This topic contains only those PANS-AIM requirements relevant for a VOR. For general PANS-AIM requirements valid for all kind of Radio navigation aids see topic Basic Data for Navaid.
A VOR (VHF omnidirectional radio range beacon) is a short-range, very-high-frequency omnidirectional beacon which provides an indication in the aircraft of the bearing of the beacon, or left-right track indication.
For a VOR, PANS-AIM requires some specific properties as part of the minimum AIP data set. These are
...frequency,... zero bearing direction
In addtion PANS-AIM ENR 4.1. and also AD2.19/AD 3.18 require
for VOR, station declination to the nearest degree used for technical line-up of the aid
The diagram below shows the AIXM classes, including the relevant data types, needed to encode that information The main class is the VOR which is a specialisation of the NavaidEquipment.
VOR Type
In is not required by PANS-AIM to provide the type of a VOR. Because in some State AIPs this informtion is published it is also coverd by this guidelines.
The VOR.type attriute may be used to code that information. The list of values of the CodeVORType class contains:
| Value | Description |
|---|---|
| 'VOR' | Conventional VOR. |
| 'DVOR' | Doppler VOR. |
| 'VOT' | VOR test facility |
| 'OTHER' | Other. |
Frequency
The VOR.frequency attribute is used to code the value of the frequency. This can be any decimal value greater than 0. However, there is a coding rules that define a range of acceptable values.
The corresponding data type contains a uom attribute. For a VOR only the value equal-to 'MHZ' shall be used.
According to ICAO Annex 10, Volume 1
The VOR shall operate in the band 111.975 MHz to 117.975 MHz. ...The channel separation shall be in increments of 50 kHz referred to the highest assignable frequency.
Station Declination & Zero Bearing Direction
The VOR.zeroBearingDirection is used to code the direction of the 'zero bearing' provided by the station. For example: magnetic north ('MAG'), true north ('TRUE').
The angular difference between the direction of the 'zero bearing' indicated by the station and the direction of the True North at the time the VOR station is calibrated is coded by the attribute VOR.declination.
In case the VOR is assigned to an AirportHeliport (see topic TBD) the magnetic variation of the VOR has to coincide with that of the related airport/heliport.
Open question zero bearing direction
In some AIPs also the date when the station declination was measured is published. Unlike for magnetic variation there is no dedicated attribute for station declination contained in AIXM 5. Corresponding information can only be recorded using a Note.
According to PANS-AIM for VOR the specific station declination should be provided rather than the local magnetic variation. However, in many AIPs the magnetic variation is published instead.
Coding Rules for VOR
TBD
Coding Examples
Example 1
In this Example the station declination of the VOR is published.
Example 2
In this example both the station declination and the magnetic variation of the VOR is published and year when it was measured.
For more examples see topic Navaid [NAV].