Radar response beacon
A racon , shortly also Racon from English Ra represents bea con , is a navigation mark , the active electromagnetic waves in the frequency range of maritime radars responds by broadcasting on the same frequency, an identifier. The radar response signal of the beacon is in turn received and evaluated by the triggering radar device, i. H. usually presented to the operator. The method thus implements a secondary radar without the need for modifications to an observing primary radar device. In addition to the unique identification of the beacon through the identifier, a particular advantage over the use of radar reflectors in the same position and size is the significantly greater range.
Radar beacons are installed , for example, on fairway barrels or set up on the coast where there are no conspicuous natural radar targets.
Racon
Racons are active devices and have a radio receiver and transmitter, the properties and the radio technology of which are specified in ITU-R recommendation M.824. The frequency ranges intended for Racon cover the range from 2.9 GHz to 3.1 GHz and from 9.3 GHz to 9.5 GHz. After receiving an external radar signal, the Racon responds with its own signal with a short delay of less than 0.7 µs. The answer includes a digital pulse sequence permanently assigned to the beacon, which makes the racon clearly identifiable. This means that nautical signs that are not large enough to reflect the radar signal sufficiently to be able to apply the principle of primary radar can also be perceived. The procedure for navigation marks with racons is basically similar to the secondary radar used in aviation , but not identical.
The racon's identifier is displayed in different ways on the radar screen, depending on the device. On older radars, the pulse train is displayed as Morse code , which begins in the navigation mark and points away from it in a line. This line is several nautical miles long on the radar screen . By displaying the direction and distance of the Racon beacon, an exact location of the ship is possible. On nautical charts , navigation marks with Racon devices are usually marked with the writing "Racon ( letter )" in the color magenta .
history
The principle of the racon was specified in a patent by Christian Hülsmeyer in 1904 , but could not be implemented at that time due to a lack of technical requirements. Theoretical development of the Racon began around 1925 in the USA by Gregory Breit and Merle Antony Tuve and in Great Britain by Sir Edward Victor Appleton , Samuel Jackson Barnett and Sir Robert Watson-Watt . The technical development of the first devices began in Great Britain around 1935, following a memorandum on air defense by Sir Watson-Watt, Germany and the USA. Before and at the beginning of the Second World War, the Racon was brought to series production and the series production of devices was introduced.
Leading Racon
The combination of two racons one behind the other is called a leading racon or radar beacon. When brought into congruence with one another, they denote as fixed points of a straight line, for example, a safe, obstacle-free entrance with sufficient water depth.
Ramark
A ramark or radar marker is a radar buoy that continuously and without external triggering emits a radar signal in the form of a Morse code. It is broadcast in the frequency band from 9.32 GHz to 9.5 GHz. When a ship's rotating radar antenna is aimed at the Ramark beacon, a center-to-edge guideline appears on the radar screen.
Individual evidence
- ↑ ITU-R Recommendation M.824: Technical parameters of radar beacons. Retrieved June 26, 2014 .