This topic contains only those PANS-AIM requirements relevant for a marker. For general PANS-AIM requirements valid for all kind of Radio navigation aids see topic Navaid [NAV] and subordinated pages.
A marker beacon serves to identify a particular location in space by means of a 75MHz transmitter which transmits a directional signal to be received by aircraft flying overhead.
There are basially two application of marker beacons
- en-route or
- forming part of an ILS system.
For a marker, PANS-AIM requires some specific properties as part of the minimum AIP data set. These are
...frequency...
The diagram below shows the AIXM classes, including the relevant data types, needed to encode that information The main class is the MarkerBeacon which is a specialisation of the NavaidEquipment.
Marker Frequency
In AIXM 5 the value of the radio emission frequency of the marker is coded by using the MarkerBeacon.frequency attribute.
The corresponding data type contains a uom attribute. For a marker only the value equal-to 'MHZ' shall be used.
In general, marker beacons operate at 75 MHz.
Marker Position
In case the marker is used as part of a ILS or Localizer system the position of it within that system has to be coded.
In an ILS/Localizer sytstem a marker may be located basically at 3 different positions: outer, middel and inner. An installation may have a marker at just one, two or all three positions.
Some ILS/Localizer sytstem provide the possibility to use them backcourse. In such cases a dedicated marker may be provide to support that kind of operation.
Correspondingly, the data type class for NavaidComponent.markerPosition attribute allows the following values to be coded 'OUTER', 'MIDDLE,' 'INNER' and 'BACKCOURSE'.
See also topic Navaid Component & Navaid Colocation.
Altough not required by PANS-AIM, this information is published in the AIP for ILS/Localizer systems. Also the ARINC 424 record type "Airport and Heliport Localizer Marker" contains a data field "Marker Type" (MKR TYPE) for the corresponding information.
Coding Rules for Marker Beacon
TBD
Coding Examples
TBD