the two position lines gives the position of the plane. For the diagram on the right, the LOPs are found as before:
Remembering that the LOPs pass through their respective stations, it is now simple to find the location of the aircraft.
Remember too, that bearings and direction are given/recorded with respect to True North and to Magnetic North. Values used by mobile stations usually need to be converted from Magnetic to True. (Fixed stations are expected to use True).